TRANSCRIPTIONAL REGULATORY ELEMENT AND ITS USE IN ENHANCING THE EXPRESSION OF HETEROLOGOUS PROTEIN

Abstract

Provided is a polynucleotide the polynucleotide can be used as a WXRE transcriptional regulatory element used to increase the protein expression level of a protein expression system. A protein expression vector or a protein expression systems comprising the above-mentioned WXRE transcriptional regulatory element as well as the use thereof are also provided. The use of the WXRE transcriptional regulatory element can increase the expression level of a heterologous protein greatly with its biological activity unchanged.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a National Stage Application under 35 U.S.C. .sctn. 371 and claims the benefit of International Application No. PCT/CN2019/100549, filed Aug. 14, 2019, which claims priority under 35 U.S.C. .sctn. 365(b) to International Application No. PCT/CN2018/100467, filed Aug. 14, 2018, the disclosure of the foregoing is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present disclosure relates to the fields of molecular biology and bioengineering. In particular, the present disclosure relates to a novel transcriptional regulatory element which uses mammalian cells to express a heterologous protein. Specifically, the present disclosure relates to a transcriptional regulatory element WXRE (WuXi Regulatory Element) which is used in a eukaryotic cell line to prepare heterologous protein and enhance the expression level of the above-mentioned protein, and an expression system of the heterologous protein comprising WXRE, as well as the use of the above-mentioned expression system in producing heterologous protein.

BACKGROUND

[0003] In biological studies, the study of the proteins has received more and more attention, and the most important thing for the protein research is the selection of a protein expression system. The protein expression system refers to a molecular biological technology which uses model organisms such as bacteria, yeast, plant cells or animal cells to express heterologous proteins. The common protein expression systems are divided into prokaryotic expression systems and eukaryotic expression systems.

[0004] Among them, the prokaryotic expression system is a system which obtains heterologous proteins by prokaryotes and mainly includes Escherichia coli expression system, Bacillus subtilis expression system, Streptomycin expression system, and the like. Among them, the Escherichia coli expression system is the most widely used. The characteristics of the prokaryotic expression system are rapid growth of the host bacteria, easy cultivation, convenient operation, low price, clear genetic background, safe genes and high protein expression level. However, the prokaryotic expression system may not regulate the expression time and the expression level; meanwhile, the expression products of the prokaryotic expression system may exist in the form of an inclusion body with low biological activity, and the post-translational processing and modifying system is imperfect (for example, glycosylation modification may not be performed).

[0005] On the other hand, the eukaryotic expression system mainly includes the expression systems of mammalian cells, yeast cells and insect cells, which are commonly used methods to express heterologous proteins in recent years. It supplements some functions which are deficient in the prokaryotic expression systems. For example, stable disulfide bonds can be formed with the eukaryotic expression system, and after a protein is translated, the protein can be correctly modified, which enables the expressed protein to have more natural activity instead of being degraded or forming inclusion bodies. Among them, a mammalian expression system has the characteristics of being capable of inducing the highly efficient expression, performing correct folding of the expressed proteins and performing complex glycosylation modification accurately, having protein activity which is close to that of the natural protein, having no need to remove the endotoxins, and the like. Meanwhile, the mammalian expression system is the only system that can express complex proteins. As for the production of antibodies such as the humanized monoclonal antibodies, said mammalian expression system has the characteristics of being able to be produced in large amount, good humanization and the like. The host cells commonly used in the mammalian expression systems include CHO cells, COS cells, BHK cells and the like.

[0006] Adalimumab (trade name: Humira) is an anti-human tumor necrosis factor (TNF) humanized monoclonal antibody, which is approved by NMPA (National Medical Products Administration) for the treatment of rheumatoid arthritis and ankylosing spondylitis and has good therapeutic effect.

[0007] Granulocyte-macrophage colony stimulating factor (GM-CSF) is a hematopoietic cell growth factor having pleiotropy and acts to regulate in the developmental and mature stages of granulocytic series and macrophages. GM-CSF also plays a key role in the differentiation of the monocytes in synovial tissues into the inflammatory dendritic cells and involves in inducing and maintaining the emergence and the development of acute arthritis. Meanwhile, the tests of serum and synovium are performed for patients suffering from rheumatoid arthritis. It is found that the level of GM-CSF factor increases significantly and is closely related to disease activity, which is mainly reflected in the deterioration of bone erosion as well as the synovial lining cells and the underlayer cells which are infiltrated with large amount of macrophages.

[0008] PD-1 is a key immune checkpoint receptor expressed by the activated T and B cells, and mediates the immunosuppression. PD-1 is a member of the CD28 receptor family, this family includes CD28, CTLA-4, ICOS, PD-1 and BTLA. Two glycoprotein ligands of PD-1 on cell surface, i.e., programmed death ligand-1 (PD-L1) and programmed death ligand-2 (PD-L2), have been identified. They are expressed on the antigen-presenting cells as well as in a variety of human cancers, and they have been shown to downregulate the activation of T cells and the cytokine secretion upon binding to PD-1.

[0009] PD-L1 is also referred to as CD274 or B7-H1. PD-L1 has up-regulated expression in a variety of tumor cells, binds to the PD-1 on T cells, inhibits the proliferation and activation of T cells, makes T cells in an inactivated state, and eventually induces the immune escape. The inhibitors of PD-L1 can block the binding of PD-1 and PD-L1, up-regulate the growth and proliferation of T cells, enhance the recognition of T cells to tumor cells, activate its attacking and killing functions, and achieve the anti-tumor effect by mobilizing the immune function of human body itself.

[0010] Since monoclonal antibodies such as Adalimumab, the monoclonal antibodies against PD-1, and the monoclonal antibodies against PD-L1 can all be produced by the mammalian expression systems, and the problem that the expression level of the heterologous proteins is low exists in the mammalian expression systems, there is an urgent need to improve the mammalian expression systems known in the prior art and provide a system which is capable of achieving significantly higher expression level of heterologous proteins. Meanwhile, the above-mentioned systems are needed to produce the humanized monoclonal antibodies.

SUMMARY

Technical Problem

[0011] The present disclosure provides a DNA sequence which is derived from CHO (Chinese Hamster Ovary) cells and can be used to enhance the expression of the heterologous protein, said DNA sequence is capable of being used for enhancing expression level of the heterologous proteins of the mammalian expression systems.

Solution to Problem

[0012] The technical solutions related in the present disclosure are as follows.

[0013] (1). A polynucleotide, wherein the polynucleotide is selected from any one of (i) to (iv):

[0014] (i) a nucleotide sequence comprising a sequence as shown in any sequence of SEQ ID NOs:3-9;

[0015] (ii) a nucleotide sequence comprising a reverse complementary sequence of the sequence as shown in any sequence of SEQ ID NOs:3-9;

[0016] (iii) a reverse complementary sequence of a sequence capable of hybridizing with the nucleotide sequence as shown in (i) or (ii) under a high stringency hybridization condition or a very high stringency hybridization condition;

[0017] (iv) a sequence having at least 90% sequence identity, alternatively at least 95% sequence identity, preferably at least 97% sequence identity, more preferably at least 98% sequence identity, most preferably at least 99% sequence identity with the nucleotide sequence as shown in (i) or (ii).

[0018] (2) The polynucleotide according to (1), wherein the polynucleotide also comprises any one selected from (v) to (viii):

[0019] (v) a nucleotide sequence comprising a sequence as shown in SEQ ID NO: 13;

[0020] (vi) a nucleotide sequence comprising a reverse complementary sequence of the sequence as shown in SEQ ID NO:13;

[0021] (vii) a reverse complementary sequence of a sequence capable of hybridizing with the nucleotide sequence as shown in (v) or (vi) under a high stringency hybridization condition or a very high stringency hybridization condition;

[0022] (viii) a sequence having at least 90% sequence identity, alternatively at least 95% sequence identity, preferably at least 97% sequence identity, more preferably at least 98% sequence identity, most preferably at least 99% sequence identity with the nucleotide sequence as shown in (v) or (vi).

[0023] (3) The polynucleotide according to (1) or (2), wherein the polynucleotide is capable of increasing the protein expression level of a protein expression system; alternatively, the protein expression system is selected from the protein expression systems of eukaryotic cells; preferably, the protein expression systems of eukaryotic cells are selected from the protein expression systems of CHO (Chinese Hamster Ovary) cells.

[0024] (4) The polynucleotide according to (1) or (2), wherein the polynucleotide is selected from a sequence comprising the sequence as shown in SEQ ID NO:4, or a sequence comprising the reverse complementary sequence of the sequence as shown in SEQ ID NO:4; alternatively, the polynucleotide is selected from a nucleotide sequence comprising the sequence as shown in SEQ ID NO:4 and the sequence as shown in SEQ ID NO:13, or a nucleotide sequence comprising the reverse complementary sequence of the sequence as shown in SEQ ID NO:4 and the reverse complementary sequence of the sequence as shown in SEQ ID NO:13.

[0025] (5) The polynucleotide according to (3), wherein the protein expression system is used to express an antibody, a fusion protein or a recombinant protein; alternatively, the antibody is selected from monoclonal antibodies, the fusion protein is the antibody against programmed death-1 (PD-1) or the antibody against programmed death-ligand 1 (PD-L1); preferably, the monoclonal antibody is Adalimumab, and said antibody against PD-1 is pembrolizumab.

[0026] (6) A WXRE transcriptional regulatory element used for enhancing the protein expression level of a protein expression system, wherein the WXRE transcriptional regulatory element comprises the polynucleotide according to any one of (1) to (5).

[0027] (7) A protein expression vector or a protein expression system, wherein the protein expression vector or the protein expression system comprises the polynucleotide according to any one of (1) to (5) or the WXRE transcriptional regulatory element according to (6); alternatively, the protein expression vector or the protein expression system also comprises at least a promoter and at least a restriction enzyme site; preferably, the protein expression vector or the protein expression system is selected from the protein expression vectors of mammalian cells or the protein expression systems of mammalian cells; more preferably, the mammalian cells are CHO cells.

[0028] (8) A cell line, wherein the cell line comprises the protein expression vector or the protein expression system according to (7).

[0029] (9) A kit, wherein the kit comprises the protein expression vector or the protein expression system according to (7), or the cell line according to (8).

[0030] (10) Use of the protein expression vector or the protein expression system according to (7), or the cell line according to (8) in the preparation of a reagent or a kit for detecting an animal disease due to the abnormality of protein expression.

[0031] (11) The use according to (10), wherein the animal disease is capable of causing the abnormal expression of a target protein in the animal, and the protein expression vector, or the protein expression system, or the cell line is capable of secreting an antibody of the target protein; alternatively, the animal is selected from mammals; preferably, the mammal is human.

[0032] In a technical solution, it can be known from the prior art that, as for rheumatoid arthritis, it is found that the level of GM-CSF factor increases significantly and is closely related to disease activity, mainly reflected in the deterioration of bone erosion as well as the synovial lining cells and the under layer thereof which are infiltrated with large amount of macrophages. Therefore, an antibody of GM-CSF can be prepared and obtained via the protein expression vector or the protein expression system related in the present disclosure, wherein the sequence of the antibody of GM-CSF is known in the prior art. Illustratively, the sequence of the antibody of GM-CSF can be selected from the sequences as shown in WO 2018050111 A1. After the antibody of GM-CSF is obtained, it is used to diagnose rheumatoid arthritis by further detecting the expression level of GM-CSF.

[0033] (12) Use of a protein expressed by the protein expression vector or the protein expression system according to (7) or the cell line according to (8) in the preparation of a drug for treating or preventing an animal disease; alternatively, the animal disease is selected from tumors or autoimmune diseases.

[0034] (13) The use according to (12), wherein the tumor is selected from cancers, and/or the autoimmune disease is selected from rheumatoid arthritis or ankylosing spondylitis.

[0035] (14) A method for preparing a protein, wherein the protein expression vector or the protein expression system according to (7), or the cell line according to (8) is selected to secrete the protein; alternatively, the protein is selected from an antibody, a fusion protein or a recombinant protein; preferably, the antibody is selected from monoclonal antibodies, the fusion protein is the antibody against programmed death-1 (PD-1) or the antibody against programmed death-ligand 1 (PD-L1); more preferably, the monoclonal antibody is Adalimumab, and said antibody against PD-1 is pembrolizumab.

[0036] (15) A screening method of a stable cell line highly expressing target protein, wherein a target gene which encodes the target protein is transfected into the cell by using the protein expression vector or the protein expression system according to (7), and the stable cell line highly expressing target protein is screened and obtained; alternatively, the protein expression vector or the protein expression system is selected from the protein expression vectors of mammalian cells or the protein expression systems of mammalian cells; more preferably, the mammalian cells are CHO cells.

[0037] (16) The screening method according to (15), wherein the screening method includes antibiotic screenings aiming at selection markers or drug pressure screenings aiming at amplified marker genes.

[0038] (17) A cell line, which is obtained by using the screening method according to any one of (15) to (16).

[0039] (18) A method for detecting an animal disease, wherein a protein secreted by the protein expression vector or the protein expression system according to (7) or the cell line according to (8) is adopted to detect whether an animal suffers from the disease; wherein the animal disease is capable of causing the abnormal expression of a target protein in the animal; and,

[0040] (i) if the secreted protein is capable of interacting with the target protein, it indicates that the animal suffers from the disease;

[0041] (ii) if the secreted protein is capable of not interacting with the target protein, it indicates that the animal does not suffer from the disease.

[0042] (19) The method according to (18), wherein the protein expression vector, or the protein expression system, or the cell line is capable of secreting an antibody of the target protein; alternatively, the animal is selected from mammals; preferably, the mammal is human.

[0043] (20) A method of treating or preventing an animal disease, wherein a protein secreted by the protein expression vector or the protein expression system according to (7) or the cell line according to (8) is administered to the animal; alternatively, the animal disease is selected from tumors or autoimmune diseases.

[0044] (21) The method according to (20), wherein the tumor is selected from cancers, and/or the autoimmune disease is selected from rheumatoid arthritis or ankylosing spondylitis.

[0045] (22) A method of preparing a target antibody, wherein the method includes the following steps:

[0046] (i) by the method for preparing a protein according to (14), preparing and obtaining the protein;

[0047] (ii) using the protein obtained in step (i) to immunize an animal, so as to obtain the corresponding target antibody.

[0048] (23) A vector, wherein the vector comprises at least any one of the polynucleotide according to (1) or (2).

[0049] (24) The vector according to (23), wherein the vector also comprises a CMV promoter; alternatively, the CMV promoter comprises a sequence as shown in SEQ ID NO: 16, or the CMV promoter comprises a sequence having at least 90% sequence identity, alternatively at least 95% sequence identity, preferably at least 97% sequence identity, more preferably at least 98% sequence identity, most preferably at least 99% sequence identity with the sequence as shown in SEQ ID NO:16.

[0050] (25) The vector according to (23) or (24), wherein the vector comprises one or more genes encoding one or more target proteins.

[0051] (26) The vector according to (25), wherein the target protein is selected from a group consisting of an antibody, a fusion protein, an enzyme, a soluble protein, a membrane protein, a structural protein, a ribosome protein, a zymogen, a cell surface receptor protein, a transcriptional regulatory protein, a translational regulatory protein, a chromatin protein, a hormone, a cell cycle regulatory protein, a G protein, a neuroactive peptide, an immunomodulatory protein, a blood component protein, an ion gate protein, a heat shock protein, dihydrofolate reductase, an antibiotic resistance protein, a functional fragment of any one of the target proteins, an epitope fragment of any one of the target proteins, and any combination thereof.

[0052] (27) An isolated host cell, wherein the host cell comprises the vector according to any one of (23) to (26).

[0053] (28) A method of preparing a host cell which expresses a target protein stably, wherein the method comprises a step of transforming an initial host cell by using the vector according to any one of (23) to (26).

[0054] (29) The host cell according to (27) or the method according to (28), wherein the host cell is a Chinese hamster ovary cell.

[0055] (30) A method of preparing a target protein, wherein the method comprises preparing the target protein by using the host cell according to (27) or via the method according to (28) or (29).

[0056] Alternatively, the present invention provides the following embodiments.

[0057] (31). A polynucleotide comprising a nucleotide sequence that is at least 85% identical to a regulatory sequence selected from the group consisting of SEQ ID NOs:3-9, a promotor, and a heterologous sequence that encodes a polypeptide, wherein the regulatory sequence, the promotor, and the heterologous sequence that encodes the polypeptide are operably linked together.

[0058] (32). The polynucleotide of (31), wherein the polynucleotide further comprises an EF1.alpha.I gene intron.

[0059] (33). The polynucleotide of (32), wherein the EF1.alpha.I gene intron comprises a sequence that is at least 80% identical to SEQ ID NO: 13.

[0060] (34). The polynucleotide of (33), wherein the regulatory sequence selected from the group consisting of SEQ ID NOs: 3-9 has a forward direction.

[0061] (35). The polynucleotide of (34), wherein the regulatory sequence selected from the group consisting of SEQ ID NOs: 3-9 has a reverse direction.

[0062] (36). A host cell for enhanced expression of an antibody, the cell comprising

[0063] a first polynucleotide encoding an antibody heavy chain or fragment thereof, wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to a sequence of any of SEQ ID NOs:3-9 or a reverse complementary sequence of the sequence of any of SEQ ID NOs:3-9; and

[0064] a second polynucleotide encoding an antibody light chain or fragment thereof, wherein the second polynucleotide is operably linked to a sequence that is at least 85% identical to a sequence of any of SEQ ID NOs:3-9 or a reverse complementary sequence of the sequence of any of SEQ ID NOs:3-9.

[0065] (37). The host cell of (36), wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 4 and the second polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 4.

[0066] (38). The host cell of (36), wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 4 and the second polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 9.

[0067] (39). The host cell of (36), wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 9 and the second polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 9.

[0068] (40). The host cell of (36), wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 4 and the second polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 17.

[0069] (41). The host cell of (36), wherein the first polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 9 and the second polynucleotide is operably linked to a sequence that is at least 85% identical to SEQ ID NO: 17.

[0070] (42). An expression vector comprising an expression cassette, wherein the expression cassette comprises a promoter operably linked to a nucleic acid sequence encoding a polypeptide, and a regulatory sequence that is at least 85% identical to a sequence selected from the group consisting of SEQ ID NOs:3-9, wherein the regulatory sequence is operably linked to the promotor.

[0071] (43). The expression vector of (42), wherein the expression vector has a sense strand and an anti-sense strand, and the sense strand comprises a sequence (from 5' to 3') that is at least 85% identical to a sequence selected from the group consisting of SEQ ID NOs:3-9.

[0072] (44). The expression vector of (42), wherein the expression vector has a sense strand and an anti-sense strand, and the anti-sense strand comprises a sequence (from 5' to 3') that is at least 85% identical to a sequence selected from the group consisting of SEQ ID NOs:3-9.

Effects of Invention

[0073] In a technical solution, the use of the transcriptional regulatory element WXRE listed in the present disclosure can greatly increase the expression amount of a heterologous protein and has great contribution to the production of mammalian proteins.

[0074] In some technical solutions, the expression amount of a heterologous protein is increased by about or at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80%. In some technical solutions, the expression amount of a heterologous protein is increased up to 80%.

[0075] In another technical solution, the use of the transcriptional regulatory element WXRE listed in the present disclosure can enable a heterologous protein to still maintain its biological activity while the expression level is greatly increased.

[0076] In another technical solution, the transcriptional regulatory element WXRE listed in the present disclosure is able to be used together with other transcriptional regulatory elements as a whole, and maintains its biochemical activity while enabling the expression level of the heterologous protein to increase greatly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0077] FIG. 1 illustrates a schematic diagram of a GFP-expressing vector without WXRE inserted therein.

[0078] FIG. 2 illustrates a schematic diagram of a GFP-expressing vector with WXRE inserted therein.

[0079] FIG. 3 illustrates the influence on the expression amount of the fusion protein after adding transcriptional regulatory element A.about.G, wherein A1 and A2 illustrate the forward and reverse directions of transcriptional regulatory element A respectively, and so forth.

[0080] FIG. 4 illustrates the influence on the specific productivity of the expression of the fusion protein after adding transcriptional regulatory element A.about.G, wherein A1 and A2 illustrate the forward and reverse directions of transcriptional regulatory element A respectively, and so forth.

[0081] FIG. 5 illustrates a schematic diagram of a vector which expresses the heavy chain of Adalimumab and has WXRE inserted therein, wherein HC means the heavy chain.

[0082] FIG. 6 illustrates a schematic diagram of a vector which expresses the light chain of Adalimumab and has WXRE inserted therein, wherein LC means the light chain.

[0083] FIG. 7 illustrates a comparison of the expression amount of Adalimumab on 14.sup.th day under different combined conditions of the transcriptional regulatory elements, wherein in sample 1 to sample 6, the components of the transcriptional regulatory element in the upstream of the heavy chain and the transcriptional regulatory element in the upstream of the light chain are found in Table 6.

[0084] FIG. 8 illustrates a schematic diagram of a vector which expresses the heavy chain of an antibody and comprises WXRE and EF1.alpha.I intron (i.e. the sequence as shown in SEQ ID NO: 13) inserted therein, wherein HC means the heavy chain.

[0085] FIG. 9 illustrates a schematic diagram of a vector which expresses the light chain of an antibody and comprises WXRE and EF1.alpha.I intron (i.e., the sequence as shown in SEQ ID NO: 13) inserted therein, wherein LC means the light chain.

[0086] FIG. 10 illustrates a schematic diagram of a vector which expresses an antibody heavy chain.

[0087] FIG. 11 illustrates a schematic diagram of a vector which expresses an antibody light chain.

STATEMENT REGARDING SEQUENCE LISTING

[0088] The Sequence Listing associated with this application is provided in text form in lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of the text file containing the Sequence Listing is 48771_0003002_ST25.txt. The text file is 61.5 KB, and was created Nov. 11, 2021, and submitted electronically via EFS-Web herewith.

DETAILED DESCRIPTION

Definition

[0089] When used in the claims and/or the specification, the word "a" or "an" or "the" may refer to "one", but may also refer to "one or more", "at least one" and "one or more than one".

[0090] As used in the claims and the specification, the words "comprising", "having", "including" or "containing" means inclusive or open-ended, and does not exclude additional, unrecited elements or method steps. Meanwhile, "comprising", "having", "including" or "containing" may also mean closed-ended, and excludes additional, unrecited elements or method steps.

[0091] Throughout this application, the term "about" denotes that a value includes the standard deviation of the error of the device or method used to determine this value.

[0092] Although the content disclosed supports that the definition of the term "or" is a substitute only as well as "and/or". Unless it is clearly denoted that it is only a substitute or the substitutes are mutually exclusive, the term "or" in the claims refers to "and/or".

[0093] The "transcriptional regulatory element" in the present disclosure refers to some polynucleotides involved in the regulation of gene transcription. Alternatively, the above-mentioned polynucleotide may be selected from DNA(s), which mainly include a promoter, an enhancer, an insulator, and the like. In the present disclosure, the transcriptional regulatory element is also referred to as WXRE (WuXi Regulatory Element). Illustratively, The WXREs in the present disclosure include transcriptional regulatory element A, transcriptional regulatory element B, transcriptional regulatory element C, transcriptional regulatory element D, transcriptional regulatory element E, transcriptional regulatory element F, and transcriptional regulatory element G.

[0094] The meaning of the "reverse complementary sequence" in the present disclosure is a sequence which is opposite to the direction of the sequence of the original polynucleotide and is also complementary to the sequence of the original polynucleotide. Illustratively, if the original polynucleotide sequence is ACTGAAC, then the reverse complementary sequence thereof is GTTCAGT.

[0095] The "internal ribosomal entry site" (IRES) in the present disclosure belongs to the translational control sequences and is usually located on the 5' end of the gene of interest, and enables the translation of RNA in a cap-independent manner. The transcribed IRES may directly bind to a ribosomal subunit, such that the initiation codon of an mRNA is appropriately oriented in a ribosome to perform translation. The IRES sequence is usually located in the 5'UTR of an mRNA (directly upstream of the initiation codon). IRES functionally replaces the need for various protein factors that interact with the translation mechanism of eukaryotes.

[0096] The "vector" in the present disclosure refers to a delivery vehicle for a polynucleotide. In some embodiments, the vector includes a polynucleotide sequence encoding a certain protein operatively inserted therein and enables the expression of this protein in a genetic engineering recombinant technique. The vector can be used to transform, transduce or transfect a host cell, and enable the genetic material element carried by the vector to be expressed in the host cell. The "vector" in the present disclosure may be any suitable vector, which includes chromosomal, non-chromosomal and synthetic nucleic acid vectors (including a group of suitable nucleic acid sequences which express the control elements). Illustratively, said vector may be a recombinant plasmid vector, a recombinant eukaryotic viral vector, a recombinant phage vector, a recombinant yeast minichromosome vector, a recombinant bacterial artificial chromosome vector, or a recombinant yeast plasmid vector.

[0097] Illustratively, the vector in the present disclosure may include the derivatives of SV40, bacterial plasmids, phage DNAs, baculovirus, yeast plasmid, vectors derived from a combination of a plasmid and a phage DNA, and vectors such as virus nuclear acids (RNA or DNA). In some embodiments, the vector is an adeno-associated virus (AAV) vector.

[0098] In a specific embodiment, the vectors related in the present disclosure are as shown in FIGS. 1 to 2, FIGS. 5 to 6 and FIGS. 8 to 9. In the schematic diagrams of the above-mentioned vectors, the meaning of CMV is human cytomegalovirus promoter (see e.g., PubMed PMID: 2985280), the meaning of TK pA is thymidine kinase polyadenylation signal (see e.g., PubMed PMID: 3018551), the meaning of SV40 is SV40 early promoter (see e.g., PubMed PMID: 6286831), the meaning of BSR is Blasticidin resistance gene: selection marker (see e.g., PubMed PMID: 7948022), the meaning of SV pA is SV40 polyadenylation signal (see e.g., PubMed PMID: 6113054), the meaning of pUC ori is the origin of the replication of pUC plasmid (see e.g., PubMed PMID: 2985470), the meaning of Amp is Ampicillin resistance gene (see e.g., PubMed PMID: 2985470), the meaning of EMCV IRES is the internal ribosomal entry site of encephalomyocarditis virus (see e.g., PubMed PMID: 8954121), the meaning of Zeocin is Zeocin resistance gene: selection marker (see e.g., PubMed PMID: 2450783), and the meaning of EF1.alpha.I is the first intron of the gene of human elongation factor 1 alpha (see e.g., PubMed PMID:2210382).

[0099] In some embodiments, the CMV promoter in the present disclosure can have a sequence that is at least or about 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% identical to SEQ ID NO:16. As used herein, a promoter refers to a region of DNA that leads to initiation of transcription of a polynucleotide encoding a polypeptide. Promoters are located near the transcription start sites of the coding sequence, upstream on the DNA (towards the 5' region of the sense strand of the coding sequence). In some embodiments, other promotors can be used. In some embodiments, the promotor is a SV40 promoter, hCMV promoter, mCMV promoter, retinoschisin promoter, a rhodopsin promoter, a rhodopsin kinase promoter, a CRX promoter, or an interphotoreceptor retinoid binding protein (IRBP) promoter. Any promoter that allows tissue-specific expression of an encoded protein can also be used.

[0100] The "host cell" in the present disclosure refers to a cell having an heterologous polynucleotide and/or a vector introduced therein. Said host cell is a eukaryotic host cell or a prokaryotic host cell, wherein the eukaryotic host cell may be a mammalian host cell, an insect host cell, a plant host cell, a fungal host cell, a eukaryotic algae host cell, a nematode host cell, a protozoan host cell, and a fish host cell. Illustratively, the host cell in the present disclosure is a eukaryotic host cell, and said eukaryotic host cell is a mammalian host cell, wherein said mammalian host cell is selected from a Chinese hamster ovary cell (CHO cell), a COS cell, a Vero cell, a SP2/0 cell, a NS/O myeloma cell, a human embryonic kidney cell, an immature hamster kidney cell, a HeLa cell, a human B cell, a cv-1/EBNA cell, an L cell, a 3T3 cell, a HEPG2 cell, a PerC6 cell, a 293 cell and an MDCK cell. Illustratively, the mammalian host cell in the present disclosure is a CHO cell.

[0101] The "protein expression system" in the present disclosure refers to a system comprising a host and a vector containing a heterologous gene, and the purpose of the expression of the heterologous gene in the host can be achieved by this system. The protein expression system generally comprises the following parts: (1) a host, i.e., an organism expressing proteins, which may be selected from bacteria, yeast, plant cells, animal cells, and the like; (2) a vector. The type of the vector matches with the host. According to the different hosts, the vectors are divided into prokaryotic (bacterial) expression vectors, yeast expression vectors, plant expression vectors, mammalian expression vectors, insect expression vectors, and the like. The vector contains a fragment of a heterologous gene. The heterologous gene can be expressed in the host via the mediation of the vector. In some embodiments, the expressed protein products are secreted. In some embodiments, the vectors are integrated into host cell DNA.

[0102] A key step in protein expression is the selection of recombinant host cells which have been successfully transfected with the vector comprising the heterologous gene coding the protein of interest. Most commonly a selection marker is included in the vector. The selection marker can be a gene or DNA sequence that allows separation of recombinant host cells containing the marker and those not containing it. The combination of a selection marker and a selection medium allows growth of recombinant host cells that have been transfected with the vector, while prohibiting the growth of host cells that have not been successfully transfected.

[0103] Antibiotic resistance genes are the most commonly used markers for recombinant host cell selection. An antibiotic resistance gene as a selection marker, in combination with a selection medium containing the antibiotic, can be used in order to achieve selection. Exemplary antibiotic selection markers include but are not limited to ampicillin resistance gene, chloramphenicol resistance gene, kanamycin resistance gene, tetracycline resistance gene, polymyxin B resistance gene, erythromycin resistance gene, carbenicillin resistance gene, streptomycin resistance gene, spectinomycin resistance gene, blasticidin resistance gene, neomycin resistance gene, puromycin resistance gene, zeocin resistance gene, and hygromycin B resistance gene. Accordingly, the selection antibiotics include but are not limited to ampicillin, chloramphenicol, kanamycin, tetracycline, polymyxin B, erythromycin, carbenicillin, streptomycin, spectinomycin, blasticidin, neomycin, puromycin, zeocin, and hygromycin B. In some embodiments, the selection marker used in the present invention is blasticidin resistance gene. In some embodiments, the selection marker used in the present invention is zeocin resistance gene.

[0104] In some aspects, the disclosure provides methods that are designed for quickly evaluating a heteromultimer (e.g., antibody) expression. For example, for efficient expression of antibodies, the antibody heavy chain and the antibody light chain needs to be expressed in roughly 1:1 ratio. If the concentration for a selection antibiotic is too low, the amount of functional vectors in the cells can be too small. If the concentration for a selection antibiotic is too high, it may create a condition that is not favorable for culturing cells. Furthermore, the ratio of the two vectors needs to be properly adjusted. It has been determined, based on tests on many different conditions, the methods provided herein can express antibodies with a high efficiency, and can be used to reliably evaluate the heteromultimer expression in a reasonably short time. Furthermore, the methods provided herein can express antibodies with a high expression level.

[0105] In some embodiments, the methods involve transfecting the cell a pair of two vectors, one carrying a heterologous gene encoding a first polypeptide and the other carrying a heterologous gene encoding a second polypeptide. Two selection markers are used. One selection marker is blasticidin resistance gene, and the other selection marker is zeocin resistance gene. In some embodiment, blasticidin is present in the selection medium in an amount of 1-15 .mu.g/mL and zeocin is present in an amount of 50-1500 .mu.g/mL. Preferably, blasticidin is present in an amount of 2-12 .mu.g/mL and zeocin is present in an amount of 100-1000 .mu.g/mL. More preferably, blasticidin is present in an amount of 3-10 .mu.g/mL and zeocin is present in an amount of 150-800 .mu.g/mL. More preferably, blasticidin is present in an amount of 4-9 .mu.g/mL and zeocin is present in an amount of 200-400 .mu.g/mL. Most preferably, blasticidin is present in an amount of 9 .mu.g/mL and zeocin is present in an amount of 400 .mu.g/mL. Alternatively, blasticidin is present in an amount of 4 .mu.g/mL and zeocin is present in an amount of 200 .mu.g/mL. In some embodiments, the ratio of blasticidin concentration to Zeocin concentration is from 1:50.about.1:40 (e.g., about 9:400). In some embodiments, the minimum concertation of blasticidin in the medium is 5, 6, 7, 8, or 9 .mu.g/mL. In some embodiments, the highest concertation of blasticidin in the medium is 15 or 20 .mu.g/mL.

[0106] In some embodiment, the selection medium further comprises serum, polysaccharide (e.g. glucose, and/or dextrose), sodium pyruvate, glutathione, ethanolamine, amino acid (e.g. glycine, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, histidine, isoleucine, leucine, lysine, glutamine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and/or valine) or a salt thereof, vitamin (e.g. ascorbic acid phosphate, choline chloride, D-calcium pantothenate, folic acid, niacinamide, pyridoxine hydrochloride, riboflavin, thiamine hydrochloride, and/or i-inositol), inorganic salt (e.g. calcium chloride, ferric nitrate, magnesium sulfate, potassium chloride, sodium bicarbonate, sodium chloride, and/or sodium phosphate dibasic), protein (e.g. human transferrin and/or recombinant insulin), and/or trace element (e.g. ammonium metavanadate, cupric sulfate, manganous chloride, and/or sodium selenite).

[0107] In some embodiments, after about 18.about.30 hours (e.g., about 24 hours) of transfection, the cells are cultured in an appropriate cell culture medium containing blasticidin (e.g., 9 .mu.g/mL) and Zeocin (e.g., 400 .mu.g/mL). The cells are then passaged to a new medium containing blasticidin and Zeocin every 2 to 4 days. When the cell viability is recovered to 90% or more, the expression level of the heteromultimer can be evaluated by fed-batch cultures. In some embodiments, the fed-batch cultures can be any medium as described herein. In some embodiments, the fed-batch cultures contain blasticidin and Zeocin.

[0108] In some embodiments, the "protein expression system" in the present methods involve a pair of two vectors, one carrying a heterologous gene encoding an antibody heavy chain and the other carrying a heterologous gene encoding an antibody light chain. The selection marker in the two vectors might be different. In one embodiment, the selection marker in the first vector is blasticidin while the selection marker in the second vector is zeocin. The concentration of blasticidin and zeocin can be any concentrations as described herein. In some embodiments, the methods can also involve one vector comprising a heterologous gene encoding an antibody heavy chain and a heterologous gene encoding an antibody light chain.

[0109] The WXRE sequence can be inserted in the two vectors. They can be the same or different, and can have the forward or reverse directions. Table 1 lists the exemplary combinations of WXREs in the two vectors.

TABLE-US-00001 TABLE 1 Combinations of WXREs # WXRE in a first vector WXRE in a second vector 1 SEQ ID NO 3 SEQ ID NO 3 2 SEQ ID NO 3 SEQ ID NO 4 3 SEQ ID NO 3 SEQ ID NO 5 4 SEQ ID NO 3 SEQ ID NO 6 5 SEQ ID NO 3 SEQ ID NO 7 6 SEQ ID NO 3 SEQ ID NO 8 7 SEQ ID NO 3 SEQ ID NO 9 8 SEQ ID NO 3 SEQ ID NO 17 9 SEQ ID NO 3 SEQ ID NO 18 10 SEQ ID NO 3 SEQ ID NO 19 11 SEQ ID NO 3 SEQ ID NO 20 12 SEQ ID NO 3 SEQ ID NO 21 13 SEQ ID NO 3 SEQ ID NO 22 14 SEQ ID NO 3 SEQ ID NO 23 15 SEQ ID NO 4 SEQ ID NO 4 16 SEQ ID NO 4 SEQ ID NO 5 17 SEQ ID NO 4 SEQ ID NO 6 18 SEQ ID NO 4 SEQ ID NO 7 19 SEQ ID NO 4 SEQ ID NO 8 20 SEQ ID NO 4 SEQ ID NO 9 21 SEQ ID NO 4 SEQ ID NO 17 22 SEQ ID NO 4 SEQ ID NO 18 23 SEQ ID NO 4 SEQ ID NO 19 24 SEQ ID NO 4 SEQ ID NO 20 25 SEQ ID NO 4 SEQ ID NO 21 26 SEQ ID NO 4 SEQ ID NO 22 27 SEQ ID NO 4 SEQ ID NO 23 28 SEQ ID NO 5 SEQ ID NO 5 29 SEQ ID NO 5 SEQ ID NO 6 30 SEQ ID NO 5 SEQ ID NO 7 31 SEQ ID NO 5 SEQ ID NO 8 32 SEQ ID NO 5 SEQ ID NO 9 33 SEQ ID NO 5 SEQ ID NO 17 34 SEQ ID NO 5 SEQ ID NO 18 35 SEQ ID NO 5 SEQ ID NO 19 36 SEQ ID NO 5 SEQ ID NO 20 37 SEQ ID NO 5 SEQ ID NO 21 38 SEQ ID NO 5 SEQ ID NO 22 39 SEQ ID NO 5 SEQ ID NO 23 40 SEQ ID NO 6 SEQ ID NO 6 41 SEQ ID NO 6 SEQ ID NO 7 42 SEQ ID NO 6 SEQ ID NO 8 43 SEQ ID NO 6 SEQ ID NO 9 44 SEQ ID NO 6 SEQ ID NO 17 45 SEQ ID NO 6 SEQ ID NO 18 46 SEQ ID NO 6 SEQ ID NO 19 47 SEQ ID NO 6 SEQ ID NO 20 48 SEQ ID NO 6 SEQ ID NO 21 49 SEQ ID NO 6 SEQ ID NO 22 50 SEQ ID NO 6 SEQ ID NO 23 51 SEQ ID NO 7 SEQ ID NO 7 52 SEQ ID NO 7 SEQ ID NO 8 53 SEQ ID NO 7 SEQ ID NO 9 54 SEQ ID NO 7 SEQ ID NO 17 55 SEQ ID NO 7 SEQ ID NO 18 56 SEQ ID NO 7 SEQ ID NO 19 57 SEQ ID NO 7 SEQ ID NO 20 58 SEQ ID NO 7 SEQ ID NO 21 59 SEQ ID NO 7 SEQ ID NO 22 60 SEQ ID NO 7 SEQ ID NO 23 61 SEQ ID NO 8 SEQ ID NO 8 62 SEQ ID NO 8 SEQ ID NO 9 63 SEQ ID NO 8 SEQ ID NO 17 64 SEQ ID NO 8 SEQ ID NO 18 65 SEQ ID NO 8 SEQ ID NO 19 66 SEQ ID NO 8 SEQ ID NO 20 67 SEQ ID NO 8 SEQ ID NO 21 68 SEQ ID NO 8 SEQ ID NO 22 69 SEQ ID NO 8 SEQ ID NO 23 70 SEQ ID NO 9 SEQ ID NO 9 71 SEQ ID NO 9 SEQ ID NO 17 72 SEQ ID NO 9 SEQ ID NO 18 73 SEQ ID NO 9 SEQ ID NO 19 74 SEQ ID NO 9 SEQ ID NO 20 75 SEQ ID NO 9 SEQ ID NO 21 76 SEQ ID NO 9 SEQ ID NO 22 77 SEQ ID NO 9 SEQ ID NO 23 78 SEQ ID NO 17 SEQ ID NO 17 79 SEQ ID NO 17 SEQ ID NO 18 80 SEQ ID NO 17 SEQ ID NO 19 81 SEQ ID NO 17 SEQ ID NO 20 82 SEQ ID NO 17 SEQ ID NO 21 83 SEQ ID NO 17 SEQ ID NO 22 84 SEQ ID NO 17 SEQ ID NO 23 85 SEQ ID NO 18 SEQ ID NO 18 86 SEQ ID NO 18 SEQ ID NO 19 87 SEQ ID NO 18 SEQ ID NO 20 88 SEQ ID NO 18 SEQ ID NO 21 89 SEQ ID NO 18 SEQ ID NO 22 90 SEQ ID NO 18 SEQ ID NO 23 91 SEQ ID NO 19 SEQ ID NO 19 92 SEQ ID NO 19 SEQ ID NO 20 93 SEQ ID NO 19 SEQ ID NO 21 94 SEQ ID NO 19 SEQ ID NO 22 95 SEQ ID NO 19 SEQ ID NO 23 96 SEQ ID NO 20 SEQ ID NO 20 97 SEQ ID NO 20 SEQ ID NO 21 98 SEQ ID NO 20 SEQ ID NO 22 99 SEQ ID NO 20 SEQ ID NO 23 100 SEQ ID NO 21 SEQ ID NO 21 101 SEQ ID NO 21 SEQ ID NO 22 102 SEQ ID NO 21 SEQ ID NO 23 103 SEQ ID NO 22 SEQ ID NO 22 104 SEQ ID NO 22 SEQ ID NO 23 105 SEQ ID NO 23 SEQ ID NO 23

[0110] The "sequence identity" and the "percent identity" in the present disclosure refer to the percentage of the same (i.e., identical) nucleotides or amino acids between two or more polynucleotides or polypeptides. The sequence identity between two or more polynucleotides or polypeptides can be determined by the following method. The nucleotide sequences or the amino acid sequences of the polynucleotides or polypeptides are aligned and the number of positions containing the same nucleotide or amino acid residue in the aligned polynucleotides or polypeptides is scored and compared with the number of positions containing different nucleotides or amino acid residues in the aligned polynucleotides or polypeptides. The polynucleotides may differ at one position, for example, by containing different nucleotides (i.e., substitutions or mutations) or by the deletion of nucleotide(s) (i.e., the insertion of nucleotide(s) or the deletion of nucleotide(s) in one or two polynucleotides). The polypeptides may differ at one position, for example, by containing different amino acids (i.e., substitutions or mutations) or by the deletion of amino acid(s) (i.e., the insertion of amino acid(s) or the deletion of amino acid(s) in one or two polypeptides). The sequence identity can be calculated by dividing the number of positions containing the same nucleotide or amino acid residue by the total number of the amino acid residues in the polynucleotide or polypeptide. For example, the percent identity can be calculated by dividing the number of positions containing the same nucleotide or amino acid residue by the total number of the nucleotides or the amino acid residues in the polynucleotide or polypeptide and multiplying the result by 100.

[0111] The "abnormal expression of a target protein in the animal" in the present disclosure means that, as compared with the expression level of the target protein in the animal under normal condition, the expression level of the target protein in the animal to be tested shows an increase or a decline; or a protein that should not be expressed under normal condition is expressed, or a protein that should be expressed is not expressed. In a technical solution, said animal refers to a mammal. In another technical solution, said mammal is human.

[0112] The term "antibody" in the present disclosure refers to an immunoglobulin, a fragment thereof, or a derivative of them, and includes any polypeptide comprising an antigen-binding site, regardless of whether it is produced in vitro or in vivo. This term includes, but is not limited to, a polyclonal antibody, a monoclonal antibody, a monospecific antibody, a bispecific antibody, a trispecific antibody, a multispecific antibody, a non-specific antibody, a humanized antibody, a fully human antibody, a chimeric antibody, a single-domain antibody, a single-stranded antibody, a synthetic antibody, a recombinant antibody, a heterozygous antibody, a mutated antibody, and a grafted antibody. The term "antibody" also includes antibody fragments such as Fab, Fab', F(ab').sub.2, Fv, scFv, Fd, dAb, and other antibody fragments that retain the antigen-binding function. Typically, such fragments will include an antigen-binding fragment.

[0113] The "fusion protein" in the present disclosure refers to a molecule comprising two or more proteins or the fragments thereof which are linked by the covalent bond via their respective main chains of the peptides, and more preferably, the fusion protein is generated by the genetic expression of the polynucleotide molecules encoding these proteins. In a preferred embodiment, the fusion protein comprises an immunoglobulin domain. In a preferred embodiment, the fusion protein is an Fc-fusion protein.

[0114] Illustratively, the antibodies that may be used in the present disclosure include, but are not limited to, Adalimumab, Bezlotoxumab, Avelumab, Dupilumab, Durvalumab, Ocrelizumab, Brodalumab, Reslizumab, Olaratumab, Daratumumab, Elotuzumab, Necitumumab, Infliximab, Obiltoxaximab, Atezolizumab, Secukinumab, Mepolizumab, Nivolumab, Alirocumab, Evolocumab, Dinutuximab, Bevacizumab, Pembrolizumab, Ramucirumab, Vedolizumab, Siltuximab, Alemtuzumab, Trastuzumab, Pertuzumab, Obinutuzumab, Brentuximab, Raxibacumab, Belimumab, Ipilimumab, Denosumab, Ofatumumab, Besilesomab, Tocilizumab, Canakinumab, Golimumab, Ustekinumab, Certolizumab, Catumaxomab, Eculizumab, Ranibizumab, Panitumumab, Natalizumab, Omalizumab, Cetuximab, Efalizumab, Ibritumomab, Fanolesomab, Tositumomab, Gemtuzumab, Palivizumab, Necitumumab, Basiliximab, Rituximab, Capromab, Satumomab, and Muromonab.

[0115] Illustratively, the fusion proteins that may be used in the present disclosure include, but are not limited to, Etanercept, Alefacept, Abatacept, Rilonacept, Romiplostim, Belatacept, and Aflibercept.

[0116] In one embodiment, the present disclosure relates to the stringency of hybridization conditions which is used to define the degree of complementarity of two polynucleotides. Alternatively, the above-mentioned polynucleotide may be selected from DNAs. The "stringency" used in the present disclosure refers to the temperature and the ionic strength condition during the hybridization and the presence or absence of certain organic solvents. The higher the stringency, the higher the degree of complementarity between the target nucleotide sequence and the marked polynucleotide sequence. "Stringent conditions" refers to the temperature and the ionic strength condition under which the nucleotide sequence merely having high-frequency complementary bases will hybridize. The term "hybridizes under high stringency or very high stringency conditions" used herein describes the conditions for hybridization and washing. The guidance for performing the hybridization reaction can be found in "Current Protocols in Molecular Biology", John Wiley and Sons, N.Y. (1989), 6.3.1-6.3.6. The specific hybridization conditions mentioned in the present disclosure are as follows: 1) high stringency hybridization conditions: 6.times. sodium chloride/sodium citrate (SSC) at about 45.degree. C., followed by one or more mashes in 0.2.times.SSC, 0.1% SDS at 65.degree. C.; 2) very high stringency hybridization conditions: 0.5M sodium phosphate, 7% SDS at 65.degree. C., followed by one or more washes at 0.2.times.SSC, 1% SDS at 65.degree. C.

[0117] In a technical solution of the present disclosure, said WXRE sequence has a sequence identity of at least or about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% (including all the ranges and percentages between these values) with the sequence of any of SEQ ID NOs: 3-9. In some embodiments, the WXRE sequence has at least or about 1, 2, 3, 4, 5, 6, 7, 9, or 10 conservative mutation relative to a sequence of any of SEQ ID NOs: 3-9. In some embodiments, the WXRE sequence differs from a sequence selected from SEQ ID NOs: 3-9 by at least or about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 nucleotides. The WXRE sequence can have a forward direction or a reverse direction. As used herein, a sequence of interest has a forward direction when the sense strand (from 5' to 3') has a sequence that is identical to the sequence of interest. A sequence of interest has a reverse direction when the sense strand has a sequence that is reverse complementary to the sequence of interest. The sequences that are reverse complementary to SEQ ID NOs: 3-9 are set forth in SEQ ID NO: 17-23 respectively. In some embodiments, the disclosure provides a sequence that is at least or about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% (including all the ranges and percentages between these values) of a sequence selected from SEQ ID NO: 17-23.

[0118] In some embodiments, the WXRE sequence can increase the expression amount of an heterologous protein by about or at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80% (e.g., as compared to a control sequence without WXRE sequence).

[0119] In a technical solution of the present disclosure, said transcriptional regulatory element may also be selected from a nucleotide sequence comprising a WXRE sequence and other sequences that may increase the level of protein expression of a eukaryotic cell line. Illustratively, the transcriptional regulatory element in the present disclosure is a nucleotide sequence comprising a WXRE sequence and a sequence having sequence identity with the sequence as shown in SEQ ID:13 (the first intron of human EF1.alpha.I).

[0120] In a technical solution of the present disclosure, said sequence having sequence identity with the sequence as shown in SEQ ID:13 has a sequence identity of at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% (including all the ranges and percentages between these values) with the sequence as shown in SEQ ID:13 (the first intron of human EF1.alpha.I). In some embodiments, the sequence can increase the expression amount of an heterologous protein by about or at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80% (e.g., as compared to a control sequence without such sequence).

[0121] In some embodiments, the WXRE sequence, the promotor, and the polynucleotide encoding a polypeptide are operably linked together. In some embodiments, the WXRE sequence, the promotor, the polynucleotide encoding a polypeptide, and one or more additional regulatory elements are operably linked together. In some embodiments, the one additional regulatory element is an intron of EF1.alpha.I (e.g., the first intron of human EF1.alpha.I). The WXRE sequence, the promotor, and the polynucleotide encoding a polypeptide that are operably linked together can have various orders. For example, the WXRE sequence can be located before the promotor (e.g., from 5' to 3' on the sense strand of the coding sequence) or after the polynucleotide encoding a polypeptide (e.g., from 5' to 3' on the sense strand of the coding sequence). In some embodiments, there are at least or about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1K, 2K, 3K, 4K or 5K nucleotides between the WXRE sequence and the promoter or between the WXRE sequence and the polynucleotide encoding a polypeptide. In some embodiments, there are no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1K, 2K, 3K, 4K or 5K nucleotides between the WXRE sequence and the promoter or between the WXRE sequence and the polynucleotide encoding a polypeptide. In some embodiments, the one or more additional regulatory elements are located between the promoter and the sequence encoding a polypeptide.

[0122] The present disclosure also provides methods of enhancing the expression of a recombinant protein or polypeptide. The methods involve inserting one or more vectors as described herein into cells (e.g., by transformation or transfection); culturing the cells in the medium; and recovering the recombinant protein or polypeptide so expressed.

[0123] The molecular biological methods adopted in the present disclosure may all be found in the corresponding methods described in the disclosed publications such as "Current Protocols in Molecular Biology" (published by Wiley), "Molecular Cloning: A Laboratory Manual" (published by Cold Spring Harbor Laboratory).

EXAMPLES

[0124] Other objects, features and advantages of the present disclosure will become apparent with the following detailed description. However, it should be understood that the detailed description and the specific examples (though representing the specific embodiments of the present disclosure) are provided for illustrative purposes only since various changes and modifications made within the spirit and scope of the present disclosure will become apparent to those skilled in the art after reading this detailed description.

[0125] All reagents used in the examples can be purchased and obtained from commercial sources, unless otherwise emphasized.

Example 1: Construction of a Vector Library and Construction of a Stable Pool which Expresses Green Fluorescent Protein

[0126] 1.1 Preparation of a Vector Library Containing a Genomic Fragment of Chinese Hamster Ovary Cells

[0127] 1.1.1 1 .mu.g of the GFP-expressing vector (i.e., the vector as shown in FIG. 1) was subjected to enzyme digestion with BamHI in the enzyme digestion kit (NEB) containing the restriction endonuclease BamHI so as to be linearized and stayed overnight at 37.degree. C. (the composition and the contents of the reagents in the enzyme digestion reaction were as shown in Table 2), wherein BamHI could be replaced with any other endonucleases corresponding to a unique restriction site which existed in the upstream of a promoter corresponding to GFP.

[0128] The schematic diagram of the GFP-expressing vector was as shown in FIG. 1.

TABLE-US-00002 TABLE 2 The composition and the contents of the reagents in the enzyme digestion reaction Reaction components Volume NEB CutSmart Buffer (Cat# B7204S) 5 .mu.L BamHI 5 .mu.L GFP-expressing vector 1 .mu.g Ultrapure water make up to a total volume of 50 .mu.L

[0129] 1.1.2 Approximate five million CHO host cells were harvested, a DNeasy Blood & Tissue Kit (QIAGEN) was used to extract the genomic DNA of the CHO host cells, and said genomic DNA was dissolved in 1004 of elution buffer inside the above-mentioned kit.

[0130] 1.1.3 Five micrograms of the genomic DNA was subjected to enzyme digestion with 100 units of restriction endonuclease BglII (NEB) or DpnII (NEB) (the composition and the contents of the reagents in the enzyme digestion reaction were as shown in Table 3). Other restriction endonucleases might also be used, as long as they matched with the cohesive ends of the endonucleases of the linearized vector in step 1.1.1.

TABLE-US-00003 TABLE 3 The composition and the contents of the reagents in the enzyme digestion reaction Reaction components Volume NEB CutSmart Buffer (Cat# B7204S) 5 .mu.L BamHI 5 .mu.L CHO genomic DNA 1 .mu.g Ultrapure water make up to a total volume of 50 .mu.L

[0131] 1.1.4 The linearized vector in 1.1.1 was treated with 2 units of calf intestinal alkaline phosphatase (NEB) at 37.degree. C. for approximate 30 minutes. Other types of alkaline phosphatases could also be used.

[0132] 1.1.5 The linearized GFP-expressing vector in 1.1.4 and the digested CHO genomic DNA in 1.1.3 were subjected to separation by agarose gel electrophoresis, respectively. The gel was cut to recover the fragments of the GFP-expressing vector and the 1-4 kb fragments of the digested genome, DNA was extracted from the agarose gel after electrophoresis using a QIAquick Gel Extraction Kit (QIAGEN).

[0133] 1.1.6 The fragments of the GFP-expressing vector and the fragments of the genome recovered in 1.1.5 were subjected to ligation using a DNA Ligation Kit (Takara, Cat #6022) for 45 minutes at 16.degree. C. (the composition and the contents of the reagents in the ligation reaction were as shown in Table 4).

TABLE-US-00004 TABLE 4 The composition and the contents of the reagents in the ligation reaction Reaction components Volume the recovered CHO genomic DNA 4 .mu.L the recovered vector 6 .mu.L Solution I 20 .mu.g Ultrapure water 10 .mu.L

[0134] 1.1.7 Ten microliter of the ligation product obtained by 1.1.6 was taken, 100 .mu.L of competent cells were added, put in the ice bath for 30 minutes, thermally stimulated at 42.degree. C. for 1 minute, and then put on the ice for 1 minute. 500 .mu.L of fresh LB medium free of antibiotic was added to each tube of cells, and the cells were subjected to a 45-minute-recovery at 37.degree. C. The step of plating was skipped and 500 mL of medium containing 100 mg/L of Ampicillin was added directly. The vector extraction was performed using a Plasmid Maxi Kit (QIAGEN). The extracted DNA was used as the vector library.

[0135] 1.1.8 The vector library obtained in 1.1.7 was linearized using the restriction endonucleases in which the restriction sites were merely located in the prokaryotic region of the backbone of the vector (for example, PvuI (NEB)), and stayed overnight under the same reaction conditions as in 1.1.1 at 37.degree. C. The DNA was recovered by the phenol-chloroform method and used for transfection the next day.

[0136] 1.2 Construction of the Stable Pool which Expresses Green Fluorescent Protein

[0137] 1.2.1 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in an Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 0.3 .mu.g to 0.6 .mu.g of the linearized vector library obtained by step 1.1.8 were mixed evenly, and the cells were resuspended with this mixed solution and transferred to an electroporation cuvette. The cells were subjected to transfection using a program corresponding to the respective host cells in a 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were suspended with 5 mL of medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation.

[0138] 1.2.2 Twenty-four hours after the transfection, equal volume of selective medium containing antibiotic corresponding to the resistance gene in the vector was added in the cell culture (in this experiment, the antibiotic was 800 .mu.g/mL of Zeocin).

[0139] 1.2.3 The cells were counted every 2 to 4 days. Cell passage was performed according to the growth situation of the cells, and screening was performed by using the selective medium with antibiotic corresponding to the resistance gene in the vector (in this experiment, the antibiotic was 400 .mu.g/mL of Zeocin). Clone screening was prepared when the cell viability recovered to 90% or more.

Example 2: Screening of a Clone Highly Expressing Green Fluorescent Protein

[0140] 2.1 Single-Cell Sorting and Expansion

[0141] 2.1.1 The cells in the recovered stable pool in the step 1.2.3 of Example 1 with a higher GFP expression level (for example, the top 0.5% of the expression level) were sorted by a FACS Arial flow cytometer into a 96-well plate for cultivation.

[0142] 2.1.2 75% of the medium in the plate was changed every 2 to 4 days until the recovered cells were visible by naked eyes.

[0143] 2.2 Screening for a Clone Highly Expressing GFP

[0144] The cells recovered in 2.1.2 were successively transferred into a new 96-well plate respectively, altogether about 300 clones (all the cells in each well were derived from one cell and were referred to as a clone herein). The expression amount of GFP was determined by a FACS Arial flow cytometer, and the clones whose detected intensities were among the top 10% were transferred to a 24-well plate for expansion.

Example 3: Screening, Identification and Verification of the Transcriptional Regulatory Element

[0145] 3.1 Identification of a Candidate Sequence of the Transcriptional Regulatory Element

[0146] 3.1.1 When the cells that were expanded to the 24-well plates in 2.2 substantially covered the bottom of the plate, and the DNeasy Blood & Tissue Kit (QIAGEN) was used to extract the genome of each clone.

[0147] 3.1.2 A forward primer and a reverse primer were respectively designed in the vector (about 200 bp away from the upstream and the downstream of the restriction site of BamHI), and the genomes extracted in 3.1.1 were successively subjected to PCR amplification, wherein the sequence of the forward primer of the PCR reaction was GCAAAAAAGGGAATAAGGGCGACACGG (SEQ ID NO:1) and the sequence of the reverse primer of the PCR reaction was CATAGCCCATATATGGAGTTCCGCGTTA (SEQ ID NO:2).

[0148] The reaction system of the above-mentioned PCR reaction was as shown in Table 5.

TABLE-US-00005 TABLE 5 The reaction system of the PCR reaction Reaction components Volume 5X Q5 Reaction Buffer 5 .mu.L 10 mM dNTPs 0.5 .mu.L 10 .mu.M forward primer 1.25 .mu.L 10 .mu.M reverse primer 1.25 .mu.L genome 1 .mu.L Q5 DNA Polymerase (Cat# M0491S) 0.25 .mu.l Ultrapure water 15.75 .mu.L

[0149] The reaction steps of the above-mentioned PCR reaction were as shown in Table 6.

TABLE-US-00006 TABLE 6 The reaction steps of the PCR reaction Temperature Time Number of Cycles 98.degree. C. 1 min 1 98.degree. C. 30 s 35 61.degree. C. 30 s 68.degree. C. 5 min 68.degree. C. 10 min 1

[0150] 3.1.3 PCR products were subjected to separation by agarose gel electrophoresis, the gel was cut to recover the specific band(s) of 1 kb or more, and the QIAquick Gel Extraction Kit (QIAGEN) was used to extract DNA.

[0151] 3.1.4 The recovered band(s) was sent for sequencing, and the sequence A.about.G of the candidate transcriptional regulatory elements were identified.

[0152] 3.1.5 The sequence A.about.G of the transcriptional regulatory elements obtained by sequencing and identification were as follows, wherein

[0153] the sequence of the transcriptional regulatory element A was the sequence as shown in SEQ ID NO:3 (the reverse complementary sequence of SEQ ID NO: 3 is SEQ ID NO: 17),

[0154] the sequence of the transcriptional regulatory element B was the sequence as shown in SEQ ID NO:4 (the reverse complementary sequence of SEQ ID NO: 4 is SEQ ID NO: 18),

[0155] the sequence of the transcriptional regulatory element C was the sequence as shown in SEQ ID NO:5 (the reverse complementary sequence of SEQ ID NO: 5 is SEQ ID NO: 19),

[0156] the sequence of the transcriptional regulatory element D was the sequence as shown in SEQ ID NO:6 (the reverse complementary sequence of SEQ ID NO: 6 is SEQ ID NO: 20),

[0157] the sequence of the transcriptional regulatory element E was the sequence as shown in SEQ ID NO:7 (the reverse complementary sequence of SEQ ID NO: 7 is SEQ ID NO: 21),

[0158] the sequence of the transcriptional regulatory element F was the sequence as shown in SEQ ID NO:8 (the reverse complementary sequence of SEQ ID NO: 8 is SEQ ID NO: 22),

[0159] the sequence of the transcriptional regulatory element G was the sequence as shown in SEQ ID NO:9 (the reverse complementary sequence of SEQ ID NO: 9 is SEQ ID NO: 23).

[0160] 3.2 Verification of the Transcriptional Regulatory Element

[0161] 3.2.1 The transcriptional regulatory element A.about.G obtained by sequencing and identification in 3.1.5 were respectively inserted into an upstream BamHI restriction site of the corresponding promoter in a vector containing the GFP gene using an In-Fusion Cloning Kit (Takara). A vector with the transcriptional regulatory element inserted therein as shown in FIG. 2 (wherein WXRE showed one of the transcriptional regulatory elements A.about.G) was obtained. The above-mentioned vector was linearized using the restriction endonucleases in which the restriction sites were merely located in the prokaryotic region of the backbone of the vector (for example, PvuI (NEB)), and stayed overnight at 37.degree. C. DNA was recovered by phenol-chloroform and used for transfection the next day.

[0162] 3.2.2 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in the Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 30 .mu.g of a linearized vector containing the protein to be expressed (obtained by 3.2.1) were mixed evenly, and the cells were resuspended with this mixed solution and transferred to the electroporation cuvette. The cells were subjected to transfection using the program corresponding to the respective host cells in the 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were resuspended with 5 mL of medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation. Each sample contained one kind of transcriptional regulatory element or was a control without any transcriptional regulatory element.

[0163] 3.2.3 Twenty-four hours after transfection, equal volume of selective medium containing antibiotic corresponding to the resistance gene in the vector was added in the cell culture. The cells were passaged using a medium containing antibiotic(s) every 2 to 4 days.

[0164] 3.2.4 After the cell viability recovered to 90% or more, the influence of the transcriptional regulatory element A.about.G on the expression level of the proteins was evaluated by fed-batch cultures.

Example 4: Influence of the Transcriptional Regulatory Elements on the Expression Level of a Protein Expression System Used to Express an Heterologous Protein

[0165] 4.1.1 The transcriptional regulatory element A.about.G were respectively constructed into the upstream BamHI position of the promoter of a fusion protein (the above-mentioned fusion protein was the A chain of PD-L1, whose sequence was the sequence as shown in SEQ ID NO: 10) in both forward and reverse directions. A vector with the transcriptional regulatory element inserted therein as shown in FIG. 2 (wherein WXRE showed one of the transcriptional regulatory element A.about.G) was obtained, wherein the number after the element name (A.about.G) indicates the direction of the WXRE regulatory element. The number 1 after the name of the transcriptional regulatory element indicated the forward direction and the number 2 indicated the reverse direction. For example, transcriptional regulatory element A1 showed the forward (i.e., 5' to 3') sequence of the sequence as shown in SEQ ID NO: 3 in the sense strand of coding sequence. Transcriptional regulatory element A2 showed the reverse complementary sequence of the sequence as shown in SEQ ID NO: 17 in the sense strand of protein coding sequence.

[0166] The above-mentioned vectors were linearized using the restriction endonucleases in which the restriction sites were merely located in the prokaryotic region of the backbone of the vector (for example, PvuI (NEB)) and stayed overnight under a condition of 37.degree. C. The DNA was recovered by phenol-chloroform and used for transfection the next day.

[0167] 4.1.2 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in the Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 30 .mu.g of the linearized vector containing the fusion protein (obtained by 4.1.1) were mixed evenly, and the cells were resuspended with this mixed solution and transferred to the electroporation cuvette. The cells were subjected to transfection using the program corresponding to the respective host cells in the 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were resuspended with 5 mL of medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation. Samples in each group only contained one transcriptional regulatory element in a certain direction (i.e., the forward direction or the reverse direction) and a sample which did not contain any transcriptional regulatory element was taken as a control.

[0168] 4.1.3 Twenty-four hours after transfection, equal volume of medium containing 800 .mu.g/mL of Zeocin was added into the transfected cells.

[0169] 4.1.4 The cells were passaged using a medium containing 400 .mu.g/mL of Zeocin every 2 to 4 days.

[0170] 4.1.5 When the cell viability recovered to 90% or more, the expression level of the fusion protein PD-L1 was subjected to evaluation by fed-batch cultures.

[0171] 4.1.6 Whether the sequence of the PD-L1 obtained by expression was identical to the sequence as shown in SEQ ID NO: 10 was verified.

[0172] 4.2 Experimental Results

[0173] As shown in FIG. 3, as compared with the control group which did not have the transcriptional regulatory element, inserting the transcriptional regulatory element in the upstream of the promoter of the fusion protein could increase the expression amount of the target protein by about 10% to 25% (see A2, B1, B2, D2, E2, F2 and G1 in FIG. 3). The promoting effect of the above-mentioned sequence on protein expression in a certain direction was superior to that in the other direction, which might be related to the directionality of the promoter.

[0174] As shown in FIG. 4, corresponding to the expression amount, the forward direction or the reverse direction of the above-mentioned transcriptional regulatory element could enable an increase about 10% in specific productivity (see A2, B1, B2, D2, E2 and F2 in FIG. 4).

[0175] Meanwhile, by verification, the sequence of the PD-L1 obtained by expression was identical to the sequence as shown in SEQ ID NO: 10.

Example 5: Influence of the Transcriptional Regulatory Elements on the Expression Level of a Protein Expression System Used to Express Adalimumab

[0176] 5.1.1 The reverse sequence of the transcriptional regulatory element A (A2), the forward sequence of the transcriptional regulatory element B (B1) and the forward sequence of the transcriptional regulatory element G (G1) were respectively constructed into the upstream of the promoter which was located at the upstream of the gene that could express Adalimumab by the In-Fusion Cloning kit of Takara (the specific conditions were as shown in Table 7). Vectors with the transcriptional regulatory element inserted therein as shown in FIG. 5 and FIG. 6 (wherein WXRE showed one of the transcriptional regulatory element A.about.G) were obtained respectively, wherein the "transcriptional regulatory element in the upstream of the heavy chain" was cloned into the vector as shown in FIG. 5 and the "transcriptional regulatory element in the upstream of the light chain" was cloned into the vector as shown in FIG. 6. Among them, the amino acid sequence of the heavy chain (HC) of Adalimumab in FIG. 5 was as shown in SEQ ID NO:11 and the amino acid sequence of the light chain (LC) of Adalimumab in FIG. 6 was as shown in SEQ ID NO:12.

[0177] The above-mentioned vector was linearized using the restriction endonucleases in which the restriction sites were merely located in the prokaryotic region of the backbone of the vector (for example, PvuI (NEB)), and stayed overnight at 37.degree. C. The DNA was recovered by phenol-chloroform and used for transfection the next day.

TABLE-US-00007 TABLE 7 Corresponding transcriptional regulatory elements under different conditions transcriptional transcriptional regulatory element in regulatory element in the upstream of the the upstream of the sample ID heavy chain light chain 1 B1 B1 2 B1 G1 3 G1 G1 4 B1 A2 5 G1 A2 6 (control) N/A N/A

[0178] 5.1.2 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in the Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 30 .mu.g of the linearized vector containing the sequence of Adalimumab (obtained by 5.1.1) were mixed evenly, and the cells were resuspended with this mixed solution and transferred to the electroporation cuvette. The cells were subjected to transfection using the program corresponding to the respective host cells in the 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were resuspended with 5 mL of a medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation. Samples in each group only contained one transcriptional regulatory element in a certain direction (i.e., the forward direction or the reverse direction), and a sample which did not contain any transcriptional regulatory element was taken as a control.

[0179] 5.1.3 A method that was designed for quickly evaluating antibody expression was used. This method can ensure that the antibody heavy chain and light chain are roughly expressed in 1:1 ratio, and can reliably evaluate the antibody expression in a reasonably short time. Twenty-four hours after transfection, equal volume of medium containing 18 .mu.g/mL of blasticidin and 800 .mu.g/mL of Zeocin was added into the transfected cells.

[0180] 5.1.4 The cells were passaged using a medium containing 9 .mu.g/mL of blasticidin and 400 .mu.g/mL of Zeocin every 2 to 4 days.

[0181] 5.1.5 When the cell viability recovered to 90% or more, the expression level of Adalimumab was subjected to evaluation by fed-batch cultures. Since both the heavy chain expression vector and the light chain expression vector of Adalimumab could be transfected into the same host cell, the heavy chain and the light chain of Adalimumab was capable of being expressed simultaneously. Since the heavy chain and the light chain mentioned above were capable of self-assembly in the host cells, a complete Adalimumab was obtained.

[0182] 5.1.5 The biological activity of the obtained Adalimumab was determined.

[0183] 5.2 Experimental Results

[0184] As compared with the control group, in part of the forward sequences containing the transcriptional regulatory element B (see sample 1, 2 and 4), the expression level of Adalimumab had an increase of 10% to 20% (as shown in FIG. 7).

[0185] By determining the biological activity of Adalimumab expressed by the present heterologous protein expression vector, it was found that its biological activity was identical to the biological activity of the known commercial Adalimumab.

Example 6: Influence of the Combination of the Transcriptional Regulatory Elements on the Expression Level of a Protein Expression System Used to Express Adalimumab

[0186] 6.1.1 Two vectors were constructed respectively as illustrated in FIG. 8 and FIG. 9, wherein WXRE is the forward sequence of the transcriptional regulatory element B (B1), EF1.alpha.I is the sequence of the first intron of human EF1.alpha.I gene as shown in SEQ ID NO: 13, HC is the nucleic acid sequence encoding the heavy chain of Adalimumab, amino acid sequence of which is shown in SEQ ID NO: 11, and LC is the nucleic amino acid sequence encoding the light chain (LC) of Adalimumab, amino acid sequence of which is shown in SEQ ID NO: 12. After completion of the construction of the above-mentioned vectors, plasmid extraction was carried out using an MN kit, and the obtained plasmid was used for cell transfection.

[0187] 6.1.2 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in the Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 30 .mu.g of the vector containing the sequence of Adalimumab (obtained by 6.1.1) were mixed evenly, and the cells were resuspended with this mixed solution and transferred to the electroporation cuvette. The cells were subjected to transfection using the program corresponding to the respective host cells in the 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were resuspended with 5 mL of a medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation. One group of samples comprised one transcriptional regulatory element, i.e., EF1.alpha.I intron, another group of samples comprised two elements, i.e., B1 and EF1.alpha.I intron, and a sample free of any transcriptional regulatory element was taken as a control.

[0188] 6.1.3 24 hours after transfection, equal volume of medium containing 8 .mu.g/mL of blasticidin and 400 .mu.g/mL of Zeocin was added into the transfected cells.

[0189] 6.1.4 The cells were passaged using a medium containing 4 .mu.g/mL of blasticidin and 200 .mu.g/mL of Zeocin every 2 to 4 days.

[0190] 6.1.5 When the cell viability recovered to 90% or more, the expression level of Adalimumab was subjected to evaluation by fed-batch cultures. Since both the heavy chain expression vector and the light chain expression vector of Adalimumab could be transfected into the same host cell, the heavy chain and the light chain of Adalimumab was capable of being expressed simultaneously. Since the heavy chain and the light chain mentioned above were capable of self-assembly in the host cells, a complete Adalimumab was obtained.

[0191] 6.1.6 The biological activity of the obtained Adalimumab was determined.

[0192] 6.2 Experimental Results

[0193] The experimental results of Example 6 were as shown in Table 8.

TABLE-US-00008 TABLE 8 Comparison of the relative expression levels of Adalimumab on Day 14 under different combination conditions of the transcriptional regulatory element Relative Change in expression level expression No. Vector (Day 14) amount 1 CMV (control) 1 2 CMV-EF1.alpha.I 1.18 increase by 18% 3 WXRE-CMV-EF1.alpha.I 1.42 increase by 42%

[0194] As could be seen from Table 8, the combination comprising WXRE and EF1.alpha.I intron significantly increase the expression level of Adalimumab.

[0195] By determining the biological activity of Adalimumab expressed by the heterologous protein expression vector, it was found that its biological activity was identical to the biological activity of the known commercial Adalimumab. Thus, the proteins that were expressed by this vector were folded properly.

Example 7: Influence of the Combination of the Transcriptional Regulatory Elements on the Expression Level of a Protein Expression System Used to Express Pembrolizumab

[0196] 7.1.1 Two vectors were constructed respectively as illustrated in FIG. 8 and FIG. 9, wherein WXRE is the forward sequence of the transcriptional regulatory element B (B1), EF1.alpha.I is the sequence of the first intron of human EF1.alpha.I gene as shown in SEQ ID NO: 13, HC is the nucleic acid sequence encoding the heavy chain of Pembrolizumab, amino acid sequence of which is shown in SEQ ID NO: 14, and LC is the nucleic amino acid sequence encoding the light chain (LC) of Pembrolizumab, amino acid sequence of which is shown in SEQ ID NO: 15. After completion of the construction of the above-mentioned vectors, plasmid extraction was carried out using an MN kit, and the obtained plasmid was used for cell transfection.

[0197] 7.1.2 The following experimental steps were same as the experimental steps described in Example 6.1.2 to 6.1.6 of the present disclosure.

[0198] 7.2 Experimental Results

[0199] The experimental results of Example 7 were as shown in Table 9.

TABLE-US-00009 TABLE 9 Comparison of the relative expression levels of pembrolizumab on Day 14 under different combination conditions of the transcriptional regulatory element Relative Change in expression level expression No. Vector (Day 14) amount 1 CMV (control) 1 2 WXRE-CMV-EF1.alpha.I 1.16 increase by 16%

[0200] As could be seen from Table 9, the combination comprising WXRE and EF1.alpha.I intron significantly increase the expression level of Pembrolizumab.

[0201] By determining the biological activity of Pembrolizumab expressed by the heterologous protein expression vector, it was found that its biological activity was identical to the biological activity of the known commercial Pembrolizumab.

Example 8: Influence of Different Antibiotic Concentrations on Expression Level of a Protein Expression System

[0202] 8.1.1 Two sets of vectors were constructed respectively as illustrated in FIG. 10 and FIG. 11. One set is for Adalimumab and the other is for Pembrolizumab. After completion of vector construction, plasmid extraction was carried out using an MN kit, and the obtained plasmid was used for cell transfection.

[0203] 8.1.2 Approximate five million CHO host cells were centrifuged, and the supernatant was discarded. At the same time, 90 .mu.L of SF Cell Line Solution and 20 .mu.L of Supplement I in the Amaxa SF Cell Line 4D-Nucleofector Kit L (Lonza, Cat #VCA-1005) and 30 .mu.g of the vector containing the sequence of Adalimumab or Pembrolizumab were mixed evenly, and the cells were resuspended with this mixed solution and transferred to the electroporation cuvette. The cells were subjected to transfection using the program corresponding to the respective host cells in the 4D-Nucleofector.TM. System electroporation instrument. The cells after electroporation were resuspended with 5 mL of a medium free of antibiotic and placed in a shaker at 37.degree. C. for cultivation.

[0204] 8.1.3 24 hours after transfection, the cells were passaged using a selection medium containing different concentrations of Blasticidin and/or Zeocin every 2 to 4 days. The specific concentrations of Blasticidin and/or Zeocin are listed in Table 10.

[0205] 8.1.4 When the cell viability recovered to 90% or more, the antibody expression level of was subjected to evaluation by fed-batch cultures. Since both the heavy chain expression vector and the light chain expression vector could be transfected into the same host cell, the antibody heavy chain and light chain were capable of being expressed simultaneously. Since the heavy chain and the light chain were capable of self-assembly in the host cells, a complete antibody was obtained.

[0206] 8.1.5 The biological activity of the obtained antibodies was determined.

[0207] 8.2 Experimental Results

[0208] The experimental results of Example 8 were shown in Table 10.

TABLE-US-00010 TABLE 10 Comparison of expression levels of Adalimumab and Pembrolizumab on Day 14 under different antibiotic concentrations Blasticidin Zeocin Concentration Concentration Titer (.mu.g/mL) (.mu.g/mL) (g/L) Adalimumab 1 9 0 0.66 2 0 400 1.14 3 9 400 1.35 4 4 200 1.24 Pembrolizumab 1 9 0 0.69 2 0 400 1.99 3 9 400 2.27 4 4 200 2.15

[0209] As could be seen from Table 10, the combination comprising Blasticidin and Zeocin attained a significantly increased expression level, as compared to the sole use of Blasticidin or Zeocin.

[0210] By determining the biological activity of Adalimumab or Pembrolizumab expressed by the heterologous protein expression vector, it was found that its biological activity was identical to the biological activity of the known commercial Adalimumab or Pembrolizumab. Thus, the proteins that were expressed by this vector were folded properly.

[0211] The above-mentioned examples of the present disclosure are examples provided for clearly illustrating the present disclosure only and are not limitations to the embodiments of the present disclosure. For those of ordinary skill in the art, other changes or variations in different forms may also be made on the basis of the above-mentioned specification. There is no need and no way to exhaust all of the embodiments herein. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principle of the present disclosure should all be included within the protection scope of the claims of the present disclosure.

Sequence CWU 1

1

23127DNAArtificial SequencePCR primer 1gcaaaaaagg gaataagggc gacacgg 27228DNAArtificial SequencePCR primer 2catagcccat atatggagtt ccgcgtta 2833619DNAChinese hamster 3gatctgcctg cctctgcccc gtgagtgctg ggattaaagg ccagcaccgc catgcctggc 60ctcctttaag tgcaggtgta gcacgccaga aataccctgc tggtgacagt gtgagccaca 120tgcgtgagac tgctgcagag gtcccagctt aggttgtgcc cttctttctt gagaaatgtc 180ttacttggtg attttgagtg gaaacatgta tttagctgac atatgagcct agtcttttat 240gtataaatgt gtgttatatt tctagataca aaaatattaa aaattagaaa tcttcagggc 300tggagagggg ttcattggtt aagagctcat tggttaaggg ctgctcctgt ataggacccg 360ggttacctgt cagcaccgta tgacggctct caaccatctg cagctcccgt tccagaggac 420ccagtgtctt cttctggcct ctacagacat acatatagac aaaacaccca tacacaaaaa 480tttaattaga aatcttaatt tttttctttc aattttctag attgactggg gataactttt 540ttgttaactt tactgtcttg aggataacgt tcagtatgag ttgtatttct agagtttgtc 600tttattttta ggcaaaaata acctttatta ccattttggg gggtgactgt tttacaactt 660ttccaacttt ctgcttcatc tcttgtgtcc tatataggcc cctatttact gtcattatta 720gagataggac ttgatgtcat gtcaactcca tctttgttat aaatctcaag aagagctaat 780ttcttttgtg ttattacaac caaaaataaa caaggtagct tataaacagt gacttatttt 840tatagttcta gatatgggaa gatcatggtg acagtagatt caatgtctag ttggaagttg 900actcttcttc atagatggaa tccttgctat aatataatct caggatggaa gggatgagct 960aagccctctg ggatctctta ttaatctgtt cattcattta cttattgcat agtgctctaa 1020ttctgttcat ggagactctg ttcttacaca ttaggtggtt agggagggac atgatcaatc 1080aggacatagg agcaacaata atttttatta tatttcccaa aatacatggc agttcctgac 1140cttgctttat tactgcaaac atacagcttg tggccattgg acttagccat atgagaaatg 1200taagaattta ttttatattg tagctgcaaa tggtaggttc atcaaattgt gccttaagtt 1260cacatcttaa tttgctacaa aaaaaaaaga ggagtagtgt aagttacatt taattttcaa 1320ttacttagta acagtttgta agtgctactt gatcctgttt tatatctagc attgagtata 1380gatcaacaag tgtttcaatt cttgtttgga catgctgttc tctccttcat cacaagttac 1440ttctggctaa acaaggcaca aatttcgcat gaccaccaat ccaaggacag ggcgacaatt 1500ttaatgagtt tcattgagag ctggccaact gagcatctgt tccttttgtt ttcctgtacg 1560tggtaagcca gtgtttctac actccttagc cttgttgctg tgtgtatagt gtggggtgga 1620tttgtttttg ctgttctttt ttcttttttc taccctctac ttcagtggtg cacggttaga 1680aatcttgtgg cgtctggcac ggtggtataa ttccttccat gctcttgggt gaggaaataa 1740gtttgctcat tgctgctcat cagtctgttt cacttgctcc cagatggtga ccttctcgtc 1800ccattcttgc ttgttttaac attattctga cacctatttt ctttcattgt ccccttaacc 1860actctaattg aataatgatt tctgtaattt ccatttggaa cacaaccagc ttcctggttc 1920cttttattgg cccacatcct gtcttctagt tcattgcttc agatttgagc caaatcatca 1980aataaaaata cgtaactgaa aaaaatgttt attgcagtgg cctcctctag catggcaaca 2040atgagagttt tcctttctta ttgctaaaca tgttatatct gtctcatgat ttcatactgt 2100ctctcctggc ctcatttact gcttgacctt taaaagaaat gactcaaaga tatttttgta 2160gttctgtaag catttctcta gttcttgttc ttcaccttta gttcttaaca gtagttttgt 2220ctgctacact gacgtggctg tgaggacttt ccttcagaaa ctggcgtctg atactgattc 2280aaactggtct ccattgtggc ctacatgtcc agctgtctcc atgtaacgcc actgaaatac 2340agtgaagcca gccttttttt cccccttatg gttcaaagca actgaatttc agtcagagta 2400attttggttt gggtatcaat actaattgta gtcttagacc ttttaattat tacttgtttg 2460cattttacag aagacattgg tccttctcaa aagcagagat gaaacctgta gtattttgtg 2520tgtagttttc ctctgctggt tgccctgtaa ctattcagtt cctgtaagga agcacagctg 2580cttcataagc taccttaggc tgacagcagt ctcctgaaag aaagagttca agaaagaaac 2640atttaaaaat aaaaatgggg aggggtccaa gtagtatttg aagccatgaa atatcttgaa 2700tatagtttgc ttttttgttt tgttttgtct gtctgtctgt ccgatgtagc tttggccata 2760tcaaccaggc tgtccttgaa ctcacagaaa tccacctgcc tccgcctccc aagtgctgga 2820tgcaccacca tgccagctag tttgcttttt agagcatctc atctgctgct cacagccctg 2880gtgctttatg ggatttgttt ggggaacatg atgagctcta tatttattgt agctttaaat 2940ggacagcggt tattgactgt cagcttagtc tttaaaatct ataatcacat tgtacctaat 3000tgtcaacctt catgtttttt aattatgaaa aaaactgaga acattaattt ttatgttatc 3060ttgttattga ctttattgaa atactacaga aaattttggt ttgaggcttt tccataattt 3120acccttacac ctcacacccc ttccataaac atgtgcagtt aaaattgaat tgttcgggca 3180cttctacctt gatacctggc ctacagtggg aaaggtctgt ctttctttgg aataagccca 3240tcagtggcct tgtgtacatt ctgtattttt gttgtttgtt attactgttt tttacttggg 3300actaataatc tgtttgaaac tgactgagat agaaagatgt gatgttcctt cccactcact 3360ccggattttg atagaagact tgttttattt atttccaaaa ttatatccgc aggaaacaag 3420ctgtttaaat tcagattatg ctgaagcaaa atggtcctgg tatgagaagc aacgtgctgt 3480tttacgagca cagagtccct tttctcataa ctgattgata gtaaatattt tcctgaagaa 3540ttattgccaa ccatgaacag tgcaactgtt tcactttttt tccgtgctac ttgctgtacc 3600agccattgtc ggtaattaa 361941114DNAChinese hamster 4gatctgaagt ttggatctgc agaacccaca caaaggccta cgggcttagt agtgtacctg 60caatttcagc acttggaagg ctgagaaagg atcccaaggg cagctggcta gctaggctag 120tgttagctga gagctctggg ttcgtggagc gactctggtt cagtgaataa gatagagagt 180gacatcagct ttgggcttcc acagcaaatg agctcacttg catgcaaaca gaaatgcaaa 240cacatgcaca aagcaaaaca aaaggaacac aggccaaagg tgggtcattc ctataccatc 300ccctcagcag ggtgcagtcc ccacaccctg acccagttcc ctcatgatgt tagagaaaat 360aactttgccc ccttcaacga acatttcagc tccagagaac ctggcccact ttgaaagctt 420taattagaaa tgtgcaatta cccggaacag atgtctgttg tgattgtgga gacataggtt 480aaagaatcac acagcagttt gcgtggttac agaaaggttg caagtaactt taaaacacag 540tttttggtaa gtctccaaca tgttacctaa catagcatgg cctcgattac atgtaagcag 600tgagtctccg gctgcctggt ttgtgagggt aatgtacttc agcaatagtg ctgaggctgt 660acagtgagtg actcatcacc ctaaaaaagt atcgaattcc agtcttcaga gttagctttc 720agtaaaacca agtcagtggt gaaatggctc agtaggtaag ggcacccgct gccaagccca 780agacctgtgt cctgtccctg ggatccagtt ggtggaaaga gagaacggac tcctgcaagg 840tggcctctga cctacatgcc tgaattctgc cagacattaa gtaaaaacaa acgcaaaaag 900ggaagtgggc tcacgcataa ggcactcact ggactctact cttctactct gtggttactt 960tttggtgttc aagcatacca taccttgatc tacatgattt ttactccaaa gacacagcca 1020gggtaatgtt gtgtgatgga tcagtcttat ttgttacttg tttactagta cttactgaga 1080ttgtcgatgg ctttaatgtc aacatgagtg tgga 111454068DNAChinese hamster 5gatcttctag gtctggctct gagttgaaag gctctgatgc tgggcgaaac atctctcctc 60tggggctcag ttttctcatc tgttagaaaa ggacacagct gacctgttgg cttctaatag 120ttggacagag gctaggattc tgagtctcat tttactacaa atattctttt aatttcttaa 180gtcactaaac agcatcagca aggcagggtc gagacatgcg agcaagaatg agattggatt 240ctgactcagg tttcaacttg ctgtcaatta ctgacaatgt aagttcattc atcttataga 300cttttgtaga acttttgttt ctctccacta taatttcgtt actgttccat attacagtat 360gctaaagtta atggtaaaag ttctcacaga attcctagtc ttttcctctt catatttaat 420ctcctttcct tcctcctgtc cttactcatt gtgaaattct cttttgtatg catgacttgg 480aaacatattt ccttggtggt aaggtagtag gagacaattt attcactttt cacgtatgtc 540gtaattggca tattgctgat aaagtttttc aaccatggga acatggtctt gtaagaatta 600tttcacattt ttcccagtcc aagcccataa tgaaaattga ttctgaattt tttctgtatt 660tttaattctt ctgtttgcag ttgtaggaga ataaccctgc agcatctgag agaccaagct 720aattacaaga atgactagaa atcctttgca tttttaaaac aattttatac atatgtcact 780ttgtctttct aaaaaataaa aataaaaaaa atacctaaga gccgagtttg tgttaaaggc 840taatgattgt attgtacaat tagtaagaat taaggacaaa ggtctcttta cctgaagttt 900cctgggtgct tttattcatt cattcattca ttcattcatt cattcattca tttagtcaaa 960ttagttcatt tctgatgcaa tgactgactg attactcccc agaccaatgc tccttcctgt 1020tttaggttca cagatagcat ttcctacctt ctcttgtcct tccttttgtc caaaattttg 1080agttctagac aaccacagaa ttgcctagaa atgctggaca gaattcatgc atctgattcc 1140tggtaagacc gtcgatgcac tataaacttg cagaagctga cagcagactg ttcttcactt 1200caactcattt atccctttcc tttgggttct gtccaaatca catcaccaga tcacaagaac 1260ctaacatcag attgagacgt aaatagatga tatcacattg gatttccacc attgagccac 1320accaccagcc acctgcctga taactttcac agtcccagaa gatattatac aagttactag 1380ggcaaaaaga gatcaaagtc tgaatcagct gtgaacccta tgaatggcaa tacctactta 1440tcaggcaata caagcccacc cgtgtgatag tggaataaca gtaatatggg caatcactgg 1500attgagtcct ggccccactg cagagaatcc atgccaagca ctgtaaatcc aggaagaaaa 1560aaaaaaacct atcactgaag aagacataaa ccctagaaag gaacttacta ctcttactta 1620actgagtgag caaagcaaca agttatcttc taagtactta tgctggtgct catacacaaa 1680attatccatc attcttaatt agagaattct ctctagtgaa tggttgtgga ttcaaagact 1740cataaatacc aagggtgcta agaatgagcg acaattaaga actcagccct aaacaagatt 1800tttatacctc atcttctaag gctcagaaac attgtggaag aaggtgtcaa aagaatgtaa 1860gagtgaaaag agtgagaagg gctgccaata tcatctttgc tatcatgaac tcacaaaagc 1920tgcagttgtt agtgccagga ctgtgtgaca ttgtcactac caacactcag ccttgggtgg 1980ggaggagggc ataatgtcat actcttcatc attgagccat tggttactaa cagattctag 2040gagaatcact ctctcttgtt atgtatccat ccatgaatct acaaggctcc attgggcagt 2100tccaaactgg aggtcagaaa aatttcactg atgaaactca ctgggacaca atcaaaaata 2160tgaaagagct ttgtagccat ctttttttct gacaagggtg ggagaggcat aacaaggaag 2220gtaaataatt gattgcatta tatacacata tgaaactgtc aaagaacgca atttaaaaag 2280tacatagtaa gtggttttcc atacaattta atttattatc acacagttgt tctttacagt 2340atgtcttgat tatctctatc cctgactccc atgtcacccc cacaaacacc ctcaatatat 2400ctccctccac cttatcaccc cttaatttct ttcattttac tattttatag ataatccact 2460gaattcaatt agtgctgtct gttggaaagc cgaaggagac cgatatgttg gcttgatttg 2520acacaggtct tctgcaggtg accaagatga agtgacttga atgtgatagc catgctatga 2580aaaagagggc ttcatgtatt gtatcaaaag ggagcgtttc tcagctcctc tctccagcct 2640ctgtctcata ttctttctgc tccgtcttcc tctgtaacat agtaaatttg tacagaacgg 2700tcacaagtca caaatttggt agactacatg atgaaatttg caatgacttt ggagtactta 2760acatggattt gaatgtccat ttggcatcgt tctagaagat aagtccaaag taagtgtgct 2820atcttaccat cttccttcct tgtaggagtc ggccacgttt cccactctag accttagctc 2880ctctagttag ctgcttcaaa gcatcaagtg gagtccgcat aatcactttg tactaattca 2940taagctcata aatccagaca aagtgaaagt caaatctcaa gtcctgggcc acttatttgt 3000tttctgtgca tcggacttag gattatttgc cctcttcctg ttccactgca tcagttctgt 3060cagtgggggg ggggggggtt gggagtgtgt gtgtgtgtgt gtgtgtgtgt gtgtgtgtgt 3120gtgtgtgtgt tgcttacaaa gctgtcataa tgatgaaaca gagtatcagt cacatggtaa 3180ccacatctaa gtagagaatg tgcttctaca atgtgagctt cctctcagtg tgtccatgtc 3240atcatagagg aggcttcttt cccagtgcac atgaaggctt cagaactaag tttgaatagg 3300actatgtgat cagccctgaa aagcctgcag tactccttgg tgctgtgctt gaaccctcct 3360gtttctctgc gcggtctttg tagggagact atggatataa actatttggg tggtctcttt 3420tttttcatca ggaagacaga ggtatactgt tgattctaga catgtcaggt tgaggaaatg 3480gaccttatgc ctaattcctt cctaattcat acagagtttc agctttaaag gacagattaa 3540tagcggtttg agatgatttc agctctgtga cctggccatt gtgctgtgtg ttagatttcc 3600atgctggtaa gtgaaacaat tttagggctc taaaaactca cttcaggctc taagcagcac 3660tccacctagc cagaatgggg gagatgcagc taaacagctg ctcatgtgag cagggttacc 3720aactccagtc gacagccagg ccagcatgac tcaccagtgt gaaactgcca agaggataat 3780ttgatctggg gctgaatgaa caggactgca gtgtctgtcc agaccaaagt gagggatcct 3840cccttgtctg catgtgaatc cagaccacac ctactgtctt gtaggctttg cttaccccca 3900cccctgtatc tcattatgat gctgttcaca agttgaagta gagccagcta tgagactcat 3960tgcataatat tcacattaga aaccactctc ttcattctat ttctatcata ggatttctaa 4020cttaacttgt tgaaggtgtg gatattgaca tctttgagaa gaagaaga 406863949DNAChinese hamster 6gatctgtgta gctgccacaa cacttgatct cggagtgagg ccctaactcc attgatgggt 60gtcagctctc atcagtcgca ctgttagcaa caggagatcc agctgactgc ctctcaagtt 120atacagtgtg tgcaccagct tccaccacag cagctgctgc tgtcagtttg gaaataaagt 180tcattcctac cttgcaggca ctttggcatt tgctttggga ttatttgcac ctcaggaaga 240tccatcacta gttttcatta ttctgaatgc aatggattat cagcctgtaa ataatcaagt 300agacctcact ggatttaaac attggaagct aagctatcaa gcagatttat gaagttcaca 360tgcttgtgca atgtgagaag ctgacttttt ggagctgcag tggcagccaa ccaagcagcc 420tgaggtttgt tcttgaaagg gagagtgtgg actaaaggaa gcctagaaag acacagaata 480aaatcaggag ggcagatcca gttaatactg aacaccacaa gtttatttct caccactctc 540atatacctta accaaaaggt gaacatgagt tccttcatac aaagcaaaca ctcttttctt 600gctgaatttt tcaccaattt ggtaaccata ccttagattc aaattctagt tacctgttct 660ttagggacag gtgtcagcac atctcagacc aagtctgttt ttatttagca taagacaccc 720catgccatga tgcaatatcc tactgtagcc acacctttga cctttaggtt ttatgatttc 780ctaaggacag ttatgaactc tctgcccttg agccaagatg gagtccagcc gtctttatgg 840gaactagcag tgcaatgtga ttctctcatc cattgcattc gtcaaaaggc aattgtgagt 900aaagggagga tgtagtggtt catctatttg cctgactgat atcctaacag ctcccctagt 960ttttaatttt tttttagttc ttgtgaagat gtcatggctg gtctggagct cctgggtata 1020ctgtagccta ttttactgtc taagcctctg gggtagctgg gattgctgga tcatggtgac 1080aggtaactca ctacccaatt ttaaagtgaa tttgtaatga aaggatgatg attgttacct 1140acttgttagg gctaggaatt gatttcttcc caacatttta gagattttcc ctgtgtatta 1200atggcattta tcttgcatct acaattgatg ctgttcaaag ctgcccaggc tggcctctaa 1260ctcacagaga tgcaaatgcc tctgcctccc gagtgctggg attaaaggcg tgcaccacta 1320atgcctggct ctttttaaaa tcttttaggt tattgcttcc taagctctag tgactatggg 1380tagatatcaa agacaataca gttttcattg gttctgtttt ggtgtgtagt ttttgttggc 1440tactttcttc tttacacaga tttcatgtag tgcacactca tcttgagctc tctacatagc 1500acaagaggac cttgcaggct tgattatcca gccgctaatt cctaagtgct gagtgacaag 1560tgtgtgacac tgtgcctctc attttgttgg ttattttaga aagagtctta ctaagttgcc 1620cagactaggc tcaaactctg aatatctccc agctttagcc tccatagtct tgcatttaca 1680ggcagtttaa tcttgagcta acagtccctg ctgataccaa gtttttattc taggtgtcca 1740agaggaactg tagcagtgaa ctccagtcta gccaaagaca cttgaccatt gcactctgga 1800tcttgtcttt agatatgtat tttgggggat ttctttttaa tcaacaggaa atcaaataaa 1860cttaaaaaag aatttacgca ggcagcactg gttcaagtat ttaatctcaa caccctgtag 1920atataggcaa aagtatctct gagcagaaag atagccaggg ttacaaagag aaaaactgtc 1980tcaaaaatta tatatatgtg agtgagtgtg tgcgtgttag ttattttaaa ttatatgtat 2040aaatgtacat gcatatgcaa gagcccatgg agatcaggag aaattgtgtt ctctaagagc 2100tgtagttact ggtgggtgaa agccaccagg gttgggagag agaaatagaa ctgtagtact 2160atgatagaac aagaagtgct cttaacctga gttatggttc tagctcaata gatacactat 2220tcacagttat tttaaagata ctgttgttgt tgtcttttac tgtgcatttg ggtgataaaa 2280catgatccaa cacactcaac aaatccacat ggagtttatt ggaaaaggga ataaagggag 2340gggtaggtgt taaccaatag ggagcagaaa tggaaagaga gaaaacagat gggaggcact 2400tgcttataaa gggaaaggaa acagttaaga atgaggctca gtagttgggg cctttgaaac 2460catagtcact gaactgcctt tggccaagat ttacatggtc tctgtatgca gaatcctaat 2520tcagtcaatt aacacatgca ccacacagcc atgcaaactt tgacagtctt tgagatgtca 2580gcaaggaaca atcacctgtg aaaaacagat cccagggcaa gggcaggtca cctggaaaag 2640agaagagaag atggatccca gagcagggag ggaatccaag tgttagagag gccactaggc 2700caggaaagga tctctaagga agcaacaggc ccaggagagt gctgatgtgg agtgacatgt 2760ggagatcaag agaaaacacc agggtgggag gagagaaatt ggcagctgga tcagggccag 2820gtcgcacaga acctagggag agggagaatc caggttatca acaattatta ctaggcagta 2880ctacattttc tgtgtcctat tatttctgta gttacttaca aaatatttga gttataaaaa 2940ggaataaaga gccgggcagt ggtggcacat ggcattaaca ccagcacttg ggagacacag 3000gcagttgcat ctatgtgagt ttgaggccag cctggtctac agagggagtc ccaggaccaa 3060aagccacaga gtaactttgt catacaaact gatccagtag gcttcatctc agatacgcag 3120tgatggttca acatacaaaa atcagtaact gtaatccacc ataaaaataa actttaaaaa 3180acactttttt attatccctt tacatgctta caaagtcatt gataagccag gtattggggg 3240tgcatgcctt taatcccagt acttgggagg cagaggcagg tggatcactg tgagttcaag 3300gccagcctga tctccagagc gagtgccagg ataggcttca aagctgcacg gagaaaccct 3360gtcttgaaaa accaataaat aaataaataa ataaatagtc attgacaaga aacaaacatc 3420ataaaagtct tggagatatt atggatacaa tttacataca cacacataat gaaggacatt 3480tacagcaaac ctatagacaa catcaaatac aatggagaga aaaaacaaag gaattcctat 3540aaaatctgta acttgacaag tttgtgaagt ctatatctac tcaatacagt acttgaagtt 3600ctagatagac ccattaaaca gctaaaggac aacaaggaaa ggaagaagta gaagtgttgt 3660tacttgttga tgatatagtg gtaccaccta agtgacacta aaaattcatc aatggaagta 3720caggtgatta aaactttcag caaagtgacg ggatacaaga gtaactaaaa caaccattag 3780ccctcctatg taaaaatggc aaacagcttg agaatgaaat aaaagaagca gcagcaatca 3840caatagcttc aaataatata aaatacattc tagtaactct aacttgttta attaaaaaaa 3900ctttaagtgt ttgaagaaag aaattgaaga agatatgagg cgatggaaa 394971128DNAChinese hamster 7gatcaggagt tcaaggccac actgaggtac acgaaattca accagtctga tagatataag 60agctgggtgc gtgtggctcg cacctcaggt ggagacagga gtataaggct ggaggaggca 120gtatttaggc ttattcatat agaggatttg taaagacagg acctccccag cacttccatc 180tgaacatttg gtacaggtaa gaagtcccta tagagttggc tcctttaatt ctcttatgtc 240tcaacattta cccaattatc tgacatctca ctcagcgttt ttactattta aaccaatttg 300aagaaatgct acagagcacc ttttaacctc tacaaacaca cataaacaca gagagagaga 360gagagagaga gagagagaga gagagagaga cagagacaga gacagagaca gagacagaga 420cagagaaaca aatgtaataa cgaaagaagt catgtcatga gaaccctgag gctgcggtcc 480acacccatct gtggccagga cacagaggcc tagaggagcc ctgtgacaca agcactctct 540acaactggcc cttgtcccgt gcagggggca gaaaggacag attttgttgt gcagaagctt 600tatcatcagc agcatacact gggcctctct gtccttcact gtcacatgct cctagggagt 660tcagtcggga ggtcatgtat gtgcactatg gacctgtccc acagacactc tgtcctaatg 720cgttctgctg gggtattttg gcaatgctgc aattgagcag tgatgtttca aggtgcacta 780gttgttcccc ccatattctc caacacaatc aatgccacat tgtaaatcaa aacattcagg 840ctcccctgtg aattgtaagg attttattat tggaatcctg gttttagata cctggagggt 900agggtagggc ttgcttcatc tattcaggtg tgtaggcaag tggctccctt gagtcttatt 960gcccagatgg attcatcaac agaatttgtt agcatctatt ttctgctgca aagagaaccc 1020ggtgaggtat ctgaggtgtc agaggtgaag gacatctcac tgagcataca tgggacacct 1080catgggaggg actgaaacct gtctgccaga gcacctgggt ctgaccat 112881352DNAChinese hamster 8gatctctcag cttcctgctt tttaaaagta ttttatttta tttttatacc cattgatgtt 60ttttgtcgtg ggtgtcggat accctgaaac tggaggtttt cattttatat ttatgttaat 120caatgttttg ccatgggtgt tgcgtcccct gaaactggag ctacagacag gtgtgagctg 180ccatgtgggg ctgggaactg aacttgagtc ctctggaaga ggagtcagtg ctcttaacta 240gtgagccatc tctctaggcc ctcagcttcc tgctttggct accagctgac atgcctctcc 300caccattatg aatgccccct caggaacctc tggaactgaa aaccaaaata aactttttaa 360agttgcttta gttcatggca ttttatcaca acaatagaca agaaactaat acagtaatac 420atggcttttt aaatgatttg acagattcat gtaagtatat agtgaatttg ggtcattttt 480caccctttaa taccattgtc atcctccttc ctaaccagct gggaccctct tcctcagcag 540gccctcttct actttcattt tttttttttt tttttgtgtg tgtgtgtgtg tgtgtgtgta 600tgtgtgctcg cgcgtgtgct gtgtccttat gtttatttat ataaaaaata gcgcattgac 660tctaactttt actacacctt actggttata tatgtatgtg tatgccatgg tacatgtgca 720gagaacaaag gacaactttc cgggagtcat ttctatcctt

ccactatgca tgtggtttct 780gggatagaac tcaggtcatt agccttggca gcaagcctct taaccctctg aaccatctcc 840ctggcctggc attttaaaat aatctttgat gcttctatca gtatcttggc cactgataat 900ctataattat ttctctaaga ctatttgttt tccacaaaca aaatgctata agctgggaga 960tttataaaga agagatacat ttggctcaca gctctggaaa ctgggaagtc caaaagcatg 1020acaccagcag ctgtcaaatg cctttctgca gtatcataag aaatcagagg acagcacatg 1080acaagaatgt tacaaaagga caggacaagt gttccaggct tggtctatgg ttttcatcat 1140ttaaggccgc caattccatc acaagtgttc tcttccctat gatttcatgt aattctaaag 1200acattctaaa accccacacc caaatactat tagcacaaga cattggagat tttagtttca 1260atcttagctt taggggagag acactcagtt cataacagta tccccaagat ttccagtatc 1320cagtgctgtc tcaatgcaat actactcaga ag 135291246DNAChinese hamster 9gatctttcca ttttctggta tcttctttaa tttctttctt ttaagactca aagttcttgc 60tagacaggtc tttcacttgt ttggttatca ttaccccaag atattttatg ttgtttggct 120attgtaaagg atgatgtttc tctgatttat ttctcagccc atttatctcc tgtgtataat 180agggctagtg attttttgag ttaatcttgt atccttccac ttagctgaag gtgtttatca 240gctgtagtag ttccctggta gagttttttg ggttacttat gtaactatca tatcatctgc 300aaacagtaaa aatttgactt cttcctttcc aatttgtatc cccttgttct cctttttgtt 360gtcatattgc cccagataga acttcaagta caagcagaag tcattctctt ctgcttcatc 420tgtgttggga tgttcaggtc ttgctggcgt agagtcccta gattctagtg gtgtcatatt 480gttttttctg ttattgaatg cgtttttata ttgttgtctt cccatctctt cttccagtgg 540gttcaggtgc cgtctcttcc tctcctggtg tgtatgggtc caaggttctc tttggtggat 600gcaagagggt ctgatactct gatgggtctt atggtgggtt caggcgggtc tggggcactc 660cctctctagg tgggggtggg aactggacta gcacagtgat gtcatcagac ttgaggttgc 720ttggtcctca gggggcaagt tgatttgcct gcagtcccca ggacaggagt tcccagagtg 780gacaggcaga agtcgggctc aaggcagggg ccaagctcta catgtgattt ttaaaatgag 840agttcagatt catgtaggca gatgataagc tcagggagag aaatgaccta tttctaaaaa 900ctgatgacgt gaagattgag agaaagggtg gatttttgaa aaagaatcgg tagggagcta 960aaaaggaaaa gagaaattaa ggatgactct caggttttgg acttgaatgt tggatggatg 1020tttgtcccat ttgtagaaag gagaacacag gtgatttaga agtctgaggt gaggatgtca 1080cctcatgact taaagaatct gaggttttag aatcaaatct cagggaacat cattagcaga 1140gggaccctgt tgggtcttgc cagatgctga gcttcagctg tctcctgttt tcccacattt 1200cctgtttttc ctaacttgta tagactctgg gaaaagaagg taccag 124610447PRTHomo sapiens 10Phe Thr Val Thr Val Pro Lys Asp Leu Tyr Val Val Glu Tyr Gly Ser1 5 10 15Asn Met Thr Ile Glu Cys Lys Phe Pro Val Glu Lys Gln Leu Asp Leu 20 25 30Ala Ala Leu Ile Val Tyr Trp Glu Met Glu Asp Lys Asn Ile Ile Gln 35 40 45Phe Val His Gly Glu Glu Asp Leu Lys Val Gln His Ser Ser Tyr Arg 50 55 60Gln Arg Ala Arg Leu Leu Lys Asp Gln Leu Ser Leu Gly Asn Ala Ala65 70 75 80Leu Gln Ile Thr Asp Val Lys Leu Gln Asp Ala Gly Val Tyr Arg Cys 85 90 95Met Ile Ser Tyr Gly Gly Ala Asp Tyr Lys Arg Ile Thr Val Lys Val 100 105 110Asn Ala Pro Tyr Asn Lys Ile Asn Gln Arg Ile Leu Val Val Asp Pro 115 120 125Val Thr Ser Glu His Glu Leu Thr Cys Gln Ala Glu Gly Tyr Pro Lys 130 135 140Ala Glu Val Ile Trp Thr Ser Ser Asp His Gln Val Leu Ser Gly Lys145 150 155 160Thr Thr Thr Thr Asn Ser Lys Arg Glu Glu Lys Leu Phe Asn Val Thr 165 170 175Ser Thr Leu Arg Ile Asn Thr Thr Thr Asn Glu Ile Phe Tyr Cys Thr 180 185 190Phe Arg Arg Leu Asp Pro Glu Glu Asn His Thr Ala Glu Leu Val Ile 195 200 205Pro Glu Leu Pro Leu Ala His Pro Pro Asn Glu Arg Thr Pro Arg Asp 210 215 220Cys Gly Cys Lys Pro Cys Ile Cys Thr Val Pro Glu Val Ser Ser Val225 230 235 240Phe Ile Phe Pro Pro Lys Pro Lys Asp Val Leu Thr Ile Thr Leu Thr 245 250 255Pro Lys Val Thr Cys Val Val Val Asp Ile Ser Lys Asp Asp Pro Glu 260 265 270Val Gln Phe Ser Trp Phe Val Asp Asp Val Glu Val His Thr Ala Gln 275 280 285Thr Gln Pro Arg Glu Glu Gln Phe Asn Ser Thr Phe Arg Ser Val Ser 290 295 300Glu Leu Pro Ile Met His Gln Asp Trp Leu Asn Gly Lys Glu Phe Lys305 310 315 320Cys Arg Val Asn Ser Ala Ala Phe Pro Ala Pro Ile Glu Lys Thr Ile 325 330 335Ser Lys Thr Lys Gly Arg Pro Lys Ala Pro Gln Val Tyr Thr Ile Pro 340 345 350Pro Pro Lys Glu Gln Met Ala Lys Asp Lys Val Ser Leu Thr Cys Met 355 360 365Ile Thr Asp Phe Phe Pro Glu Asp Ile Thr Val Glu Trp Gln Trp Asn 370 375 380Gly Gln Pro Ala Glu Asn Tyr Lys Asn Thr Gln Pro Ile Met Asp Thr385 390 395 400Asp Gly Ser Tyr Phe Val Tyr Ser Lys Leu Asn Val Gln Lys Ser Asn 405 410 415Trp Glu Ala Gly Asn Thr Phe Thr Cys Ser Val Leu His Glu Gly Leu 420 425 430His Asn His His Thr Glu Lys Ser Leu Ser His Ser Pro Gly Lys 435 440 44511451PRTArtificial SequenceAntibody heavy chain 11Glu Val Gln Leu Val Glu Ser Gly Gly Gly Leu Val Gln Pro Gly Arg1 5 10 15Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Thr Phe Asp Asp Tyr 20 25 30Ala Met His Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu Trp Val 35 40 45Ser Ala Ile Thr Trp Asn Ser Gly His Ile Asp Tyr Ala Asp Ser Val 50 55 60Glu Gly Arg Phe Thr Ile Ser Arg Asp Asn Ala Lys Asn Ser Leu Tyr65 70 75 80Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr Tyr Cys 85 90 95Ala Lys Val Ser Tyr Leu Ser Thr Ala Ser Ser Leu Asp Tyr Trp Gly 100 105 110Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ser Thr Lys Gly Pro Ser 115 120 125Val Phe Pro Leu Ala Pro Ser Ser Lys Ser Thr Ser Gly Gly Thr Ala 130 135 140Ala Leu Gly Cys Leu Val Lys Asp Tyr Phe Pro Glu Pro Val Thr Val145 150 155 160Ser Trp Asn Ser Gly Ala Leu Thr Ser Gly Val His Thr Phe Pro Ala 165 170 175Val Leu Gln Ser Ser Gly Leu Tyr Ser Leu Ser Ser Val Val Thr Val 180 185 190Pro Ser Ser Ser Leu Gly Thr Gln Thr Tyr Ile Cys Asn Val Asn His 195 200 205Lys Pro Ser Asn Thr Lys Val Asp Lys Lys Val Glu Pro Lys Ser Cys 210 215 220Asp Lys Thr His Thr Cys Pro Pro Cys Pro Ala Pro Glu Leu Leu Gly225 230 235 240Gly Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met 245 250 255Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val Ser His 260 265 270Glu Asp Pro Glu Val Lys Phe Asn Trp Tyr Val Asp Gly Val Glu Val 275 280 285His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Tyr Asn Ser Thr Tyr 290 295 300Arg Val Val Ser Val Leu Thr Val Leu His Gln Asp Trp Leu Asn Gly305 310 315 320Lys Glu Tyr Lys Cys Lys Val Ser Asn Lys Ala Leu Pro Ala Pro Ile 325 330 335Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro Gln Val 340 345 350Tyr Thr Leu Pro Pro Ser Arg Asp Glu Leu Thr Lys Asn Gln Val Ser 355 360 365Leu Thr Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu 370 375 380Trp Glu Ser Asn Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro385 390 395 400Val Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu Thr Val 405 410 415Asp Lys Ser Arg Trp Gln Gln Gly Asn Val Phe Ser Cys Ser Val Met 420 425 430His Glu Ala Leu His Asn His Tyr Thr Gln Lys Ser Leu Ser Leu Ser 435 440 445Pro Gly Lys 45012214PRTArtificial SequenceAntibody light chain 12Asp Ile Gln Met Thr Gln Ser Pro Ser Ser Leu Ser Ala Ser Val Gly1 5 10 15Asp Arg Val Thr Ile Thr Cys Arg Ala Ser Gln Gly Ile Arg Asn Tyr 20 25 30Leu Ala Trp Tyr Gln Gln Lys Pro Gly Lys Ala Pro Lys Leu Leu Ile 35 40 45Tyr Ala Ala Ser Thr Leu Gln Ser Gly Val Pro Ser Arg Phe Ser Gly 50 55 60Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser Ser Leu Gln Pro65 70 75 80Glu Asp Val Ala Thr Tyr Tyr Cys Gln Arg Tyr Asn Arg Ala Pro Tyr 85 90 95Thr Phe Gly Gln Gly Thr Lys Val Glu Ile Lys Arg Thr Val Ala Ala 100 105 110Pro Ser Val Phe Ile Phe Pro Pro Ser Asp Glu Gln Leu Lys Ser Gly 115 120 125Thr Ala Ser Val Val Cys Leu Leu Asn Asn Phe Tyr Pro Arg Glu Ala 130 135 140Lys Val Gln Trp Lys Val Asp Asn Ala Leu Gln Ser Gly Asn Ser Gln145 150 155 160Glu Ser Val Thr Glu Gln Asp Ser Lys Asp Ser Thr Tyr Ser Leu Ser 165 170 175Ser Thr Leu Thr Leu Ser Lys Ala Asp Tyr Glu Lys His Lys Val Tyr 180 185 190Ala Cys Glu Val Thr His Gln Gly Leu Ser Ser Pro Val Thr Lys Ser 195 200 205Phe Asn Arg Gly Glu Cys 21013943DNAHomo sapiens 13gtaagtgccg tgtgtggttc ccgcgggcct ggcctcttta cgggttatgg cccttgcgtg 60ccttgaatta cttccacgcc cctggctgca gtacgtgatt cttgatcccg agcttcgggt 120tggaagtggg tgggagagtt cgaggccttg cgcttaagga gccccttcgc ctcgtgcttg 180agttgaggcc tggcttgggc gctggggccg ccgcgtgcga atctggtggc accttcgcgc 240ctgtctcgct gctttcgata agtctctagc catttaaaat ttttgatgac ctgctgcgac 300gctttttttc tggcaagata gtcttgtaaa tgcgggccaa gatctgcaca ctggtatttc 360ggtttttggg gccgcgggcg gcgacggggc ccgtgcgtcc cagcgcacat gttcggcgag 420gcggggcctg cgagcgcggc caccgagaat cggacggggg tagtctcaag ctggccggcc 480tgctctggtg cctggcctcg cgccgccgtg tatcgccccg ccctgggcgg caaggctggc 540ccggtcggca ccagttgcgt gagcggaaag atggccgctt cccggccctg ctgcagggag 600ctcaaaatgg aggacgcggc gctcgggaga gcgggcgggt gagtcaccca cacaaaggaa 660aagggccttt ccgtcctcag ccgtcgcttc atgtgactcc acggagtacc gggcgccgtc 720caggcacctc gattagttct cgagcttttg gagtacgtcg tctttaggtt ggggggaggg 780gttttatgcg atggagtttc cccacactga gtgggtggag actgaagtta ggccagcttg 840gcacttgatg taattctcct tggaatttgc cctttttgag tttggatctt ggttcattct 900caagcctcag acagtggttc aaagtttttt tcttccattt cag 94314447PRTArtificial SequenceAntibody heavy chain 14Gln Val Gln Leu Val Gln Ser Gly Val Glu Val Lys Lys Pro Gly Ala1 5 10 15Ser Val Lys Val Ser Cys Lys Ala Ser Gly Tyr Thr Phe Thr Asn Tyr 20 25 30Tyr Met Tyr Trp Val Arg Gln Ala Pro Gly Gln Gly Leu Glu Trp Met 35 40 45Gly Gly Ile Asn Pro Ser Asn Gly Gly Thr Asn Phe Asn Glu Lys Phe 50 55 60Lys Asn Arg Val Thr Leu Thr Thr Asp Ser Ser Thr Thr Thr Ala Tyr65 70 75 80Met Glu Leu Lys Ser Leu Gln Phe Asp Asp Thr Ala Val Tyr Tyr Cys 85 90 95Ala Arg Arg Asp Tyr Arg Phe Asp Met Gly Phe Asp Tyr Trp Gly Gln 100 105 110Gly Thr Thr Val Thr Val Ser Ser Ala Ser Thr Lys Gly Pro Ser Val 115 120 125Phe Pro Leu Ala Pro Cys Ser Arg Ser Thr Ser Glu Ser Thr Ala Ala 130 135 140Leu Gly Cys Leu Val Lys Asp Tyr Phe Pro Glu Pro Val Thr Val Ser145 150 155 160Trp Asn Ser Gly Ala Leu Thr Ser Gly Val His Thr Phe Pro Ala Val 165 170 175Leu Gln Ser Ser Gly Leu Tyr Ser Leu Ser Ser Val Val Thr Val Pro 180 185 190Ser Ser Ser Leu Gly Thr Lys Thr Tyr Thr Cys Asn Val Asp His Lys 195 200 205Pro Ser Asn Thr Lys Val Asp Lys Arg Val Glu Ser Lys Tyr Gly Pro 210 215 220Pro Cys Pro Pro Cys Pro Ala Pro Glu Phe Leu Gly Gly Pro Ser Val225 230 235 240Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr 245 250 255Pro Glu Val Thr Cys Val Val Val Asp Val Ser Gln Glu Asp Pro Glu 260 265 270Val Gln Phe Asn Trp Tyr Val Asp Gly Val Glu Val His Asn Ala Lys 275 280 285Thr Lys Pro Arg Glu Glu Gln Phe Asn Ser Thr Tyr Arg Val Val Ser 290 295 300Val Leu Thr Val Leu His Gln Asp Trp Leu Asn Gly Lys Glu Tyr Lys305 310 315 320Cys Lys Val Ser Asn Lys Gly Leu Pro Ser Ser Ile Glu Lys Thr Ile 325 330 335Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro Gln Val Tyr Thr Leu Pro 340 345 350Pro Ser Gln Glu Glu Met Thr Lys Asn Gln Val Ser Leu Thr Cys Leu 355 360 365Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn 370 375 380Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser385 390 395 400Asp Gly Ser Phe Phe Leu Tyr Ser Arg Leu Thr Val Asp Lys Ser Arg 405 410 415Trp Gln Glu Gly Asn Val Phe Ser Cys Ser Val Met His Glu Ala Leu 420 425 430His Asn His Tyr Thr Gln Lys Ser Leu Ser Leu Ser Leu Gly Lys 435 440 44515218PRTArtificial SequenceAntibody light chain 15Glu Ile Val Leu Thr Gln Ser Pro Ala Thr Leu Ser Leu Ser Pro Gly1 5 10 15Glu Arg Ala Thr Leu Ser Cys Arg Ala Ser Lys Gly Val Ser Thr Ser 20 25 30Gly Tyr Ser Tyr Leu His Trp Tyr Gln Gln Lys Pro Gly Gln Ala Pro 35 40 45Arg Leu Leu Ile Tyr Leu Ala Ser Tyr Leu Glu Ser Gly Val Pro Ala 50 55 60Arg Phe Ser Gly Ser Gly Ser Gly Thr Asp Phe Thr Leu Thr Ile Ser65 70 75 80Ser Leu Glu Pro Glu Asp Phe Ala Val Tyr Tyr Cys Gln His Ser Arg 85 90 95Asp Leu Pro Leu Thr Phe Gly Gly Gly Thr Lys Val Glu Ile Lys Arg 100 105 110Thr Val Ala Ala Pro Ser Val Phe Ile Phe Pro Pro Ser Asp Glu Gln 115 120 125Leu Lys Ser Gly Thr Ala Ser Val Val Cys Leu Leu Asn Asn Phe Tyr 130 135 140Pro Arg Glu Ala Lys Val Gln Trp Lys Val Asp Asn Ala Leu Gln Ser145 150 155 160Gly Asn Ser Gln Glu Ser Val Thr Glu Gln Asp Ser Lys Asp Ser Thr 165 170 175Tyr Ser Leu Ser Ser Thr Leu Thr Leu Ser Lys Ala Asp Tyr Glu Lys 180 185 190His Lys Val Tyr Ala Cys Glu Val Thr His Gln Gly Leu Ser Ser Pro 195 200 205Val Thr Lys Ser Phe Asn Arg Gly Glu Cys 210 21516680DNAhuman cytomegalovirus 16gttgacattg attattgact agttattaat agtaatcaat tacggggtca ttagttcata 60gcccatatat ggagttccgc gttacataac ttacggtaaa tggcccgcct ggctgaccgc 120ccaacgaccc ccgcccattg acgtcaataa tgacgtatgt tcccatagta acgccaatag 180ggactttcca ttgacgtcaa tgggtggagt atttacggta aactgcccac ttggcagtac 240atcaagtgta tcatatgcca agtacgcccc ctattgacgt caatgacggt aaatggcccg 300cctggcatta tgcccagtac atgaccttat gggactttcc tacttggcag tacatctacg 360tattagtcat cgctattacc atggtgatgc ggttttggca gtacatcaat gggcgtggat 420agcggtttga ctcacgggga tttccaagtc tccaccccat tgacgtcaat gggagtttgt 480tttggcacca aaatcaacgg gactttccaa aatgtcgtaa caactccgcc ccattgacgc 540aaatgggcgg taggcgtgta cggtgggagg tctatataag cagagctcgt ttagtgaacc 600gtcagatcgc ctggagacgc catccacgct gttttgacct ccatagaaga caccgggacc 660gatccagcct ccggactcta 680173619DNAChinese hamster 17ttaattaccg acaatggctg gtacagcaag tagcacggaa aaaaagtgaa acagttgcac 60tgttcatggt tggcaataat tcttcaggaa aatatttact atcaatcagt tatgagaaaa 120gggactctgt gctcgtaaaa cagcacgttg cttctcatac caggaccatt ttgcttcagc 180ataatctgaa tttaaacagc ttgtttcctg cggatataat tttggaaata aataaaacaa 240gtcttctatc aaaatccgga gtgagtggga aggaacatca catctttcta tctcagtcag 300tttcaaacag attattagtc ccaagtaaaa aacagtaata acaaacaaca aaaatacaga 360atgtacacaa ggccactgat gggcttattc caaagaaaga cagacctttc ccactgtagg 420ccaggtatca aggtagaagt

gcccgaacaa ttcaatttta actgcacatg tttatggaag 480gggtgtgagg tgtaagggta aattatggaa aagcctcaaa ccaaaatttt ctgtagtatt 540tcaataaagt caataacaag ataacataaa aattaatgtt ctcagttttt ttcataatta 600aaaaacatga aggttgacaa ttaggtacaa tgtgattata gattttaaag actaagctga 660cagtcaataa ccgctgtcca tttaaagcta caataaatat agagctcatc atgttcccca 720aacaaatccc ataaagcacc agggctgtga gcagcagatg agatgctcta aaaagcaaac 780tagctggcat ggtggtgcat ccagcacttg ggaggcggag gcaggtggat ttctgtgagt 840tcaaggacag cctggttgat atggccaaag ctacatcgga cagacagaca gacaaaacaa 900aacaaaaaag caaactatat tcaagatatt tcatggcttc aaatactact tggacccctc 960cccattttta tttttaaatg tttctttctt gaactctttc tttcaggaga ctgctgtcag 1020cctaaggtag cttatgaagc agctgtgctt ccttacagga actgaatagt tacagggcaa 1080ccagcagagg aaaactacac acaaaatact acaggtttca tctctgcttt tgagaaggac 1140caatgtcttc tgtaaaatgc aaacaagtaa taattaaaag gtctaagact acaattagta 1200ttgataccca aaccaaaatt actctgactg aaattcagtt gctttgaacc ataaggggga 1260aaaaaaggct ggcttcactg tatttcagtg gcgttacatg gagacagctg gacatgtagg 1320ccacaatgga gaccagtttg aatcagtatc agacgccagt ttctgaagga aagtcctcac 1380agccacgtca gtgtagcaga caaaactact gttaagaact aaaggtgaag aacaagaact 1440agagaaatgc ttacagaact acaaaaatat ctttgagtca tttcttttaa aggtcaagca 1500gtaaatgagg ccaggagaga cagtatgaaa tcatgagaca gatataacat gtttagcaat 1560aagaaaggaa aactctcatt gttgccatgc tagaggaggc cactgcaata aacatttttt 1620tcagttacgt atttttattt gatgatttgg ctcaaatctg aagcaatgaa ctagaagaca 1680ggatgtgggc caataaaagg aaccaggaag ctggttgtgt tccaaatgga aattacagaa 1740atcattattc aattagagtg gttaagggga caatgaaaga aaataggtgt cagaataatg 1800ttaaaacaag caagaatggg acgagaaggt caccatctgg gagcaagtga aacagactga 1860tgagcagcaa tgagcaaact tatttcctca cccaagagca tggaaggaat tataccaccg 1920tgccagacgc cacaagattt ctaaccgtgc accactgaag tagagggtag aaaaaagaaa 1980aaagaacagc aaaaacaaat ccaccccaca ctatacacac agcaacaagg ctaaggagtg 2040tagaaacact ggcttaccac gtacaggaaa acaaaaggaa cagatgctca gttggccagc 2100tctcaatgaa actcattaaa attgtcgccc tgtccttgga ttggtggtca tgcgaaattt 2160gtgccttgtt tagccagaag taacttgtga tgaaggagag aacagcatgt ccaaacaaga 2220attgaaacac ttgttgatct atactcaatg ctagatataa aacaggatca agtagcactt 2280acaaactgtt actaagtaat tgaaaattaa atgtaactta cactactcct cttttttttt 2340tgtagcaaat taagatgtga acttaaggca caatttgatg aacctaccat ttgcagctac 2400aatataaaat aaattcttac atttctcata tggctaagtc caatggccac aagctgtatg 2460tttgcagtaa taaagcaagg tcaggaactg ccatgtattt tgggaaatat aataaaaatt 2520attgttgctc ctatgtcctg attgatcatg tccctcccta accacctaat gtgtaagaac 2580agagtctcca tgaacagaat tagagcacta tgcaataagt aaatgaatga acagattaat 2640aagagatccc agagggctta gctcatccct tccatcctga gattatatta tagcaaggat 2700tccatctatg aagaagagtc aacttccaac tagacattga atctactgtc accatgatct 2760tcccatatct agaactataa aaataagtca ctgtttataa gctaccttgt ttatttttgg 2820ttgtaataac acaaaagaaa ttagctcttc ttgagattta taacaaagat ggagttgaca 2880tgacatcaag tcctatctct aataatgaca gtaaataggg gcctatatag gacacaagag 2940atgaagcaga aagttggaaa agttgtaaaa cagtcacccc ccaaaatggt aataaaggtt 3000atttttgcct aaaaataaag acaaactcta gaaatacaac tcatactgaa cgttatcctc 3060aagacagtaa agttaacaaa aaagttatcc ccagtcaatc tagaaaattg aaagaaaaaa 3120attaagattt ctaattaaat ttttgtgtat gggtgttttg tctatatgta tgtctgtaga 3180ggccagaaga agacactggg tcctctggaa cgggagctgc agatggttga gagccgtcat 3240acggtgctga caggtaaccc gggtcctata caggagcagc ccttaaccaa tgagctctta 3300accaatgaac ccctctccag ccctgaagat ttctaatttt taatattttt gtatctagaa 3360atataacaca catttataca taaaagacta ggctcatatg tcagctaaat acatgtttcc 3420actcaaaatc accaagtaag acatttctca agaaagaagg gcacaaccta agctgggacc 3480tctgcagcag tctcacgcat gtggctcaca ctgtcaccag cagggtattt ctggcgtgct 3540acacctgcac ttaaaggagg ccaggcatgg cggtgctggc ctttaatccc agcactcacg 3600gggcagaggc aggcagatc 3619181114DNAChinese hamster 18tccacactca tgttgacatt aaagccatcg acaatctcag taagtactag taaacaagta 60acaaataaga ctgatccatc acacaacatt accctggctg tgtctttgga gtaaaaatca 120tgtagatcaa ggtatggtat gcttgaacac caaaaagtaa ccacagagta gaagagtaga 180gtccagtgag tgccttatgc gtgagcccac ttcccttttt gcgtttgttt ttacttaatg 240tctggcagaa ttcaggcatg taggtcagag gccaccttgc aggagtccgt tctctctttc 300caccaactgg atcccaggga caggacacag gtcttgggct tggcagcggg tgcccttacc 360tactgagcca tttcaccact gacttggttt tactgaaagc taactctgaa gactggaatt 420cgatactttt ttagggtgat gagtcactca ctgtacagcc tcagcactat tgctgaagta 480cattaccctc acaaaccagg cagccggaga ctcactgctt acatgtaatc gaggccatgc 540tatgttaggt aacatgttgg agacttacca aaaactgtgt tttaaagtta cttgcaacct 600ttctgtaacc acgcaaactg ctgtgtgatt ctttaaccta tgtctccaca atcacaacag 660acatctgttc cgggtaattg cacatttcta attaaagctt tcaaagtggg ccaggttctc 720tggagctgaa atgttcgttg aagggggcaa agttattttc tctaacatca tgagggaact 780gggtcagggt gtggggactg caccctgctg aggggatggt ataggaatga cccacctttg 840gcctgtgttc cttttgtttt gctttgtgca tgtgtttgca tttctgtttg catgcaagtg 900agctcatttg ctgtggaagc ccaaagctga tgtcactctc tatcttattc actgaaccag 960agtcgctcca cgaacccaga gctctcagct aacactagcc tagctagcca gctgcccttg 1020ggatcctttc tcagccttcc aagtgctgaa attgcaggta cactactaag cccgtaggcc 1080tttgtgtggg ttctgcagat ccaaacttca gatc 1114194068DNAChinese hamster 19tcttcttctt ctcaaagatg tcaatatcca caccttcaac aagttaagtt agaaatccta 60tgatagaaat agaatgaaga gagtggtttc taatgtgaat attatgcaat gagtctcata 120gctggctcta cttcaacttg tgaacagcat cataatgaga tacaggggtg ggggtaagca 180aagcctacaa gacagtaggt gtggtctgga ttcacatgca gacaagggag gatccctcac 240tttggtctgg acagacactg cagtcctgtt cattcagccc cagatcaaat tatcctcttg 300gcagtttcac actggtgagt catgctggcc tggctgtcga ctggagttgg taaccctgct 360cacatgagca gctgtttagc tgcatctccc ccattctggc taggtggagt gctgcttaga 420gcctgaagtg agtttttaga gccctaaaat tgtttcactt accagcatgg aaatctaaca 480cacagcacaa tggccaggtc acagagctga aatcatctca aaccgctatt aatctgtcct 540ttaaagctga aactctgtat gaattaggaa ggaattaggc ataaggtcca tttcctcaac 600ctgacatgtc tagaatcaac agtatacctc tgtcttcctg atgaaaaaaa agagaccacc 660caaatagttt atatccatag tctccctaca aagaccgcgc agagaaacag gagggttcaa 720gcacagcacc aaggagtact gcaggctttt cagggctgat cacatagtcc tattcaaact 780tagttctgaa gccttcatgt gcactgggaa agaagcctcc tctatgatga catggacaca 840ctgagaggaa gctcacattg tagaagcaca ttctctactt agatgtggtt accatgtgac 900tgatactctg tttcatcatt atgacagctt tgtaagcaac acacacacac acacacacac 960acacacacac acacacacac acactcccaa cccccccccc ccccactgac agaactgatg 1020cagtggaaca ggaagagggc aaataatcct aagtccgatg cacagaaaac aaataagtgg 1080cccaggactt gagatttgac tttcactttg tctggattta tgagcttatg aattagtaca 1140aagtgattat gcggactcca cttgatgctt tgaagcagct aactagagga gctaaggtct 1200agagtgggaa acgtggccga ctcctacaag gaaggaagat ggtaagatag cacacttact 1260ttggacttat cttctagaac gatgccaaat ggacattcaa atccatgtta agtactccaa 1320agtcattgca aatttcatca tgtagtctac caaatttgtg acttgtgacc gttctgtaca 1380aatttactat gttacagagg aagacggagc agaaagaata tgagacagag gctggagaga 1440ggagctgaga aacgctccct tttgatacaa tacatgaagc cctctttttc atagcatggc 1500tatcacattc aagtcacttc atcttggtca cctgcagaag acctgtgtca aatcaagcca 1560acatatcggt ctccttcggc tttccaacag acagcactaa ttgaattcag tggattatct 1620ataaaatagt aaaatgaaag aaattaaggg gtgataaggt ggagggagat atattgaggg 1680tgtttgtggg ggtgacatgg gagtcaggga tagagataat caagacatac tgtaaagaac 1740aactgtgtga taataaatta aattgtatgg aaaaccactt actatgtact ttttaaattg 1800cgttctttga cagtttcata tgtgtatata atgcaatcaa ttatttacct tccttgttat 1860gcctctccca cccttgtcag aaaaaaagat ggctacaaag ctctttcata tttttgattg 1920tgtcccagtg agtttcatca gtgaaatttt tctgacctcc agtttggaac tgcccaatgg 1980agccttgtag attcatggat ggatacataa caagagagag tgattctcct agaatctgtt 2040agtaaccaat ggctcaatga tgaagagtat gacattatgc cctcctcccc acccaaggct 2100gagtgttggt agtgacaatg tcacacagtc ctggcactaa caactgcagc ttttgtgagt 2160tcatgatagc aaagatgata ttggcagccc ttctcactct tttcactctt acattctttt 2220gacaccttct tccacaatgt ttctgagcct tagaagatga ggtataaaaa tcttgtttag 2280ggctgagttc ttaattgtcg ctcattctta gcacccttgg tatttatgag tctttgaatc 2340cacaaccatt cactagagag aattctctaa ttaagaatga tggataattt tgtgtatgag 2400caccagcata agtacttaga agataacttg ttgctttgct cactcagtta agtaagagta 2460gtaagttcct ttctagggtt tatgtcttct tcagtgatag gttttttttt ttcttcctgg 2520atttacagtg cttggcatgg attctctgca gtggggccag gactcaatcc agtgattgcc 2580catattactg ttattccact atcacacggg tgggcttgta ttgcctgata agtaggtatt 2640gccattcata gggttcacag ctgattcaga ctttgatctc tttttgccct agtaacttgt 2700ataatatctt ctgggactgt gaaagttatc aggcaggtgg ctggtggtgt ggctcaatgg 2760tggaaatcca atgtgatatc atctatttac gtctcaatct gatgttaggt tcttgtgatc 2820tggtgatgtg atttggacag aacccaaagg aaagggataa atgagttgaa gtgaagaaca 2880gtctgctgtc agcttctgca agtttatagt gcatcgacgg tcttaccagg aatcagatgc 2940atgaattctg tccagcattt ctaggcaatt ctgtggttgt ctagaactca aaattttgga 3000caaaaggaag gacaagagaa ggtaggaaat gctatctgtg aacctaaaac aggaaggagc 3060attggtctgg ggagtaatca gtcagtcatt gcatcagaaa tgaactaatt tgactaaatg 3120aatgaatgaa tgaatgaatg aatgaatgaa tgaataaaag cacccaggaa acttcaggta 3180aagagacctt tgtccttaat tcttactaat tgtacaatac aatcattagc ctttaacaca 3240aactcggctc ttaggtattt tttttatttt tattttttag aaagacaaag tgacatatgt 3300ataaaattgt tttaaaaatg caaaggattt ctagtcattc ttgtaattag cttggtctct 3360cagatgctgc agggttattc tcctacaact gcaaacagaa gaattaaaaa tacagaaaaa 3420attcagaatc aattttcatt atgggcttgg actgggaaaa atgtgaaata attcttacaa 3480gaccatgttc ccatggttga aaaactttat cagcaatatg ccaattacga catacgtgaa 3540aagtgaataa attgtctcct actaccttac caccaaggaa atatgtttcc aagtcatgca 3600tacaaaagag aatttcacaa tgagtaagga caggaggaag gaaaggagat taaatatgaa 3660gaggaaaaga ctaggaattc tgtgagaact tttaccatta actttagcat actgtaatat 3720ggaacagtaa cgaaattata gtggagagaa acaaaagttc tacaaaagtc tataagatga 3780atgaacttac attgtcagta attgacagca agttgaaacc tgagtcagaa tccaatctca 3840ttcttgctcg catgtctcga ccctgccttg ctgatgctgt ttagtgactt aagaaattaa 3900aagaatattt gtagtaaaat gagactcaga atcctagcct ctgtccaact attagaagcc 3960aacaggtcag ctgtgtcctt ttctaacaga tgagaaaact gagccccaga ggagagatgt 4020ttcgcccagc atcagagcct ttcaactcag agccagacct agaagatc 4068203949DNAChinese hamster 20tttccatcgc ctcatatctt cttcaatttc tttcttcaaa cacttaaagt ttttttaatt 60aaacaagtta gagttactag aatgtatttt atattatttg aagctattgt gattgctgct 120gcttctttta tttcattctc aagctgtttg ccatttttac ataggagggc taatggttgt 180tttagttact cttgtatccc gtcactttgc tgaaagtttt aatcacctgt acttccattg 240atgaattttt agtgtcactt aggtggtacc actatatcat caacaagtaa caacacttct 300acttcttcct ttccttgttg tcctttagct gtttaatggg tctatctaga acttcaagta 360ctgtattgag tagatataga cttcacaaac ttgtcaagtt acagatttta taggaattcc 420tttgtttttt ctctccattg tatttgatgt tgtctatagg tttgctgtaa atgtccttca 480ttatgtgtgt gtatgtaaat tgtatccata atatctccaa gacttttatg atgtttgttt 540cttgtcaatg actatttatt tatttattta tttattggtt tttcaagaca gggtttctcc 600gtgcagcttt gaagcctatc ctggcactcg ctctggagat caggctggcc ttgaactcac 660agtgatccac ctgcctctgc ctcccaagta ctgggattaa aggcatgcac ccccaatacc 720tggcttatca atgactttgt aagcatgtaa agggataata aaaaagtgtt ttttaaagtt 780tatttttatg gtggattaca gttactgatt tttgtatgtt gaaccatcac tgcgtatctg 840agatgaagcc tactggatca gtttgtatga caaagttact ctgtggcttt tggtcctggg 900actccctctg tagaccaggc tggcctcaaa ctcacataga tgcaactgcc tgtgtctccc 960aagtgctggt gttaatgcca tgtgccacca ctgcccggct ctttattcct ttttataact 1020caaatatttt gtaagtaact acagaaataa taggacacag aaaatgtagt actgcctagt 1080aataattgtt gataacctgg attctccctc tccctaggtt ctgtgcgacc tggccctgat 1140ccagctgcca atttctctcc tcccaccctg gtgttttctc ttgatctcca catgtcactc 1200cacatcagca ctctcctggg cctgttgctt ccttagagat cctttcctgg cctagtggcc 1260tctctaacac ttggattccc tccctgctct gggatccatc ttctcttctc ttttccaggt 1320gacctgccct tgccctggga tctgtttttc acaggtgatt gttccttgct gacatctcaa 1380agactgtcaa agtttgcatg gctgtgtggt gcatgtgtta attgactgaa ttaggattct 1440gcatacagag accatgtaaa tcttggccaa aggcagttca gtgactatgg tttcaaaggc 1500cccaactact gagcctcatt cttaactgtt tcctttccct ttataagcaa gtgcctccca 1560tctgttttct ctctttccat ttctgctccc tattggttaa cacctacccc tccctttatt 1620cccttttcca ataaactcca tgtggatttg ttgagtgtgt tggatcatgt tttatcaccc 1680aaatgcacag taaaagacaa caacaacagt atctttaaaa taactgtgaa tagtgtatct 1740attgagctag aaccataact caggttaaga gcacttcttg ttctatcata gtactacagt 1800tctatttctc tctcccaacc ctggtggctt tcacccacca gtaactacag ctcttagaga 1860acacaatttc tcctgatctc catgggctct tgcatatgca tgtacattta tacatataat 1920ttaaaataac taacacgcac acactcactc acatatatat aatttttgag acagtttttc 1980tctttgtaac cctggctatc tttctgctca gagatacttt tgcctatatc tacagggtgt 2040tgagattaaa tacttgaacc agtgctgcct gcgtaaattc ttttttaagt ttatttgatt 2100tcctgttgat taaaaagaaa tcccccaaaa tacatatcta aagacaagat ccagagtgca 2160atggtcaagt gtctttggct agactggagt tcactgctac agttcctctt ggacacctag 2220aataaaaact tggtatcagc agggactgtt agctcaagat taaactgcct gtaaatgcaa 2280gactatggag gctaaagctg ggagatattc agagtttgag cctagtctgg gcaacttagt 2340aagactcttt ctaaaataac caacaaaatg agaggcacag tgtcacacac ttgtcactca 2400gcacttagga attagcggct ggataatcaa gcctgcaagg tcctcttgtg ctatgtagag 2460agctcaagat gagtgtgcac tacatgaaat ctgtgtaaag aagaaagtag ccaacaaaaa 2520ctacacacca aaacagaacc aatgaaaact gtattgtctt tgatatctac ccatagtcac 2580tagagcttag gaagcaataa cctaaaagat tttaaaaaga gccaggcatt agtggtgcac 2640gcctttaatc ccagcactcg ggaggcagag gcatttgcat ctctgtgagt tagaggccag 2700cctgggcagc tttgaacagc atcaattgta gatgcaagat aaatgccatt aatacacagg 2760gaaaatctct aaaatgttgg gaagaaatca attcctagcc ctaacaagta ggtaacaatc 2820atcatccttt cattacaaat tcactttaaa attgggtagt gagttacctg tcaccatgat 2880ccagcaatcc cagctacccc agaggcttag acagtaaaat aggctacagt atacccagga 2940gctccagacc agccatgaca tcttcacaag aactaaaaaa aaattaaaaa ctaggggagc 3000tgttaggata tcagtcaggc aaatagatga accactacat cctcccttta ctcacaattg 3060ccttttgacg aatgcaatgg atgagagaat cacattgcac tgctagttcc cataaagacg 3120gctggactcc atcttggctc aagggcagag agttcataac tgtccttagg aaatcataaa 3180acctaaaggt caaaggtgtg gctacagtag gatattgcat catggcatgg ggtgtcttat 3240gctaaataaa aacagacttg gtctgagatg tgctgacacc tgtccctaaa gaacaggtaa 3300ctagaatttg aatctaaggt atggttacca aattggtgaa aaattcagca agaaaagagt 3360gtttgctttg tatgaaggaa ctcatgttca ccttttggtt aaggtatatg agagtggtga 3420gaaataaact tgtggtgttc agtattaact ggatctgccc tcctgatttt attctgtgtc 3480tttctaggct tcctttagtc cacactctcc ctttcaagaa caaacctcag gctgcttggt 3540tggctgccac tgcagctcca aaaagtcagc ttctcacatt gcacaagcat gtgaacttca 3600taaatctgct tgatagctta gcttccaatg tttaaatcca gtgaggtcta cttgattatt 3660tacaggctga taatccattg cattcagaat aatgaaaact agtgatggat cttcctgagg 3720tgcaaataat cccaaagcaa atgccaaagt gcctgcaagg taggaatgaa ctttatttcc 3780aaactgacag cagcagctgc tgtggtggaa gctggtgcac acactgtata acttgagagg 3840cagtcagctg gatctcctgt tgctaacagt gcgactgatg agagctgaca cccatcaatg 3900gagttagggc ctcactccga gatcaagtgt tgtggcagct acacagatc 3949211128DNAChinese hamster 21atggtcagac ccaggtgctc tggcagacag gtttcagtcc ctcccatgag gtgtcccatg 60tatgctcagt gagatgtcct tcacctctga cacctcagat acctcaccgg gttctctttg 120cagcagaaaa tagatgctaa caaattctgt tgatgaatcc atctgggcaa taagactcaa 180gggagccact tgcctacaca cctgaataga tgaagcaagc cctaccctac cctccaggta 240tctaaaacca ggattccaat aataaaatcc ttacaattca caggggagcc tgaatgtttt 300gatttacaat gtggcattga ttgtgttgga gaatatgggg ggaacaacta gtgcaccttg 360aaacatcact gctcaattgc agcattgcca aaatacccca gcagaacgca ttaggacaga 420gtgtctgtgg gacaggtcca tagtgcacat acatgacctc ccgactgaac tccctaggag 480catgtgacag tgaaggacag agaggcccag tgtatgctgc tgatgataaa gcttctgcac 540aacaaaatct gtcctttctg ccccctgcac gggacaaggg ccagttgtag agagtgcttg 600tgtcacaggg ctcctctagg cctctgtgtc ctggccacag atgggtgtgg accgcagcct 660cagggttctc atgacatgac ttctttcgtt attacatttg tttctctgtc tctgtctctg 720tctctgtctc tgtctctgtc tctctctctc tctctctctc tctctctctc tctctctctg 780tgtttatgtg tgtttgtaga ggttaaaagg tgctctgtag catttcttca aattggttta 840aatagtaaaa acgctgagtg agatgtcaga taattgggta aatgttgaga cataagagaa 900ttaaaggagc caactctata gggacttctt acctgtacca aatgttcaga tggaagtgct 960ggggaggtcc tgtctttaca aatcctctat atgaataagc ctaaatactg cctcctccag 1020ccttatactc ctgtctccac ctgaggtgcg agccacacgc acccagctct tatatctatc 1080agactggttg aatttcgtgt acctcagtgt ggccttgaac tcctgatc 1128221352DNAChinese hamster 22cttctgagta gtattgcatt gagacagcac tggatactgg aaatcttggg gatactgtta 60tgaactgagt gtctctcccc taaagctaag attgaaacta aaatctccaa tgtcttgtgc 120taatagtatt tgggtgtggg gttttagaat gtctttagaa ttacatgaaa tcatagggaa 180gagaacactt gtgatggaat tggcggcctt aaatgatgaa aaccatagac caagcctgga 240acacttgtcc tgtccttttg taacattctt gtcatgtgct gtcctctgat ttcttatgat 300actgcagaaa ggcatttgac agctgctggt gtcatgcttt tggacttccc agtttccaga 360gctgtgagcc aaatgtatct cttctttata aatctcccag cttatagcat tttgtttgtg 420gaaaacaaat agtcttagag aaataattat agattatcag tggccaagat actgatagaa 480gcatcaaaga ttattttaaa atgccaggcc agggagatgg ttcagagggt taagaggctt 540gctgccaagg ctaatgacct gagttctatc ccagaaacca catgcatagt ggaaggatag 600aaatgactcc cggaaagttg tcctttgttc tctgcacatg taccatggca tacacataca 660tatataacca gtaaggtgta gtaaaagtta gagtcaatgc gctatttttt atataaataa 720acataaggac acagcacacg cgcgagcaca catacacaca cacacacaca cacacacaaa 780aaaaaaaaaa aaaaatgaaa gtagaagagg gcctgctgag gaagagggtc ccagctggtt 840aggaaggagg atgacaatgg tattaaaggg tgaaaaatga cccaaattca ctatatactt 900acatgaatct gtcaaatcat ttaaaaagcc atgtattact gtattagttt cttgtctatt 960gttgtgataa aatgccatga actaaagcaa ctttaaaaag tttattttgg ttttcagttc 1020cagaggttcc tgagggggca ttcataatgg tgggagaggc atgtcagctg gtagccaaag 1080caggaagctg agggcctaga gagatggctc actagttaag agcactgact cctcttccag 1140aggactcaag ttcagttccc agccccacat ggcagctcac acctgtctgt agctccagtt 1200tcaggggacg caacacccat ggcaaaacat tgattaacat aaatataaaa tgaaaacctc 1260cagtttcagg gtatccgaca cccacgacaa aaaacatcaa tgggtataaa aataaaataa 1320aatactttta aaaagcagga agctgagaga tc

1352231246DNAChinese hamster 23ctggtacctt cttttcccag agtctataca agttaggaaa aacaggaaat gtgggaaaac 60aggagacagc tgaagctcag catctggcaa gacccaacag ggtccctctg ctaatgatgt 120tccctgagat ttgattctaa aacctcagat tctttaagtc atgaggtgac atcctcacct 180cagacttcta aatcacctgt gttctccttt ctacaaatgg gacaaacatc catccaacat 240tcaagtccaa aacctgagag tcatccttaa tttctctttt cctttttagc tccctaccga 300ttctttttca aaaatccacc ctttctctca atcttcacgt catcagtttt tagaaatagg 360tcatttctct ccctgagctt atcatctgcc tacatgaatc tgaactctca ttttaaaaat 420cacatgtaga gcttggcccc tgccttgagc ccgacttctg cctgtccact ctgggaactc 480ctgtcctggg gactgcaggc aaatcaactt gccccctgag gaccaagcaa cctcaagtct 540gatgacatca ctgtgctagt ccagttccca cccccaccta gagagggagt gccccagacc 600cgcctgaacc caccataaga cccatcagag tatcagaccc tcttgcatcc accaaagaga 660accttggacc catacacacc aggagaggaa gagacggcac ctgaacccac tggaagaaga 720gatgggaaga caacaatata aaaacgcatt caataacaga aaaaacaata tgacaccact 780agaatctagg gactctacgc cagcaagacc tgaacatccc aacacagatg aagcagaaga 840gaatgacttc tgcttgtact tgaagttcta tctggggcaa tatgacaaca aaaaggagaa 900caaggggata caaattggaa aggaagaagt caaattttta ctgtttgcag atgatatgat 960agttacataa gtaacccaaa aaactctacc agggaactac tacagctgat aaacaccttc 1020agctaagtgg aaggatacaa gattaactca aaaaatcact agccctatta tacacaggag 1080ataaatgggc tgagaaataa atcagagaaa catcatcctt tacaatagcc aaacaacata 1140aaatatcttg gggtaatgat aaccaaacaa gtgaaagacc tgtctagcaa gaactttgag 1200tcttaaaaga aagaaattaa agaagatacc agaaaatgga aagatc 1246

Claims

1.-20. (canceled)

21. A vector comprising a heterologous nucleotide sequence and a nucleotide sequence selected from the group consisting of (i) to (ii): (i) a sequence having at least 90% sequence identity with any of SEQ ID NOs: 3-9; and (ii) a sequence having at least 90% sequence identity with a reverse complementary sequence of any of SEQ ID NOs: 3-9.

22. The vector of claim 21, further comprising a nucleotide sequence selected from the group consisting of (iii) to (iv): (iii) a sequence having at least 80% sequence identity with SEQ ID NO: 13; and (iv) a sequence having at least 80% sequence identity with a reverse complementary sequence of SEQ ID NO: 13

23. The vector of claim 21, further comprising a CMV promoter.

24. The vector of claim 23, wherein the CMV promoter comprises a nucleotide sequence having at least 80% sequence identity with SEQ ID NO: 16.

25. The vector of claim 23, wherein the CMV promoter comprises a nucleotide sequence that is identical to SEQ ID NO: 16.

26. The vector of claim 22, wherein the nucleotide sequence selected from the group consisting of (iii) to (iv) has at least 90% sequence identity with SEQ ID NO: 13.

27. The vector of claim 22, wherein the nucleotide sequence selected from the group consisting of (iii) to (iv) is identical to SEQ ID NO: 13.

28. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 3.

29. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 4.

30. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 5.

31. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 6.

32. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 7.

33. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 8.

34. The vector of claim 21, wherein the nucleotide sequence selected from the group consisting of (i) to (ii) has at least 90% sequence identity to SEQ ID NO: 9.

35. The vector of claim 21, wherein the heterologous nucleotide sequence encodes one or more proteins, wherein the one or more proteins are selected from a group consisting of an antibody, a fusion protein, an enzyme, a soluble protein, a membrane protein, a structural protein, a ribosome protein, a zymogen, a cell surface receptor protein, a transcriptional regulatory protein, a translational regulatory protein, a chromatin protein, a hormone, a cell cycle regulatory protein, a G protein, a neuroactive peptide, an immunomodulatory protein, a blood component protein, an ion gate protein, a heat shock protein, a dihydrofolate reductase, an antibiotic resistance protein, and a fragment thereof.

36. A host cell comprising the vector of claim 21.

37. The host cell of claim 36, wherein the host cell is a Chinese hamster ovary (CHO) cell.

38. A method of preparing a host cell that stably expresses a protein, the method comprising: inserting into a host cell the vector of claim 21.

39. The method of claim 38, wherein the host cell is a Chinese hamster ovary (CHO) cell.

40. A method of preparing a protein, comprising: culturing the host cell of claim 36 under conditions for production of the protein.