WO2002020591A1 - A novel polypeptide-homo complement receptor 12 and polynucleotide encoding said polypeptide - Google Patents

Abstract

The invention discloses a new kind of polypeptide-HOMO complement receptor 12 and polynucleotide encoding said polypeptide and a process for producing said polypeptide by DNA recombinant methods. It also discloses the method of applying the polypeptide for the treatment of various kinds of diseases, such as cancer, hemopathy, HIV infection, immune disease and phlogosis, antagonist and the therapeutic use of the polypeptide is also disclosed. In addition, it refers to the use of polynucleotide encoding said HOMO complement receptor 12.

Description

 A new polypeptide-complement receptor 12-and a polynucleotide encoding the polypeptide TECHNICAL FIELD

 The present invention belongs to the field of biotechnology. Specifically, the present invention describes a novel polypeptide-complement receptor 12, and a polynucleotide sequence encoding the polypeptide. The invention also relates to a method and application for preparing such polynucleotides and polypeptides. Background technique

 Erythrocyte complement receptor (E-CR) is a protein that binds and regulates the C3b / C4b immune tolerance complex (UC), which affects the clearance efficiency of IC and tissue sedimentation, and provides assistance for human factor I-transduced cleavage Factor (Birmingham, D. et al 1990 FASEB J. 4: 2188) (Hebert, LA et al., 1991 Ara. J. Kidney Dis. 17: 353). Therefore, the E-CR1 system is an important person that provides safety protection for the IC cycle. E-CR belongs to complement receptor type I (CR1) (Fearon, D. T. et al., 1980 J. Exp. Med. 152: 20). The CR1 molecule is one of the regulators of C activation (RCA). RCA regulators are a group of C3b and C4b binding proteins that regulate RCA in their own tissues and circulation. Human CR1 is expressed in most peripheral blood cells, with almost more than 85% of the total circulating CR1 in red blood cells (Siegel, Let al., 1981 Lancet 2: 556). Human CR1 is a single-chain glycoprotein. According to the molecular weight, human CR1 protein can be divided into four allotypes, mainly A or F. Correspondingly, CR1 transcripts are divided into four types from 1.3KD to 1.5KD. CR1-A extracellular polypeptides consist of 30 repeat units, each repeat unit contains 59-76 amino acids, called short consensus repeats SCRs (Klickstein, LB et al., 1987 J. Exp. Med. 165 : 1095) (Hourcade, D. et al., 1988J. Exp. Med. L68: 1255). Of all the repeating units, every 7 repeating units have the highest homology, so these 7 repeating units are further defined as long homologous repeats (LHRs). The CR1-A type contains 4 LHRs, and the first two SCRs in most three N-terminal LHRs are specific binding sites for the ligand. SCRsl and SCRs2 mainly specifically combine C4b, SCRs8 and SCRs9, SCRsl5 and SCsR16 mainly specifically combine C3b (lickstein, L.B. et al., 1988 J. Exp. Med. 168: 1699).

Orangutan E-CR1 has 98.8% homology with human 220, OOOMr CR1. It may be another splicing form of human E-CR1 precursor mRNA. The 8 SCRs encoded by the orangutan E-CR1 gene are followed by a 24 amino acid hydrophobic region, followed by a stop code. The presence of this stop code in the C-terminal hydrophobic region indicates that the protein may be unstable, although these 24 amino acid sequences provide sufficient hydrophobic regions for complete membrane adhesion. (lein, P. et al., 1985 Biochira. Biophys. Acta. 815: 468) Orangutan E-CR1 head 6.5 SCRs are closest to human head 6.5 SCRs (Hourcade, D. etal., 1990 J. Biol. Chem. 265: 974).

 Gene chip analysis revealed that in the bladder mucosa, PMA + Ecv 304 cell line, LPS + Ecv 304 cell line thymus, normal fibroblasts 1024NC, Fi brob last, growth factor stimulation, 1024NT, scar-forming fc growth factor stimulation, 1013HT , Scar into fc without stimulation with growth factor, 1 01 3HC, bladder cancer cell EJ, bladder cancer, bladder cancer, liver cancer, liver cancer cell line, placenta, spleen, prostate cancer, jejunum adenocarcinoma, cardia cancer, The expression profile of the polypeptide of the present invention is very similar to the expression profile of the complement receptor, so the functions of the two may also be similar. The present invention is named complement receptor 12.

 As mentioned above, the complement receptor 12 protein plays an important role in regulating important functions of the body such as cell division and embryo development, and it is believed that a large number of proteins are involved in these regulatory processes, so there is always a need in the art to identify more complements that participate in these processes. Receptor 12 protein, especially the amino acid sequence of this protein is identified. Isolation of the gene encoding the new complement receptor 12 protein also provides the basis for research to determine the role of this protein in health and disease states. This protein may form the basis for the development of diagnostic and / or therapeutic drugs for diseases, so it is important to isolate its coding DNA. Disclosure of invention

 It is an object of the present invention to provide isolated novel polypeptides-complement receptor 12 and fragments, analogs and derivatives thereof.

 Another object of the invention is to provide a polynucleotide encoding the polypeptide.

 It is another object of the present invention to provide a recombinant vector containing a polynucleotide encoding complement receptor 12. Another object of the present invention is to provide a genetically engineered host cell containing a polynucleotide encoding complement receptor 12.

 Another object of the present invention is to provide a method for producing complement receptor 12.

 Another object of the present invention is to provide antibodies against the polypeptide-complement receptor 12 of the present invention.

 Another object of the present invention is to provide mimetic compounds, antagonists, agonists, and inhibitors directed to the polypeptide-complement receptor 12 of the present invention.

 Another object of the present invention is to provide a method for diagnosing and treating diseases related to abnormalities of complement receptor 12. The present invention relates to an isolated polypeptide, which is of human origin and comprises: a polypeptide having the amino acid sequence of SEQ ID No. 2, or a conservative variant, biologically active fragment or derivative thereof. Preferably, the polypeptide is a polypeptide having the amino acid sequence of SEQ ID NO: 2.

The invention also relates to an isolated polynucleotide comprising a nucleotide sequence or a variant thereof selected from the group consisting of: (a) a polynucleotide encoding a polypeptide having the amino acid sequence of SEQ ID No. 2;

 (b) a polynucleotide complementary to polynucleotide (a);

 (c) A polynucleotide having at least 70% identity to a polynucleotide sequence of (a) or (b).

 More preferably, the sequence of the polynucleotide is one selected from the group consisting of: (a) a sequence having positions 409-747 in SEQ ID NO: 1; and (b) a sequence having 1-1294 in SEQ ID NO: 1 Sequence of bits.

 The invention further relates to a vector, in particular an expression vector, containing the polynucleotide of the invention; a host cell genetically engineered with the vector, including a transformed, transduced or transfected host cell; and a method comprising culturing said Host cell and method of preparing the polypeptide of the present invention by recovering the expression product.

 The invention also relates to an antibody capable of specifically binding to a polypeptide of the invention.

 The invention also relates to a method for screening compounds that mimic, activate, antagonize or inhibit complement receptor 12 protein activity, which comprises utilizing the polypeptide of the invention. The invention also relates to compounds obtained by this method.

 The invention also relates to a method for detecting a disease or disease susceptibility related to abnormal expression of complement receptor 12 protein in vitro, which comprises detecting a mutation in the polypeptide or a polynucleotide sequence encoding the same in a biological sample, or detecting a mutation in a biological sample. The amount or biological activity of a polypeptide of the invention.

 The present invention also relates to a pharmaceutical composition comprising a polypeptide of the present invention or a mimetic thereof, an activator, an antagonist or an inhibitor, and a pharmaceutically acceptable carrier.

 The present invention also relates to the use of the polypeptide and / or polynucleotide of the present invention in the preparation of a medicament for treating cancer, developmental disease or immune disease or other diseases caused by abnormal expression of complement receptor 12.

 Other aspects of the invention will be apparent to those skilled in the art from the disclosure of the techniques herein.

 The following terms used in this specification and claims have the following meanings unless specifically stated: "Nucleic acid sequence" refers to an oligonucleotide, a nucleotide or a polynucleotide and a fragment or part thereof, and may also refer to a genomic or synthetic DNA or RNA, they can be single-stranded or double-stranded, representing the sense or antisense strand. Similarly, the term "amino acid sequence" refers to an oligopeptide, peptide, polypeptide or protein sequence and fragments or portions thereof. When the "amino acid sequence" in the present invention relates to the amino acid sequence of a naturally occurring protein molecule, such "polypeptide" or "protein" does not mean to limit the amino acid sequence to a complete natural amino acid related to the protein molecule .

A protein or polynucleotide "variant" refers to an amino acid sequence having one or more amino acids or nucleotide changes, or a polynucleotide sequence encoding it. The changes may include deletions, insertions or substitutions of amino acids or nucleotides in the amino acid sequence or nucleotide sequence. Variants may have "conservative" changes in which the substituted amino acid has a structural or chemical property similar to the original amino acid, such as replacing isoleucine with leucine. Variants can also have non-conservative changes, such as replacing glycine with tryptophan. "Deletion" refers to the deletion of one or more amino acids or nucleotides in an amino acid sequence or nucleotide sequence.

 "Insertion" or "addition" refers to an alteration in the amino acid sequence or nucleotide sequence that results in an increase in one or more amino acids or nucleotides compared to a naturally occurring molecule. "Replacement" refers to the replacement of one or more amino acids or nucleotides with different amino acids or nucleotides.

 "Biological activity" refers to a protein that has the structure, regulation, or biochemical function of a natural molecule. Similarly, the term "immunologically active" refers to the ability of natural, recombinant, or synthetic proteins and fragments thereof to induce a specific immune response and to bind specific antibodies in a suitable animal or cell.

 An "agonist" refers to a molecule that, when bound to complement receptor 12, causes a change in the protein to regulate the activity of the protein. An agonist may include a protein, a nucleic acid, a carbohydrate, or any other molecule that can bind the complement receptor 12.

 An "antagonist" or "inhibitor" refers to a molecule that, when bound to complement receptor 12, can block or modulate the biological or immunological activity of complement receptor 12. Antagonists and inhibitors may include proteins, nucleic acids, carbohydrates or any other molecule that can bind complement receptor 12.

 "Regulation" refers to a change in the function of complement receptor 12, including an increase or decrease in protein activity, a change in binding properties, and any other biological, functional, or immune properties of complement receptor 12.

 "Substantially pure '" means substantially free of other proteins, lipids, sugars or other substances with which it is naturally associated. Those skilled in the art can purify complement receptor 12 using standard protein purification techniques. Substantially pure Complement receptor 12 can generate a single main band on a non-reducing polyacrylamide gel. The purity of complement receptor 12 polypeptide can be analyzed by amino acid sequence.

 "Complementary" or "complementary" refers to the natural binding of a nucleotide by base-pairing under conditions of acceptable salt concentration and temperature. For example, the sequence "C-T-G-A" can be combined with the complementary sequence "G-A-C-T". The complementarity between two single-stranded molecules may be partial or complete. The degree of complementarity between nucleic acid strands has a significant effect on the efficiency and strength of hybridization between nucleic acid strands.

 "Homology" refers to the degree of complementarity and can be partially homologous or completely homologous. "Partial homology" refers to a partially complementary sequence that at least partially inhibits hybridization of a fully complementary sequence to a target nucleic acid. This inhibition of hybridization can be detected by performing hybridization (Sou thern blot or Nor thern blot, etc.) under conditions of reduced stringency. Substantially homologous sequences or hybridization probes can compete and inhibit the binding of completely homologous sequences to the target sequence under conditions of reduced stringency. This does not mean that the conditions of reduced stringency allow non-specific binding, because the conditions of reduced stringency require that the two sequences be combined with each other as a specific or selective interaction.

"Percent identity" means the sequence is the same or similar in the comparison of two or more amino acid or nucleic acid sequences Percentage. The percent identity can be determined electronically, such as by the MEGALIGN program (Lasergene sof tware package, DNASTAR, Inc., Madi son Wis.). The MEGALIGN program can compare two or more sequences based on different methods such as the Clus ter method (Higg ins, DG and PM Sharp (1988) Gene 73: 237-244). _{0 The} Clus ter method compares each pair by checking the distance between all pairs. Group sequences are arranged in clusters. The clusters are then assigned in pairs or groups. The percent identity between two amino acid sequences such as sequence A and sequence B is calculated by the following formula:

 Number of residues matching between sequence A and sequence X 100 Number of residues in sequence A-number of interval residues in sequence A-number of interval residues in sequence B

May be measured as Jotun He in the percentage of identity between nucleic acid sequences Clus ter or a method well known in the art (He in J., (1990) Methods in emzumo logy 183: 625-645) 0

"Similarity" refers to the degree of identical or conservative substitutions of amino acid residues at corresponding positions in the alignment of amino acid sequences. Amino acids used for conservative substitutions, for example, negatively charged amino acids may include aspartic acid and glutamic acid; positively charged amino acids may include lysine and arginine; having an uncharged head group is Similar hydrophilic amino acids may include leucine, isoleucine and valine; glycine and alanine; asparagine and glutamine; serine and threonine; phenylalanine and tyrosine.

 "Antisense" refers to a nucleotide sequence that is complementary to a particular DNA or RNA sequence. The "antisense strand" refers to a nucleic acid strand that is complementary to the "sense strand".

 "Derivative" refers to a chemical modification of HFP or a nucleic acid encoding it. Such a chemical modification may be the replacement of a hydrogen atom with an alkyl group, an acyl group or an amino group. Nucleic acid derivatives can encode polypeptides that retain the main biological characteristics of natural molecules.

"Antibody" refers to a complete antibody molecule and its fragments, such as Fa, F (ab ') ₂ and Fv, which can specifically bind to the epitope of complement receptor 12.

 A "humanized antibody" refers to an antibody in which the amino acid sequence of a non-antigen binding region is replaced to become more similar to a human antibody, but still retains the original binding activity.

 The term "isolated" refers to the removal of a substance from its original environment (for example, its natural environment if it occurs naturally). For example, a naturally occurring polynucleotide or polypeptide is not isolated when it is present in a living animal, but the same polynucleotide or polypeptide is separated from some or all of the substances that coexist with it in the natural system. Such a polynucleotide may be part of a vector, or such a polynucleotide or polypeptide may be part of a composition. Since the carrier or composition is not part of its natural environment, they are still isolated.

As used herein, "isolated" refers to the separation of a substance from its original environment (if natural Material, the original environment is the natural environment). For example, polynucleotides and polypeptides in a natural state in a living cell are not isolated and purified, but the same polynucleotides or polypeptides are separated and purified if they are separated from other substances existing in the natural state. .

 As used herein, "isolated complement receptor 12" means that complement receptor 12 is substantially free of other proteins, lipids, carbohydrates, or other substances with which it is naturally associated. Those skilled in the art can purify complement receptor 12 using standard protein purification techniques. Substantially pure polypeptides can produce a single main band on a non-reducing polyacrylamide gel. The purity of the complement receptor 12 polypeptide can be analyzed by amino acid sequence.

 The present invention provides a new polypeptide-complement receptor 12, which basically consists of the amino acid sequence shown in SEQ ID NO: 2. The polypeptide of the present invention may be a recombinant polypeptide, a natural polypeptide, or a synthetic polypeptide, and preferably a recombinant polypeptide. The polypeptides of the present invention may be naturally purified products or chemically synthesized products, or produced using recombinant techniques from prokaryotic or eukaryotic hosts (eg, bacteria, yeast, higher plants, insects, and mammalian cells). Depending on the host used in the recombinant production protocol, the polypeptide of the invention may be glycosylated, or it may be non-glycosylated. Polypeptides of the invention may also include or exclude starting methionine residues.

 The invention also includes fragments, derivatives and analogs of complement receptor 12. As used herein, the terms "fragment", "derivative" and "analog" refer to a polypeptide that substantially maintains the same biological function or activity of the complement receptor 12 of the present invention. The fragment, derivative or analog of the polypeptide of the present invention may be: (I) a kind in which one or more amino acid residues are substituted with conservative or non-conservative amino acid residues (preferably conservative amino acid residues), and the substitution The amino acid may or may not be encoded by a genetic codon; or (Π) such a type in which a group on one or more amino acid residues is substituted by another group to include a substituent; or (III) such A type in which a mature polypeptide is fused to another compound (such as a compound that extends the half-life of a polypeptide, such as polyethylene glycol); or (IV) a type of polypeptide sequence in which an additional amino acid sequence is fused into a mature polypeptide ( Such as the leader sequence or secreted sequence or the sequence used to purify this polypeptide or protease sequence) As explained herein, such fragments, derivatives and analogs are considered to be within the knowledge of those skilled in the art.

 The present invention provides an isolated nucleic acid (polynucleotide), which basically consists of a polynucleotide encoding a polypeptide having the amino acid sequence of SEQ ID NO: 2. The polynucleotide sequence of the present invention includes a nucleotide sequence of SEQ ID NO: 1. The polynucleotide of the present invention is found from a cDNA library of human fetal brain tissue. It contains a full-length nucleotide sequence of 1294 bases, and its open reading frame of 409-747 encodes 112 amino acids. According to the comparison of gene chip expression profiles, it was found that this polypeptide has a similar expression profile as the complement receptor, and it can be inferred that the complement receptor 12 has a similar function as the complement receptor.

The polynucleotide of the present invention may be in the form of DNA or RNA. DNA forms include cDNA, genomic DNA, or synthetic DNA. DNA can be single-stranded or double-stranded. DNA can be coding or non-coding Code chain. The coding region sequence encoding a mature polypeptide may be the same as the coding region sequence shown in SEQ ID NO: 1 or a degenerate variant. As used in the present invention, a "degenerate variant" refers to a nucleic acid sequence encoding a protein or polypeptide having SEQ ID NO: 2 but different from the coding region sequence shown in SEQ ID NO: 1 in the present invention.

 The polynucleotide encoding the mature polypeptide of SEQ ID NO: 2 includes: only the coding sequence of the mature polypeptide; the coding sequence of the mature polypeptide and various additional coding sequences; the coding sequence of the mature polypeptide (and optional additional coding sequences); Coding sequence.

 The term "polynucleotide encoding a polypeptide" refers to a polynucleotide that includes the polypeptide and a polynucleotide that includes additional coding and / or non-coding sequences.

 The invention also relates to variants of the polynucleotides described above, which encode polypeptides or fragments, analogs and derivatives of polypeptides having the same amino acid sequence as the invention. This polynucleotide variant can be a naturally occurring allelic variant or a non-naturally occurring variant. These nucleotide variants include substitution variants, deletion variants, and insertion variants. As known in the art, an allelic variant is an alternative form of a polynucleotide that may be a substitution, deletion, or insertion of one or more nucleotides, but does not substantially change the function of the polypeptide it encodes .

 The invention also relates to a polynucleotide that hybridizes to the sequence described above (having at least 50%, preferably 70% identity between the two sequences). The present invention particularly relates to polynucleotides that can hybridize to the polynucleotides of the present invention under stringent conditions. In the present invention, "strict conditions" means: (1) hybridization and elution at lower ionic strength and higher temperature, such as 0.2xSSC, 0.1% SDS, 60 ° C; or (2) Add a denaturant during hybridization, such as 50 ° /. (V / v) formamide, 0.1 ° /. Calf serum / 0.1 ° /. F i co l l, 42 ° C, etc .; or (3) hybridization occurs only when the identity between the two sequences is at least 95% or more, and more preferably 97% or more. Moreover, the polypeptide encoded by the hybridizable polynucleotide has the same biological function and activity as the mature polypeptide shown in SEQ ID NO: 2.

 The invention also relates to nucleic acid fragments that hybridize to the sequences described above. As used in the present invention, a "nucleic acid fragment" contains at least 10 nucleotides in length, preferably at least 20-30 nucleotides, more preferably at least 50-60 nucleotides, most preferably at least 100 nucleotides. Nucleotides or more. Nucleic acid fragments can also be used in nucleic acid amplification techniques, such as PCR, to identify and / or isolate polynucleotides encoding complement receptor 12.

 The polypeptides and polynucleotides in the present invention are preferably provided in an isolated form and are more preferably purified to homogeneity.

 The specific polynucleotide sequence encoding the complement receptor 12 of the present invention can be obtained by various methods. For example, polynucleotides are isolated using hybridization techniques well known in the art. These techniques include, but are not limited to: 1) hybridization of probes to genomic or cDNA libraries to detect homologous polynucleotide sequences, and 2) antibody screening of expression libraries to detect cloned polynucleosides with common structural characteristics Acid fragments.

The DNA fragment sequence of the present invention can also be obtained by the following methods: 1) Isolation of double-stranded DNA from genomic DNA Sequence; 2) chemically synthesize a DNA sequence to obtain double-stranded DNA of the polypeptide.

 Of the methods mentioned above, genomic DNA isolation is the least commonly used. Direct chemical synthesis of DNA sequences is the method of choice. The more commonly used method is the isolation of cDNA sequences. The standard method for isolating the cDNA of interest is to isolate mRNA from donor cells that overexpress the gene and perform reverse transcription to form a plasmid or phage cDNA library. Various methods have been developed for mRNA extraction, and kits are also commercially available (Qiagene;). The construction of cDNA libraries is also a common method (Sambrook, et al., Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory. New York, 1989). Commercially available cDNA libraries are also available, such as different cDNA libraries from Clontech. When combined with polymerase reaction technology, even very small expression products can be cloned.

 The genes of the present invention can be selected from these cDNA libraries by conventional methods. These methods include (but are not limited to): (1) DNA-DNA or DNA-RNA hybridization; (2) the presence or absence of marker gene functions; (3) determining the level of complement receptor 12 transcripts; (4) passing Immunological techniques or assays for biological activity to detect gene-expressed protein products. The above methods can be used singly or in combination.

 In the method (1), the probe used for hybridization is homologous to any part of the polynucleotide of the present invention, and its length is at least 10 nucleotides, preferably at least 30 nucleotides, more preferably At least 50 nucleotides, preferably at least 100 nucleotides. In addition, the length of the probe is usually within 2,000 nucleotides, preferably within 1000 nucleotides. The probe used here is generally a DNA sequence chemically synthesized based on the gene sequence information of the present invention. The genes or fragments of the present invention can of course be used as probes. DNA probes can be labeled with radioisotopes, luciferin, or enzymes (such as alkaline phosphatase).

 In the (4) method, the protein product of complement receptor 12 gene expression can be detected using immunological techniques such as

Western blot, radioimmunoprecipitation, enzyme-linked immunosorbent assay (ELISA), etc.

 A method using PCR technology to amplify DNA / RM (Saiki, et al. Science 1985; 230: 1350-1354) is preferably used to obtain the gene of the present invention. In particular, when it is difficult to obtain full-length cDNA from a library, the RACE method (RACE-rapid cDNA end rapid amplification method) may be preferably used. The primers for PCR may be appropriately based on the polynucleotide sequence information of the present invention disclosed herein. Select and synthesize using conventional methods. The amplified DNA / RM fragments can be isolated and purified by conventional methods such as by gel electrophoresis.

 The polynucleotide sequence of the gene of the present invention or various DNA fragments and the like obtained as described above can be determined by a conventional method such as dideoxy chain termination method (Sanger et al. PNAS, 1977, 74: 5463-5467). Such polynucleotide sequences can also be determined using commercial sequencing kits. In order to obtain the full-length cDNA sequence, sequencing must be repeated. Sometimes it is necessary to determine the cDNA sequence of multiple clones in order to splice into a full-length cDNA sequence.

The present invention also relates to a vector comprising the polynucleotide of the present invention, and a host cell produced by genetic engineering using the vector of the present invention or directly using a complement receptor 12 coding sequence, and the production of the present invention by recombinant technology Said method of polypeptide.

 In the present invention, a polynucleotide sequence encoding the complement receptor 12 may be inserted into a vector to constitute a recombinant vector containing the polynucleotide of the present invention. The term "vector" refers to bacterial plasmids, phages, yeast plasmids, plant cell viruses, mammalian cell viruses such as adenoviruses, retroviruses, or other vectors well known in the art. Vectors suitable for use in the present invention include, but are not limited to: T7 promoter-based expression vectors expressed in bacteria (Rosenberg, et al. Gene, 1987, 56: 125); pMSXND expression vectors expressed in mammalian cells (Lee and Na thans, J Bi o Chera. 263: 3521, 1988) and baculovirus-derived vectors expressed in insect cells. In short, as long as it can be replicated and stabilized in the host, any plasmid and vector can be used to construct a recombinant expression vector. An important feature of expression vectors is that they usually contain an origin of replication, a promoter, a marker gene, and translational regulatory elements.

 Methods known to those skilled in the art can be used to construct expression vectors containing a DNA sequence encoding complement receptor 12 and appropriate transcriptional / translational regulatory elements. These methods include in vitro recombinant DNA technology, DNA synthesis technology, in vivo recombination technology, and the like (Sambroook, et al. Molecular Cloning, Labora tory Manua, cold Harbor Labora tory. New York, 1989). The DNA sequence [J can be operably linked to an appropriate promoter in an expression vector to guide mRNA synthesis. Representative examples of these promoters are: the lac or trp promoter of E. coli; the PL promoter of lambda phage; eukaryotic promoters include the CMV immediate early promoter, the HSV thymidine kinase promoter, and the early and late SV40 promoters , Retroviral LTRs and other known promoters that control the expression of genes in prokaryotic or eukaryotic cells or their viruses. The expression vector also includes a ribosome binding site and a transcription terminator for translation initiation. Insertion of enhancer sequences into the vector will enhance its transcription in higher eukaryotic cells. Enhancers are cis-acting factors for DNA expression, usually about 10 to 300 base pairs, which act on promoters to enhance gene transcription. Examples include 100 to 270 base pair SV40 enhancers on the late side of the origin of replication, polyoma enhancers and adenoviral enhancers on the late side of the origin of replication.

 In addition, the expression vector preferably contains one or more selectable marker genes to provide phenotypic traits for selection of transformed host cells, such as dihydrofolate reductase, neomycin resistance, and green for eukaryotic cell culture. Fluorescent protein (GFP), or tetracycline or ampicillin resistance for E. coli.

 Those of ordinary skill in the art will know how to select appropriate vector / transcription regulatory elements (such as promoters, enhancers, etc.) and selectable marker genes.

In the present invention, the polynucleotide encoding the complement receptor 12 or the recombinant vector containing the polynucleotide can be transformed or transduced into a host cell to constitute a genetically engineered host cell containing the polynucleotide or the recombinant vector. The term "host cell" refers to a prokaryotic cell, such as a bacterial cell; or a lower eukaryotic cell, such as a yeast cell; or a higher eukaryotic cell, such as a mammalian cell. Representative examples are: E. coli, Streptomyces; fine Bacterial cells such as Salmonella typhimurium; fungal cells such as yeast; plant cells; insect cells such as fly S2 or Sf9; animal cells such as CH0, COS or Bowes melanoma cells.

Transformation of a host cell with a DNA sequence described in the present invention or a recombinant vector containing the DNA sequence can be performed using conventional techniques well known to those skilled in the art. When the host is a prokaryote such as E. coli, competent cells capable of DNA uptake can be in the exponential growth phase were harvested, treated with CaC l ₂ method used in steps well known in the art. The alternative is to use MgC l ₂ . If necessary, transformation can also be performed by electroporation. When the host is a eukaryotic organism, the following DM transfection methods can be used: calcium phosphate co-precipitation method, or conventional mechanical methods such as microinjection, electroporation, and liposome packaging.

 Using conventional recombinant DNA technology, the polynucleotide sequence of the present invention can be used to express or produce recombinant complement receptors 12 (Scence, 1984; 224: 1431). Generally there are the following steps:

 (1) using the polynucleotide (or variant) encoding the human complement receptor 12 of the present invention, or transforming or transducing a suitable host cell with a recombinant expression vector containing the polynucleotide;

 (2) culturing host cells in a suitable medium;

 (3) Isolate and purify protein from culture medium or cells.

 In step (2), the medium used in the culture may be selected from various conventional mediums according to the host cells used. Culture is performed under conditions suitable for host cell growth. After the host cells have grown to an appropriate cell density, the selected promoter is induced by a suitable method (such as temperature conversion or chemical induction), and the cells are cultured for a period of time.

 In step (3), the recombinant polypeptide may be coated in a cell, expressed on a cell membrane, or secreted outside the cell. If necessary, recombinant proteins can be isolated and purified by various separation methods using their physical, chemical, and other properties. These methods are well known to those skilled in the art. These methods include, but are not limited to: conventional renaturation treatment, protein precipitant treatment (salting out method), centrifugation, osmotic disruption, ultrasonic treatment, ultracentrifugation, molecular sieve chromatography (gel filtration), adsorption chromatography, ion Exchange chromatography, high performance liquid chromatography (HPLC), and various other liquid chromatography techniques and combinations of these methods.

Brief description of the drawings

 The following drawings are used to illustrate specific embodiments of the present invention, but not to limit the scope of the present invention as defined by the claims.

 Fig. 1 is a comparison diagram of gene chip expression profiles of complement receptor 12 and complement receptor of the present invention. Pictured above is the complement receptor

Figure 12 shows a graph of the complement of the complement receptor. Among them, 1-bladder mucosa, 2-PMA + Ecv304 cell line, 3-LPS + Ecv304 cell line thymus, 4-normal fibroblasts 1 024NC, 5-Fibroblas t, growth factor stimulation, 1024NT, 6- scar into fc growth factor stimulation, 1013HT, 7- scar into fc without growth factor stimulation, 1013HC, 8-bladder cancer cell EJ, 9-bladder cancer, 10-bladder cancer, 11-liver cancer, 12-liver cancer cell line, 13-fetal skin, 14-spleen, 15-prostate cancer, 16-jejunum adenocarcinoma, 17 cardia cancer.

 Figure 2 shows the polyacrylamide gel electrophoresis (SDS-PAGE) of isolated complement receptor 12. 12kDa is the molecular weight of the protein. The arrow indicates the isolated protein band. The best way to implement the invention

 The present invention is further described below with reference to specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In the following examples, the experimental methods without specific conditions are generally described in accordance with the general conditions such as those described in Sambrook et al., Molecular Cloning: Laboratory Manual (New York: Cod Harbor Harbor Labora tory Pres s, 1989), Or as recommended by the manufacturer. Example 1: Cloning of complement receptor 12

Total human fetal brain RNA was extracted by one-step method with guanidine isothiocyanate / phenol / chloroform. Poly (A) mRNA was isolated from total RNA using Quik raRNA I solat ion Kit (product of Qiegene). 2ug poly (A) mRNA is reverse transcribed to form cDNA. The Smart cDNA cloning kit (purchased from Clontech) was used to insert the cDNA fragment into the multiple cloning site of the pBSK (+) vector (Clontech) to transform DH5α to form a cDNA library. Dye terminate cycle react ion sequencing kit (Perkin-Elmer) and ABI 377 automatic sequencer (Perkin-Elmer) were used to determine the sequences at the 5 'and 3' ends of all clones. The determined cDNA sequence was compared with the existing public DM sequence database (Genebank), and it was found that the cDNA sequence of one of the clones 0749 _g 07 was new DNA. A series of primers were synthesized to determine the inserted cDNA fragments of the clone in both directions. The results showed that the full-length cDNA contained in the 0749g07 clone was 1294bp (as shown in Seq ID N0: 1), and there was a 339bp open reading frame (0RF) from 409bp to 747bp, encoding a new protein (such as Seq ID N0 : Shown in 2). We named this clone _P BS-0749g07, and the encoded protein was named complement receptor 12. Example 2: Cloning of a gene encoding complement receptor 12 by RT-PCR

 CDNA was synthesized using fetal brain total RNA as a template and ol igo-dT as a primer for reverse transcription reaction. After purification using Qiagene's kit, the following primers were used for PCR amplification:

 Pr iraerl: 5,-GTCTATAAATATGATAAGCAAGTG -3, (SEQ ID NO: 3)

 Pr imer 2: 5'- CTGAATTGAATGTCTTTAATTTCA -3 '(SEQ ID NO: 4)

 Primerl is a forward sequence located at the 5th end of SEQ ID NO: 1, starting at lbp;

Pr imer2 is the 3′-end reverse sequence in SEQ ID NO: 1. Amplification reaction conditions: 50 mmol / L KC1, 10 crypto ol / L Tris-Cl, (pH8.5), 1.5 mmol / L MgCl ₂₎ 200 μ mol / L dNTP, lOpmol in a reaction volume of 50 μ 1 Primer, 1U Taq DNA polymerase (Clontech). The reaction was performed on a PE9600 DM thermal cycler (Perkin-Elmer) under the following conditions for 25 cycles: 94 ° C 30sec; 55 ° C 30sec; 72 ° C 2min. During RT-PCR, β-actin was set as a positive control and template blank was set as a negative control. The amplified product was purified using a QIAGEN kit and ligated to a PCR vector (Invitrogen product) using a TA cloning kit. DM sequence analysis results showed that the DNA sequence of the PCR product was exactly the same as that of 1 to 1294bp shown in SEQ ID NO: 1. Example 3: Northern blot analysis of complement receptor 12 gene expression:

Total RNA extraction in one step [Anal. Biochem 1987, 162, 156-159] ₀ This method involves acid guanidinium thiocyanate-chloroform extraction. That is, the tissue is homogenized with 4M guanidinium isothiocyanate-25mM sodium citrate, 0.2M sodium acetate (pH4.0), and 1 volume of phenol and 1/5 volume of chloroform-isoamyl alcohol (49: 1 ), Centrifuge after mixing. The aqueous layer was aspirated, isopropanol (0.8 vol) was added and the mixture was centrifuged to obtain RNA precipitate. The resulting RNA pellet was washed with 70% ethanol, dried and dissolved in water. Using 20 μ _§ RNA, electrophoresis was performed on a 1.2% agarose gel containing 20 mM 3- (N-morpholino) propanesulfonic acid (pH 7.0)-5 mM sodium acetate-1 mM EDTA-2.2M formaldehyde. It was then transferred to a nitrocellulose membrane. Preparation ³² P- DNA probe labeled with a- ³² P dATP by random priming method. The DNA probe used was the PCR-amplified complement receptor 12 coding region sequence (409bp to 747bp) shown in FIG. 1. The 32P- labeled probes (about 2 x l0 ⁶ cpm / ml) and RNA was transferred to nitrocellulose membrane 42 ^D C hybridized overnight in a solution, the solution comprising 50% formamide - 25raM KH ₂ P0 ₄ (pH 7.4)-5 x SSC-5 x Denhardt's solution was hybridized with 200 μg / ml salmon sperm DN ', and the filter was washed in 1 x SSC-0.1% SDS at 55 ° C for 30 min. Then, Phosphor Imager was used for analysis and quantification. Example 4: In vitro expression, isolation and purification of recombinant complement receptor 12

 Based on SEQ ID NO: 1 and the coding region sequence shown in Figure 1, a pair of specific amplification primers was designed, the sequence is as follows:

 Primer3: 5 '-CATGCTAGCATGTCATCACAGTGCCTAGAAACT-3' (Seq ID No: 5)

Primer4: 5'-CATGGATCCTTAAAAAAAGGAAGAAAAAGAAAG-3 '(Seq ID No: 6) The 5' ends of these two primers contain Nhel and BamHI digestion sites, respectively, followed by the coding sequences of the 5 'and 3' ends of the target gene, respectively. Nhel and BamHI restriction sites correspond to selective endonuclease sites on the expression vector plasmid pET-28b (+) (Novagen, Cat. No. 69865.3). The PCR reaction was performed using the pBS-0749 _g 07 plasmid containing the full-length target gene as a template. The PCR reaction conditions are as follows: a total volume of 50μ1, containing 10 pg of pBS-0749g07 plasmid, primers? 1 ^ 0161 "-3 and 卩: 1: 111161: -4 min! Also for 1 (^ 11101, Advantage polymerase Mix (Clontech) Product) 1 μ 1. Cycle parameters: 94 ° C 20s, 60 ° C 30s, 68. C 2 min, a total of 25 cycles. Nhel and BamHI were used to double-digest the amplified product and plasmid pET-28 (+), respectively, and large fragments were recovered and ligated with T4 ligase. The ligation product was transformed into E. coli DH5a by the calcium chloride method, cultured overnight in LB plates containing kanamycin (final concentration 30 μ § / πι1), and positive clones were selected by colony PCR method and sequenced. A positive clone (pET-0749gO7) with the correct sequence was selected, and the recombinant plasmid was transformed into E. coli BL21 (DE3) plySs (product of Novagen) by the calcium chloride method. In LB liquid medium containing kanamycin (final concentration 30 g / ml), the host strain BL21 (pET-0749g07) was at 37. C. Cultivate to logarithmic growth phase, add IPTG to a final concentration of 1 ol / L, and continue to cultivate for 5 hours. The bacteria were collected by centrifugation, and the supernatant was collected by centrifugation. The supernatant was collected by centrifugation. Chromatography was performed using an affinity chromatography column His s. Bind Quick Cartridge (product of Novagen) capable of binding to 6 histidines (6His-Tag). The purified protein complement receptor 12 was obtained. After SDS-PAGE electrophoresis, a single band was obtained at 12 kDa (Figure 2). The band was transferred to a PVDF membrane and the N-terminal amino acid sequence was analyzed by the Edams hydrolysis method. As a result, the 15 amino acids at the N-terminus were identical to the 15 amino acid residues at the N-terminus shown in SEQ ID NO: 2. Example 5 Production of anti-complement receptor 12 antibodies

 A peptide synthesizer (product of PE company) was used to synthesize the following complement receptor 12-specific peptides:

 NH2-Met-Ser-Ser-Gln-Cys-Leu-Glu-Thr-Arg-Thr-Val-I le-Tyr-Arg-Ser-C00H (SEQ ID NO: 7). The polypeptide is coupled to hemocyanin and bovine serum albumin to form a complex, respectively. For the method, see: Avraraeas, et al. Immunochemi s try, 1969; 6: 43. Rabbits were immunized with 4 mg of the hemocyanin-polypeptide complex with complete Freund's adjuvant. After 15 days, the rabbits were immunized with hemocyanin-polypeptide complex and incomplete Freund's adjuvant once. A titer plate coated with a 15 μg / ml bovine serum albumin peptide complex was used as an ELISA to determine the antibody titer in rabbit serum. Protein A-Sepharose was used to isolate total IgG from antibody-positive rabbit serum. The peptide was bound to a Sepharos B column activated by cyanogen bromide, and the anti-peptide antibody was separated from the total IgG by affinity chromatography. The immunoprecipitation method demonstrated that the purified antibody specifically binds to complement receptor 12. Example 6: Application of the polynucleotide fragment of the present invention as a hybridization probe

 Suitable oligonucleotide fragments selected from the polynucleotides of the present invention are used as hybridization probes in a variety of ways. For example, the probes can be used to hybridize to genomic or cDNA libraries of normal tissue or pathological tissue from different sources to It is determined whether it contains the polynucleotide sequence of the present invention and a homologous polynucleotide sequence is detected. Further, the probe can be used to detect the polynucleotide sequence of the present invention or its homologous polynucleotide sequence in normal tissues or Whether the expression in tissue cells is abnormal.

The purpose of this embodiment is to select a suitable oligonucleotide fragment from the polynucleotide SEQ ID NO: 1 of the present invention as a hybridization probe, and to identify whether some tissues contain the polynucleoside of the present invention by using a filter hybridization method. Sour Sequence or a homologous polynucleotide sequence thereof. Filter hybridization methods include dot blotting, Southern blotting, Northern blotting, and copying methods. They are all used to fix the polynucleotide sample to be tested on the filter and then hybridize using basically the same steps. These same steps are as follows: The sample-immobilized filter is first pre-hybridized with a probe-free hybridization buffer, so that the non-specific binding site of the sample on the filter is saturated with the carrier and the synthetic polymer. The pre-hybridization solution is then replaced with a hybridization buffer containing the labeled probe and incubated to hybridize the probe to the target nucleic acid. After the hybridization step, the unhybridized probes are removed by a series of membrane washing steps. This embodiment utilizes higher-intensity washing conditions (such as lower salt concentration and higher temperature) to reduce the hybridization background and retain only strong specific signals. The probes used in this embodiment include two types: the first type of probes are oligonucleotide fragments that are completely the same as or complementary to the polynucleotide SEQ ID NO: 1 of the invention; the second type of probes are partially related to the invention The polynucleotide SEQ ID NO: 1 is the same or complementary oligonucleotide fragment. In this embodiment, the dot blot method is used to fix the sample on the filter membrane. Under the high-intensity washing conditions, the first type of probe and the sample have the strongest hybridization specificity and are retained.

First, the selection of the probe

 The selection of oligonucleotide fragments from the polynucleotide SEQ ID NO: 1 of the present invention for use as hybridization probes should follow the following principles and several aspects to be considered:

 1. The preferred range of probe size is 18-50 nucleotides;

 2.The GC content is 30% -70%, and the non-specific hybridization increases when it exceeds;

 3, there should be no complementary regions inside the probe;

 4. Those that meet the above conditions can be used as primary selection probes, and then further computer sequence analysis, including the primary selection probe and its source sequence region (ie, SEQ ID NO: 1) and other known genomic sequences and their complements The region is compared for homology. If the homology with the non-target molecule region is greater than 85% or there are more than 15 consecutive bases, then the primary probe should not be used;

5. Whether the preliminary selection probe is finally selected as a probe with practical application value should be further determined by experiments.

 After completing the above analysis, select and synthesize the following two probes:

 Probe 1 (probel), which belongs to the first class of probes, is completely homologous or complementary to the gene fragment of SEQ ID NO: 1 (41Nt):

 5'-TGTCATCACAGTGCCTAGAAACTCGAACTGTAATATATCGT-3 '(SEQ ID NO: 8)

 Probe 2 (probe2), which belongs to the second type of probe, is equivalent to the replacement mutant sequence (right) of the gene fragment of SEQ ID NO: 1 or its complementary fragment:

5'-TGTCATCACAGTGCCTAGAACCTCGAACTGTAATATATCGT-3 '(SEQ ID NO: 9) For other commonly used reagents and their preparation methods not related to the following specific experimental steps, please refer to the literature: DNA PROBES GH Keller; MM Manak; S tockton Pres s , 1989 (USA) and more commonly used points Books on subcloning experiment manuals such as "Guide to Molecular Cloning Experiments" (Second Edition, 1998) [US] Sambrook and others, Science Press.

 Sample Preparation:

 1.Extract DNA from fresh or frozen tissue

 Steps: 1) Place fresh or freshly thawed normal liver tissue in ice and hold phosphate buffered saline

(PBS). Cut the tissue into small pieces with scissors or a scalpel. Keep tissue moist during operation. 2) Centrifuge the tissue at 1,000 g for 10 minutes. 3) Suspend the precipitate (about 10 ml / g) with cold homogenization buffer (0.25 mol / L sucrose; 25 ramol / L Tris-HCl, pH 7.5; 25 legs ol / LnaCl; 25 sides ol / L MgCl ₂ ). 4) 'Homogenize the tissue suspension at 4 ° C at full speed with an electric homogenizer until the tissue is completely broken. 5) Centrifuge at 1000g for 10 minutes. 6) Resuspend the cell pellet (1 to 5 ml per 0.1 g of the original tissue sample), and centrifuge at 1,000 g for 10 minutes. 7) Resuspend the pellet with lysis buffer (add 1 ml per 0.1 g of the initial tissue sample), and then follow the following phenol extraction method.

 2, DNA phenol extraction method

Steps: 1) Wash the cells with 1-10 ml of cold PBS and centrifuge at 1000 g for 10 minutes. 2) Resuspend the pelleted cells (1 × 10 ⁸ cells / ml) with cold cell lysate and apply a minimum of 100ul lysis buffer. 3) Add SDS to a final concentration of 1%. If SDS is directly added to the cell pellet before resuspending the cells, the cells may form large clumps that are difficult to break, and reduce the overall yield. This is particularly serious when extracting> 10 ⁷ cells. 4) Add proteinase K to a final concentration of 200ug / ml. 5) Incubate at 50 ° C for 1 hour or shake gently at 37 ° C overnight. 6) Extract with an equal volume of phenol: chloroform: isoamyl alcohol (25: 24: 1) and centrifuge in a small centrifuge tube for 10 minutes. The two should be clearly separated, otherwise centrifuge again. 7) Transfer the water phase to a new tube. 8) Extract with an equal volume of chloroform: isoamyl alcohol (24: 1) and centrifuge for 10 minutes. 9) Transfer the DNA-containing aqueous phase to a new tube. The DNA was then purified and ethanol precipitated.

 3.Purification and ethanol precipitation of DM

Steps: 1) Add 10 volume of 2mol / L sodium acetate and 2 volumes of cold 100% ethanol to the DNA solution and mix. Leave at -20 ° C for 1 hour or overnight. 2) Centrifuge for 10 minutes. 3) Carefully aspirate or pour out the ethanol. 4) Wash the pellet with 500ul of 70% cold ethanol and centrifuge for 5 minutes. 5) Carefully aspirate or pour out the ethanol. Wash the pellet with 500ul of cold ethanol and centrifuge for 5 minutes. 6) Carefully aspirate or pour out the ethanol, then invert on the absorbent paper to drain the residual ethanol. Air-dry for 10-15 minutes to evaporate the surface ethanol. Be careful not to allow the pellet to dry completely, otherwise it will be more difficult to re-dissolve. 7) Resuspend the DNA pellet in a small volume of TE or water. Low-speed vortexing or pipetting, with a dropper, while gradually increasing the TE, mixed until fully dissolved DNA, ¹⁰⁶ cells per 1-5 χ extracted plus about lul.

 The following steps 8-13 are only used when contamination must be removed, otherwise step 14 can be performed directly.

8) Add RNase A to the DNA solution to a final concentration of 100ug / ml, and incubate at 37 ° C for 30 minutes. 9) Join The final concentrations of SDS and proteinase K were 0.5% and 100ug / ml. Incubate at 37 ° C for 30 minutes. 10) Extract the reaction solution with an equal volume of phenol: chloroform: isoamyl alcohol (25: 24: 1) and centrifuge for 10 minutes. 11) Carefully remove the aqueous phase and re-extract with an equal volume of chloroform: isoamyl alcohol (24: 1) and centrifuge for 10 minutes. 12) Carefully remove the water phase, add 1/10 volume of 2mol / L sodium acetate and 2.5 volume of cold ethanol, mix and let stand at -20 ° C for 1 hour. 13) Wash the precipitate with 70% ethanol and 100% ethanol, air dry, and resuspend the nucleic acid. The process is the same as steps 3-6. 14) Determine A ₂₆ . And A ₂₈ . To detect the purity and yield of DNA. 15) Store at -20 ° C after dispensing.

Preparation of sample film:

1) Take 4 X 2 pieces of nitrocellulose membrane (NC membrane) of appropriate size, and mark the spotting position and sample number on it with a pencil. Two _NC membranes are required for each probe, so that it can be used in subsequent experiments. In the step, the film is washed with high-strength conditions and strength conditions, respectively.

 2) Pipette and control 15 microliters each, spot on the sample film, and dry at room temperature.

 3) Place on filter paper impregnated with 0.1 Iraol / LNaOH, 1.5 mol / L NaCl for 5 minutes (twice), dry and place on filter paper impregnated with 0.5 mol / L Tris-HCl (pH 7.0), 3 mol / L NaCl Allow to dry for 5 minutes (twice).

 4) Clamped in clean filter paper, wrapped in aluminum foil, and dried under vacuum at 60-80 ° C for 2 hours.

 Labeling of probes

1) 3 μl Probe (0.1OD / 10 μ 1), add 2 μl Kinase buffer, 8-10 uCi y- ³² P-dATP + 2U Kinase to make up to a final volume of 20 μ 1.

 2) Incubate at 37 ° C for 2 hours.

 3) Add 1/5 volume of bromophenol blue indicator (BPB \

 4) Pass Sephadex G-50 column.

5) Start collecting the first peak before ³² P-Probe washes out (monitoring can be used to monitor;).

 6) 5 drops / tube, collect 10-15 tubes.

 7) Monitor the amount of isotope with a liquid scintillator

8) The combined solution after the first peak was collected as ³² P-Prob _e (the second peak to prepare the desired free γ_ ³² Ρ- dATP). Pre-hybridization

 Place the sample film in a plastic bag, add 3-10 mg of prehybridization solution (lOxDenhardt's; 6xSSC, 0.1 lrag / ml CT DNA (calf thymus DM).), Seal the bag, and shake at 68 ° C for 2 hours .

 Cross

 Cut a corner of the plastic bag, add the prepared probe, seal the bag, and shake it at 42 ° C in a water bath overnight.

 Wash film:

 High-intensity washing film:

1) Take out the hybridized sample membrane. 2) 2xSSC, 0.1% SDS, wash at 40 ° C for 15 minutes (twice).

 3) Wash in 0.1xSSC, 0.1% SDS at 40 ° C for 15 minutes (twice).

 4) Wash in 0.1xSSC, 0.1% SDS at 55 ° C for 30 minutes (twice), and dry at room temperature. Low-intensity washing film:

 1) Take out the hybridized sample membrane.

 2) 2xSSC, 0.1% SDS, 37. C Wash for 15 minutes (twice).

 3) Wash in 0.1xSSC, 0.1% SDS at 37 ° C for 15 minutes (twice).

 4) Wash in 0.1xSSC, 0.1% SDS at 40 ° C for 15 minutes (twice), and dry at room temperature.

X-ray autoradiography:

 -70 ° C, X-ray autoradiography (compression time depends on the radioactivity of the hybrid spot).

 Experimental results:

 The hybridization experiments performed under low-intensity membrane washing conditions showed no significant difference in the radiation intensity of the above two probes. However, in the hybridization experiments performed under high-intensity membrane washing conditions, the radioactive intensity of probe 1 was significantly stronger. To the radioactive intensity of the hybridization spot of another probe. Therefore, probe 1 can be used to qualitatively and quantitatively analyze the presence and differential expression of the polynucleotide of the present invention in different tissues. Example 7 DNA Mi croarray

 Gene chip or DNA microarray is a new technology that many national laboratories and large pharmaceutical companies are currently developing and developing. It refers to the orderly and high-density arrangement of a large number of target gene fragments on glass, The data is compared and analyzed on a carrier such as silicon using fluorescence detection and computer software to achieve the purpose of fast, efficient, and high-throughput analysis of biological information. The polynucleotide of the present invention can be used as target DNA for gene chip technology for high-throughput research of new gene functions; search for and screen new tissue-specific genes, especially new genes related to diseases such as tumors; diagnosis of diseases such as hereditary diseases . The specific method steps have been reported in the literature, for example, see the literature DeR i s i, J. L., Lyer, V. & Brown, P. 0.

(1997) Science 278, 680-686. And Hell, R. A., Schema, M., Cha i, A., Sha lom, D., (1997) PNAS 94: 2150-2155.

 (A) spotting

A total of 4,000 polynucleotide sequences of various full-length cDNAs are used as target DNA, including the polynucleotide of the present invention. They were respectively amplified by PCR. After purification, the amplified product was adjusted to a concentration of about 500 ng / ul, and spotted on a glass medium with a Cartesian 7500 spotting instrument (purchased from Cartesian Company, USA). The distance between points is 280 μm. The spotted slides were hydrated, dried, and cross-linked in a UV cross-linker. After elution, the slides were fixed to fix the DNA on the glass slides to prepare chips. The specific method steps have been variously reported in the literature. The post-spot processing steps of this embodiment are:

 1. Hydration in a humid environment for 4 hours;

 2. 0.2% SDS was washed for 1 minute;

3. Wash twice with ddH ₂ 0 for 1 minute each time;

4. NaBH _{4 is} blocked for 5 minutes;

 5. 95 ° C water for 2 minutes;

 6. Wash with 0.2% SDS for 1 minute;

7. Rinse twice with ddH ₂ 0;

 8. Dry and store at 25 ° C in the dark for future use.

 (Two) probe marking

 Total mRNA was extracted from human mixed tissues and specific tissues (or stimulated cell lines) in one step, and the mRNA was purified using Oligotex mRNA Midi Kit (purchased from QiaGen), and separated by reverse transcription. Photo reagent Cy3dUTP (5-Amino-propargyl-2'_deoxyuridine 5'-triphate coupled to Cy3 fluorescent dye, purchased from Amersham Phamacia Biotech) was used to label mRNA of human mixed tissue, and the fluorescent reagent Cy5dUTP (5- Amino-propargy 2 2 ' -deoxyuridine 5'-triphate coupled to Cy5 fluorescent dye (purchased from Amersham Phamacia Biotech) was used to label the mRNA of specific tissues (or stimulated cell lines) of the body, and probes were prepared after purification. For specific steps and methods, see:

Schena,

 M., Shalon, D., Heller, R. (1996) Proc. Natl. Acad. Sci. USA. Vol. 93: 10614-10619. Sc hena, M., Shalon, Dari., Davis, RW (1995) Science.270. (20): 467-480.

 (Three) cross

 Combine the probes from the two tissues with the chips in UniHyb ™ Hybridization

Solution (purchased from TeleChem) was used for hybridization for 16 hours, and washed with a washing solution (lx SSC, 0.2¾SDS) at room temperature, and then scanned with a ScanArray 3000 scanner (purchased from General Scanning, USA). Software (American Biodiscovery company) performs data analysis and processing to calculate the Cy3 / Cy5 ratio of each point.

The above specific tissues (or stimulated cell lines) are bladder mucosa, PMA + Ecv304 cell line, LPS + Ecv304 cell line thymus, normal fibroblasts 1024NC, Fibroblast, growth factor stimulation, 1024NT, scar into fc growth factor stimulation 1013HT, scar into fc without stimulation with growth factor, 1013HC, bladder Cystocarcinoma cells EJ, bladder cancer, bladder cancer, liver cancer, liver cancer cell lines, placenta, spleen, prostate cancer, jejunal adenocarcinoma, cardia cancer. Draw a chart based on these 17 Cy3 / Cy5 ratios. (figure 1 ). It can be seen from the figure that the complement receptor 12 and complement receptor expression profiles according to the present invention are very similar.

Claims

Request for Rights

 1. An isolated polypeptide-complement receptor 12, characterized in that it comprises: a polypeptide having the amino acid sequence shown in SEQ ID NO: 2, or an active fragment, analog or derivative thereof.

 2. The polypeptide according to claim 1, characterized in that the amino acid sequence of the polypeptide, analog or derivative has at least 95% identity with the amino acid sequence shown in SEQ ID NO: 2.

 3. The polypeptide according to claim 2, characterized in that it comprises a polypeptide having the amino acid sequence shown in SEQ ID NO: 2.

 4. An isolated polynucleotide, characterized in that said polynucleotide comprises one selected from the group consisting of: (a) encoding a polypeptide having an amino acid sequence shown in SEQ ID NO: 2 or a fragment thereof, an analog thereof; Polynucleotides of derivatives;

 • (b) a polynucleotide complementary to polynucleotide (a); or

 (c) A polynucleotide that is at least 70% identical to (a) or (b).

 5. The polynucleotide according to claim 4, wherein the polynucleotide comprises a polynucleotide encoding an amino acid sequence represented by SEQ ID NO: 2.

 6. The polynucleotide according to claim 4, characterized in that the sequence of the polynucleotide comprises the sequence of positions 409-747 in SEQ ID NO: 1 or the sequence of positions 1-1294 in SEQ ID NO: 1 sequence.

 7. A recombinant vector containing an exogenous polynucleotide, characterized in that it is a recombinant constructed from the polynucleotide according to any one of claims 4 to 6 with a plasmid, virus or a carrier expression vector Carrier. S. A genetically engineered host cell containing an exogenous polynucleotide, which is characterized in that it is selected from one of the following host cells:

 (a) a host cell transformed or transduced with the recombinant vector of claim 7; or

 (b) a host cell transformed or transduced with a polynucleotide according to any one of claims 4-6.

9. A method for preparing a polypeptide having complement receptor 12 activity, characterized in that the method comprises: (a) culturing the engineered host cell of claim 8 under conditions in which complement receptor 12 is expressed; (b) ) A polypeptide having complement receptor 12 activity is isolated from the culture.

 10. An antibody capable of binding to a polypeptide, characterized in that said antibody is an antibody capable of specifically binding to complement receptor 12.

 11. A class of compounds that mimic or regulate the activity or expression of a polypeptide, characterized in that they are compounds that mimic, promote, antagonize or inhibit the activity of complement receptor 12.

 12. The compound according to claim 11, characterized in that it is an antisense sequence of a polynucleoside 'acid sequence or a fragment thereof as shown in SEQ ID NO: 1.

1 3. Use of a compound according to claim 11, characterized in that the compound is used for regulating complement Method of Receptor 12 Activity in vivo and in vitro.

 14. A method for detecting a disease or disease susceptibility related to the polypeptide according to any one of claims 1-3, characterized in that it comprises detecting the expression amount of the polypeptide, or detecting the polypeptide Activity, or detecting a nucleotide variation in a polynucleotide that causes abnormal expression or activity of the polypeptide.

15. Use of a polypeptide according to any one of claims 1-3, characterized in that it is used to screen mimetics, agonists, antagonists or inhibitors of complement receptor 12, or for peptide fingerprinting Identification. 16. The use of a nucleic acid molecule according to any one of claims 4 to 6, characterized in that it is used as a primer for a nucleic acid amplification reaction, or as a probe for a hybridization reaction, or for manufacturing a gene chip. Or microarray.

17. Use of a polypeptide, polynucleotide or compound according to any one of claims 1 to 6 and 11, characterized in that said polypeptide, polynucleotide or mimetic, agonist, antagonist The agent or inhibitor is composed of a safe and effective dose with a pharmaceutically acceptable carrier as a pharmaceutical composition for diagnosing or treating a disease associated with a complement receptor 12 abnormality.

 18. The use of a polypeptide, polynucleotide or compound according to any one of claims 1-6 and 11, characterized in that the polypeptide, polynucleotide or compound is used for preparing for treating malignant tumors, blood, etc. Disease, HIV infection and immune diseases and drugs of various inflammations.