WO2001055399A1 - A novel polypeptide, a human dipeptide aminopeptidase 28 and the polynucleotide encoding the polypeptide - Google Patents

Abstract

The present invention discloses a novel polypeptide, a human dipeptide aminopeptidase 28, the polynucleotide encoding the polypeptide and the method for producing the polypeptide by DNA recombinant technology. The invention also discloses the uses of the polypeptide in methods for treating various diseases, such as malignant tumour, hemopathy, HIV infection, immunological disease, and various inflammation etc. The invention also discloses the agonists against the polypeptide and the therapeutic action thereof. The invention also discloses the uses of the polynucleotide encoding the novel human dipeptide aminopeptidase 28.

Description

 A new polypeptide, a human dipeptide aminopeptidase 28, and a polynucleotide encoding the polypeptide TECHNICAL FIELD

 The present invention belongs to the field of biotechnology. Specifically, the present invention describes a new polypeptide, a human dipeptide aminopeptidase 28, and a polynucleotide sequence encoding the polypeptide. The invention also relates to a preparation method and application of the polynucleotide and polypeptide. Background technique

 The prolyl oligopeptidase protein family contains many evolutionarily linked peptidases, whose catalytic function of cleaving peptide chains is provided by a charge transfer system, similar to serine proteases. This family includes enzymes: prolyl endopeptidase (PE), which cleaves the C-terminus of peptides and cuts at the proline. The sequences of PE found in humans and bacteria are very conserved.

 The bacterial protease I I cleaves the C-terminus of the peptide, and the cleavage points are at proline and arginine.

 Dipeptidase IV (DPP IV). DPP IV cleaves the dipeptide in turn from the N-terminus of the polypeptide, provided that the second residue at the N-terminus is proline.

 Yeast vacuolar dipeptidyl aminopeptidase A, B (DPAP A, B);

 Acyl peptide hydrolase.

 The characteristic conserved sequences of this family are: Dx (3) -AX (3)-[LIVMFYW] -x (14) -GxS- xGG- [LI VMFYW]. In 1992, Wada et al. And cDNA of the dipeptidyl aminopeptidase DPPX protein found in rat brain. They named them DPPX-S and DPPX-L. They all belong to the prolyl oligopeptidase protein family, and the transmembrane region and the C-terminal extramembrane region of the two are consistent. DPPX-S mRNA is expressed in the brain and surrounding tissues such as the kidney, testis, and ovary, while DPPX-L is expressed only in the brain. Neither is expressed in the heart, liver, and spleen. In situ hybridization indicates that the two are not distributed in the brain. DPPX-L mRNA is expressed only in a limited range in the brain, with the highest expression in the pineal gland. DPPX-S is expressed in a larger area in the brain. The difference in the expression profiles of the two indicates that the peptides metabolized by the two have regional limitations.

 The polypeptide of the present invention is 48% identical to the aforementioned DPPX-S, 69% similar, and contains a conserved sequence characteristic of the dipeptide aminopeptidase family. Therefore, this protein is considered to be a new dipeptide aminopeptide The enzyme has a biological function similar to DPPX-S and is named human dipeptide aminopeptidase XX.

As mentioned above, the human dipeptide aminopeptidase 28 protein plays an important role in regulating important functions of the body, such as cell division and embryonic development, and it is believed that a large number of proteins are involved in these regulatory processes, so there has been a need to identify more involved in these Process of human dipeptidyl aminopeptidase 28 protein, especially identifying this protein White amino acid sequence. Isolation of the novel human dipeptide aminopeptidase 28 protein encoding gene also provides a basis for the study 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-human dipeptide aminopeptidase 28 and fragments, analogs and derivatives thereof.

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

 Another object of the present invention is to provide a recombinant vector containing a polynucleotide encoding a human dipeptide aminopeptidase 28.

 It is another object of the present invention to provide a genetically engineered host cell containing a polynucleotide encoding a human dipeptide aminopeptidase 28.

 Another object of the present invention is to provide a method for producing human dipeptide aminopeptidase 28.

 Another object of the present invention is to provide an antibody against the polypeptide-human dipeptide aminopeptidase 28 of the present invention.

 Another object of the present invention is to provide mimic compounds, antagonists, agonists, and inhibitors against the polypeptide-human dipeptide aminopeptidase 28 of the present invention.

 Another object of the present invention is to provide a method for diagnosing and treating diseases associated with abnormalities in human dipeptide aminopeptidase 28.

 The present invention relates to an isolated polypeptide, which is of human origin, and includes: a polypeptide having the amino acid sequence of SEQ ID D. 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 D. 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 29-787 in SEQ ID NO: 1; and (b) a sequence having 1-1769 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 the activity of the human dipeptide aminopeptidase 28 protein, 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 human dipeptide aminopeptidase 28 protein in vitro, comprising detecting mutations in the polypeptide or a polynucleotide sequence encoding the same in a biological sample, or detecting The amount or biological activity of a polypeptide of the invention in a biological sample.

 The invention also relates to a pharmaceutical composition comprising a polypeptide of the 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 manufacture of a medicament for treating cancer, developmental disease or immune disease or other diseases caused by abnormal expression of human dipeptide aminopeptidase 28.

 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 "variant" of a protein or polynucleotide 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 can have "conservative" changes, in which the amino acid substituted 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 combined with human dipeptide aminopeptidase 28, causes a change in the protein and thereby regulates the activity of the protein. An agonist may include a protein, a nucleic acid, a carbohydrate, or any other molecule that can bind human dipeptide aminopeptidase 28.

 An "antagonist" or "inhibitor" refers to a molecule that, when combined with human dipeptide aminopeptidase 28, can block or regulate the biological or immunological activity of human dipeptide aminopeptidase 28. Antagonists and inhibitors may include proteins, nucleic acids, carbohydrates or any other molecule that can bind human dipeptidyl aminopeptidase 28.

 "Regulation" refers to a change in the function of human dipeptide aminopeptidase 28, including an increase or decrease in protein activity, a change in binding characteristics, and any other biological, functional, or immune properties of human dipeptide aminopeptidase 28 change.

 By "substantially pure" is meant substantially free of other proteins, lipids, sugars or other substances with which it is naturally associated. Those skilled in the art can purify human dipeptide aminopeptidase 28 using standard protein purification techniques. The substantially pure human dipeptide aminopeptidase 28 produces a single main band on a non-reducing polyacrylamide gel. The purity of the human dipeptide aminopeptidase 28 polypeptide can be analyzed by amino acid sequence.

 "Complementary" or "complementary" refers to the natural binding of polynucleotides 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. The inhibition of such hybridization can be detected by performing hybridization (Southern imprinting or Northern blotting, etc.) under conditions of reduced stringency. Substantially homologous sequences or hybridization probes can compete and inhibit the binding of fully homologous sequences to the target sequence under conditions of reduced stringency. This does not mean that conditions with reduced stringency allow non-specific binding, because conditions with reduced stringency require that the two sequences bind to each other as either specific or selective interactions.

"Percent identity" refers to the percentage of sequences that are identical or similar in the comparison of two or more amino acid or nucleic acid sequences. The percent identity can be determined electronically, such as by the MEGALIGN program (Lasergene sof tware package, DNASTAR, Inc., Madison Wis.). The MEGALIGN program can compare two or more sequences according to different methods such as the C lus ter method (Higgin, DG, and PM Sharp (1988) Gene 73: 237-244). ₀ C lus ter method passes the inspection. Between all pairs The distance arranges each group of sequences into 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: The number of matching residues between sequence A and sequence X 1 00 The number of residues in sequence A-the interval residues in sequence A Number of interval residues in sequence B

 The percent identity between nucleic acid sequences can also be determined by the Cluster method or by methods known in the art such as Jo tun He in (He in J., (1990) Me thods in emzumo l ogy 183: 625-645) .

 "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 DM or RNA sequence. "Antisense strand" refers to a nucleic acid strand that is complementary to a "sense strand."

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

"Antibody" refers to a complete antibody molecule and its fragments, such as Fa,? (& 1) ') ₂ and? ^ It can specifically bind to the epitope of human dipeptide aminopeptidase 28.

 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 thing, but the same polynucleotide or polypeptide is separated from some or all of the natural system-substances that coexist with it. Such a polynucleotide may be part of a certain vector, or such a polynucleotide or polypeptide may be part of a certain composition. Since the carrier or composition is not a component of its natural environment, they are still isolated. As used herein, "isolated" refers to the separation of a substance from its original environment (if it is a natural substance, 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 coexist in a natural state Separated in other materials, it is isolated and purified.

 As used herein, "isolated human dipeptide aminopeptidase 28" means that human dipeptide aminopeptidase 28 is substantially free of other proteins, lipids, carbohydrates, or other substances with which it is naturally associated. Those skilled in the art can purify human dipeptidyl aminopeptidase 28 using standard protein purification techniques. Substantially pure polypeptides produce a single main band on a non-reducing polyacrylamide gel. The purity of the human dipeptide aminopeptidase 28 polypeptide can be analyzed by amino acid sequence.

 The present invention provides a new polypeptide, human dipeptide aminopeptidase 28, 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 can be naturally purified products or chemically synthesized products, or can be produced from prokaryotic or eukaryotic hosts (eg, bacteria, yeast, higher plants, insects, and mammalian cells) using recombinant techniques. 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 human dipeptide aminopeptidase 28. As used in the present invention, the terms "fragment", "derivative" and "analog" refer to a polypeptide that substantially maintains the same biological function or activity of the human dipeptidyl aminopeptidase 28 of the present invention. A fragment, derivative, or analog of the polypeptide of the present invention may be: (i) one 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) a type in which a group on one or more amino acid residues is replaced by another group to include a substituent; or (Π Ι) Such a type in which the mature polypeptide is fused to another compound (such as a compound that prolongs the half-life of the polypeptide, such as polyethylene glycol); or (IV) such a type of polypeptide sequence in which an additional amino acid sequence is fused into the mature polypeptide (Such as a leader sequence or a secreted sequence or a sequence used to purify this polypeptide or a protease sequence) As set forth 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 the 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 polynucleotide sequence of 1769 bases, and its open reading frames 29-787 encode 252 amino acids. According to the amino acid sequence homology comparison, it was found that this polypeptide has 48% homology with DPPX-S. It can be deduced that the human dipeptide aminopeptidase 28 has similar structure and function to DPPX-S.

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. The coding region sequence encoding a mature polypeptide may be the same as the coding region sequence shown in SEQ ID NO: 1 The same or degenerate variants. 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 comprising the polypeptide and a polynucleotide comprising 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. Variants of this polynucleotide can be naturally occurring allelic variants or non-naturally occurring variants. 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 present 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 0.2 xSSC, 0.1% SDS, 6 (TC; or (2) ) Add a denaturant during hybridization, such as 50% (v / v) formamide, 0.1% calf serum / 0.1% F i co ll, 42 ° C, etc .; or (3) only in two sequences Hybridization occurs when the identity between at least 95% and more preferably 97%. Furthermore, the polypeptide encoded by the hybridizable polynucleotide has the same biological function as the mature polypeptide shown in SEQ ID NO: 2 And active.

 The invention also relates to nucleic acid fragments that hybridize to the sequences described above. As used herein, 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 More than nucleotides. Nucleic acid fragments can also be used in nucleic acid amplification techniques, such as PCR, to identify and / or isolate polynucleotides encoding human dipeptidyl aminopeptidase 28.

 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 human dipeptide aminopeptidase 28 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 DM 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 often 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. There are many mature techniques for extracting mRNA, 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 polymerase reaction technology is used in combination, 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): (l) DNA-DNA or DNA-RNA hybridization; (2) the presence or absence of a marker gene function; (3) determination of the level of the human dipeptide aminopeptidase 28 transcript; ( 4) Detecting gene-expressed protein products by immunological techniques or by measuring biological activity. 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 2000 nucleotides, preferably within 1000 nucleotides. The probe used here is usually a DM 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 method (4), immunological techniques such as Western blotting, radioimmunoprecipitation, and enzyme-linked immunosorbent assay (ELISA) can be used to detect protein products expressed by the human dipeptide aminopeptidase 28 gene.

 A method using DNA technology to amplify DNA / RNA (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 a full-length cDNA from a library, the RACE method (RACE-Rapid Amplification of cDNA Ends) can be preferably used. The primers used for PCR can be appropriately based on the polynucleotide sequence information of the present invention disclosed herein. Select and synthesize using conventional methods. The amplified DNA / RNA 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 and the like. In order to obtain the full-length cDNA sequence, the 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 a polynucleotide of the present invention, and a vector or a direct use of the vector of the present invention. A genetically engineered host cell using the human dipeptide aminopeptidase 28 coding sequence, and a method for producing the polypeptide of the present invention by recombinant technology.

 In the present invention, a polynucleotide sequence encoding the human dipeptide aminopeptidase 28 can 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 (Rosenberg, et al. Gene, 1987, 56: 125) expressed in bacteria; pMSXND expression vectors expressed in mammalian cells ( Lee and Nathans, J Bio Chem. 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 human dipeptide aminopeptidase 28 and appropriate transcriptional / translational regulatory elements. These methods include in vitro recombinant DNA technology, DNA synthesis technology, and in vivo recombination technology (Sambroook, et al. Molecular Cloning, a Laboratory Manual, cold Spring Harbor Laboratory. New York, 1989). The DNA sequence 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. Illustrative examples include SV40 enhancers of 100 to 270 base pairs on the late side of the origin of replication, polyoma enhancers on the late side of the origin of replication, and adenoviral enhancers.

 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 control elements (such as promoters, enhancers, etc.) and selectable marker genes.

In the present invention, a polynucleotide encoding human dipeptide aminopeptidase 28 or a recombinant vector containing the polynucleotide can be transformed or transduced into a host cell to form a genetically engineered host containing the polynucleotide or the recombinant vector. Primary cells. 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: Escherichia coli, Streptomyces; bacterial cells such as Salmonella typhimurium; fungal cells such as yeast; plant cells; insect cells such as fly S 2 or Sf 9; animal cells such as CH0, COS or Bowes melanoma cells, etc. .

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 absorbing DM may be harvested after exponential growth phase, 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 DNA 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 human dipeptide aminopeptidase 28 (Science, 1 984; 224: 1431). Generally there are the following steps:

(1) using the polynucleotide (or variant) encoding human human dipeptide aminopeptidase 28 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), depending on the host cell used, the medium used in the culture may be selected from various conventional mediums. 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 desired, recombinant proteins can be separated 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 invention, but not to limit the scope of the invention as defined by the claims.

FIG. 1 is a comparison diagram of amino acid sequence homology between the human dipeptide aminopeptidase 28 and DPPX-S of the present invention. The upper sequence is human dipeptide aminopeptidase 28, and the lower sequence is DPPX-S. Use the same word between two sequences Symbolic amino acids, similar amino acids are represented by "+".

 Figure 2 shows the polyacrylamide gel electrophoresis (SDS-PAGE) of isolated human dipeptide aminopeptidase 28. 28kDa 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 performed according to conventional conditions such as those described in Sambrook et al., Molecular Cloning: Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989), or according to the manufacturer Suggested conditions.

 Example 1: Cloning of human dipeptide aminopeptidase 28

 Human fetal brain total RNA was extracted by one-step method with guanidine isothiocyanate / phenol / chloroform. Poly (A) mRNA was isolated from total RNA using the Quik mRNA Isolation Kit (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 fragments into the multiple cloning site of the pBSK (+) vector (Clontech) to transform DH5a. The bacteria formed 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 0465a06 was new DNA. The inserted cDNA fragments contained in this clone were determined in both directions by synthesizing a series of primers. The results showed that the full-length cDNA contained in the 0465a06 clone was 1769bp (as shown in Seq IDN0: 1), and there was a 759bp open reading frame (0RF) from the 29th to 787bp, encoding a new protein (such as Seq ID NO: 2). We named this clone pBS-0465a06 and the encoded protein was named human dipeptide aminopeptidase 28. Example 2: Homologous search of cDNA clones

 The sequence of the human dipeptide aminopeptidase 28 of the present invention and the protein sequence encoded by the same are used by the Blast program

(Basiclocal Alignment search tool) [Al tschul, SF et al.

J. Mol. Biol. 1990; 215: 403-10], homology search in databases such as Genbank, Swissport. The gene with the highest homology to the human dipeptide aminopeptidase 28 of the present invention is a known DPPX-S, and the protein encoded by the accession number in Genbank is M76429. The protein homology results are shown in Figure 1. The two are highly homologous, with an identity of 48%; a similarity of 69%. Example 3: Cloning of a gene encoding human dipeptide aminopeptidase 28 by RT-PCR

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

 Primer 1: 5,-GATGAGAGTATGTGGAGGTAATGA-3, (SEQ ID NO: 3)

 Primer2: 5,-ACAATCATTACATTTATTAGGTTT-3, (SEQ ID NO: 4)

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

 Primer2 is the 3 'end reverse sequence in SEQ ID NO: 1.

Amplification conditions: 50 mmol / L KC1, 10 mmol / L Tris-Cl, (pH 8.5), 1.5 mmol / L MgCl ₂ , 200 μ mol / L dNTP, lOpmol primers in a 50 μ 1 reaction volume, Taq DM polymerase of 111 (Clontech). The reaction was performed on a PE9600 DM thermal cycler (Perkin-Elmer) for 25 cycles under the following conditions: 94 ° C 30sec; 55 ° C 30sec; 72. C 2min. During RT-PCR, β-act in 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. The DNA sequence analysis results showed that the DNA sequence of the PCR product was exactly the same as that of 1 to 1769bp shown in SEQ ID NO: 1. Example 4: Northern blot analysis of human dipeptide aminopeptidase 28 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 guanidine isothiocyanate-25mM sodium citrate, 0.2M sodium acetate (pH4.0), and 1 time volume of phenol and 1/5 volume of chloroform-isoamyl alcohol (49: 1 ) And centrifuge after mixing. Aspirate the aqueous layer, add isopropanol (0.8 vol) and centrifuge the mixture 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) -5raM sodium acetate-ImM EDTA-2.2M formaldehyde. It was then transferred to a nitrocellulose membrane. Preparation ³² P- DM probe labeled with a- ³² P dATP by random priming method. The DNA probe used was the PCR amplified human dipeptide aminopeptidase 28 coding region sequence (29bp to 787bp) shown in FIG. 1. A 32P-labeled probe (about 2 x 10 ⁶ cpm / ml) was hybridized with a nitrocellulose membrane to which RNA was transferred at 42 ° C overnight in a solution containing 50% formamide-25m H ₂ P0 ₄ (pH7.4) -5 x SSC-5 x Denhardt's solution and 200 g / ml salmon sperm DNA. After hybridization, 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 5: In vitro expression, isolation and purification of recombinant human dipeptide aminopeptidase 28

According to SEQ ID NO: 1 and the coding region sequence shown in FIG. 1, a pair of specific amplification primers is designed, and the sequences are as follows: Primer 3: 5'-CATGCTAGCATGAGAGTATGTGGAGGTAATGAA-3 '(Seq ID No: 5)

Primer4: 5,-CATGGATCCTCACGTATGAGTTCTTTGATGTCG- 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). PCR was performed using the pBS-0465a06 plasmid containing the full-length target gene as a template. The PCR reaction conditions are as follows: a total volume of 50 μl contains 10 pg of pBS-0465a06 plasmid, primers Primer-3 and Primer- 4 points, and ¹ J is lOpmol, Advantage polymerase Mix (Clontech) 1 μ1. 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. After being cultured overnight on an LB plate containing kanamycin (final concentration 30 _M g / ml), positive clones were screened by colony PCR method and sequenced. A positive clone ( _P ET_0465a06) with the correct sequence was selected, and the recombinant plasmid was transformed into E. coli BL21 (DE3) plySs (product of Novagen) using the calcium chloride method. In LB liquid medium containing kanamycin (final concentration 30 g / ml), the host strain BL21 (pET-0465a06) was cultured at 37 ° C to the logarithmic growth phase, and IPTG was added to a final concentration of 1 ol / L , 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. The affinity chromatography column His. Bind Quick Cartridge (product of Novagen) was used to obtain 6 histidine (6His-Tag). The purified human dipeptide aminopeptidase 28 was purified. After SDS-PAGE electrophoresis, a single band was obtained at 28 kDa (Figure 2). The band was transferred to a PVDF membrane and the N-terminal amino acid sequence was analyzed by 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 6 Production of anti-human dipeptide aminopeptidase 28 antibody

 The following peptides specific for human dipeptide aminopeptidase 28 were synthesized using a peptide synthesizer (product of PE):

NH2-Met-Arg-Val-Cys-Gly-Gly-Asn-Glu-Phe-Glu-Arg-Arg-Ser-Ile-Gln-C00H (SEQ ID NO: 7). The polypeptide is coupled to hemocyanin and bovine serum albumin to form a complex, respectively. For methods, see: Avrameas, et al. Immunochemistry, 1969; 6: 43. Rabbits were immunized with 4 mg of the hemocyanin polypeptide complex plus complete Freund's adjuvant, and 15 days later, the hemocyanin polypeptide complex plus incomplete Freund's adjuvant was used to boost immunity once. A titer plate coated with a 15 g / ml bovine serum albumin peptide complex was used as an ELISA to determine antibody titers in rabbit serum. Total IgG was isolated from antibody-positive rabbit serum using protein A-Sepharose. The peptide was bound to a cyanogen bromide-activated Sepharose4B column, and anti-peptide antibodies were separated from the total IgG by affinity chromatography. The immunoprecipitation method proved that the purified antibody could specifically bind to human dipeptide aminopeptidase 28. Example 7: Use of a 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 tissue or pathology. 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 a filter hybridization method. Acid sequence or a homologous polynucleotide sequence thereof. Filter hybridization methods include dot blotting, Southern imprinting, Nor thern blotting, and copying methods. They all use the same steps to fix the polynucleotide sample to be tested on the filter and then hybridize. These same steps are as follows: The sample-immobilized filter is first prehybridized with a probe-free hybridization buffer to saturate the non-specific binding site of the sample on the filter, the carrier, and the synthetic polymer. The pre-hybridization solution is then replaced with a hybridization buffer containing labeled probes and incubated to hybridize the probes to the target nucleic acid. After the hybridization step, the unhybridized probes are removed by a series of membrane washing steps. This embodiment uses 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 present invention; the second type of probes are partially related to the present invention The polynucleotide SEQ ID NO: 1 is the same or complementary oligonucleotide fragment. In this example, 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. GC content is 30 »/. -70%, non-specific hybridization increases;

 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 regions are compared for homology. If the homology with the non-target molecular region is greater than 85% or there are more than 15 consecutive bases, 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 type of probe, is completely homologous or complementary to the gene fragment of SEQ ID NO: 1 (41Nt):

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

 Probe 2 (probe2), which belongs to the second type of probe, is equivalent to the replacement mutant sequence of the gene fragment of SEQ ID NO: 1 or its complementary fragment (41Nt):

 5-TGAGAGTATGTGGAGGTAATCAATTTGAAAGACGTTCCATT-3 '(SEQ ID NO: 9) For other commonly used reagents and their preparation methods related to the following specific experimental procedures, please refer to the literature: DNA PROBES GH el ler; MM Manak; Stockton Press, 1989 (USA ) And more commonly used molecular cloning experiment manual books such as "Molecular Cloning Experiment Guide" (Second Edition 1998) [US] Sambrook et al., Science Press.

 Sample Preparation:

 1.Extract DNA from fresh or frozen tissue

Steps: 1) Place fresh or freshly thawed normal liver tissue in a plate immersed in ice and filled with phosphate buffered saline (PBS). Cut the tissue into small pieces with scissors or a scalpel. Tissue should be kept 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 mmol / L Tris-HCl, pH 7.5; 25 mmol / LnaCl; 25 mmol / 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 (l-5 ml per 0.1 g of the initial tissue sample), and centrifuge at 1,000 g for 10 minutes. 7) Resuspend the pellet with lysis buffer (1 ml per 0.1 g of the initial tissue sample), and then follow the phenol extraction method below.

 2, DNA phenol extraction method

Steps: 1) Wash the cells with 1-10 ml of cold PBS and centrifuge at 1,000 g for 10 minutes. 2) Resuspend the pelleted cells with cold cell lysate (lx 10 ⁸ cells / ml). Use 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, DNA purification and ethanol precipitation

Steps: 1) Add 1/10 volume of 2mol / L sodium acetate and 2 volumes of cold 100% ethanol to the DNA solution. Medium, mix well. 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 off the residual ethanol. Air dry for 10-15 minutes to allow the surface ethanol to evaporate. 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. Vortex at low speed or suck with a dropper while gradually increasing TE, mix until the DNA is fully lysed, and add approximately 1 ul per 1-5 x 10 ^δ cells.

 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) Add SDS and proteinase K to the final concentration of 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 aqueous phase, add 10 volumes of 2mol / L sodium acetate and 2.5 volumes of cold ethanol, and mix well at -20 ° C for 1 hour. 13) Wash the pellet with 70% ethanol and 100% ethanol, air dry, and resuspend the nucleic acid. The process is the same as steps 3-6. 14) Measure 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 membranes (NC membranes) of appropriate size, and gently mark the spotting position and sample number on them with a pencil. Two NC membranes are required for each probe for subsequent experiments. In the step, the film is washed with high-strength conditions and strength conditions, respectively.

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

 3) Place on filter paper impregnated with 0.1 mol / L NaOH, 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 μ I inase buffer, 8-10 uCi γ- ³² P-dATP + 2U Kinase, to make up to a final volume of 20 μ 1.

 2) Incubate at 37 ° C for 1 hour.

 3) 1/5 volume bromophenol blue indicator (BPB).

 4) Pass through a Sephadex G-50 column.

5) Before the ³² P-Probe is washed out, start collecting the first peak (can be monitored by Monitor).

6) 5 drops / tube, collect 10-15 tubes. 7) Monitor the amount of isotope with a liquid scintillator

8) After combining the collection solutions of the first peak, the ³² P-Probe (the second peak is free γ- ³² P-dATP) is prepared.

 Pre-hybridization

 The sample membrane was placed in a plastic bag, and 3- 10 mg of prehybridization solution (10xDenhardt's; 6xSSC, 0.1 mg / ral) was added.

CT DNA (calf thymus DNA). ) After sealing the bag, 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) 0.1xSSC, 0.1% SDS, wash at 40 ° C for 15 minutes (twice).

 4) In 0.1xSSC, 0.1% SDS, wash 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, wash at 37 ° C for 15 minutes (twice).

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

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

X-ray autoradiography:

 -70 ° C, X-ray autoradiography (pressing 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 radioactive 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 than that of hybridization spots. The radioactive intensity of the hybridization spot of the other probe. Therefore, the presence and differential expression of the polynucleotide of the present invention in different tissues can be analyzed qualitatively and quantitatively with the probe 1. Example 8 DNA Microarray

Gene microarray or DNA microarray is a new technology that many national laboratories and large pharmaceutical companies are currently researching and developing. It refers to the orderly and high density of a large number of target gene fragments. It is arranged on a carrier such as glass and silicon, and then the data is compared and analyzed by fluorescence detection and computer software, so as to achieve the purpose of analyzing biological information quickly, efficiently and with high throughput. 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, refer to the literature DeRisi, JL, Lyer, V. & Brown, P.0. (1997) Science 278, 680-686. And the literature Helle, R. A,, Schema , M., Chai, A., Shalom, D., (1997) PNAS 94: 2150-2155.

 (A) spotting

 A total of 4,000 polynucleotide sequences of various full-length cDNAs are used as the target DM, including the polynucleotide of the present invention. They were amplified by PCR respectively. After purification, the amplified product was adjusted to a concentration of about 500 ng / ul, and spotted on a glass medium using a Cartesian 7500 spotter (purchased from Cartesian, USA). The distance is 280 μηι. The spotted slides were hydrated, dried, and cross-linked in a purple diplomatic coupling instrument. After elution, the DNA was fixed on a glass slide to prepare a chip. The specific method steps have been reported in the literature in various ways. 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. 0.2 ° /. Wash with 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 normal liver and liver cancer in one step, and mRNA was purified using Oligotex mRNA Midi Kit (purchased from QiaGen). The fluorescent reagent Cy3dUTP (5-Amino-propargyl-2'-deoxyur idine) was reverse-transcribed separately. 5'-tr iphate coupled to Cy3 fluorescent dye (purchased from Amersham Phamacia Biotech) was used to label mRNA of normal liver tissue. Cy5dUTP (5-Amino-propargyl-2'-deoxyur idine) 5'-tr iphate coupled to Cy5 fluorescent was used. Dye (purchased from Amersham Phamacia Biotech) was used to label liver cancer tissue mRNA, and the probe was 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. Schena, M., Shalon, Dari., Davis, RW (1995) Science. 270. (20): 467-480. (3) Hybridization

 Probes from the above two types of tissues were hybridized with the chip in a UniHyb ™ Hybridization Solution (purchased from TeleChem) hybridization solution for 16 hours, washed with a washing solution (lx SSC, 0.2% SDS) at room temperature and scanned with ScanArray 3000. Instrument (purchased from General Scanning Company, USA) for scanning, and the scanned image was analyzed and processed with Imagene software (Biodi scovery Company, USA) to calculate the Cy3 / Cy5 ratio of each point, and the point whose ratio is less than 0.5 and greater than 2 is considered Genes with differential expression. The experimental results show that Cy3signal = 5861.58 (take the average of four experiments), Cy5signal = 6877.63 (take the average of four experiments), Cy3 / Cy5 = 0.85227, the expression of the polynucleotide of the present invention in the above two tissues No significant difference. Industrial applicability

 The polypeptide of the present invention and the antagonists, agonists and inhibitors of the polypeptide can be directly used in the treatment of diseases, for example, it can treat malignant tumors, adrenal deficiency, skin diseases, various inflammations, HIV infections and immune diseases.

 Prolyl oligopeptidase family proteins contain many evolutionarily linked peptidases, and the catalytic function of cleaving peptide chains is provided by a charge transfer system, similar to serine proteases. Both dipeptidyl aminopeptidases DPPX-S and DPPX-L belong to the prolyl oligopeptidase protein family. DPPX-S mRNA is expressed in the brain and surrounding tissues such as the kidney, testis, and ovary, while DPPX-L is expressed only in the brain. DPPX-L mRNA is expressed only in a limited range in the brain, with the highest expression in the pineal gland. DPPX-S is expressed in a larger range in the brain.

 The polypeptide of the present invention has 48% identity and 69% similarity with the above-mentioned DPPX-S, and contains a conserved sequence characteristic of the dipeptide aminopeptidase family,

 The polypeptide of the present invention contains a characteristic sequence of the dipeptide aminopeptidase protein family, which is a homologous protein with the dipeptide-like aminopeptidase DPPX-S, and has similar biological functions, and abnormal expression will cause peptide chain shear Abnormalities, especially in brain and surrounding tissues such as kidneys, testes, and ovaries, and cause related diseases.

It can be seen that the abnormal expression of the human dipeptide aminopeptidase 28 of the present invention will produce various diseases, especially neurological diseases, renal diseases, gonad diseases, and certain endocrine diseases. These diseases include, but are not limited to: neurological diseases : Astrocytoma, oligodendroglioma, ependymoma, medulloblastoma, Meningiomas, Pituitary Adenoma, Schwannomas, Neurofibromas, Intracranial granulomas, Alzheimer's disease, Parkinson's disease, Chorea, Depression, Amnesia, Huntington's disease, Epilepsy, Migraine, Dementia Disease, multiple sclerosis, schizophrenia, depression, paranoia, anxiety, obsessive-compulsive disorder, phobia, neurasthenia, neural tube insufficiency, brain developmental malformations, neuronal migration disorders, cerebellar hypoplasia, Down syndrome

 Renal diseases: glomerulonephritis, nephrotic syndrome, tubular acidosis, interstitial glomerulonephritis, pyelonephritis, renal tubular adenoma, nephroblastoma

 Gonad disorders: testicular and epididymal inflammation, testicular tumors, epididymal tumors, hydatidiform moles, chorionic carcinoma, fallopian tube cancer, ovarian tumors and tumor-like lesions, infertility

 Endocrine diseases: diabetes insipidus, precocious puberty, giant disease and acromegaly, prolactin hyperemia, pituitary syndrome, hypohypoxia in adults, dwarfism, pituitary tumors

 The abnormal expression of the human dipeptide aminopeptidase 28 of the present invention will also produce certain hereditary, hematological and immune system diseases.

 The polypeptide of the present invention and the antagonists, agonists and inhibitors of the polypeptide can be directly used in the treatment of diseases, for example, it can treat various diseases, especially neurological diseases, renal diseases, gonad diseases, some endocrine diseases, some Hereditary, hematological and immune system diseases. The invention also provides methods for screening compounds to identify agents that increase (agonist) or suppress (antagonist) human dipeptide aminopeptidase 28. Agonists enhance biological functions such as human dipeptide aminopeptidase 28 to stimulate cell proliferation, while antagonists prevent and treat disorders related to excessive cell proliferation, such as various cancers. For example, mammalian cells or membrane preparations expressing human dipeptide aminopeptidase 28 can be cultured with labeled human dipeptide aminopeptidase 28 in the presence of a drug. The ability of the drug to increase or block this interaction is then determined.

 Antagonists of human dipeptide aminopeptidase 28 include antibodies, compounds, receptor deletions, and the like that have been screened. Antagonists of human dipeptidyl aminopeptidase 28 can bind to human dipeptidyl aminopeptidase 28 and eliminate its function, or inhibit the production of the polypeptide, or bind to the active site of the polypeptide so that the polypeptide cannot exert its biology Features.

When screening compounds as antagonists, human dipeptidyl aminopeptidase 28 can be added to the bioanalytical assay to determine whether the compound is a compound by measuring the effect of the compound on the interaction between human dipeptidyl aminopeptidase 28 and its receptor. Antagonist. Receptor deletions and analogs that act as antagonists can be screened in the same manner as described above for screening compounds. Polypeptide molecules capable of binding to human dipeptide aminopeptidase 28 can be obtained by screening a random peptide library composed of various possible combinations of amino acids bound to a solid phase. In screening, the human dipeptide aminopeptidase 28 molecule should generally be labeled. The present invention provides a method for producing an antibody using a polypeptide, a fragment, a derivative, an analog thereof, or a cell thereof as an antigen. These antibodies can be polyclonal or monoclonal antibodies. The invention also provides antibodies against the human dipeptide aminopeptidase 28 epitope. These antibodies include (but are not limited to): polyclonal antibodies, monoclonal antibodies, chimeric antibodies, single chain antibodies, Fab fragments, and fragments produced by Fab expression libraries.

Polyclonal antibodies can be produced by injecting human dipeptide aminopeptidase 28 directly into immunized animals (such as rabbits, mice, rats, etc.). A variety of adjuvants can be used to enhance the immune response, including but not limited to Freund's Agent. Techniques for preparing monoclonal antibodies to human dipeptidyl aminopeptidase 28 include, but are not limited to, hybridoma technology (Kohler and Milstein. Nature, 1975, 256: 495-497), triple tumor technology, human beta-cell hybridoma technology, EBV -Hybridoma technology, etc. Chimeric antibodies combining human constant regions and non-human variable regions can be produced using existing techniques (Morrison et al, PNAS, 1985, 81: 6851). ₀ Existing techniques for producing single-chain antibodies (US Pat No. .4946778) can also be used to produce single chain antibodies against human dipeptidyl aminopeptidase 28.

 Antibodies against human dipeptidyl aminopeptidase 28 can be used in immunohistochemical techniques to detect human dipeptidyl aminopeptidase 28 in biopsy specimens.

 Monoclonal antibodies that bind to human dipeptide aminopeptidase 28 can also be labeled with radioisotopes and injected into the body to track their location and distribution. This radiolabeled antibody can be used as a non-invasive diagnostic method to locate tumor cells and determine whether there is metastasis.

 Antibodies can also be used to design immunotoxins that target a particular part of the body. For example, human dipeptidyl aminopeptidase 28 high affinity monoclonal antibodies can covalently bind to bacterial or plant toxins (such as diphtheria toxin, ricin, ormosine, etc.). A common method is to attack the amino group of an antibody with a thiol cross-linking agent such as SPDP and bind the toxin to the antibody through the exchange of disulfide bonds. This hybrid antibody can be used to kill human dipeptide aminopeptidase 28 positive cell.

 The antibodies of the present invention can be used to treat or prevent human dipeptide aminopeptidase 28-related diseases. Administration of an appropriate amount of antibody can stimulate or block the production or activity of human dipeptidyl aminopeptidase 28.

 The invention also relates to a diagnostic test method for quantitative and localized detection of human dipeptide aminopeptidase 28 levels. These tests are well known in the art and include FISH assays and radioimmunoassays. The level of human dipeptide aminopeptidase 28 detected in the test can be used to explain the importance of human dipeptide aminopeptidase 28 in various diseases and to diagnose diseases in which human dipeptide aminopeptidase 28 functions.

 The polypeptide of the present invention can also be used for peptide mapping analysis. For example, the polypeptide can be specifically cleaved by physical, chemical or enzymatic analysis, and subjected to one-dimensional or two-dimensional or three-dimensional gel electrophoresis analysis, and more preferably mass spectrometry analysis.

The polynucleotide encoding human dipeptide aminopeptidase 28 can also be used for a variety of therapeutic purposes. Gene therapy technology can For the treatment of abnormal cell proliferation, development or metabolism caused by the non-expression or abnormal / inactive expression of human dipeptide aminopeptidase 28. Recombinant gene therapy vectors (such as viral vectors) can be designed to express variant human dipeptide aminopeptidase 28 to inhibit endogenous human dipeptide aminopeptidase 28 activity. For example, a variant human dipeptidyl aminopeptidase 28 may be a shortened human dipeptidyl aminopeptidase 28 lacking a signaling domain, and although it can bind to a downstream substrate, it lacks signaling activity. Therefore, the recombinant gene therapy vector can be used for treating diseases caused by abnormal expression or activity of human dipeptide aminopeptidase 28. Virus-derived expression vectors such as retrovirus, adenovirus, adenovirus-associated virus, herpes simplex virus, parvovirus, and the like can be used to transfer a polynucleotide encoding human dipeptide aminopeptidase 28 into a cell. Methods for constructing recombinant viral vectors carrying a polynucleotide encoding human dipeptidyl aminopeptidase 28 can be found in the existing literature (Sambrook, et al.). In addition, a recombinant polynucleotide encoding human dipeptide aminopeptidase 28 can be packaged into liposomes and transferred into cells.

 Methods for introducing a polynucleotide into a tissue or cell include: directly injecting the polynucleotide into a tissue in vivo; or introducing the polynucleotide into a cell in vitro through a vector (such as a virus, phage, or plasmid), and then transplanting the cell Into the body and so on.

 Oligonucleotides (including antisense RNA and DNA) and ribozymes that inhibit human dipeptide aminopeptidase 28 mRNA are also within the scope of the present invention. A ribozyme is an enzyme-like RNA molecule that specifically decomposes specific RNA. Its mechanism of action is that the ribozyme molecule specifically hybridizes with a complementary target RNA for endonucleation. Antisense RNA, DNA, and ribozymes can be obtained using any existing RNA or DNA synthesis technology, such as solid-phase phosphate amide chemical synthesis to synthesize oligonucleotides. Antisense RNA molecules can be obtained by in vitro or in vivo transcription of DM sequences encoding the RNA. This DM sequence has been integrated downstream of the RNA polymerase promoter of the vector. In order to increase the stability of the nucleic acid molecule, it can be modified in a variety of ways, such as increasing the sequence length on both sides, and the linkage between ribonucleosides using phosphorothioate or peptide bonds instead of phosphodiester bonds.

The polynucleotide encoding human dipeptide aminopeptidase 28 can be used for the diagnosis of diseases related to human dipeptide aminopeptidase 28. The polynucleotide encoding human dipeptide aminopeptidase 28 can be used to detect the expression of human dipeptide aminopeptidase 28 or the abnormal expression of human dipeptide aminopeptidase 28 in a disease state. For example, the DNA sequence encoding human dipeptidyl aminopeptidase 28 can be used to hybridize biopsy specimens to determine the expression of human dipeptidyl aminopeptidase 28. Hybridization techniques include Southern blotting, Nor thern blotting, and in situ hybridization. These techniques and methods are publicly available and mature, and related kits are commercially available. A part or all of the polynucleotides of the present invention can be used as probes to be fixed on a micro array or a DNA chip (also called a "gene chip") for analyzing differential expression analysis and gene diagnosis of genes in tissues. Human dipeptidyl aminopeptidase 28-specific primers can be used for RNA-polymerase chain reaction (RT-PCR) in vitro amplification to detect human dipeptidyl aminopeptidase 28 transcription products. Detection of mutations in the human dipeptide aminopeptidase 28 gene can also be used to diagnose human dipeptide aminopeptidase 28-related diseases. Human dipeptide aminopeptidase 28 mutations include point mutations, translocations, deletions, recombinations, and any other abnormalities compared to the normal wild-type human dipeptide aminopeptidase 28 DNA sequence. Mutations can be detected using existing techniques such as Southern blotting, DNA sequence analysis, PCR and in situ hybridization. In addition, mutations may affect protein expression, so Northern blotting and Western blotting can be used to indirectly determine whether a gene is mutated.

 The sequences of the invention are also valuable for chromosome identification. The sequence specifically targets a specific position on a human chromosome and can hybridize to it. Currently, specific sites for each gene on the chromosome need to be identified. Currently, only a few chromosome markers based on actual sequence data (repeating polymorphisms) are available for marking chromosome positions. According to the present invention, in order to associate these sequences with disease-related genes, an important first step is to locate these DNA sequences on a chromosome.

 In short, PCR primers (preferably 15-35bp) are prepared based on cDNA, and the sequences can be located on chromosomes. These primers were then used for PCR screening of somatic hybrid cells containing individual human chromosomes. Only those heterozygous cells containing the human gene corresponding to the primer will produce amplified fragments.

 PCR localization of somatic hybrid cells is a quick way to localize DNA to specific chromosomes. Using the oligonucleotide primers of the present invention, in a similar manner, a set of fragments from a specific chromosome or a large number of genomic clones can be used to achieve sublocalization. Other similar strategies that can be used for chromosomal localization include in situ hybridization, chromosome pre-screening with labeled flow sorting, and pre-selection of hybridization to construct chromosome-specific cDNA libraries.

 Fluorescent in situ hybridization (FISH) of cDNA clones with metaphase chromosomes allows precise chromosomal localization in one step. For a review of this technique, see Verma et al., Human Chromosomes: a Manual of Basic Techniques, Pergaraon Press, New York (1988).

 Once the sequence is located at the exact chromosomal location, the physical location of the sequence on the chromosome can be correlated with the genetic map data. These data can be found in, for example, V. Mckusick, Mendel ian Inheritance in Man (available online with Johns Hopkins University Welch Medical Library). Linkage analysis can then be used to determine the relationship between genes and diseases that have been mapped to chromosomal regions.

Next, the differences in cDNA or genomic sequences between the affected and unaffected individuals need to be determined. If a mutation is observed in some or all diseased individuals and the mutation is not observed in any normal individuals, the mutation may be the cause of the disease. Comparing affected and unaffected individuals usually involves first looking for structural changes in the chromosome, such as deletions or translocations that are visible at the chromosomal level or detectable using cDNA sequence-based PCR. Based on the resolution capabilities of current physical mapping and gene mapping technologies, cDNAs that are accurately mapped to disease-related chromosomal regions can be one of 50 to 500 potentially pathogenic genes (assuming 1 megabase mapping capability and every 20kb corresponds to a gene).

 The polypeptides, polynucleotides and mimetics, agonists, antagonists and inhibitors of the present invention can be used in combination with a suitable pharmaceutical carrier. These carriers can be water, glucose, ethanol, salts, buffers, glycerol, and combinations thereof. The composition comprises a safe and effective amount of the polypeptide or antagonist, and carriers and excipients which do not affect the effect of the drug. These compositions can be used as drugs for the treatment of diseases.

 The invention also provides a kit or kit containing one or more containers containing one or more ingredients of the pharmaceutical composition of the invention. Along with these containers, there may be instructional instructions given by government agencies that manufacture, use, or sell pharmaceuticals or biological products, which prompts permission for administration on the human body by government agencies that produce, use, or sell. In addition, the polypeptides of the invention can be used in combination with other therapeutic compounds.

 The pharmaceutical composition can be administered in a convenient manner, such as by a topical, intravenous, intraperitoneal, intramuscular, subcutaneous, intranasal or intradermal route of administration. Human dipeptide aminopeptidase 28 is administered in an amount effective to treat and / or prevent a specific indication. The amount and dose range of human dipeptidyl aminopeptidase 28 administered to a patient will depend on many factors, such as the mode of administration, the health conditions of the person to be treated, and the judgment of the diagnostician.

Claims

Claim

 1. An isolated polypeptide-human dipeptide aminopeptidase 28, 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 1, further comprising 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) a polynucleotide encoding a polypeptide having an amino acid sequence shown in SEQ ID NO: 2 or a fragment, analog, or derivative thereof;

 (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 29-787 in SEQ ID NO: 1 or the sequence of positions 1-1 769 in SEQ ID NO: 1 sequence.

 7. A recombination vector containing an exogenous polynucleotide, characterized in that it is a recombination constructed by the polynucleotide according to any one of claims 4-6 and a plasmid, virus or a carrier expression vector Carrier.

 8. A genetically engineered host cell containing an exogenous polynucleotide, 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 human dipeptide aminopeptidase ₂₈ activity, characterized in that the method includes:

 (a) culturing the engineered host cell of claim 8 under the condition of expressing human dipeptide aminopeptidase 28;

 (b) A polypeptide having human dipeptide aminopeptidase 28 activity is isolated from the culture.

10. An antibody capable of binding to a polypeptide, characterized in that the antibody is an antibody capable of specifically binding to human dipeptide aminopeptidase 28.

1 1. 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 human dipeptide aminopeptidase 28.

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

13. Use of the compound according to claim 11, characterized in that the compound is used for a method for regulating the activity of human dipeptide aminopeptidase 28 in vitro and in vivo.

 14. A method for detecting a disease or susceptibility to a disease associated with a polypeptide according to any one of claims 1-3, characterized in that it comprises detecting the expression level of the polypeptide, or detecting the activity of the polypeptide 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 for screening mimetics, agonists, antagonists or inhibitors of human dipeptide aminopeptidase 28; or Identification of peptide fingerprints.

 16. The use of a nucleic acid molecule according to any one of claims 4-6, 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 1 1, 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 abnormality of human dipeptide aminopeptidase 28.

18. Use of a polypeptide, polynucleotide or compound according to any one of claims 1 to 6 and 1 1, characterized in that the polypeptide, polynucleotide or compound is used for preparing a treatment such as a malignant tumor, Hematology, H IV infection and immune diseases and various types of inflammation drugs.