CN1307130A - Polypeptide-xylose isomerase 43 and polynucleotide for coding said polypeptide - Google Patents

Abstract

The present inventino discloses one new kind of polypeptide, xylose isomerase 43, polynucleotides encoding this polypeptide and DNA recombination process to produce the polypeptide. The present invention also discloses the method of applying the polypeptide in treating various diseases, such as malignant tumor, nosohemia, HIV infection, immunological diseases and inflammations. The present invention also discloses the antagnoist resisting the polypeptide and its treatment effect. The present invention also discloses the application of the polynucleotides encoding the xylose isomerase 43.

Description

New polypeptide-xylose isomerase 43 and polynucleotide coding such polypeptide

The present invention belongs to the field of biotechnology, and is especially one new kind of polypeptide, xylose isomerase 43 and its encoding polynucleotide sequence. The present invention also relates to the preparation process and application of the polynucleotides and polypeptides.

Xylose isomerase family proteins share a common feature in that each of their subunits is folded in a quartet form in a 222-symmetric tertiary structure, each monomer is composed of two domains, domain I is further folded (β/α) into an 8-barrel structure, domain II lacks the β sheet structure, and has extensive contacts with the linked subunits of domain I.

The activity of xylose isomerase depends on two divalent cations. They are bound to each monomer and are one of the structures essential for xylose isomerization activity. Crystal structure studies were performed on cation-free xylose isomerases and xylose isomerases bound by various substrates and inhibitors, and it was found that there are many reaction models for xylose isomerases as intermediates for many reaction pathways. These models in turn provide specific reaction mechanisms for various chemical reactions of xylose isomerase: a cyclic pathway catalyzed by activated histidine, isomerization by hydride conversion, and a cyclic closed pathway possibly catalyzed by polar water molecules. But more recently, high-definition X-ray structural maps, site mutation, and isotope exchange experiments have shown that this mechanism is achieved through a hydride transformation. The mechanism is described generally in the order of reaction as follows: ring opening, isomerization and ring reformation. In the catalytic step, the proton at the C2 atom on the substrate is first transferred to the proton acceptor, then the H atom of C2 is transferred as a hydride to C1, and finally the 01 anion accepts a proton from the proton acceptor.

In xylose isomerase, catalytic metal cations catalyze isomerization starting at the site of action a, moving to the site of action B during the action and staying all the way around the site of B, which is close to the substrate. The redistribution of nuclei during the catalysis process indicates that the metal ion acts as a lewis acid, which cleaves the substrate and catalyzes the hydride conversion. These metal ions may be magnesium ions, manganese ions or cobalt ions. One of these two cations is called a "structural cation" because it permanently occupies the binding site. This is consistent with the 02 and 04 atoms of the substrate. Other metal cations, known as "catalytic metals", are consistent with one imidazole group, one water molecule, and the carboxyl groups of three proteins.

The activation site for xylose isomerase is located in its octagonally folded α/β barrel structure, surrounded by several hydrophobic residues.A lysine located at position 183 plays a very critical role in the isomerization of xyloseChain epsilon-NH₃The radical providing a proton to the carboxyl group of the substrate to form a hydroxyl group, and ε -NH₃The group may be a proton donor.

Xylose isomerase catalyzing the reaction between aldose and ketoseThe reversible isomerization converts xylose to xylulose and glucose to fructose. This reaction begins sugar metabolism as it will . The specificity of this reaction makes xylose isomerase industrially very important and it can be used to produce high fructose corn syrup and alcohol. Also for the above reasons, xylose isomerase is very important for human metabolism. Its expression is abnormal, resulting in a series of metabolic diseases.

Since the xylose isomerase 43 protein plays an important role in the important functions in the body as described above and it is believed that a large number of proteins are involved in these regulatory processes, there is a continuing need in the art to identify more xylose isomerase 43 proteins involved in these processes, and in particular to identify the amino acid sequence of such proteins. The isolation of the gene encoding the novel xylose isomerase 43 protein also provides a basis for studies to determine the role of the protein in health and disease states. This protein may form the basis for the development of a disease diagnostic and/or therapeutic agent, and therefore, it is very important to isolate its encoding DNA.

It is an object of the present invention to provide an isolated novel polypeptide, xylose isomerase 43, and fragments, analogues and derivatives thereof.

Another objective 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 xylose isomerase 43.

It is another object of the present invention to provide a genetically engineered host cell containing a polynucleotide encoding xylose isomerase 43.

It is another object of the present invention to provide a method for producing xylose isomerase 43.

Another objective of the invention is to provide an antibody against xylose isomerase 43, which is a polypeptide of the invention.

Another objective of the invention is to provide mimetics, antagonists, agonists, and inhibitors for the polypeptide of xylose isomerase 43.

It is another object of the present invention to provide a method for diagnosing and treating diseases associated with abnormality of xylose isomerase 43.

The present invention relates to an isolated polypeptide, which is of human origin, comprising: 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 present invention also relates to an isolated polynucleotide comprising a nucleotide sequence 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 sharing at least 70% identity with the polynucleotide sequence of (a) or (b).

More preferably, the sequence of the polynucleotide is one selected from the group consisting of: (a) has the sequence of position 344-1507 in SEQ ID NO 1; and (b) has the sequence of 1-1719 in SEQ ID NO: 1.

The present invention furthermore relates to a vector, in particular an expression vector, comprising a polynucleotide according to the invention; a host cell genetically engineered with the vector, including transformed, transduced or transfected host cells; a method for producing the polypeptide of the present invention comprising culturing the host cell and recovering the expression product.

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

The invention also relates to a method for screening compounds that mimic, activate, antagonize, or inhibit the activity of xylose isomerase 43 protein, which comprises using the polypeptide of the invention. The invention also relates to the compounds obtained by this process.

The invention also relates to an in vitro method for detecting a disease or a disease susceptibility associated with abnormal expression of xylose isomerase 43 protein, which comprises detecting a mutation in the polypeptide or its encoding polynucleotide sequence in a biological sample, or detecting the amount or biological activity of the 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, activator, antagonist or inhibitor thereof and a pharmaceutically acceptable carrier.

The invention also relates to the use of the polypeptide and/or polynucleotide of the invention in the preparation of a medicament for the treatment of cancer, developmental or immune diseases or other diseases caused by abnormal expression of xylose isomerase 43.

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

The following terms used in the specification and claims have the following meanings, unless otherwise specified: "nucleic acid sequence" refers to an oligonucleotide, nucleotide or polynucleotide and fragments or portions thereof, and may also refer to genomic or synthetic DNA or RNA, which may be single-stranded or double-stranded, representing either 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 "amino acid sequence" in the present invention refers to the amino acid sequence of a naturally occurring protein molecule, such "polypeptide" or "protein" is not meant to limit the amino acid sequence to the complete natural amino acid associated with the protein molecule.

A protein or polynucleotide "variant" refers to an amino acid sequence having one or more amino acid or nucleotide changes or a polynucleotide sequence encoding it. The alteration may comprise a deletion, insertion or substitution of an amino acid or a nucleotide in the amino acid sequence or the nucleotide sequence. Variants may have "conservative" changes, where the substituted amino acid has similar structural or chemical properties as the original amino acid, such as the substitution of isoleucine with leucine. Variants may also have non-conservative changes, such as replacement of 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 a change in an amino acid sequence or nucleotide sequence resulting in an increase of one or more amino acids or nucleotides compared to the naturally occurring molecule. "substitution" refers to the replacement of one or more amino acids or nucleotides by different amino acids or nucleotides.

"biological activity" refers to a protein having the structural, regulatory, or biochemical functions of a native molecule. Similarly, the term "immunological activity" refers to the ability of natural, recombinant or synthetic proteins and fragments thereof to induce a specific immune response and to bind to specific antibodies in a suitable animal or cell.

An "agonist" is a molecule that, when bound to xylose isomerase 43, causes the protein to change, thereby modulating the activity of the protein. Agonists may include proteins, nucleic acids, carbohydrates, or any other molecule that can bind xylose isomerase 43.

An "antagonist" or "inhibitor" refers to a molecule that blocks or modulates the biological or immunological activity of xylose isomerase 43 when bound to xylose isomerase 43. Antagonists and inhibitors may include proteins, nucleic acids, carbohydrates or any other molecules that can bind xylose isomerase 43.

"modulation" refers to a change in the function of xylose isomerase 43, including an increase or decrease in protein activity, a change in binding characteristics, and a change in any other biological, functional, or immunological property of xylose isomerase 43.

By "substantially pure" is meant substantially free of other proteins, lipids, carbohydrates or other materials with which it is naturally associated. One skilled in the art can purify xylose isomerase 43 using standard protein purification techniques. Substantially pure xylose isomerase 43 produced a single main band on a non-reducing polyacrylamide gel. The purity of xylose isomerase 43 polypeptide can be analyzed by amino acid sequence analysis.

"complementary" or "complementation" refers to the natural binding of polynucleotides by base pairing under the conditions of salt concentration and temperature allowed. For example, the sequence "C-T-G-A" may bind to the complementary sequence "G-A-C-T". The complementarity between the 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, which may be partial or complete. "partial homology" refers to a partially complementary sequence that at least partially inhibits hybridization of a fully complementary sequence to a target nucleic acid. Inhibition of such hybridization can be detected by hybridization (Southern blot or Northern blot) under conditions of reduced stringency. Substantially homologous sequences or hybridization probes compete for and inhibit the binding of fully 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, as the conditions of reduced stringency require specific or selective interaction of the two sequences with each other.

"percent identity" refers to the percentage of sequence identity or similarity in a comparison of two or more amino acid or nucleic acid sequences. Percent identity can be determined electronically, such as by the MEGALIGN program (Lasergene software assembler, DNASTAR, Inc., Madison Wis.). MEGALIGN can compare two or more sequences according to different methods, such as the Cluster method (Higgins, D.G. and P.M.Sharp (1988) Gene 73: 237-.Cluster method arranges groups of sequences into clusters by checking the distance between all pairs. 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 percent identity between nucleic acid sequences can also be determined by Cluster method or by Methods well known in the art such as Jotun Hein (Hein J., (1990) Methods in emzumology 183: 625-.

"similarity" refers to the degree of identical or conservative substitution of amino acid residues at corresponding positions in the alignment between amino acid sequences. Amino acids 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; amino acids with uncharged head groups having similar hydrophilicity can 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. "antisense strand" refers to a nucleic acid strand that is complementary to the "sense strand".

"derivative" refers to HFP or a chemical modification of the nucleic acid encoding it. Such chemical modification may be replacement of a hydrogen atom with an alkyl group, an acyl group or an amino group. The nucleic acid derivative may encode a polypeptide that retains the main biological properties of the native molecule.

"antibody" refers to intact antibody molecules and fragments thereof, e.g., Fa, F (ab')₂And Fv, which specifically binds to an antigenic determinant of xylose isomerase 43.

"humanized antibody" refers to an antibody in which the amino acid sequence of the non-antigen binding region has been replaced to more closely resemble that of a human antibody, but which retains the original binding activity.

The term "isolated" refers to the removal of a substance from its original environment (e.g., its natural environment if it is naturally occurring). For example, a naturally occurring polynucleotide or polypeptide present in a living animal is not isolated, but the same polynucleotide or polypeptide is isolated from some or all of the materials with which it coexists in its natural system. Such polynucleotides may be part of a vector, or such polynucleotides or polypeptides may be part of a composition. Since the carrier or composition is not a component of its natural environment, it remains isolated.

As used herein, "isolated" refers to a substance that is separated from its original environment (which, if it is a natural substance, is the natural environment). If the polynucleotide or polypeptide in its native state in a living cell is not isolated or purified, the same polynucleotide or polypeptide is isolated or purified if it is separated from other substances coexisting in its native state.

As used herein, "isolated xylose isomerase 43" means that xylose isomerase 43 is essentially free of other proteins, lipids, carbohydrates or other materials with which it is naturally associated. One skilled in the art can purify xylose isomerase 43 using standard protein purification techniques. Substantially pure polypeptides are capable of producing a single major band on a non-reducing polyacrylamide gel. The purity of xylose isomerase 43 polypeptide can be analyzed by amino acid sequence analysis.

The present invention provides one new kind of polypeptide, xylose isomerase 43, which 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, a synthetic polypeptide, preferably a recombinant polypeptide. The polypeptides of the invention can be naturally purified products, or chemically synthesized products, or using recombinant technology from prokaryotic or eukaryotic hosts (e.g., bacteria, yeast, higher plant, insect and mammalian cells). Depending on the host used in the recombinant production protocol, the polypeptides of the invention may be glycosylated or may be non-glycosylated. The polypeptides of the invention may or may not also include an initial methionine residue.

The invention also includes fragments, derivatives and analogs of xylose isomerase 43. As used herein, the terms "fragment," "derivative," and "analog" refer to a polypeptide that retains substantially the same biological function or activity of the xylose isomerase 43 of the present invention. The fragment, derivative or analogue of the polypeptide of the invention may be: (ii) one in which one or more amino acid residues are substituted with a conserved or non-conserved amino acid residue (preferably a conserved amino acid residue), and the substituted amino acid may or may not be encoded by the genetic code; or (II) one in which one or more of the amino acid residues are substituted with other groups, including a substituent; or (iii) one in which the mature polypeptide is fused to another compound (such as a compound that increases the half-life of the polypeptide, e.g., polyethylene glycol); or (IV) a polypeptide sequence in which additional amino acid sequences are fused to the mature polypeptide (e.g., a leader or secretory sequence or a sequence used to purify the polypeptide or a proprotein sequence) by way of illustration herein, such fragments, derivatives and analogs are considered to be within the knowledge of those skilled in the art.

The present invention provides isolated nucleic acids (polynucleotides) consisting essentially 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 polynucleotides of the invention are found in cDNA libraries of human fetal brain tissue. It comprises a polynucleotide sequence of 1719 bases in full length, and its open reading frame 344-1507 encodes 387 amino acids. The polypeptide has a characteristic sequence of xylose isomerase family protein, and the structure and function of the xylose isomerase 43 represented by the xylose isomerase family protein can be deduced.

The polynucleotide of the present invention may be in the form of DNA or RNA. The form of DNA includes cDNA, genomic DNA or artificially synthesized DNA. The DNA may be single-stranded or double-stranded. The DNA may be the coding strand or the non-coding strand. The sequence of the coding region encoding the mature polypeptide may be identical to the sequence of the coding region shown in SEQ ID NO. 1 or may be a degenerate variant. As used herein, "degenerate variant" refers herein to a nucleic acid sequence that encodes a protein or polypeptide having SEQ ID NO.2, but differs from the sequence of the coding region shown in SEQ ID NO. 1.

The polynucleotide encoding the mature polypeptide of SEQ ID NO.2 comprises: only the coding sequence for the mature polypeptide; the coding sequence for the mature polypeptide and various additional coding sequences; the coding sequence (and optionally additional coding sequences) as well as non-coding sequences for the mature polypeptide.

The term "polynucleotide encoding a polypeptide" is meant to include polynucleotides encoding the polypeptide and polynucleotides including additional coding and/or non-coding sequences.

The present invention also relates to variants of the above-described polynucleotides which encode a polypeptide having the same amino acid sequence as the present invention or fragments, analogs and derivatives of the polypeptide. The variant of the polynucleotide may be a naturally occurring allelic variant or a non-naturally occurring variant. These nucleotide variants include substitution variants, deletion variants and insertion variants. As is known in the art, an allelic variant is a substitution of a polynucleotide, which may be a substitution, deletion, or insertion of one or more nucleotides, without substantially altering the function of the polypeptide encoded thereby.

The invention also relates to polynucleotides (having at least 50%, preferably 70% identity between two sequences) which hybridize to the sequences described above. The present invention particularly relates to polynucleotides which hybridize under stringent conditions to the polynucleotides of the present invention. In the present invention, "stringent conditions" mean: (1) hybridization and elution at lower ionic strength and higher temperature, such as 0.2 XSSC, 0.1% SDS,60 ℃; or (2) adding denaturant during hybridization, such as 50% (v/v) formamide, 0.1% calf serum/0.1% Ficoll,42 deg.C, etc.; or (3) hybridization occurs only when the identity between two sequences is at least 95% or 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 which hybridize to the sequences described above. As used herein, a "nucleic acid fragment" is at least 10 nucleotides, preferably at least 20-30 nucleotides, more preferably at least 50-60 nucleotides, and most preferably at least 100 nucleotides in length. The nucleic acid fragments may also be used in amplification techniques of nucleic acids (e.g., PCR) to determine and/or isolate a polynucleotide encoding xylose isomerase 43.

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

The specific polynucleotide sequence encoding xylose isomerase 43 of the present invention can be obtained in a variety of ways. 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 polynucleotide fragments with common structural features.

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

Among the above-mentioned methods, isolation of genomic DNA is least frequently used. Direct chemical synthesis of DNA sequences is a frequently used method. A more frequently 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 highly express the gene and reverse transcribe the mRNA to form a plasmid or phage cDNA library. There are a number of well-established techniques for extracting mRNA and kits are commercially available (Qiagene). The construction of cDNA libraries is also a common procedure (Sambrook, et a1., 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 techniques are used in combination, even very few expression products can be cloned.

The gene of the present invention can be screened from these cDNA libraries by a conventional method. These methods include (but are not limited to): (1) DNA-DNA or DNA-RNA hybridization; (2) the appearance or loss of function of a marker gene; (3) determining the level of a transcript of xylose isomerase 43; (4) the protein product of gene expression is detected by immunological techniques or by assaying for biological activity. The above methods can be used singly or in combination of multiple methods.

In method (1), the probe used for hybridization is homologous to any portion of the polynucleotide of the present invention, and has a length of at least 10 nucleotides, preferably at least 30 nucleotides, more preferably at least 50 nucleotides, and most preferably at least 100 nucleotides. In addition, the length of the probe is usually within 2000 nucleotides, preferably within 1000 nucleotides. The probe used herein is generally a DNA sequence chemically synthesized on the basis of the sequence information of the gene of the present invention. The gene of the present invention itself or a fragment thereof can of course be used as a probe. The DNA probe may be labeled with a radioisotope, fluorescein or an enzyme (e.g., alkaline phosphatase), etc.

In method (4), the detection of the protein product expressed by the xylose isomerase 43 gene can be carried out by immunological techniques such as Western blotting, radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), etc.

A method of amplifying DNA/RNA using PCR technology (Saiki, et al. Science 1985; 230: 1350-. Particularly, when it is difficult to obtain a full-length cDNA from a library, it is preferable to use the RACE method (RACE-cDNA terminal rapid amplification method), and primers used for PCR can be appropriately selected based on the sequence information of the polynucleotide of the present invention disclosed herein and synthesized by a conventional method. The amplified DNA/RNA fragments can be isolated and purified by conventional methods, such as by gel electrophoresis.

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

The invention also relates to vectors comprising the polynucleotides of the invention, as well as genetically engineered host cells engineered with the vectors of the invention or directly with the xylose isomerase 43 coding sequence, and methods for producing the polypeptides of the invention by recombinant techniques.

In the present invention, the polynucleotide sequence encoding xylose isomerase 43 may be inserted into a vector to constitute a recombinant vector containing the polynucleotide of the present invention. The term "vector" refers to a bacterial plasmid, bacteriophage, yeast plasmid, plant cell virus, mammalian cell virus such as adenovirus, retrovirus, or other vector well known in the art. Vectors suitable for use in the present invention include, but are not limited to: expression vectors based on the T7 promoter for expression in bacteria (Rosenberg, et al. Gene,1987,56: 125); pMSXND expression vector expressed in mammalian cells (Lee and Nathans, J Bio chem.263:3521,1988) and baculovirus-derived vectors expressed in insect cells. In general, any plasmid or vector can be used to construct a recombinant expression vector so long as it can replicate and is stable in the host. An important feature of expression vectors is that they typically contain an origin of replication, a promoter, a marker gene, and translational regulatory elements.

Methods well known to those skilled in the art can be used to construct a recombinant vector containing encoded xyloseThe DNA sequence of isomerase 43 and expression vector of suitable transcription/translation regulatory elements. These methods include in vitro recombinant DNA techniques, DNA synthesis techniques, in vivo recombinant techniques, etc. (Sambrook, et al molecular Cloning, a laboratory Manual, cold Spring Harbor laboratory. New York, 1989). The DNA sequence may be operably linked to a suitable promoter in an expression vector to direct mRNA synthesis. Representative examples of such promoters are: lac or trp promoter of E.coli; p of lambda phage_LA promoter; eukaryotic promoters include CMV immediate early promoter, HSV thymidine kinase promoter, early and late SV40 promoter, LTRs of retrovirus, and other known promoters capable of controlling the expression of genes in prokaryotic or eukaryotic cells or viruses. The expression vector also includes a ribosome binding site for translation initiation, a transcription terminator, and the like. The insertion of enhancer sequences into vectors will enhance transcription in higher eukaryotic cells. Enhancers are cis-acting elements of DNA, usually about 10 to 300 base pairs, that act on a promoter to increase transcription of a gene. Examples include the SV40 enhancer at the late side of the replication origin at 100 to 270 bp, the polyoma enhancer at the late side of the replication origin, and adenovirus 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 Fluorescent Protein (GFP) for eukaryotic cell culture, or tetracycline or ampicillin resistance for E.coli, and the like.

It will be clear to one of ordinary skill in the art how to select the appropriate vector/transcriptional regulatory element (e.g., promoter, enhancer, etc.) and selectable marker gene.

In the present invention, the polynucleotide encoding xylose isomerase 43 or the recombinant vector containing the polynucleotide may 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 prokaryotic cells, such as bacterial cells; or lower eukaryotic cells, such as yeast cells; or higher eukaryotic cells, such as mammalian cells. Representative examples are: escherichia coli, streptomyces; bacterial cells such as salmonella typhimurium; fungal cells such as yeast; a plant cell; insect cells such as Drosophila S2 or Sf 9; animal cells such as CHO, COS or Bowes melanoma cells.

Transformation of a host cell with a DNA sequence according to the invention or a recombinant vector containing said DNA sequence may be carried out by conventional techniques well known to those skilled in the art. When the host is prokaryote such as Escherichia coli, it can be absorbedCompetent cells of DNA can be harvested after exponential growth phase using CaCl₂Methods, the steps used are well known in the art. Alternatively, MgCl is used₂. If desired, transformation can also be carried out by electroporation. When the host is a eukaryote, the following DNA transfection methods may be used: calcium phosphate coprecipitation, or conventional mechanical methods such as microinjection, electroporation, liposome encapsulation, and the like.

The recombinant xylose isomerase 43 can be expressed or produced by conventional recombinant DNA techniques using the polynucleotide sequence of the present invention (Science, 1984; 224: 1431). Generally, the following steps are performed:

(1) transforming or transducing a suitable host cell with a polynucleotide (or variant) of the invention encoding human xylose isomerase 43, or with a recombinant expression vector containing the polynucleotide;

(2) culturing the host cell in a suitable medium;

(3) isolating and purifying the protein from the culture medium or the cells.

In step (2), the medium used in the culture may be selected from various conventional media depending on the host cell used. The culturing is performed under conditions suitable for growth of the host cell. After the host cells have been grown to an appropriate cell density, the selected promoter is induced by suitable means (e.g., temperature shift or chemical induction) and the cells are cultured for an additional period of time.

In step (3), the recombinant polypeptide may be encapsulated in the cell, or expressed on the cell membrane, or secreted out of the cell. If necessary, the recombinant protein can be isolated and purified by various separation methods using its 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, cell lysis by osmosis, sonication, ultracentrifugation, molecular sieve chromatography (gel filtration), adsorption chromatography, ion exchange chromatography, High Performance Liquid Chromatography (HPLC), and other various liquid chromatography techniques and combinations thereof.

The polypeptide of the present invention and the antagonist, the agonist and the inhibitor of the polypeptide can be directly used for treating diseases, such as malignant tumors, adrenal gland deficiency, skin diseases, various inflammations, HIV infection, immunological diseases, etc.

Crystal structure studies were performed on cation-free xylose isomerases and xylose isomerases bound by various substrates and inhibitors, and it was found that there are many reaction models for xylose isomerases as intermediates for many reaction pathways. Xylose isomerase catalyzes the reversible isomerization between aldose and ketose, converting xylose to xylulose and glucose to fructose. This reaction begins sugar metabolism as it will . It is important for the human body to act like enzymes in the conversion of metabolic substances and energy.

Sequences characteristic of the xylose isomerase family of proteins are essential for their biological activity.

The polypeptide of the invention is a polypeptide containing a characteristic sequence of the protein family, and the abnormal expression of the polypeptide can cause the abnormal conversion of substances and energy in metabolism and produce related diseases.

It can be seen that abnormal expression of xylose isomerase 43 according to the present invention will result in various diseases, especially organic acidemia, other substance metabolic disorders, various tumors, embryonic development disorders, including but not limited to:

organic acidemia: isovalerianaemia, propionemia, methylmalonic aciduria, combined carboxylase deficiency, glutaric acidemia type I

Dysbolic disorders selected from phenylketonuria, albinism, tryptophanaemia, glycinemia, glutamate metabolism deficiency, metabolic deficiency of the urea cycle, mucopolysaccharidosis types I-VII, mucolipidosis, Leonian syndrome, xanthine diabetes, orotic acid diabetes, adenosine deaminase deficiency, hyperlipoproteinemia, familial homo α -lipoproteinemia, congenital lactose intolerance, hereditary fructose intolerance, galactosemia, fructose metabolism deficiency, glycogen storage disease

Embryonic development disorders: congenital abortion, cleft palate, limb insufficiency, limb differentiation disorder, hyaline membrane disease, atelectasis, polycystic kidney, cryptorchism, congenital inguinal hernia, twin uterus, vaginal atresia, hypospadiae, amphoteric malformation, atrial septal defect, ventricular septal defect, pulmonary artery stenosis, patent ductus arteriosus, neural tube defect, congenital hydrocephalus, iris defect, congenital glaucoma or cataract, congenital deafness

Tumors of various tissues: gastric cancer, liver cancer, lung cancer, esophageal cancer, breast cancer, leukemia, lymphoma, thyroid tumor, uterine fibroids, neuroblastoma, astrocytoma, ependymoma, glioma, neurofibroma, colon cancer, melanoma, adrenal cancer, bladder cancer, bone cancer, osteosarcoma, myeloma, bone marrow cancer, uterine cancer, endometrial cancer, gallbladder cancer, colon cancer, thymic tumor, tumors of the nasal cavity and sinuses, nasopharyngeal cancer, laryngeal cancer, tracheal tumor, fibroma, fibrosarcoma, lipoma, liposarcoma, leiomyoma

Abnormal expression of xylose isomerase 43 according to the present invention will also result in certain genetic, hematological and immune system diseases, etc.

The polypeptide of the present invention and the antagonist, the agonist and the inhibitor of the polypeptide can be directly used for treating diseases, such as various diseases, especially organic acidemia, other substance metabolic disturbance diseases, various tumors, embryonic development disorder, certain hereditary, hematologic diseases, immune system diseases, etc.

The invention also provides methods of screening compounds to identify agents that increase (agonists) or inhibit (antagonists) xylose isomerase 43. Agonists enhance biological functions such as the stimulation of cell proliferation by xylose isomerase 43, while antagonists prevent and treat disorders associated with excessive cell proliferation such as various cancers. For example, mammalian cells or a membrane preparation expressing xylose isomerase 43 can be cultured together with the labeled xylose isomerase 43 in the presence of a drug. The ability of the agent to enhance or repress this interaction is then determined.

The antagonists of xylose isomerase 43 include antibodies, compounds, receptor deletants and analogues. Antagonists of xylose isomerase 43 bind to xylose isomerase 43 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 biological function.

In screening compounds for antagonists, xylose isomerase 43 can be added to a bioassay to determine whether a compound is an antagonist by determining its effect on the interaction between xylose isomerase 43 and its receptor. Receptor deletants and analogs that act as antagonists can be screened using the same methods described above for compounds. Polypeptide molecules capable of binding to xylose isomerase 43 can be obtained by screening a random polypeptide library consisting of various possible combinations of amino acids bound to a solid phase. In screening, the xylose isomerase 43 molecule should be generally labeled.

The present invention provides methods for producing antibodies using polypeptides, and fragments, derivatives, analogs, or cells thereof, as antigens. These antibodies may be polyclonal or monoclonal. The invention also provides antibodies directed against an epitope of xylose isomerase 43. These antibodies include (but are not limited to): polyclonal antibodies, monoclonal antibodies, chimeric antibodies, single chain antibodies, Fab fragments, and fragments produced by a Fab expression library.

Polyclonal antibody production can be achieved by direct injection of xylose isomerase 43 into immunized animals (such as rabbits, mice, rats, etc.), and various adjuvants can be used to enhance the immune response, including but not limited to Freund's adjuvant. Techniques for preparing monoclonal antibodies to xylose isomerase 43 include, but are not limited to, hybridoma technology (Kohler and Milstein. Nature,1975,256:495-497), trioma technology, human B-cell hybridoma technology, EBV-hybridoma technology, and the like. Chimeric antibodies that combine human constant regions with non-human variable regions can be produced using established techniques (Morrison et al, PNAS,1985,81: 6851). The existing technology for producing single-chain antibodies (U.S. Pat. No.4946778) can also be used for producing single-chain antibodies against xylose isomerase 43.

Antibodies against xylose isomerase 43 can be used in immunohistochemical techniques to detect xylose isomerase 43 in biopsy specimens.

Monoclonal antibodies that bind xylose isomerase 43 may also be labeled with a radioisotope, and injected into the body to track its location and distribution. The radiolabeled antibody can be used as a non-invasive diagnostic method for locating tumor cells and judging whether metastasis exists.

Antibodies can also be used to design immunotoxins directed to a particular site in the body. For example, a monoclonal antibody with high affinity for xylose isomerase 43 can be covalently bound to a bacterial or plant toxin (e.g., diphtheria toxin, ricin, ormosine, etc.). One common approach is to attack the amino group of the antibody with a thiol cross-linking agent such as SPDP and bind the toxin to the antibody by exchange of disulfide bonds, and this hybrid antibody can be used to kill cells positive for xylose isomerase 43.

Theantibodies of the present invention are useful for treating or preventing diseases associated with xylose isomerase 43. Administration of an appropriate dose of the antibody can stimulate or block the production or activity of xylose isomerase 43.

The invention also relates to diagnostic assays for quantitative and positional detection of xylose isomerase 43 levels. These assays are well known in the art and include FISH assays and radioimmunoassays. The level of xylose isomerase 43 detected in the assay can be used to explain the importance of xylose isomerase 43 in various diseases and to diagnose diseases in which xylose isomerase 43 plays a role.

The polypeptides of the invention may also be used for peptide profiling, for example, where the polypeptides may be specifically cleaved by physical, chemical or enzymatic means and subjected to one or two or three dimensional gel electrophoresis analysis, preferably mass spectrometry.

Polynucleotides encoding xylose isomerase 43 may also be used for a variety of therapeutic purposes. Gene therapy techniques can be used to treat cell proliferation, development or metabolic abnormalities due to the non-expression or abnormal/inactive expression of xylose isomerase 43. Recombinant gene therapy vectors (e.g., viral vectors) can be designed to express variant xylose isomerase 43 to inhibit endogenous xylose isomerase 43 activity. For example, a variant xylose isomerase 43 may be a shortened xylose isomerase 43 lacking a signaling domain, which binds to a downstream substrate but lacks signaling activity. Therefore, the recombinant gene therapy vector can be used for treating diseases caused by abnormal expression or activity of xylose isomerase 43. Expression vectors derived from viruses such as retrovirus, adenovirus, adeno-associated virus, herpes simplex virus, parvovirus, and the like can be used to transfer the polynucleotide encoding xylose isomerase 43 into cells. Methods for constructing recombinant viral vectors carrying a polynucleotide encoding xylose isomerase 43 can be found in the literature (Sambrook, et al.). Alternatively, the recombinant xylose isomerase 43-encoding polynucleotide may be packaged into liposomes for transfer into cells.

The method for introducing the polynucleotide into the tissue or the cell comprises: injecting the polynucleotide directly into the in vivo tissue; or introducing the polynucleotide into cells in vitro via a vector (e.g., a virus, phage, or plasmid), and then transplanting the cells into the body.

Oligonucleotides (including antisense RNA and DNA) and ribozymes that inhibit xylose isomerase 43 mRNA are also within the scope of the invention. Ribozymes are enzyme-like RNA molecules that specifically cleave specific RNAs and act by specifically hybridizing the ribozyme molecules with complementary target RNAs followed by endonucleolytic action. Antisense RNA and DNA and ribozymes can be obtained by any existing RNA or DNA synthesis techniques, such as solid phase phosphoramidite chemical synthesis method for oligonucleotide synthesis. Antisense RNA molecules can be obtained by in vitro or in vivo transcription of the DNA sequence encoding the RNA. This DNA sequence has been integrated into the vector downstream of the RNA polymerase promoter. In order to increase the stability of a nucleic acid molecule, it can be modified in various ways, such as increasing the length of the flanking sequences, using phosphothioester or peptide bonds instead of phosphodiester linkages for the linkages between ribonucleosides.

The polynucleotide encoding xylose isomerase 43 can be used for diagnosis of diseases associated with xylose isomerase 43. The polynucleotide encoding xylose isomerase 43 can be used to detect the presence or absence of expression of xylose isomerase 43 or abnormal expression of xylose isomerase 43 in a disease state. For example, a DNA sequence encoding xylose isomerase 43 can be used to hybridize biopsy specimens to determine the expression of xylose isomerase 43. The hybridization techniques include Southern blotting, Northern blotting, in situ blotting, etc. The technical methods are all published mature technologies, and related kits are all available from commercial sources. A part or all of the polynucleotide of the present invention can be immobilized as a probe on a Microarray (Microarray) or a DNA chip (also referred to as "gene chip") for analysis of differential expression of genes in tissues and gene diagnosis. The transcript of xylose isomerase 43 can also be detected by RNA-polymerase chain reaction (RT-PCR) in vitro amplification using primers specific for xylose isomerase 43.

Detection of mutations in the xylose isomerase 43 gene can also be used to diagnose diseases associated with xylose isomerase 43. The mutant forms of xylose isomerase 43 include point mutations, translocations, deletions, recombinations and any other abnormalities compared to the normal wild-type xylose isomerase 43 DNA sequence. The mutation can be detected by known techniques such as Southern blotting, DNA sequencing, PCR and in situ hybridization. In addition, since mutation may affect the expression of protein, the presence or absence of mutation in a gene can be indirectly determined by Northern blotting or Western blotting.

The sequences of the invention are also valuable for chromosome identification. The sequence will be specific for a particular location on a human chromosome and will hybridize to it. Currently, there is a need to identify specific sites on each gene on the chromosome. Currently, only few chromosomal markers based on actual sequence data (repeat polymorphisms) are available for marking chromosomal locations. According to the present invention, the first step important in correlating these sequenceswith disease-associated genes is the mapping of these DNA sequences to chromosomes.

Briefly, PCR primers (preferably 15-35bp) are prepared from the cDNA and the sequence can be mapped to the chromosome. These primers were then used for PCR screening of somatic cell hybrids containing individual human chromosomes. Only those heterozygous cells containing the human gene corresponding to the primer will produce amplified fragments.

The PCR mapping method of somatic cell heterozygous cell is a rapid method for mapping DNA to specific chromosome. Using the oligonucleotide primers of the present invention, sublocalization can be achieved using a panel of fragments from a particular chromosome or a large number of genomic clones by similar methods. Other similar strategies that can be used for chromosome mapping include in situ hybridization, prescreening with labeled flow sorted chromosomes, and preselection by hybridization to construct chromosome-specific cDNA libraries.

Fluorescence In Situ Hybridization (FISH) of cDNA clones to metaphase chromosomes allows accurate chromosomal location in one step. For a review of this technology, see Verma et al, Human Chromosomees: a Manual of Basic Techniques, Pergamon Press, New York (1988).

Once a sequence is located at an exact chromosomal location, the physical location of the sequence on the chromosome can be correlated with genetic map data. These data can be found, for example, in V.Mckusick, Mendelian Inheritance in Man (available online with Johns Hopkins University Welch Medical Library). The relationship between the gene and the disease that has been mapped to the chromosomal region can then be determined by linkage analysis.

Next, it is necessary to determine the differences in cDNA or genomic sequence between affected and unaffected individuals. If a mutation is observedin some or all of the affected individuals, but not in any normal individuals, then the mutation may be the cause of the disease. Comparing diseased and non-diseased individuals generally involves first looking for structural changes in the chromosome, such as deletions or translocations that are visible from the chromosomal level or detectable using PCR based cDNA sequences. Based on the resolution of current physical mapping and gene mapping techniques, cDNAs that are precisely mapped to chromosomal regions associated with disease can be one of 50 to 500 potential disease-causing genes (assuming 1 megabase mapping resolution and one gene per 20 kb).

The polypeptides, polynucleotides and mimetics, agonists, antagonists and inhibitors of the invention may 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 a carrier and an excipient which do not affect the effect of the medicine. These compositions can be used as medicaments for the treatment of diseases.

The invention also provides a kit or kit comprising one or more containers filled with one or more of the ingredients of the pharmaceutical compositions of the invention. Along with these containers, there may be an instructional cue given by a governmental regulatory agency that regulates the manufacture, use or sale of pharmaceuticals or biological products, which cue reflects approval by the governmental agency of manufacture, use or sale for human administration. In addition, the polypeptides of the invention may be used in combination with other therapeutic compounds.

The pharmaceutical compositions may be administered in a convenient manner, such as by topical, intravenous, intraperitoneal, intramuscular, subcutaneous, intranasal or intradermal routes ofadministration. Xylose isomerase 43 is administered in an amount effective to treat and/or prevent the particular indication. The amount of xylose isomerase 43 to be administered to the patient and the dosage range will depend on many factors, such as the mode of administration, the health condition of the subject to be treated and the judgment of the diagnosing physician.

The following drawings are included to illustrate specific embodiments of the invention and are not intended to limit the scope of the invention as defined by the claims.

FIG. 1 is a comparison of the amino acid sequence homology between xylose isomerase 43 of the present invention and a protein of the xylose isomerase family of the structural domain. The upper sequence is xylose isomerase 43 and the lower sequence is the domain xylose isomerase family protein. Identical amino acids are represented by one-character amino acids between the two sequences, and similar amino acids are represented by "+".

FIG. 2 is a polyacrylamide gel electrophoresis (SDS-PAGE) of the isolated xylose isomerase 43. 43kDa is the molecular weight of the protein. The arrow indicates the isolated protein band.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Experimental procedures without specific conditions noted in the following examples, molecular cloning is generally performed according to conventional conditions such as Sambrook et al: the conditions described in the Laboratory Manual (New York: Cold spring harbor Laboratory Press,1989), or according to the manufacturer's recommendations. Example 1:cloning of xylose isomerase 43

Extraction of human fetal brain Total RNA by the one-step method of guanidinium isothiocyanate/phenol/chloroform extraction of Poly (A) mRNA.2ug Poly (A) from Total RNA by reverse transcription with Quik mRNA Isolation Kit (Qiagene products) to form cDNA by reverse transcription, directed insertion of cDNA fragments into the multiple cloning site of pBSK (+) vector (Clontech) using Smart cDNA cloning Kit (Clontech), transformation of DH5 α, formation of cDNA library by bacteria comparison of 5 'and 3' end sequences of all clones with Dyetermate cycle sequencing Kit (Perkin-Elmer products) and ABI 377 automatic sequencer (Perkin-Elmer products), comparison of the determined cDNA sequence with the existing public DNA sequence database (Genebank), finding that one of the cDNA sequences named as cDNA 24g12 is a novel DNA, determination of the inserted cDNA fragment by synthesizing a series of primers, determination of the full-length cDNA sequence of the clone contained in this clone No. 17124 g cDNA as shown in the sequence of the open reading frame No. 2. the cDNA encoding the full-length protein found in this example No. 1-DNA sequence found by the two-way of the sequence of the cDNA clone No. 17124 g cDNA sequence found in this example No. 1, the sequence found by the two-way, the analysis of the sequence of the cDNA sequence found that the cDNA included in the clone No. 3 g cDNA was found in this clone No. 3 g cDNA was found, the sequence of the clone No. 3 was found, the sequence of the clone found in the clone No. 3 was found, the sequence of the clone No. 3. the clone was found

The sequence of xylose isomerase 43 of the present invention and the protein sequence encoded by it were determined by using the profile scan program (basic Alignment search tool) in GCG [ Altschul, SF et al.J.mol.biol.1990; 215:403-10], domain analysis was performed in the database of prosite et al. The xylose isomerase 43 of the present invention has homology with the domain xylose isomerase family protein, and the results of homology are shown in FIG. 1. Example 3: cloning of the Gene encoding xylose isomerase 43 by RT-PCR

cDNA was synthesized by reverse transcription using total fetal brain cell RNA as a template and oligo-dT as a primer, purified using Qiagene's kit, and then amplified by PCR using the following primers:

Primer1:5’-CGAGCAGGAGCAGCGACGGCACAC-3’(SEQ ID NO:3)

Primer2:5’-AAAACAAATTATTTTATTAAGTGC-3’(SEQ ID NO:4)

primer1 is the forward sequence starting at the 1bp located 5' to SEQ ID NO 1;

primer2 is the 3' reverse sequence of SEQ ID NO: 1.

Conditions of the amplification reaction: 50mmol/L KCl,10mmol/L Tris-Cl, (pH8.5),1.5mmol/L MgCl in a reaction volume of 50. mu.l₂200. mu. mol/L dNTP,10pmol primer, 1U of Taq DNA polymerase (product of Clontech corporation) was reacted on a DNA thermal cycler model PE9600 (Perkin-Elmer corporation) for 25 cycles under the conditions of 94 ℃ for 30sec, 55 ℃ for 30sec, 72 ℃ for 2min, β -action as a positive control and a template blank as a negative control at the time of RT-PCR, the amplified product was purified with a QIAGEN kit, ligated to a pCR vector (product of Invitrogen) with a TA cloning kit, and the DNA sequence analysis result showed that the DNA sequence of the PCR product was completely identical to 1-1719bp shown in SEQ ID NO: 1.Example 4: northern blot analysis of expression of xylose isomerase 43 gene:

total RNA was extracted by one-step method [ anal. biochem 1987,162, 156-159-]. The method comprises acidic guanidinium thiocyanate phenol-chloroform extraction. I.e., the tissue was homogenized with 4M guanidinium isothiocyanate-25 mM sodium citrate, 0.2M sodium acetate (pH4.0), 1 volume phenol and 1/5 volumes chloroform-isoamyl alcohol (49: 1) were added, mixed and centrifuged. The aqueous layer was aspirated, isopropanol (0.8 vol) was added and the mixture was centrifuged to obtain RNA precipitate. The resulting RNA precipitate was washed with 70% ethanol, dried and dissolved in water. With 20. mu.g of RNA in 20mM 3- (N-morpholino) propanesulfonic acidAcid (pH7.0) -5mM sodium acetate-1 mM EDTA-2.2M Formaldehyde on a 1.2% agarose gel for electrophoresis, then transferred to a nitrocellulose membrane using α -³²P dATP prepared by random primer method³²P-labeled DNA probes. The DNA probe used was the PCR-amplified xylose isomerase 43 coding region sequence (344bp to 1507bp) shown in FIG. 1. 32P-labeled Probe (about 2X 10)⁶cpm/ml) was hybridized with RNA-transferred nitrocellulose membrane overnight at 42 ℃ in a solution containing 50% formamide-25 mM KH₂PO₄(pH7.4) -5 XSSC-5 XDenhardt's solution and 200. mu.g/ml salmon sperm DNA. After hybridization, the filters were washed in 1 XSSC-0.1% SDS at 55 ℃ for 30 min. Then, analysis and quantification were performed using a Phosphor Imager. Example 5: in vitro expression, isolation and purification of recombinant xylose isomerase 43

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

Primer3:5’-CATGCTAGCATGCAGGCTGACAAGACCAAGGCA-3’(Seq ID No:5)

Primer4:5’-CATGGATCCTTACATGAATTTCAGTTTGGGTTC-3’(Seq ID No:6)

the 5 ' ends of these two primers contain NheI and BamHI cleavage sites, respectively, followed by coding sequences at the 5 ' end and 3 ' end of the gene of interest, respectively, and the NheI and BamHI cleavage sites correspond to the selective endonuclease sites on the expression vector plasmidpET 28b (+) (Novagen, Cat. No. 69865.3). Using pBS-0424g12 plasmid containing the full-length gene of interest as a template, PCR was performed under conditions of 10pmol of pBS-0424g12 plasmid 10, Primer-3 and Primer-4, respectively, 10pmol of Advantage polymerase Mix (Clontech) in a total volume of 50. mu.l, 1. mu.l of cycle parameters: 94. 20s at 94 ℃, 30s at 60 ℃ for 2min at 68 ℃,25 cycles, double digestion of NheI and BamHI amplified products and plasmid pET-28(+) with DNA, respectively, recovering large fragments, ligating the products with sequencing enzyme, ligating the products with the DNA, obtaining a DNA, cloning products, transferring the amplified products to a DNA fragment containing DNA sequence of Escherichia coli DNA, after centrifugation, the DNA sequence obtained by the PCR, the method of PCR, the DNA cloning, the DNA sequence obtained by adding the DNA fragment DNA sequence obtained by the method of DNA fragment DNA, DNA fragment DNA, DNA fragment DNA, DNA fragment DNA

The following xylose isomerase 43-specific polypeptides were synthesized using a polypeptide synthesizer (product of PE Co.):

NH₂-Met-Gln-Ala-Asp-Lys-Thr-Lys-Ala-Ala-Asp-Leu-Arg-Ala-Ala-Tyr-COOH (SEQ ID NO: 7). The polypeptide is respectively coupled with hemocyanin and bovine serum albumin to form a complex, and the method is as follows: avarameas, et al, immunochemistry, 1969; 6:43. 4mg of the hemocyanin polypeptide compound and complete Freund's adjuvant are used for immunizing rabbits, and the hemocyanin polypeptide compound and the complete Freund's adjuvant are used for boosting immunization once after 15 days. The titer of antibody in rabbit serum was determined by ELISA using a titer plate coated with 15. mu.g/ml bovine serum albumin polypeptide complex. Total IgG was isolated from antibody-positive rabbit sera using protein A-Sepharose. The polypeptides were bound to a cyanogen bromide activated Sepharose4B column and anti-polypeptide antibodies were separated from total IgG by affinity chromatography. Immunoprecipitation demonstrated that the purified antibody specifically bound to xylose isomerase 43. Example 7: use of the Polynucleotide fragments of the invention as hybridization probes

The selection of suitable oligonucleotide fragments from the polynucleotide of the present invention can be used as hybridization probes for identifying whether they contain the polynucleotide sequence of the present invention and detecting homologous polynucleotide sequences, and for detecting whether the expression of the polynucleotide sequence of the present invention or its homologous polynucleotide sequence in normal tissue or pathological tissue cells is abnormal.

The object of this example is to select suitable oligonucleotide fragments from the polynucleotide of the invention SEQ ID NO. 1 for use as hybridization probes and to identify tissues containing the polynucleotide sequence of the invention or its homologous polynucleotide sequences by filter hybridization. Filter hybridization methods include dot blotting, Southern blotting, Northern blotting, and replica methods, all of which are methods in which a polynucleotide sample to be tested is immobilized on a filter and then hybridized by substantially the same procedure. These same steps are: the filter on which the sample is immobilized is first prehybridized with a hybridization buffer that does not contain a probe so that the nonspecific binding sites of the sample on the filter are saturated with the support and synthetic polymer. The prehybridization buffer is then replaced with a hybridization buffer containing labeled probes and incubated to allow hybridization of the probes to the target nucleic acids. Following the hybridization step, unhybridized probes are removed by a series of membrane washing steps. This example utilizes higher intensity membrane wash conditions (e.g., lower salt concentration and higher temperature) to reduce hybridization background and retain only a highly specific signal. The probes selected for this embodiment include two types: the first type of probe is an oligonucleotide fragment that is identical or complementary to the polynucleotide of the invention, SEQ ID NO 1; the second type of probe is an oligonucleotide fragment, the part of which is identical or complementary to the polynucleotide of the invention, SEQ ID NO 1. In this embodiment, the dot blot method is used to fix the sample on the filter membrane, and the hybridization specificity of the first type probe and the sample is the strongest and is retained under the condition of higher-strength membrane washing. First, selection of probe

The selection of oligonucleotide fragments for use as hybridization probes from the polynucleotide of the invention, SEQ ID NO 1, follows the following principles and several aspects to be considered: 1, the size of the probe is preferably 18-50 nucleotides; 2, the GC content is 30-70%, and when the GC content exceeds the GC content, non-specific hybridization is increased; 3, no complementary region should be arranged in the probe; 4, those satisfying the above conditions can be used as primary probes, and then further subjected to computer sequence analysis, including the primary probes

The selection probes are respectively related to the region of the source sequence (i.e. SEQ ID NO:1) and other known genome sequences and

the complementary regions are compared for homology, if the homology with the non-target molecule region is more than 85% or more than 15

If the consecutive bases are identical, the primary probe should not be used; whether the initially selected probe is finally selected as a probe having practical application value should be further determined by experiments.

After the above analysis, the following two probes were selected and synthesized:

probe 1(probe1), belonging to the first category of probes, is completely homologous or complementary to the gene fragment of SEQ ID NO:1 (41 Nt):

5’-TGCAGGCTGACAAGACCAAGGCAGCCGACCTGCGTGCCGCC-3’(SEQ ID NO:8)

probe 2(probe2), belonging to the second category of probes, corresponds to the substitution mutation sequence (41Nt) of the gene fragment of SEQ ID NO:1 or its complementary fragment:

5’-TGCAGGCTGACAAGACCAAGCCAGCCGACCTGCGTGCCGCC-3’(SEQ ID NO:9)

for other common reagents and their formulation methods not listed in connection with the following specific experimental procedures, reference is made to the literature: DNA PROBES g.h.keller; man ak, m.m.manak; stockton Press,1989(USA) and more generally books of molecular cloning, A laboratory Manual, scientific Press, molecular cloning, A guide to molecular cloning (second edition 1998) [ U.S.]SammBruk et al.

Sample preparation: 1, extraction of DNA from fresh or frozen tissue

The method comprises the following steps: 1) fresh or freshly thawed normal liver tissue is placed in a dish soaked on ice and containing Phosphate Buffered Saline (PBS). The tissue is cut into small pieces with scissors or a scalpel. Tissue should be kept moist during the procedure. 2)The minced tissue was centrifuged at 1000g for 10 minutes. 3) The slurry was homogenized with cold homogenization buffer (0.25mol/L sucrose; 25mmol/LTris-HCl, pH 7.5; 25 mmol/LnaCl; 25mmol/L MgCl₂) The pellet was suspended (approximately 10 ml/g). 4) At 4 deg.CThe tissue suspension was homogenized at full speed with an electric homogenizer until the tissue was completely disrupted. 5) Centrifuge at 1000g for 10 min. 6) Resuspend the cell pellet (1-5 ml per 0.1g of initial tissue sample) and centrifuge at 1000g for 10 min. 7) The pellet was resuspended in lysis buffer (1 ml per 0.1g of initial tissue sample) and then subjected to the following phenol extraction procedure. 2, phenol extraction of DNA

The method comprises the following steps: 1) cells were washed with 1-10ml cold PBS and centrifuged at 1000g for 10 min. 2) Resuspending the pelleted cells with Cold cell lysate (1X 10)⁸Cells/ml) a minimum of 100ul lysis buffer was used. 3) Adding SDS to a final concentration of 1%, if SDS is added directly to the cell pellet before resuspending the cells, the cells may form large clumps that are difficult to break, and overall yield is reduced. This is at extraction>10⁷Cells are particularly severe. 4) Proteinase K was added to a final concentration of 200 ug/ml. 5) The reaction was incubated at 50 ℃ for 1 hour or shaken gently overnight at 37 ℃. 6) Extracted with equal volumes of phenol, chloroform, isoamyl alcohol (25: 24: 1) and centrifuged in a small centrifuge tube for 10 minutes. The two phases are clearly separated, otherwise centrifugation is carried out again. 7) The aqueous phase was transferred to a new tube. 8) Extracted with chloroform isoamyl alcohol (24: 1) of equal volume and centrifuged for 10 minutes. 9) The aqueous phase containing the DNA was transferred to a new tube. Then, DNA purification and ethanol precipitation were performed. 3, DNA purification and ethanol precipitation

The method comprises the following steps: 1) 1/10 volumes of 2mol/L sodium acetate and 2 volumes of cold 100% ethanol were added to the DNA solution and mixed well. Left at-20 ℃ for 1 hour or overnight. 2) Centrifuge for 10 minutes. 3) Carefully aspirate or pour out the ethanol. 4) The pellet was washed with 500ul of 70% cold ethanol and centrifuged for 5 minutes. 5) Carefully aspirate or pour out the ethanol. The pellet was washed with 500ul cold ethanol and centrifuged for 5 minutes. 6) Carefully suck out or pour out the ethanol and invert it on absorbent paper to drain off the residual ethanol. Air-drying for 10-15 minutes to evaporate the surface ethanol. Care was taken not to completely dry the pellet, otherwise it was difficult to re-dissolve. 7) Resuspend the DNA pellet in a small volume of TE or water. Vortex at low speed or blow with dropper while gradually increasing TE, mixing until DNA is fully dissolved, each 1-5 × 10⁶The cell extracts approximately 1ul of force.

The following steps 8-13 are only used when contamination has to be removed, noStep 14 may be performed directly. 8) RNase A was added to the DNA solution at a final concentration of 100ug/ml and incubated at 37 ℃ for 30 minutes. 9) SDS and proteinase K were added to final concentrations of 0.5% and 100ug/ml, respectively. Incubate at 37 ℃ for 30 minutes. 10) The reaction mixture was extracted with phenol, chloroform and isoamyl alcohol (25: 24: 1) at equal volumes and centrifuged for 10 minutes. 11) The aqueous phase was carefully removed, re-extracted with an equal volume of chloroform to isoamyl alcohol (24: 1), and centrifuged for 10 minutes. 12) The aqueous phase was carefully removed, 1/10 volumes of 2mol/L sodium acetate and 2.5 volumes of cold ethanol were added, mixed well and placed at-20 ℃ for 1 hour. 13) Washing the pellet with 70% ethanol and 100% ethanol, air drying, and resuspending the nucleic acids in the same manner as in steps 3-6. 14)Measurement A₂₆₀And A₂₈₀To check the purity and yield of DNA. 15) Subpackaging and storing at-20 ℃. Preparation of sample films:

1) 4X 2 pieces of nitrocellulose membrane (NC membrane) of appropriate size were taken, and the spotting position and the number were lightly marked with a pencil, two pieces of NC membrane were required for each probe, so that the membranes were washed with high-intensity conditions and intensity conditions, respectively, in the following experimental steps.

2) Pipette 15. mu.l of each sample and control, spot onto the membrane, and dry at room temperature.

3) The resulting mixture was placed on a filter paper impregnated with 0.1mol/L NaOH and 1.5mol/L NaCl for 5 minutes (twice), air-dried, placed on a filter paper impregnated with 0.5mol/L Tris-HCl (pH7.0) and 3mol/L NaCl for 5 minutes (twice), and air-dried.

4) Clamping in clean filter paper, wrapping with aluminum foil, and vacuum drying at 60-80 deg.C for 2 hr.

Labeling of probes

1) Mu.l Probe (0.1 OD/10. mu.l), 2. mu.l Kinase buffer, 8-10 uCi. gamma. -³²P-dATP +2UKinase, to a final volume of 20. mu.l.

2) Incubate at 37 ℃ for 2 hours.

3) Add 1/5 volumes of bromophenol blue indicator (BPB).

4) Passing through SePhadex G-50 column.

5) To have³²The first peak (which can be monitored by Monitor) begins to collect before the P-Probe is washed out.

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

7) Monitoring isotope content with liquid scintillation meter

8) The collected liquid of the first peak is combined to obtain the product³²P-Probe (second peak is free gamma-³²P-dATP)。

Prehybridization

The membrane was placed in a plastic bag, 3-10mg of prehybridization solution (10 XDenhardt's; 6 XSSC, 0.1mg/ml CT DNA (calf thymus DNA)) was added, the bag was sealed, and shaken in a water bath at 68 ℃ for 2 hours.

Hybridization of

Cutting off a corner of the plastic bag, adding the prepared probe, sealing the bag opening, and then shaking overnight in a water bath at 42 ℃.

Washing the membrane: high-strength membrane washing:

1) and taking out the hybridized sample membrane.

2) Wash in 2 XSSC, 0.1% SDS at 40 ℃ for 15 min (2 times).

3)0.1 XSSC, 0.1% SDS, for 15 minutes (2 times) at 40 ℃.

4)0.1 XSSC, 0.1% SDS, washed at 55 ℃ for 30 minutes (2 times), and air-dried at room temperature. And (3) low-strength membrane washing:

1) and taking out the hybridized sample membrane.

2) Wash in 2 XSSC, 0.1% SDS at 37 ℃ for 15 min (2 times).

3)0.1 XSSC, 0.1% SDS, for 15 minutes (2 times) at 37 ℃.

4)0.1 XSSC, 0.1% SDS, for 15 minutes (2 times) at 40 ℃ and air-dried at room temperature.

X-ray self-development:

x-ray autoradiography (the tabletting time depends on the radioactivity of the hybridization spots) at-70 ℃.

The experimental results are as follows:

the hybridization experiment is carried out under the condition of low-strength membrane washing, and the radioactivity of the hybridization spots of the two probes is not obviously different; in the hybridization experiment performed under the high-intensity membrane washing condition, the radioactive intensity of the hybridization spot of the probe1 is obviously stronger than that of the other probe. Thus, probe1 can be used to qualitatively and quantitatively analyze the presence and differential expression of the polynucleotides of the present invention in different tissues. Example 8 DNA Microarray

The gene chip or gene Microarray is anew technology developed and developed by many national laboratories and major pharmaceutical companies, and it means that a large number of target gene fragments are orderly arranged on carriers such as glass, silicon and the like in high density, and then data comparison and analysis are performed by fluorescence detection and computer software, so as to achieve the purpose of analyzing biological information rapidly, efficiently and in high flux. The polynucleotide of the present invention can be used as a target DNA for gene chip technology for high-throughput research of new gene functions; searching and screening new tissue-specific genes, particularly new genes related to diseases such as tumor and the like; diagnosis of a disease, such as a genetic disease. The specific process steps have been reported in the literature, for example, in DeRisi, J.L., Lyer, V.&Brown, P.O. (1997) Science278,680-686, Helle, R.A., Schema, M., Chai, A., Shalom, D., (1997) PNAS 94:2150-

The total of 4000 different full-length cDNAs were used as target DNAs, including the polynucleotide of the present invention. They were amplified by PCR, the resulting amplification products were purified and then the concentration thereof was adjusted to about 500ng/ul, and spotted on a glass medium with a spotting instrument of Cartesian 7500 (from Cartesian, USA) at a distance of 280 μm from the spot. Hydrating and drying the spotted glass slide, placing the glass slide in an ultraviolet crosslinking instrument for crosslinking, eluting and drying the glass slide to fix the DNA on the glass slide to prepare the chip. The concrete steps of the method are reported in the literature, and the sample application post-treatment step of the embodiment is as follows:

1. hydrating in a humid environment for 4 hours;

2.0.2% SDS for 1 minute;

3．ddH₂o washes twice, each for 1 minute;

4．NaBH₄sealing for 5 minutes;

water at 5.95 ℃ for 2 minutes;

6.0.2% SDS for 1 minute;

7．ddH₂flushing twice;

8. air-dried and stored in the dark at 25 ℃ for later use. (II) Probe labeling

Total mRNA was extracted from normal liver and liver cancer, respectively, by a one-step method, and mRNA was purified using Oligotex mRNA Midi Kit (purchased from QiaGen), mRNA of normal liver tissue was labeled with a fluorescent reagent Cy3dUTP (5-Amino-propyl-2 '-deoxyuridine 5' -triphosphate coupled to Cy3 fluorescent dye, respectively, purchased from Amersham pharmacia Biotech, Amersham pharmacia Biotech) by reverse transcription, mRNA of liver tissue was labeled with a fluorescent reagent Cy5dUTP (5-Amino-propyl-2 '-deoxyuridine 5' -triphosphate coupled to Cy5fluorescent dye, purchased from Amersham pharmacia Biotech), and mRNA of liver tissue was prepared after purification. The specific steps refer to and the method is as follows: schena, M., Shalon, D., Heller, R. (1996) Proc.Natl.Acad.Sci.USA.Vol.93:10614-10619.Schena, M., Shalon, Dari., Davis, R.W. (1995) science.270.(20):467-

Separately putting probes from the above two tissues together with the chip in UniHyb^TMHybridization was carried out in hybridization solution (available from TeleChem) for 16 hours, washed with washing solution (1 XSSC, 0.2% SDS) at room temperature, scanned with ScanArray 3000 scanner (available from General screening, USA), and the scanned images were subjected to data analysis using Imagene software (available from Biodiscovery, USA), and a ratio of Cy3/Cy5 was calculated for each spot, and a spot having a ratio of less than 0.5 and greater than 2 was considered to be a gene whose expression was differentiated. The experimental results show that the expression of the polynucleotide of the present invention in the above two tissues has no significant difference in Cy3 signal =4809.78 (averaged over four experiments), Cy5signal =4444.62 (averaged over four experiments), and Cy3/Cy5= 1.08216.

Sequence listing (1) general information:

(ii) name of the invention: xylose isomerase 43 and its coding sequence

(iii) number of sequences: 9(2) information of SEQ ID NO:1:

sequence characteristics:

(A) length: 1719bp

(B) Type (2): nucleic acids

(C) Chain property: double chain

(D) Topological structure: linearity

(ii) type of molecule: cDNA

(xi) sequence description: SEQ ID NO 1: 1 CGAGCAGGAGCAGCGACGGCACACGGCCTACATTTCGGAGCTCAAGGCCAAGCTGCATGA 61 GGAGAAGACCAAGGAGCTGCAGGCGCTGCGCGAGGGGCTCATCCGGCAGCACGAGCAGGA121 GGTGGCGCGCACCGCCAAGATCAAGGAGGGCGAGCTGCAGCGGCTGCAGGCCACGCTGAA181 CGTGCTGCGCGACGGCGCGGCCGACAAGGTCAAGACGGCGCTGCTGACCGAGGCGCGCGA241 GGAGGCGCGCAGGGCCTTCGATGGAGAGCGCCTGCGGCTGCAGCAGGAGATCCTGGAGCT301 CAAGGCAGCGCGCAAGCAGGCAGAGGAGGCGCTCAGTAACTGCATGCAGGCTGACAAGAC361 CAAGGCAGCCGACCTGCGTGCCGCCTACCAGGCGCACCAAGACGAGGTGCACCGCATCAA421 GCGCGAGTGCGAGCGCGACATCCGCAGGCTGATGGATGAGATCAAAGGGAAAGACCGTGT481 GATTCTGGTCTTGGAGAAGGAACTTGGCGTGCAGGCTGGGCAGACCCAGAAGCTGCTTCT541 GCAGAAAGAGGCTTTGGATGAGCAGCTGGTTCAGGCCAAGGAGGCCGAGCGGCACCACAG601 TAGTCCAAAGAGAGAGCTCCCGCCCGGGATCGGGGACATGGTGGAGCTCATGGGCGTCCA661 GGATCAACATATGGACGAGCGAGATGTGAGGCGATTTCAACTAAAAATTGCTGAACTGAA721 TTCAGTGATACGGAAGCTGGAAGACAGAAATACGCTGTTGGCAGATGAGAGGAATGAACT781 GCTGAAACGCTCACGAGAGACCGAGGTTCAGCTGAAGCCCCTGGTGGAGAAGAACAAGCG841 GATGAACAAGAAGAATGAGGATCTGTTGCAGAGTATCCAGAGGATGGAGGAGAAAATCAA901 GAACCTCACGCGGGAAGACGTGGAAATGAAGCATGTTGTGGAGACATTTTTTGGATTTGA 961 TGAGGAGTCTGTGGACTCAGAAACGTTGTCCGAAACATCCTACAACACAGACAGGACAGA1021 CAGGACCCCAGCCACGCCCGAAGAAGACTTGGACGATGCCACAGCCCGAGAGGAGGCTGA1081 CCTGCGCTTCTGCCAGCTGACCCGGGAGTACCAGGCCCTGCAACGCGCCTACGCCCTGCT1141 CCAGGAGCAGGTGGGAGGCACGCTGGACGCTGAGAGGGAGGCCCGGACTCGGGAGCAGCT1201 ACAAGCTGATCTGCTGAGGTGTCAGGCCAAAATCGAAGATTTGGAGAAGTTACTGGTTGA1261 GAAGGGACAGGATTCCAAGTGGGTTGAAGAGAAGCAGCTGCTCATCAGAACAAACCAAGA1321 CTTGCTGGAAAAGATTTACAGACTGGAAATGGAAGAGAACCAGCTGAAGAATGAAATGCA1381 AGACGCCAAGGATCAGAACGAGCTGTTAGAATTCAGAGTGCTAGAACTCGAAGTAAGAGA1441 CTCTATCTGTTGTAAACTCTCAAACGGAGCAGACATTCTCTTTGAACCCAAACTGAAATT1501 CATGTAAAGCTCTCAGATGTTTTCAAGCATGTGTAAAGGGGACATGTTATAGTTTCTTTC1561 TTTCTTTCTTTCTTTTTTTTTTAAATCTGTATGTTCAGAATAATTTCACTGCCTTAATGT1621 GTTCTGGAGAGCGTGCTCACCCAAGTCTATGGACATGTACCAGAGCTAATATATTTATTG1681 CCTATGGCTTGTTTTGCACTTAATAAAATAATTTGTTTT

(3) Information of SEQ ID NO:2:

sequence characteristics:

(A) length: 387 amino acids

(B) Type (2): amino acids

(D) Topological structure: linearity

(ii) type of molecule: polypeptides

(xi) sequence description: SEQ ID NO 2: 1 Met Gln Ala Asp Lys Thr Lys Ala Ala Asp Leu Arg Ala Ala Tyr 16 Gln Ala His Gln Asp Glu Val His Arg Ile Lys Arg Glu Cys Glu31 Arg Asp Ile Arg Arg Leu Met Asp Glu Ile Lys Gly Lys Asp Arg 46 Val Ile Leu Val Leu Glu Lys Glu Leu Gly Val Gln Ala Gly Gln 61 Thr Gln Lys Leu Leu Leu Gln Lys Glu Ala Leu Asp Glu Gln Leu 76 Val Gln Ala Lys Glu Ala Glu Arg His His Ser Ser Pro Lys Arg 91 Glu Leu Pro Pro Gly Ile Gly Asp Met Val Glu Leu Met Gly Val106 Gln Asp Gln His Met Asp Glu Arg Asp Val Arg Arg Phe Gln Leu121 Lys Ile Ala Glu Leu Asn Ser Val Ile Arg Lys Leu Glu Asp Arg136 Asn Thr Leu Leu Ala Asp Glu Arg Asn Glu Leu Leu Lys Arg Ser151 Arg Glu Thr Glu Val Gln Leu Lys Pro Leu Val Glu Lys Asn Lys166 Arg Met Asn Lys Lys Asn Glu Asp Leu Leu Gln Ser Ile Gln Arg181 Met Glu Glu Lys Ile Lys Asn Leu Thr Arg Glu Asp Va1 Glu Met196 Lys His Val Val Glu Thr Phe Phe Gly Phe Asp Glu Glu Ser Val211 Asp Ser Glu Thr Leu Ser Glu Thr Ser Tyr Asn Thr Asp Arg Thr226 Asp Arg Thr Pro Ala Thr Pro Glu Glu Asp Leu Asp Asp Ala Thr241 Ala Arg Glu Glu Ala Asp Leu Arg Phe Cys Gln Leu Thr Arg Glu256 Tyr Gln Ala Leu Gln Arg Ala Tyr Ala Leu Leu Gln Glu Gln Val271 Gly Gly Thr Leu Asp Ala Glu Arg Glu Ala Arg Thr Arg Glu Gln286 Leu Gln Ala Asp Leu Leu Arg Cys Gln Ala Lys Ile Glu Asp Leu301 Glu Lys Leu Leu Val Glu Lys Gly Gln Asp Ser Lys Trp Val Glu316 Glu Lys Gln Leu Leu Ile Arg Thr Asn Gln Asp Leu Leu Glu Lys331 Ile Tyr Arg Leu Glu Met Glu Glu Asn Gln Leu Lys Asn Glu Met346 Gln Asp Ala Lys Asp Gln Asn Glu Leu Leu Glu Phe Arg Val Leu361 Glu Leu Glu Val Arg Asp Ser Ile Cys Cys Lys Leu Ser Asn Gly376 Ala Asp Ile Leu Phe Glu Pro Lys Leu Lys Phe Met

(4) Information of SEQ ID NO 3

Sequence characterization

(A) Length: 24 bases

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotides

(xi) sequence description: 3, SEQ ID NO: CGAGCAGGAGCAGCGACGGCACAC 24(5) information of SEQ ID NO.4

Sequence characterization

(A) Length: 24 bases

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotides

(xi) sequence description: SEQ ID NO 4: AAAACAAATTATTTTATTAAGTGC 24(6) information of SEQ ID NO 5

Sequence characterization

(A) Length: 33 base

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotide (xi) sequence description: SEQ ID NO 5: CATGCTAGCATGCAGGCTGACAAGACCAAGGCA 33(7) information of SEQ ID NO 6

Sequence characterization

(A) Length: 33 base

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotides

(xi) sequence description: 6: CATGGATCCTTACATGAATTTCAGTTTGGGTTC 33 SEQ ID NO

(8) Information of SEQ ID NO:7:

sequence characteristics:

(A) length: 15 amino acids

(B) Type (2): amino acids

(D) Topological structure: linearity

(ii) type of molecule: polypeptide (xi) sequence description: 7 Met-Gln-Ala-Asp-Lys-Thr-Lys-Ala-Ala-Asp-Leu-Arg-Ala-Ala-Tyr15

(9) Information of SEQ ID NO 8

Sequence characterization

(A) Length: 41 bases

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotides

(xi) sequence description: 8: TGCAGGCTGACAAGACCAAGGCAGCCGACCTGCGTGCCGCC 41 SEQ ID NO

(10) Information of SEQ ID NO 9

Sequence characterization

(A) Length: 41 bases

(B) Type (2): nucleic acids

(C) Chain property: single strand

(D) Topological structure: linearity

(ii) type of molecule: oligonucleotides

(xi) sequence description: 9: TGCAGGCTGACAAGACCAAGCCAGCCGACCTGCGTGCCGCC 41 SEQ ID NO

Claims (18)

1. An isolated polypeptide-xylose isomerase 43, characterized in that it comprises: 2, or an active fragment, analogue or derivative of the polypeptide thereof.

2. The polypeptide of claim 1, wherein the amino acid sequence of said polypeptide, analog or derivative has at least 95% identity to the amino acid sequence set forth 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 the polynucleotide comprises one selected from the group consisting of:

(a) a polynucleotide encoding a polypeptide having the amino acid sequence shown in SEQ ID NO.2 or a fragment, an analogue or a derivative thereof;

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

(c) A polynucleotide sharing at least 70% identity to (a) or (b).

5. The polynucleotide of claim 4, wherein the polynucleotide comprises a polynucleotide encoding the amino acid sequence of SEQ ID No. 2.

6. The polynucleotide according to claim 4, wherein the sequence of the polynucleotide comprises the sequence at positions 344-1507 of SEQ ID NO. 1 or the sequence at positions 1-1719 of SEQ ID NO. 1.

7. A recombinant vector containing an exogenous polynucleotide, characterized in that it is a recombinant vector constructed from the polynucleotide of any one of claims 4 to 6 and a plasmid, virus or expression vector.

8. A genetically engineered host cell comprising an exogenous polynucleotide, wherein the genetically engineered host cell is selected from the group consisting of:

(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 to 6.

9. A method for producing a polypeptide having xylose isomerase 43 activity, characterized in that the method comprises:

(a) culturing the engineered host cell of claim 8 under conditions to express xylose isomerase 43;

(b) isolating the polypeptide having xylose isomerase 43 activity from the culture.

10. An antibody capable of binding to a polypeptide, wherein said antibody is an antibody capable of specifically binding to xylose isomerase 43.

11. A class of compounds that mimic or modulate the activity or expression of a polypeptide, characterized in that they are compounds that mimic, promote, antagonize, or inhibit the activity of xylose isomerase 43.

12. The compound of claim 11, which is an antisense sequence to the polynucleotide sequence shown in SEQ ID No. 1 or a fragment thereof.

13. Use of a compound according to claim 11 for a method of modulating the activity of xylose isomerase 43 in vivo or in vitro.

14. A method for detecting a disease or a susceptibility to a disease associated with the polypeptide of any of claims 1-3, comprising detecting the amount of expression of the polypeptide, or detecting the activity of the polypeptide, or detecting a nucleotide variation in the polynucleotide that causes an abnormality in the amount of expression or activity of the polypeptide.

15. Use of a polypeptide according to any of claims 1 to 3 for screening for mimetics, agonists, antagonists or inhibitors of xylose isomerase 43; or for peptide fingerprinting.

16. Use of a nucleic acid molecule according to any of claims 4 to 6 as a primer in a nucleic acid amplification reaction, or as a probe in a hybridization reaction, or for the manufacture of gene chips or microarrays.

17. The use of the polypeptide, polynucleotide or compound of any of claims 1-6 and 11, wherein said polypeptide, polynucleotide or its mimetics, agonists, antagonists or inhibitors are used in a safe and effective amount in combination with a pharmaceutically acceptable carrier to form a pharmaceutical composition for the diagnosis or treatment of a disease associated with xylose isomerase 43 abnormality.

18. Use of the polypeptide, polynucleotide or compound of any of claims 1-6 and 11, wherein said polypeptide, polynucleotide or compound is used for the preparation of a medicament for the treatment of, for example, malignant tumors, hematological disorders, HIV infection and immunological disorders and various types of inflammation.