Novel N-acetylglucosaminyltransferase, nucleic acid coding for the same, and uses thereof for diagnosis of cancer or tumor

Abstract

Described are an enzyme having an activity to transfer N-acetylglucosamine to a non-reducing terminal of Galβ1-4Glc or Galβ1-4GlcNAc group through β1,3-linkage; nucleic acid coding for the enzyme; and method for diagnosis of a cancer and/or tumor, especially a cancer and/or tumor of a digestive organ, using the expression amount of the gene of the enzyme as an index. A gene coding for a novel enzyme having an activity to transfer N-acetylglucosamine to a non-reducing terminal of Galβ1-4Glc or Galβ1-4GlcNAc group through β1,3-linkage was cloned from human stomach cells, and sequenced, and the enzyme was expressed. Since this enzyme is not produced substantially or at all in cancer and/or tumor cells, especially in cancer or tumor cells of a digestive organ, the cancer and/or tumor may be diagnosed using the expression of the gene of the enzyme as an index.

1 . An isolated nucleic acid encoding: 
 a protein comprising an amino acid sequence of SEQ ID NO: 1, or    a protein comprising an amino acid sequence of SEQ ID NO:1 and wherein one or more amino acids of the protein are substituted or deleted, or wherein one or more amino acids of the protein are inserted or added,    wherein an activity of said protein is an ability to transfer N-acetylglucosamine to a non-reducing terminal of a Galb1-4Glc or a Galb1-4GlcNAc group through a b1,3-linkage.    
     
     
         2 . The isolated nucleic acid according to  claim 1 , which hybridizes under stringent hybridization conditions with a nucleic acid comprising a nucleotide sequence according to SEQ ID NO:2 or a nucleotide sequence according to SEQ ID NO:4.  
     
     
         3 . The isolated nucleic acid according to  claim 2 , which comprises a nucleotide sequence according to SEQ ID NO:2 or 4.  
     
     
         4 . A recombinant vector comprising the isolated nucleic acid according to  claim 1 , wherein said recombinant vector can express said nucleic acid in a host cell.  
     
     
         5 . A cell comprising the isolated nucleic acid according to  claim 1 , wherein the nucleic acid is expressed said cell.  
     
     
         6 . An isolated nucleic acid for measurement of said nucleic acid according to  claim 1 , which specifically hybridizes with said nucleic acid according to  claim 1 .  
     
     
         7 . The isolated nucleic acid according to  claim 6 , which has a sequence complementary to a part of a nucleic acid comprising a nucleotide sequence according to SEQ ID NO:2 or according to SEQ ID NO:4.  
     
     
         8 . The isolated nucleic acid according to  claim 6 , which is a probe or a primer.  
     
     
         9 . The isolated nucleic acid according to  claim 8 , which has not less than bases.  
     
     
         10 . A method for measuring said isolated nucleic acid according to  claim 1 , comprising: 
 hybridizing the isolated nucleic acid for measurement of the nucleic acid according to  claim 1 , which specifically hybridizes with the nucleic acid according to  claim 1 , and    measuring the hybridized nucleic acid.    
     
     
         11 . A method for measuring said isolated nucleic acid according to  claim 1 , comprising: 
 amplifying a nucleic acid by using as primers a pair of nucleic acids, and using as a template said nucleic acid according to  claim 1  to produce an amplification product, and    measuring the amplification product.    
     
     
         12 . A method for diagnosis of a cancer and/or tumor, comprising: 
 hybridizing a nucleic acid to an mRNA transcribed from a gene comprising a sequence encoding a protein comprising an amino acid sequence according to SEQ ID NO:3 or to a cDNA generated by transcription of said mRNA, and    measuring the hybridized nucleic acid, so as to measure an expression amount of the gene of said protein, whereby an expression amount of the gene is indicative of the presence of cancer and/or a tumor.    
     
     
         13 . A method for diagnosis of a cancer and/or tumor, comprising: 
 amplifying a nucleic acid using as primers a pair of nucleic acids for measurement of nucleic acid, and using as a template an mRNA transcribed from a gene encoding a protein comprising an amino acid sequence according to SEQ ID NO:3 or a cDNA generated by transcribing said mRNA to produce an amplification product, and    measuring the amplification product, to determine an expression amount of the gene encoding said protein, whereby an expression amount of the gene is indicative of the presence of cancer and/or a tumor.