MN Gene and Protein

Abstract

Identified herein is the location of the MN protein binding site, and MN proteins/polypeptides that compete for attachment to vertebrate cells with immobilized MN protein. Such MN proteins/polypeptides prevent cell-cell adhesion and the formation of intercellular contacts. The MN protein binding site is a therapeutic target that can be blocked by organic or inorganic molecules, preferably organic molecules, more preferably proteins/polypeptides that specifically bind to that site. Therapeutic methods for inhibiting the growth of preneoplastic/neoplastic vertebrate cells that abnormally express MN protein are disclosed. Vectors are provided that encode the variable domains of MN-specific antibodies and a flexible linker polypeptide separating those domains. Further vectors are disclosed that encode a cytotoxic protein/polypeptide operatively linked to the MN gene promoter, and which vectors preferably further encode a cytokine. The MN gene promoter is characterized, and the binding site for a repressor of MN transcription is disclosed.

1 - 30 . (canceled) 
     
     
         31 . A vector comprising an expression control sequence operatively linked to a nucleic acid encoding a variable light chain and/or a variable heavy chain, or one or more fragments from a variable light chain and/or from a variable heavy chain, of an antibody or antibody fragment that specifically binds an extracellular domain epitope of MN protein;
 wherein said MN protein is encoded by a nucleic acid selected from the group consisting of:   (a) SEQ ID NO: 1;   (b) nucleotide sequences that are at least 80% homologous to SEQ ID NO: 1; and   (c) nucleotide sequences that differ from SEQ ID NO: 1 or from the nucleotide sequences of (b) due to the degeneracy of the genetic code; and   wherein said antibody or antibody fragment specifically binds to the MN protein having the amino acid sequence of SEQ ID NO: 2.   
     
     
         32 . The vector of  claim 31  wherein said extracellular domain epitope is within the MN protein's proteoglycan-like domain, represented by SEQ ID NO: 50, or within the MN protein's carbonic anhydrase domain, represented by SEQ ID NO: 51. 
     
     
         33 . The vector of  claim 31  wherein said nucleic acid encodes both a variable light chain and a variable heavy chain of an antibody that specifically binds said extracellular domain epitope. 
     
     
         34 . The vector of  claim 33 , wherein the variable light chain and the variable heavy chain are synthesized as a single polypeptide and are separated by a flexible linker polypeptide. 
     
     
         35 . The vector of  claim 31 , wherein said nucleic acid encodes one or more hypervariable regions of said MN-specific antibody or antibody fragment. 
     
     
         36 . The vector of  claim 31 , wherein said nucleic acid encodes hypervariable regions of the variable heavy chain and/or hypervariable regions of the variable light chain from said MN-specific antibody or antibody fragment. 
     
     
         37 . The vector of  claim 31 , wherein said nucleic acid encodes hypervariable regions of the variable heavy chain of said MN-specific antibody or antibody fragment. 
     
     
         38 . The vector of  claim 31 , wherein said nucleic acid encodes hypervariable regions of the variable light chain of said MN-specific antibody or antibody fragment. 
     
     
         39 . The vector of  claim 31 , wherein said antibody or antibody fragment is selected from the group consisting of an Fab fragment, an F(ab′) 2  fragment, an scFv fragment, an Fv fragment, a diabody, a single-chain antibody, a bispecific antibody, and a chimeric antibody. 
     
     
         40 . The vector of  claim 31 , wherein the MN protein is specifically bound by either the M75 monoclonal antibody that is secreted from the hybridoma VU-M75, which was deposited at the American Type Culture Collection under ATCC No. HB 11128, or by the MN12 monoclonal antibody that is secreted from the hybridoma MN 12.2.2, which was deposited at the American Type Culture Collection under ATCC No. HB 11647. 
     
     
         41 . The vector of  claim 31 , wherein the nucleotide sequences of (b) are at least 90% homologous to SEQ ID NO: 1. 
     
     
         42 . The vector of  claim 32  wherein said extracellular domain epitope is within said carbonic anhydrase domain. 
     
     
         43 . The vector of  claim 32  wherein said extracellular domain epitope is within said proteoglycan-like domain. 
     
     
         44 . The vector of  claim 34 , wherein said flexible linker polypeptide has the amino acid sequence of SEQ ID NO: 116. 
     
     
         45 . The vector of  claim 31 , wherein the expression control sequence comprises a MN gene promoter, or a fragment of a MN gene promoter that has promoter activity. 
     
     
         46 . The vector of  claim 45  wherein the MN gene promoter has the nucleotide sequence of SEQ ID NO: 27.