Tropomyosin isoforms, and diagnostic and therapeutic uses therefor

Abstract

A novel isoform of tropomyosin is disclosed. The isoform is closely related to epithelial human tropomyosin (hTM) and more particularly to hTM5 except the last coding exon. The novel isoform, is called TC22. Northern blot analysis with TC22-specific probe revealed that normal culture cell lines and normal epithelial tissues expressed very little, if at all, TC22 message, whereas their transformed counterparts and tumor tissues including dysfunction of the alimentary canal, significantly increased the expression of TC22. Assays directed at determining the level of TC22 are useful in diagnostics and therapeutics of dysfunction of the alimentary canal. Specific antibodies and mimics for TC22 are also disclosed for use in diagnostics and therapeutics of dysfunction of the alimentary canal.

1. An isolated tropomyosin isoform (TI) protein, the isoform identified as TC22, consisting of the amino acid sequence set forth in SEQ ID NO:2. 
     
     
       2. An isolated tropomyosin isoform (TI) protein fragment consisting of the amino acid sequence set forth in SEQ ID NO:1. 
     
     
       3. A labeled TI protein fragment wherein the TI protein fragment of  claim 2  is labeled. 
     
     
       4. A composition comprising the TI protein of  claim 1 . 
     
     
       5. A composition comprising the TI protein fragment of  claim 2 . 
     
     
       6. A molecular complex comprising either the tropomyosin isoform (TI) protein consisting of the amino acid sequence set forth in the SEQ ID NO: 2 or the TI protein fragment consisting of the amino acid sequence set forth in SEQ ID NO: 1 and a binding molecule comprising at least a Fab, Fab′, F(ab′) 2  or F(v) portion of an antibody, wherein said antibody portion binds to the amino acid sequence set forth in SEQ ID NO:1 and wherein said complex is formed by immunoreacting said tropomyosin isoform and said binding molecule. 
     
     
       7. The molecular complex of claim 6, further comprising a detectable labeling component wherein detection of said molecular complex is an indicator of a dysfunction associated with the alimentary canal and/or the epithelium thereof. 
     
     
       8. The molecular complex of claim 6, wherein said tropomyosin isoform protein is obtained from a biological sample from alimentary canal tissue or body fluids selected from the group consisting of peripheral blood, serum, urine, and stool. 
     
     
       9. The molecular complex of claim 7, wherein said labeling is selected from the group consisting of an enzyme, a fluorophore, a chromophore, a radioisotope, a dye, colloidal gold, latex particles and chemiluminescent agents. 
     
     
       10. The molecular complex of claim 6, wherein said binding molecule is formed from a test kit comprising a predetermined amount of a label selected from the group consisting of an enzyme, a fluorophore, a chromophore, a radioisotope, a dye, colloidal gold, latex particles and chemiluminescent agents and a binding molecule which immunoreacts with a targeting partner having the amino acid sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 2; and directions for use of said kit. 
     
     
       11. The molecular complex of claim 10, wherein the amino acid sequence in the test kit is SEQ ID NO: 2. 
     
     
       12. The molecular complex of claim 6, wherein said binding molecule is the binding site of an antibody selected from the group consisting of polyclonal antibodies, monoclonal antibodies, and chimeric bispecific antibodies. 
     
     
       13. The molecular complex of claim 12, wherein said antibodies are monoclonal antibodies. 
     
     
       14. The molecular complex of claim 6, prepared by a method for testing a mammalian subject for dysfunction of the alimentary canal or the epithelium thereof associated with the expression of a tropomyosin isoform (TI) protein identified as TC22, consisting of the amino acid sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 2, said method comprising:
 (a) obtaining a biological sample from the alimentary canal or body fluids of a subject,   (b) contacting said sample with a binding molecule which immunoreacts with a targeting partner having an amino acid sequence set forth in SEQ ID NO: 1 or SEQ ID NO: 2,   (c) observing the formation of said molecular complex wherein the extent of complex formation is diagnostic of said alimentary canal or epithelium-related dysfunction.   
     
     
       15. The molecular complex of claim 14, wherein said biological sample is selected from alimentary canal tissue or body fluids selected from the group consisting of epithelium tissue of alimentary canal, peripheral blood, serum, urine and stool. 
     
     
       16. The molecular complex of claim 15, wherein said binding molecule is a portion of Fab, Fab′, F(ab′) 2  or a fragments thereof. 
     
     
       17. The molecular complex of claim 6, wherein said binding molecule is prepared by a method comprising:
 (a) obtaining cells from an animal immunized with a tropomyosin isoform (TI) protein, or a fragments thereof having an amino acid sequence set forth in SEQ ID NO: 1 and/or SEQ ID NO: 2,   (b) fusing said cells with cells from a self-perpetuating cell line to form fused hybrid cell colonies,   (c) identifying the hybrid cells colonies that produce binding molecules that immunoreact with targeting partners having the amino acid sequence set forth in SEQ ID NO:1, and   (d) culturing said hybrid cells colonies identified in step (c).