DNA encoding a human subunit 5-HT3-C of the 5-HT3 serotonin receptor

Abstract

DNA encoding human 5-HT3-C has been cloned and characterized. The recombinant protein is capable of forming biologically active human 5-HT3-C protein. The cDNA has been expressed in recombinant host cells that produce active recombinant protein. In addition, the recombinant host cells are utilized to establish a method for identifying modulators of the receptor activity, and receptor modulators are identified.

What is claimed is:  
     
         1 . An isolated and purified DNA molecule that encodes human 5-HT3-C protein, or a functional derivative thereof, wherein said protein optionally functions as a subunit to modify the function of a serotonin 5-HT3-A receptor.  
     
     
         2 . The isolated and purified DNA molecule of  claim 1 , having a nucleotide sequence selected from a group consisting of: (SEQ.ID.NO.:4); (SEQ.ID.NO.:5); and functional derivatives thereof.  
     
     
         3 . The isolated and purified DNA molecule of  claim 1 , wherein said DNA molecule is genomic DNA.  
     
     
         4 . An expression vector for expression of a human 5-HT3-C protein in a recombinant host, wherein said vector contains a recombinant gene encoding human 5-HT3-C protein, or a functional derivative thereof, wherein said protein modifies the function of the human serotonin 5-HT3-A receptor.  
     
     
         5 . The expression vector of  claim 4 , comprising a nucleotide sequence selected from a group consisting of: (SEQ.ID.NO.:4); (SEQ.ID.NO.:5); and functional derivatives thereof.  
     
     
         6 . The expression vector of  claim 4 , wherein the expression vector contains genomic DNA encoding human 5-HT3-C protein.  
     
     
         7 . A recombinant host cell containing a recombinantly cloned gene encoding human 5-HT3-C protein wherein said protein functions as a modifier of the human 5-HT3-A receptor, or functional derivative thereof.  
     
     
         8 . The recombinant host cell of  claim 7 , wherein said recombinantly cloned gene has a nucleotide sequence selected from a group consisting of: (SEQ.ID.NO.:4); (SEQ.ID.NO.:5); and functional derivatives thereof.  
     
     
         9 . The recombinant host cell of  claim 7 , wherein said cloned gene encoding human 5-HT3-C protein is genomic DNA.  
     
     
         10 . A protein, in substantially pure form that functions as human 5-HT3-C protein wherein said protein optionally functions as a modifier of the human serotonin 5-HT3-A receptor.  
     
     
         11 . The protein according to  claim 10 , having an amino acid sequence selected from a group consisting of: (SEQ.ID.NO.:9), and functional derivatives thereof.  
     
     
         12 . A monospecific antibody immunologically reactive with human 5-HT3-C protein.  
     
     
         13 . The antibody of  claim 12 , wherein said antibody blocks activity of the 5-HT3-C protein.  
     
     
         14 . A process for expression of human 5-HT3-C protein wherein said protein optionally functions as a modifier of the human serotonin 5-HT3-A receptor in a recombinant host cell, comprising: 
 (a) transferring the expression vector of  claim 4  into suitable host cells; and    (b) culturing the host cells under conditions that allow expression of the human 5-HT3-C protein from the expression vector.    
     
     
         15 . A method of identifying compounds that modulate human 5-HT3-C protein activity, comprising: 
 (a) combining a modulator of human 5-HT3-C protein activity with human 5-HT3-C protein wherein said protein functions as a modifier of the human 5-HT3-A receptor; and    (b) measuring an effect of the modulator on the protein.    
     
     
         16 . A compound active in the method of  claim 15 , wherein the effect of the modulator on the human 5-HT3-C protein is inhibiting or enhancing binding of human 5-HT3 receptor ligands to a human serotonin 5-HT3 receptor complex.  
     
     
         17 . A compound active in the method of  claim 15 , wherein the modulator stimulates or inhibits the function of human 5-HT3-C in the 5-HT3 receptor complex.  
     
     
         18 . A compound active in the method of  claim 15 , wherein said compound is an agonist or antagonist of the human serotonin 5-HT3 receptor complex comprising 5-HT3-A and 5-HT3-C proteins.  
     
     
         19 . A compound active in the method of  claim 15 , wherein said compound is a modulator of expression of a 5-HT3-C subunit.  
     
     
         20 . A pharmaceutical composition comprising a compound active in the method of  claim 15 , wherein said compound is a modulator of human 5-HT3-C subunit activity.  
     
     
         21 . A method of treating a patient in need of such treatment for a condition that is mediated by a human 5-HT3-C , comprising administration of a human 5-HT3-C modulating compound active in the method of claim  15 .