Method of expressing genes in mammalian cells

Abstract

The present invention relates to a method of expressing a heterologous gene in mammalian cells and a recombinant DNA construct for use in the method. The invention also relates to a method of specifically killing cells which constitutively express AFP.

What is claimed is:  
     
         1 . A method of expressing a heterologous gene in a mammalian liver cell comprising inserting a DNA construct into a mammalian liver cell, said construct comprising an AFP enhancer region and an AFP promoter functionally linked to the heterologous gene in the absence of an AFP silencer region, and expressing the heterologous gene in the mammalian liver cells.  
     
     
         2 . The method of  claim 1  wherein the construct comprises three or more AFP enhancer regions.  
     
     
         3 . A method of killing cells which constitutively express AFP comprising inserting a DNA construct into a mammalian cell, said construct comprising an enhancer region, an AFP silencer region and a promoter sequence functionally linked to a direct toxin gene and expressing the toxin gene in the mammalian cells under conditions such that the cells which constitutively express AFP are substantially killed.  
     
     
         4 . The method of  claim 3  wherein the construct comprises three or more silencer regions.  
     
     
         5 . The method of  claim 3  wherein the construct comprises three or more enhancer regions.  
     
     
         6 . A isolated mutated silencer region comprising the sequence in FIG. 14.  
     
     
         7 . An isolated mutated AFP enhancer domain selected from the group consisting of A and B.  
     
     
         8 . The isolated mutated AFP enhancer of  claim 7 , selected from the group consisting of A1, A2, A3 and A4.  
     
     
         9 . The isolated mutated AFP enhancer domain A1 of  claim 8  comprising the sequence in FIG. 14.  
     
     
         10 . The isolated mutated enhancer domain A2 of  claim 8  comprising the sequence in FIG. 14.  
     
     
         11 . The isolated mutated enhancer domain A3 of  claim 8  comprising the sequence in FIG. 14.  
     
     
         12 . The isolated mutated enhancer domain A4 of  claim 8  comprising the sequence in FIG. 14.  
     
     
         13 . The isolated mutant enhancer domain B of  claim 7  comprising the sequence in FIG. 14.  
     
     
         14 . An isolated HToxin gene comprising the sequence of FIG. 15B.