ROLE OF THE PROMOTER IN THE SENSITIVITY OF HUMAN THYMIDINE KINASE TO LACK OF ZN2+

Previous studies had indicated that lack of Zn2+ inhibits the expressi on of thymidine kinase activity and produces a corresponding reduction in the concentration of its mRNA. The present investigations have sho wn that with human thymidine kinase this is associated with increased binding of a specific protein to the gene's promoter in the region bet ween -55 and -83 bp 5' to the transcription initiation site. A second binding site for the protein is present within the sixth exon of the h uman thymidine kinase gene.