The UGA43 negative regulatory gene of Saccharomyces cerevisiae contains both a GATA-1 type zinc finger and a putative leucine zipper

Summary

The UGA43 gene of Saccharomyces cerevisiae is required for repression of inducible genes involved in the utilization of 4-aminobutyric acid (GABA) or urea as nitrogen sources. The UGA43 gene has been cloned by complementation of a uga43 mutation. The N-terminal region of the UGA43 protein is very similar to the DNA-binding zinc-finger region typical of the GATA regulatory factor family in vertebrates. UGA43 is the first reported instance of a GATA protein with a negative regulatory function. The C-terminal region of the predicted UGA43 protein contains a putative leucine zipper. Sequencing of three uga43 mutant alleles suggests that the GATA and putative leucine-zipper regions are both required for the repressive activity of UGA43. UGA43 appears to be a highly regulated gene. On “poor” nitrogen sources, UGA43 transcripts are measured at high levels whereas they are nearly undetectable in conditions of nitrogen catabolite repression. The levels measured on “poor” nitrogen sources are further increased in uga43 mutant cells, suggesting that UGA43 exerts negative autoregulation.