Evidence for co-regulation of Cu,Zn superoxide dismutase and metallothionein gene expression in yeast through transcriptional control by copper via the ACE 1 factor.

Saccharomyces cerevisiae mutant strain DTY26, lacking ACE1, the protein mediator for the induction of metallothionein gene expression, is unable to increase Cu,Zn superoxide dismutase mRNA in response to copper. In the wild-type strain DTY22 transcription of both Cu,Zn superoxide dismutase and metallothionein genes is induced by copper and silver, as expected on the basis of previous results indicating that ACE1 binds only Ag(I) besides Cu(I). We conclude that at the transcriptional level Cu,ZnSOD is co-regulated with metallothionein. Furthermore, structural similarities between the two promoters were found, which could explain the co-regulation effect and the quantitative differences in the response of the two genes to copper.