Copper ions and the regulation of Saccharomyces cerevisiae metallothionein genes under aerobic and anaerobic conditions

Jeffrey Strain, Valeria Cizewski Culotta

Research output: Contribution to journalArticlepeer-review

Abstract

We have previously reported that the Saccharomyces cerevisiae CRS5 metallothionein gene is negatively regulated by oxygen. The mechanism of this repression was the focus of the current study. We observed that the aerobic repression of CRS5 is rapid and occurs within minutes of exposing anaerobic cultures to air. Furthermore, the CUP1 metallothionein gene of S. cerevisiae was found to be subject to a similar down-regulation of gene expression. We provide evidence that the aerobic repression of yeast metallothioneins involves copper ions and Ace1, the copper trans-activator of CUP1 and CRS5 gene expression. A functional Ace1 binding site was found to be necessary for the aerobic repression of CRS5. Moreover, the aerobic down-regulation of the metallothioneins was abolished when cells were treated with elevated levels of copper. Our studies show that anaerobic cultures accumulate higher levels of copper than do aerobic cells and that this copper is rapidly lost when cells are exposed to air. In fact, the kinetics of this copper loss closely parallels the kinetics of CUP1 and CRS5 gene repression. The yeast metallothionein genes, therefore, serve as excellent markers for variations in copper accumulation and homeostasis that occur in response to changes in the oxidative status of the cell.

Original languageEnglish (US)
Pages (from-to)139-145
Number of pages7
JournalMolecular and General Genetics
Volume251
Issue number2
DOIs
StatePublished - 1996

Keywords

  • Copper
  • Metallothionein
  • Yeast

ASJC Scopus subject areas

  • Genetics

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