MOLECULAR MECHANISMS CONTROLLING SENSITIVITY TO TOXIC METAL-IONS IN YEAST

Contamination of the environment has made toxic metal ions a major hea lth issue. The use of yeasts as model systems for the identification o f molecular mechanisms that control sensitivity to these agents is par ticularly attractive because of the ease of genetic manipulation and t he availability of the complete Saccharomyces cerevisiae genomic seque nce. This paper reviews information on those genes and mechanisms that have been identified in both the budding yeast S. cerevisiae and the fission yeast Schizosaccharomyces pombe as being capable of modulating sensitivity to important toxic metals. The factors that influence sen sitivity to toxic metal ions include cellular thiols (glutathione, phy tochelatins, labile sulfide, and metallothioneins) and the products of genes directly and indirectly involved in the transport or sequestrat ion of the metal ion. A complete understanding of the molecular basis of sensitivity to toxic metal ions in lower organisms is expected to p rovide useful insights in the metal ion detoxification pathways and di seases related to these pathways in humans. (C) 1997 Academic Press.