Translation termination efficiency can be regulated in Saccharomyces cerevisiae by environmental stress through a prion-mediated mechanism

• Published in: The EMBO journal 1999-04, Vol.18 (7), p.1974-1981
• Main Authors: Eaglestone, S, Cox, B.S, Tuite, M.F
• Format: Article
• Language: English
• Subjects: binding proteins; Environmental stress; Ethanol; eukaryote release factor; Fungal Proteins - genetics; Genes, Fungal; growth rate; heat stress; heat tolerance; Hot Temperature; Models, Biological; mutation; Peptide Termination Factors; Phenotype; prion; prions; Prions - genetics; Protein Biosynthesis; regulation; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae Proteins; Suppression, Genetic; tolerance; translation; yeast (Saccharomyces cerevisiae)
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1093/emboj/18.7.1974

[PSI + ] is a protein‐based heritable phenotype of the yeast Saccharomyces cerevisiae which reflects the prion‐like behaviour of the endogenous Sup35p protein release factor. [PSI + ] strains exhibit a marked decrease in translation termination efficiency, which permits decoding of translation termination signals and, presumably, the production of abnormally extended polypeptides. We have examined whether the [PSI + ]‐ induced expression of such an altered proteome might confer some selective growth advantage over [psi − ] strains. Although otherwise isogenic [PSI + ] and [psi − ] strains show no difference in growth rates under normal laboratory conditions, we demonstrate that [PSI + ] strains do exhibit enhanced tolerance to heat and chemical stress, compared with [psi − ] strains. Moreover, we also show that the prion‐like determinant [PSI + ] is able to regulate translation termination efficiency in response to environmental stress, since growth in the presence of ethanol results in a transient increase in the efficiency of translation termination and a loss of the [PSI + ] phenotype. We present a model to describe the prion‐mediated regulation of translation termination efficiency and discuss its implications in relation to the potential physiological role of prions in S.cerevisiae and other fungi.