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

EMBO J. 1999 Apr 1;18(7):1974-81. 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fungal Proteins / genetics*
  • Genes, Fungal
  • Hot Temperature
  • Models, Biological
  • Peptide Termination Factors
  • Phenotype
  • Prions / genetics*
  • Protein Biosynthesis*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins*
  • Suppression, Genetic


  • Fungal Proteins
  • Peptide Termination Factors
  • Prions
  • SUP35 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins