The PNM2 mutation in the prion protein domain of SUP35 has distinct effects on different variants of the [PSI+] prion in yeast

Irina L. Derkatch, Michael E. Bradley, Ping Zhou, Susan W. Liebman

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

We have previously described different variants of the yeast prion [PSI+] that can be obtained and maintained in the same genetic background. These [PSI+] variants, which differ in the efficiency of nonsense suppression, mitotic stability and the efficiency of curing by GuHCl, may correspond to different [PSI+] prion conformations of Sup35p or to different types of prion aggregates. Here we investigate the effects of overexpressing a mutant allele of SUP35 and find different effects on weak and strong [PSI+] variants: the suppressor phenotype of weak [PSI+] factors is increased, whereas the suppressor effect of strong [PSI+] factors is reduced. The SUP35 mutation used was originally described as a 'Psi no more' mutation (PNM2) because it caused loss of [PSI+]. However, none of the [PSI+] variants in the strains used in our study were cured by PNM2. Indeed, when overexpressed, PNM2 induced the de novo appearance of both weak and strong [PSI+] variants with approximately the same efficiency as the overexpressed wild-type SUP35 allele. Our data suggest that the change in the region of oligopeptide repeats in the Sup35p N-terminus due to the PNM2 mutation modifies, but does not impair, the function of the prion domain of Sup35p.

Original languageEnglish (US)
Pages (from-to)59-67
Number of pages9
JournalCurrent Genetics
Volume35
Issue number2
DOIs
StatePublished - Apr 2 1999
Externally publishedYes

Keywords

  • [PSI]
  • Nonsense-suppression
  • PNM mutant
  • Prions
  • SUP35
  • Translation termination

ASJC Scopus subject areas

  • Genetics

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