Ssb1 chaperone is a [PSI+] prion-curing factor

Curr Genet. 2001 Apr;39(2):62-7. doi: 10.1007/s002940000180.


Yeast SUP7' or SUP11 nonsense suppressors have no phenotypic expression in strains deficient in the isopentenylation of A37 in tRNA. Here we show that such strains spontaneously produce cells with a nonsense suppressor phenotype which is related to the cytoplasmically inherited determinant and manifests all the key features of the [PSI+] prion. A screen of a multicopy yeast genomic library for genes that inactivate the [PSI+]-related suppressor phenotype resulted in the isolation of the SSB1 gene. Moreover, we demonstrate that multicopy plasmid encoding the Ssb1 chaperone cures cells of the [PSI+] prion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cloning, Molecular
  • Codon, Nonsense
  • Fungal Proteins / genetics*
  • Genes, Fungal / genetics
  • Genotype
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism
  • Molecular Chaperones* / genetics*
  • Molecular Chaperones* / metabolism
  • Mutation
  • Phenotype
  • Plasmids / genetics
  • Prions / genetics
  • Prions / metabolism*
  • RNA, Transfer / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Suppression, Genetic


  • Codon, Nonsense
  • Fungal Proteins
  • HSP70 Heat-Shock Proteins
  • Molecular Chaperones
  • Prions
  • SSB1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • RNA, Transfer