title: Evolutionary conservation of prion-forming abilities of the yeast Sup35 protein.
abstract: Saccharomyces cerevisiae prion [PSI ] is a self-propagating isoform of the eukaryotic release factor eRF3 (Sup35p). Sup35p consists of the evolutionary conserved release factor domain (Sup35C) and two evolutionary variable regions - Sup35N, which serves as a prion-forming domain in S. cerevisiae, and Sup35M. Here, we demonstrate that the prion form of Sup35p is not observed among industrial and natural strains of yeast. Moreover, the prion ([PSI + ]) state of the endogenous S. cerevisiae Sup35p cannot be transmitted to the next generations via heterologous Sup35p or Sup35NM, originating from the distantly related yeast species Pichia methanolica. This suggests the existence of a 'species barrier' in yeast prion conversion. However, the chimeric Sup35p, containing the Sup35NM region of Pichia, can be turned into a prion in S. cerevisiae by overproduction of the identical Pichia Sup35NM. Therefore, the prion-forming potential of Sup35NM is conserved in evolution. In the heterologous system, overproduction of Pichia Sup35p or Sup35NM induced formation of the prion form of S. cerevisiae Sup35p, albeit less efficiently than overproduction of the endogenous Sup35p. This implies that prion induction by protein overproduction does not require strict correspondence of the 'inducer' and 'inducee' sequences, and can overcome the 'species barrier'.
authors.affiliation: School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.
authors.forename: Y O
authors.initials: YO
authors.lastname: Chernoff
authors.forename: A P
authors.initials: AP
authors.lastname: Galkin
authors.forename: E
authors.initials: E
authors.lastname: Lewitin
authors.forename: T A
authors.initials: TA
authors.lastname: Chernova
authors.forename: G P
authors.initials: GP
authors.lastname: Newnam
authors.forename: S M
authors.initials: SM
authors.lastname: Belenkiy
mesh_terms: D000595:Amino Acid Sequence; D002455:Cell Division; D017124:Conserved Sequence; D003433:Crosses, Genetic; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors; D010843:Pichia / Q000235:genetics; D011328:Prions / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012440:Saccharomyces / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D005656:Fungal Proteins; D010454:Peptide Termination Factors; D011328:Prions; D011993:Recombinant Fusion Proteins; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins