The [PSI+] prion of yeast: a problem of inheritance.
The [PSI(+)] prion of the yeast Saccharomyces cerevisiae was first identified by Brian Cox some 40 years ago as a non-Mendelian genetic element that modulated the efficiency of nonsense suppression. Following the suggestion by Reed Wickner in 1994 that such elements might be accounted for by invoking a prion-based model, it was subsequently established that the [PSI(+)] determinant was the prion form of the Sup35p protein. In this article, we review how a combination of classical genetic approaches and modern molecular and biochemical methods has provided conclusive evidence of the prion basis of the [PSI(+)] determinant. In so doing we have tried to provide a historical context, but also describe the results of more recent experiments aimed at elucidating the mechanism by which the [PSI(+)] (and other yeast prions) are efficiently propagated in dividing cells. While understanding of the [PSI(+)] prion and its mode of propagation has, and will continue to have, an impact on mammalian prion biology nevertheless the very existence of a protein-based mechanism that can have a beneficial impact on a cell's fitness provides equally sound justification to fully explore yeast prions.
Tuite
Mick F
MF
Protein Science Group, Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK. M.F.Tuite@kent.ac.uk
Cox
Brian S
BS
D000595:Amino Acid Sequence; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010454:Peptide Termination Factors; D010641:Phenotype; D011328:Prions / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D018832:Molecular Chaperones; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins