[PSI+]: an epigenetic modulator of translation termination efficiency.
The [PSI+] factor of the yeast Saccharomyces cerevisiae is an epigenetic regulator of translation termination. More than three decades ago, genetic analysis of the transmission of [PSI+] revealed a complex and often contradictory series of observations. However, many of these discrepancies may now be reconciled by a revolutionary hypothesis: protein conformation-based inheritance (the prion hypothesis). This model predicts that a single protein can stably exist in at least two distinct physical states, each associated with a different phenotype. Propagation of one of these traits is achieved by a self-perpetuating change in the protein from one form to the other. Mounting genetic and biochemical evidence suggests that the determinant of [PSI+] is the nuclear encoded Sup35p, a component of the translation termination complex. Here we review the series of experiments supporting the yeast prion hypothesis and provide another look at the 30 years of work preceding this theory in light of our current state of knowledge.
Serio
T R
TR
University of Chicago, Department of Molecular Genetics and Cell Biology, Illinois 60637, USA. tserio@midway.uchicago.edu
Lindquist
S L
SL
D000595:Amino Acid Sequence; D000818:Animals; D018389:Codon, Nonsense; D005656:Fungal Proteins / Q000378:metabolism*; D006801:Humans; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors; D011328:Prions / Q000378:metabolism*; D014176:Protein Biosynthesis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D018389:Codon, Nonsense; D005656:Fungal Proteins; D018832:Molecular Chaperones; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; C080775:SUP45 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins