[PSI] and [URE3] as yeast prions.
[URE3] is a non-Mendelian genetic element that mimics recessive mutations in the chromosomal URE2 gene making cells derepressed for nitrogen catabolic enzymes. [PSI] is a non-Mendelian enhancer of readthrough of translational termination similar in its effects to some mutations in the chromosomal SUP35 gene. Three lines of evidence led to the proposal that both [URE3] and [PSI] are prions, infectious proteins analogous to the scrapie agent mediating transmissible spongiform encephalopathies of mammals. 1) Both [PSI] and [URE3] are reversibly curable. 2) [PSI] propagation requires SUP35 and [URE3] propagation requires URE2 with recessive chromosomal mutants having the same phenotypes as the presence of the respective dominant non-Mendelian element. 3) Overproduction of Sup35p and Ure2p increases the frequency of cells acquiring [PSI] or [URE3], respectively.
Wickner
R B
RB
Section on Genetics of Simple Eukaryotes, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, MD 20892-0830, USA.
Masison
D C
DC
Edskes
H K
HK
D000595:Amino Acid Sequence; D000818:Animals; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D005979:Glutathione Peroxidase; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors; D011328:Prions / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D005656:Fungal Proteins; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae