NR AMZX
AU Zhou,P.; Derkatch,I.L.; Uptain,S.M.; Patino,M.M.; Lindquist,S.L.; Liebman,S.W.
TI The yeast non-Mendelian factor [ETA+] is a variant of [PSI+], a prion-like form of release factor eRF3
QU EMBO Journal 1999 Mar 1; 18(5): 1182-91
PT journal article
AB The yeast non-Mendelian factor [ETA+] is lethal in the presence of certain mutations in the SUP35 and SUP45 genes, which code for the translational release factors eRF3 and eRF1, respectively. One such mutation, sup35-2, is now shown to contain a UAG stop codon prior to the essential region of the gene. The non-Mendelian inheritance of [ETA+] is reminiscent of the yeast [PSI+] element, which is due to a self-propagating conformation of Sup35p. Here we show that [ETA+] and [PSI+] share many characteristics. Indeed, like [PSI+], the maintenance of [ETA+] requires the N-terminal region of Sup35p and depends on an appropriate level of the chaperone protein Hsp104. Moreover, [ETA+] can be induced de novo by excess Sup35p, and [ETA+] cells have a weak nonsense suppressor phenotype characteristic of weak [PSI+]. We conclude that [ETA+] is actually a weak, unstable variant of [PSI+]. We find that although some Sup35p aggregates in [ETA+] cells, more Sup35p remains soluble in [ETA+] cells than in isogenic strong [PSI+] cells. Our data suggest that the amount of soluble Sup35p determines the strength of translational nonsense suppression associated with different [PSI+] variants.
MH Cell Division/genetics; Fungal Proteins/genetics; Gene Expression Regulation, Fungal/genetics; Genes, Fungal/genetics; Heat-Shock Proteins/genetics; Mutation; Peptide Termination Factors/*genetics; Prions/*genetics; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Suppression, Genetic/genetics; Translation, Genetic/genetics
AD Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
SP englisch
PO England