The PNM2 mutation in the prion protein domain of SUP35 has distinct effects on different variants of the [PSI+] prion in yeast.

Autor: Derkatch, Irina L., Bradley, Michael E., Zhou, Ping, Liebman, S. W.
Zdroj: Current Genetics; Mar1999, Vol. 35 Issue 2, p59-67, 9p
Abstrakt: We have previously described different variants of the yeast prion [ PSI +] that can be obtained and maintained in the same genetic background. These [ PSI +] variants, which differ in the efficiency of nonsense suppression, mitotic stability and the efficiency of curing by GuHCl, may correspond to different [ PSI +] prion conformations of Sup35p or to different types of prion aggregates. Here we investigate the effects of overexpressing a mutant allele of SUP35 and find different effects on weak and strong [ PSI +] variants: the suppressor phenotype of weak [ PSI +] factors is increased, whereas the suppressor effect of strong [ PSI +] factors is reduced. The SUP35 mutation used was originally described as a “Psi no more” mutation ( PNM2) because it caused loss of [ PSI +]. However, none of the [ PSI +] variants in the strains used in our study were cured by PNM2. Indeed, when overexpressed, PNM2 induced the de novo appearance of both weak and strong [ PSI +] variants with approximately the same efficiency as the overexpressed wild-type SUP35 allele. Our data suggest that the change in the region of oligopeptide repeats in the Sup35p N-terminus due to the PNM2 mutation modifies, but does not impair, the function of the prion domain of Sup35p. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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