Abstract
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.
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Received: 12 October / 15 December 1998
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Derkatch, I., Bradley, M., Zhou, P. et al. The PNM2 mutation in the prion protein domain of SUP35 has distinct effects on different variants of the [PSI+] prion in yeast. Curr Genet 35, 59–67 (1999). https://doi.org/10.1007/s002940050433
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DOI: https://doi.org/10.1007/s002940050433