The yeast prion [URE3] can be greatly induced by a functional mutated URE2 allele.
The non-Mendelian element [URE3] of yeast is considered to be a prion form of the Ure2 protein. The [URE3] phenotype occurs at a frequency of 10(-5) in haploid yeast strains, is reversible, and its frequency is increased by overexpressing the URE2 gene. We created a new mutant of the Ure2 protein, called H2p, which results in a 1000-fold increase in the rate of [URE3] occurrence. To date, only the overexpression of various C-terminal truncated mutants of Ure2p gives rise to a comparable level. The h2 allele is, thus, the first characterized URE2 allele that induces prion formation when expressed at a low level. By shuffling mutated and wild-type domains of URE2, we also created the first mutant Ure2 protein that is functional and induces prion formation. We demonstrate that the domains of URE2 function synergistically in cis to induce [URE3] formation, which highlights the importance of intramolecular interactions in Ure2p folding. Additionally, we show using a green fluorescent protein (GFP) fusion protein that the h2 allele exhibits numerous filiform structures that are not generated by the wild-type protein.
Fernandez-Bellot
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Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
Guillemet
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Cullin
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D000483:Alleles; D001483:Base Sequence; D017931:DNA Primers; D005656:Fungal Proteins / Q000235:genetics*; D005979:Glutathione Peroxidase; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D016296:Mutagenesis; D011328:Prions / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D017931:DNA Primers; D005656:Fungal Proteins; D008164:Luminescent Proteins; D011328:Prions; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae