The [URE3] prion is an aggregated form of Ure2p that can be cured by overexpression of Ure2p fragments.
The [URE3] nonchromosomal genetic element is a prion of Ure2p, a regulator of nitrogen catabolism in Saccharomyces cerevisiae. Ure2p1-65 is the prion domain of Ure2p, sufficient to propagate [URE3] in vivo. We show that full length Ure2p-green fluorescent protein (GFP) or a Ure2p1-65-GFP fusion protein is aggregated in cells carrying [URE3] but is evenly distributed in cells lacking the [URE3] prion. This indicates that [URE3] involves a self-propagating aggregation of Ure2p. Overexpression of Ure2p1-65 induces the de novo appearance of [URE3] by 1,000-fold in a strain initially [ure-o], but cures [URE3] from a strain initially carrying the [URE3] prion. Overexpression of several other fragments of Ure2p or Ure2-GFP fusion proteins also efficiently cures the prion. We suggest that incorporation of fragments or fusion proteins into a putative [URE3] "crystal" of Ure2p poisons its propagation.
Edskes
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HK
Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA.
Gray
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VT
Wickner
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RB
D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics*; D005816:Genetic Complementation Test; D005979:Glutathione Peroxidase; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism; D010957:Plasmids; D011328:Prions / Q000737:chemistry / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins