Analyzing the birth and propagation of two distinct prions, [PSI+] and [Het-s](y), in yeast.
Various proteins, like the infectious yeast prions and the noninfectious human Huntingtin protein (with expanded polyQ), depend on a Gln or Asn (QN)-rich region for amyloid formation. Other prions, e.g., mammalian PrP and the [Het-s] prion of Podospora anserina, although still able to form infectious amyloid aggregates, do not have QN-rich regions. Furthermore, [Het-s] and yeast prions appear to differ dramatically in their amyloid conformation. Despite these differences, a fusion of the Het-s prion domain to GFP (Het-sPrD-GFP) can propagate in yeast as a prion called [Het-s](y). We analyzed the properties of two divergent prions in yeast: [Het-s](y) and the native yeast prion [PSI(+)] (prion form of translational termination factor Sup35). Curiously, the induced appearance and transmission of [PSI(+)] and [Het-s](y) aggregates is remarkably similar. Overexpression of tagged prion protein (Sup35-GFP or Het-sPrD-GFP) in nonprion cells gives rise to peripheral, and later internal, ring/mesh-like aggregates. The cells with these ring-like aggregates give rise to daughters with one (perivacuolar) or two (perivacuolar and juxtanuclear) dot-like aggregates per cell. These line, ring, mesh, and dot aggregates are not really the transmissible prion species and should only be regarded as phenotypic markers of the presence of the prions. Both [PSI(+)] and [Het-s](y) first appear in daughters as numerous tiny dot-like aggregates, and both require the endocytic protein, Sla2, for ring formation, but not propagation.
Mathur
Vidhu
V
Department of Biological Sciences, University of Illinois, Chicago, IL 60607, USA.
Taneja
Vibha
V
Sun
Yidi
Y
Liebman
Susan W
SW
D000199:Actins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D009154:Mutation; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D014617:Vacuoles / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C083891:HET-S protein, Podospora anserina; D010454:Peptide Termination Factors; D011993:Recombinant Fusion Proteins; C082266:SLA2 protein, S cerevisiae; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins