title: Analysis of [SWI+] formation and propagation events.
abstract: The budding yeast, Saccharomyces cerevisiae, harbors several prions that are transmitted as altered, heritable protein conformations. [SWI+] is one such prion whose determinant is Swi1, a subunit of the evolutionarily conserved chromatin-remodeling complex SWI/SNF. Despite the importance of Swi1, the molecular events that lead to [SWI+] prionogenesis remain poorly understood. In this study, we have constructed floccullin-promoter-based URA3 reporters for [SWI+] identification. Using these reporters, we show that the spontaneous formation frequency of [SWI+] is significantly higher than that of [PSI+] (prion form of Sup35). We also show that preexisting [PSI+] or [PIN+] (prion form of Rnq1), or overproduction of Swi1 prion-domain (PrD) can considerably promote Swi1 prionogenesis. Moreover, our data suggest a strain-specific effect of overproduction of Sse1 - a nucleotide exchange factor of the molecular chaperone Hsp70, and its interaction with another molecular chaperone Hsp104 on [SWI+] maintenance. Additionally, we show that Swi1 aggregates are initially ring/ribbon-like then become dot-like in mature [SWI+] cells. In the presence of [PSI+] or [PIN+], Swi1 ring/ribbon-like aggregates predominantly colocalize with the Sup35 or Rnq1 aggregates; without a preexisting prion, however, such colocalizations are rarely seen during Swi1-PrD overproduction-promoted Swi1 prionogenesis. We have thus demonstrated a complex interacting mechanism of yeast prionogenesis.
authors.affiliation: Department of Biochemistry and Molecular Genetics, the Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-650, Chicago, IL, 60611, USA.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Du
authors.affiliation: Department of Biochemistry and Molecular Genetics, the Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-650, Chicago, IL, 60611, USA.
authors.forename: Dustin Kenneth
authors.identifier: 0000-0001-8583-5389
authors.initials: DK
authors.lastname: Goncharoff
authors.affiliation: Department of Biochemistry and Molecular Genetics, the Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-650, Chicago, IL, 60611, USA.
authors.forename: Xudong
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Biochemistry and Molecular Genetics, the Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-650, Chicago, IL, 60611, USA.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
mesh_terms: D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D010454:Peptide Termination Factors / Q000378:metabolism; D011328:Prions / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D010454:Peptide Termination Factors; D011328:Prions; C404807:RNQ1 protein, S cerevisiae; C068068:SUP35 protein, S cerevisiae; C078562:SWI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C554167:URA3 protein, S cerevisiae