title: Prion domain interaction responsible for species discrimination in yeast [PSI+] transmission.
abstract: BACKGROUND
  The yeast [PSI+] factor is transmitted by a prion mechanism involving self-propagating Sup35 aggregates. As with mammalian prions, a species barrier prevents prion transmission between yeast species. The N-terminal of Sup35 of Saccharomyces cerevisiae, necessary for [PSI+], contains two species-signature elements-a Gln/Asn-rich region (residues 1-41; designated NQ) that is followed by oligopeptide repeats (designated NR).
  
  
  RESULTS
  In this study, we show that S. cerevisiae[PSI+] is transmissible through plasmid shuffling and cytoplasmic transfer to heterotypic Sup35s whose NQ is replaced with the S. cerevisiae NQ. In addition to homology, the N-terminal location is essential for NQ mediated susceptibility to [PSI+] transmission amongst heterotypic Sup35s. In vitro, a swap of NQ of S. cerevisiae Sup35 led to cross seeding of amyloid formation.
  
  
  CONCLUSIONS
  These findings suggest that NQ discriminates self from non-self, and is sufficient to initiate [PSI+] transmission irrespective of whether NR is heterotypic. NR as well as NQ alone coalesces into existing [PSI+] aggregates, showing their independent potentials to interact with the identical sequence in the [PSI+] conformer. The role of NQ and NR in [PSI+] prion formation is discussed.
authors.affiliation: Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hara
authors.forename: Toru
authors.initials: T
authors.lastname: Nakayashiki
authors.forename: Colin G
authors.initials: CG
authors.lastname: Crist
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D009154:Mutation; D010454:Peptide Termination Factors; D010455:Peptides / Q000737:chemistry; D010957:Plasmids; D017096:Prion Diseases / Q000635:transmission; D011328:Prions / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics; D013045:Species Specificity
chemical_list: D010454:Peptide Termination Factors; D010455:Peptides; D011328:Prions; D011993:Recombinant Fusion Proteins; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins