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Prion domain interaction responsible for species discrimination in yeast [PSI+] transmission

Hideyuki Hara1, Toru Nakayashiki, Colin G Crist

  • 1Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.

Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|January 31, 2004
PubMed
Abstract

Insights

The yeast [PSI+] prion transmission barrier between species is overcome by swapping the N-terminal Gln/Asn-rich (NQ) region of Sup35. This NQ region alone is sufficient to initiate prion transmission, acting as a self/non-self discriminator.

Area of Science:

  • Prion biology
  • Yeast genetics
  • Protein aggregation

Background:

  • The yeast [PSI+] factor, a prion, propagates via self-forming Sup35 aggregates.
  • A species barrier normally prevents prion transmission between different yeast species.
  • Saccharomyces cerevisiae Sup35's N-terminal region contains Gln/Asn-rich (NQ) and repeat (NR) elements crucial for [PSI+].

Purpose of the Study:

  • To investigate the role of specific Sup35 domains in overcoming the prion species barrier.
  • To determine if the NQ region is sufficient to mediate [PSI+] transmission between yeast species.

Main Methods:

  • Plasmid shuffling and cytoplasmic transfer to introduce heterotypic Sup35 variants.
  • In vitro amyloid formation assays to assess cross-seeding.
  • Genetic manipulation of Sup35 N-terminal domains (NQ and NR).

Main Results:

  • [PSI+] transmission was achieved in yeast expressing heterotypic Sup35 with swapped S. cerevisiae NQ regions.
  • The N-terminal location of the NQ region is critical for mediating transmission susceptibility.
  • In vitro, swapping the NQ region of S. cerevisiae Sup35 induced cross-seeding of amyloid formation.

Conclusions:

  • The NQ region acts as a "self" versus "non-self" determinant, sufficient for initiating [PSI+] transmission.
  • Both NQ and NR domains can independently aggregate with existing [PSI+] conformers.
  • The findings elucidate the domain-specific roles of NQ and NR in [PSI+] prion formation and transmission.

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