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[ PHI + ], a novel Sup35‐prion variant propagated with non‐Gln/Asn oligopeptide repeats in the absence of the chaperone protein Hsp104
Author(s) -
Crist Colin G.,
Nakayashiki Toru,
Kurahashi Hiroshi,
Nakamura Yoshikazu
Publication year - 2003
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2003.00661.x
Subject(s) - oligopeptide , biology , yeast , direct repeat , biochemistry , fungal prion , microbiology and biotechnology , genetics , saccharomyces cerevisiae , peptide , gene , base sequence
Background: The [ PSI + ] element of the budding yeast is an aggregated form of the translation release factor Sup35 that is propagated and transmitted cytoplasmically in a manner analogous to that of mammalian prions. The N‐terminal of Sup35, necessary for [ PSI + ], contains oligopeptide repeats and multiple Gln/Asn residues. Results: We replaced the Gln/Asn‐rich prion repeats of Sup35 with non‐Gln/Asn repeats from heterologous yeast strains. These non‐Gln/Asn repeat Sup35s propagated a novel [ PSI + ] variant, [ PHI + ], that appeared de novo 10 3 times more frequent than [ PSI + ]. [ PHI + ] was stably inherited in a non‐Mendelian fashion, but not eliminated upon the inactivation of Hsp104, unlike known [ PSI + ] elements. In vitro , non‐Gln/Asn repeat domains formed amyloid fibres that were shorter and grew more slowly than did Gln/Asn‐rich prion domains, while [ PHI + ] aggregates were smaller than [ PSI + ] aggregates in vivo . Conclusions: These findings suggest the existence of an alternative, Hsp104‐independent pathway to replicate non‐Gln/Asn variant Sup35 prion seeds.