Prion Domain Initiation of Amyloid Formation In vitro from Native Ure2p

• Published in: Science (American Association for the Advancement of Science) 1999-02, Vol.283 (5406), p.1339-1343
• Main Authors: Taylor, Kimberly L., Cheng, Naiqian, Williams, Robert W., Steven, Alasdair C., Wickner, Reed B.
• Format: Article
• Language: English
• Subjects: Amides; Amyloid - chemistry; Amyloid - metabolism; Amyloid - ultrastructure; Amyloids; Biological and medical sciences; Biopolymers - chemistry; Birefringence; Brewer's yeast; Cell aggregates; Chemical Precipitation; Classical genetics, quantitative genetics, hybrids; Coloring Agents - metabolism; Congo Red - metabolism; Copolymers; Dimerization; Electron microscopy; Endopeptidases - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - chemistry; Fungal Proteins - metabolism; Fungal Proteins - ultrastructure; Genetic aspects; Genetics of eukaryotes. Biological and molecular evolution; Glutathione Peroxidase; Hot Temperature; Medical genetics; Microscopy, Electron; Nitrogen; Peptide Fragments - chemistry; Precipitates; Prions; Prions - chemistry; Prions - metabolism; Prions - ultrastructure; Protein Denaturation; Protein Structure, Secondary; Proteins; Pteridophyta, spermatophyta; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Vegetals
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.283.5406.1339

The [URE3] non-Mendelian genetic element of Saccharomyces cerevisiae is an infectious protein (prion) form of Ure2p, a regulator of nitrogen catabolism. Here, synthetic Ure2p$^{1-65}$ were shown to polymerize to form filaments 40 to 45 angstroms in diameter with more than 60 percent β sheet. Ure2p$^{1-65}$ specifically induced full-length native Ure2p to copolymerize under conditions where native Ure2p alone did not polymerize. Like Ure2p in extracts of [URE3] strains, these 180- to 220-angstrom-diameter filaments were protease resistant. The Ure2p$^{1-65}$-Ure2p cofilaments could seed polymerization of native Ure2p to form thicker, less regular filaments. All filaments stained with Congo Red to produce the green birefringence typical of amyloid. This self-propagating amyloid formation can explain the properties of [URE3].