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  • The EMBO Journal (2005) 24, 3082 - 3092
  • doi:10.1038/sj.emboj.7600772

Published online: 11 August 2005

Prion generation in vitro: amyloid of Ure2p is infectious

Andreas Brachmann1,a, Ulrich Baxa1,2 and Reed Brendon Wickner1

  1. Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
  2. Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, National Institutes of Health, Bethesda, MD, USA

Correspondence to:

Reed Brendon Wickner, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive , Bethesda, MD 20892-0830, USA. Tel.: +1 301 496 3452; Fax: +1 301 402 0240; E-mail: wickner@helix.nih.gov

aPresent address: Institut für Genetik, Department Biologie I, Ludwig-Maximilians-Universität München, Maria-Ward-Strasse 1a, 80638 München, Germany

Received 6 June 2005; Accepted 15 July 2005

[URE3] is a prion (infectious protein) of the Ure2 protein of yeast. In vitro, Ure2p can form amyloid filaments, but direct evidence that these filaments constitute the infectious form is still missing. Here we demonstrate that recombinant Ure2p converted into amyloid can infect yeast cells lacking the prion. Infection produced a variety of [URE3] variants. Extracts of [URE3] strains, as well as amyloid of Ure2p formed in an extract-primed reaction could transmit to uninfected cells the [URE3] variant present in the cells from which the extracts were made. Infectivity and determinant of [URE3] variants resided within the N-terminal 65 amino acids of Ure2p. Notably, we could show that amyloid filaments of recombinant Ure2p are nearly as infectious per mass of Ure2p as extracts of [URE3] strains. Sizing experiments indicated that infectious particles in vitro and in vivo were >20 nm in diameter, suggesting that they were amyloid filaments and not smaller oligomeric structures. Our data indicate that there is no substantial difference between filaments formed in vivo and in vitro.

  • Keywords:

    • amyloid,
    • prion transformation,
    • prion variants,
    • [URE3]