Amyloid aggregates of the HET-s prion protein are infectious
- Marie-Lise Maddelein†,‡,
- Suzana Dos Reis†,
- Stéphane Duvezin-Caubet§,
- Bénédicte Coulary-Salin†, and
- Sven J. Saupe†
- †Laboratoire de Génétique Moléculaire des Champignons et §Laboratoire de Génétique Moléculaire des Systèmes Mitochondriaux, Institut de Biochimie et de Génétique Cellulaires, Unité Mixte de Recherche 5095, Centre National de la Recherche Scientifique, Université de Bordeaux 2, 1 Rue Camille St. Saëns, 33077 Bordeaux Cedex, France
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Communicated by Reed B. Wickner, National Institutes of Health, Bethesda, MD (received for review March 29, 2002)
Abstract
The [Het-s] infectious element of the filamentous fungus Podospora anserina is a prion. We have recently reported that recombinant HET-s protein aggregates in vitro into amyloid fibers. In vivo, the protein aggregates specifically in the [Het-s] prion strains. Here, we show that biolistic introduction of aggregated recombinant HET-s protein into fungal cells induces emergence of the [Het-s] prion with a high frequency. Thus, we demonstrate that prion infectivity can be created de novo, in vitro from recombinant protein in this system. Although the amyloid filaments formed from HET-s could transmit [Het-s] efficiently, neither the soluble form of the protein nor amorphous aggregates would do so. In addition, we have found that (i) [Het-s] infectivity correlates with the ability to convert HET-s to amyloids in vitro, (ii) [Het-s] infectivity is resistant to proteinase K digestion, and (iii) HET-s aggregates formed in vivo in [Het-s] strains have the ability to convert the recombinant protein to aggregates. Together, our data designate the HET-s amyloids as the molecular basis of [Het-s] prion propagation.
Footnotes
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↵ ‡ To whom reprint requests should be addressed. E-mail: ML.Maddelein{at}ibgc.u-bordeaux2.fr.
- Copyright © 2002, The National Academy of Sciences
