Amyloid aggregates of the HET-s prion protein are infectious.
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.
Maddelein
Marie-Lise
ML
Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires, Unité Mixte de Recherche 5095, Centre National de la Recherche Scientifique, Université de Bordeaux 2, France. ML.Maddelein@ibgc.u-bordeaux2.fr
Dos Reis
Suzana
S
Duvezin-Caubet
Stéphane
S
Coulary-Salin
Bénédicte
B
Saupe
Sven J
SJ
D000682:Amyloid / Q000737:chemistry / Q000378:metabolism*; D019470:Biolistics; D019286:Endopeptidase K; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011328:Prions / Q000378:metabolism* / Q000472:pathogenicity; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020037:Sordariales / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*
D000682:Amyloid; D005656:Fungal Proteins; C083891:HET-S protein, Podospora anserina; D011328:Prions; D011994:Recombinant Proteins; D019286:Endopeptidase K