title: Two structurally similar fungal prions efficiently cross-seed in vivo but form distinct polymers when coexpressed.
abstract: HET-s is a prion protein of the filamentous fungus Podospora anserina. An orthologue of this protein, called FgHET-s has been identified in Fusarium graminearum. The region of the FgHET-s protein corresponding to the prion forming domain of HET-s, forms amyloid fibrils in vitro. These fibrils seed HET-s(218-289) fibril formation in vitro and vice versa. The amyloid fold of HET-s(218-289) and FgHET-s(218-289) are remarkably similar although they share only 38% identity. The present work corresponds to the functional characterization of the FgHET-s(218-289) region as a prion forming domain in vivo. We show that FgHET-s(218-289) is capable of prion propagation in P. anserina and is able to substitute for the HET-s PFD in the full-length HET-s protein. In accordance with the in vitro cross-seeding experiments, we detect no species barrier between P. anserina and F. graminearum PFDs. We use the yeast Saccharomyces cerevisiae as a host to compare the prion performances of the two orthologous PFDs. We find that FgHET-s(218-289) leads to higher spontaneous prion formation rates and mitotic prion stability than HET-s(218-289). Then we analysed the outcome of HET-s(218-289)/FgHET-s(218-289) coexpression. In spite of the cross-seeding ability of HET-s(218-289) and FgHET-s(218-289), in vivo, homotypic polymerization is favoured over mixed fibril formation.
authors: Institut de Biochimie et de Génétique Cellulaire, UMR 5095, CNRS - Université de Bordeaux 2, 1 rue Camille St Saens, 33077 Bordeaux cedex, France.
authors: Laura
authors: L
authors: Benkemoun
authors: Frédérique
authors: F
authors: Ness
authors: Raimon
authors: R
authors: Sabaté
authors: Johanna
authors: J
authors: Ceschin
authors: Annick
authors: A
authors: Breton
authors: Corinne
authors: C
authors: Clavé
authors: Sven J
authors: SJ
authors: Saupe
mesh_terms: D005656:Fungal Proteins; D005670:Fusarium / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D048468:Podospora / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011328:Prions / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; C083891:HET-S protein, Podospora anserina; D011328:Prions