NR ACXK
AU Coustou-Linares,V.; Maddelein,M.L.; Begueret,J.; Saupe,S.J.
TI In vivo aggregation of the HET-s prion protein of the fungus Podospora anserina
QU Molecular Microbiology 2001 Dec; 42(5): 1325-35
PT journal article
AB We have proposed that the [Het-s] infectious cytoplasmic element of the filamentous fungus Podospora anserina is the prion form of the HET-s protein. The HET-s protein is involved in a cellular recognition phenomenon characteristic of filamentous fungi and known as heterokaryon incompatibility. Under the prion form, the HET-s protein causes a cell death reaction when co-expressed with the HET-S protein, from which it differs by only 13 amino acid residues. We show here that the HET-s protein can exist as two alternative states, a soluble and an aggregated form in vivo. As shown for the yeast prions, transition to the infectious prion form leads to aggregation of a HET-s - green fluorescent protein (GFP) fusion protein. The HET-s protein is aggregated in vivo when highly expressed. However, we could not demonstrate HET-s aggregation at wild-type expression levels, which could indicate that only a small fraction of the HET-s protein is in its aggregated form in vivo in wild-type [Het-s] strains. The antagonistic HET-S form is soluble even at high expression level. A double amino acid substitution in HET-s (D23A P33H), which abolishes prion infectivity, suppresses in vivo aggregation of the GFP fusion. Together, these results further support the model that the [Het-s] element corresponds to an abnormal self-perpetuating aggregated form of the HET-s protein.
MH Cell Aggregation; DNA Primers; Fungal Proteins/genetics/*metabolism; Luminescent Proteins/genetics; Microscopy, Fluorescence; Polymerase Chain Reaction; Recombinant Fusion Proteins/metabolism; Sordariales/*genetics/pathogenicity/physiology; Support, Non-U.S. Gov't; Virulence/genetics
AD Laboratoire de Parasitologie Moleculaire, UMR 5016 CNRS/Universite de Bordeaux 2, Bordeaux, France.
SP englisch
PO England