NR AQHZ
AU Bradley,M.E.; Liebman,S.W.
TI The Sup35 domains required for maintenance of weak, strong or undifferentiated yeast [PSI+] prions
QU Molecular Microbiology 2004 Mar; 51(6): 1649-59
PT journal article
AB The Sup35 protein can exist in a non-infectious form or in various infectious forms called [PSI+] prion variants (or prion strains). Each of the different [PSI+] prion variants converts non-infectious Sup35 molecules into that prion variant's infectious form. One definition of a 'prion domain' is the minimal fragment of a prion protein that is necessary and sufficient to maintain the prion form. We now demonstrate that the Sup35 N region (residues 1-123), which is frequently referred to as the 'prion domain', is insufficient to maintain the weak or strong [PSI+] variants per se, but appears to maintain them in an 'undifferentiated' [PSI+] state that can differentiate into weak or strong [PSI+] variants when transferred to the full-length Sup35 protein. In contrast, Sup35 residues 1-137 are necessary and sufficient to faithfully maintain weak or strong [PSI+] variants. This implicates Sup35 residues 124-137 in the variant-specific maintenance of the weak or strong [PSI+] forms. Structure predictions indicate that the residues in the 124-137 region form an alpha-helix and that the 1-123 region may have beta structure. In view of these findings, we discuss a plausible molecular basis for the [PSI+] prion variants as well as the inherent difficulties in defining a 'prion domain'.
MH Animals; Blotting, Western; Gene Expression Regulation, Fungal; Phenotype; Polymerase Chain Reaction; Prions/*chemistry/*genetics/metabolism; Protein Structure, Secondary; Saccharomyces cerevisiae/*chemistry/genetics/metabolism; Saccharomyces cerevisiae Proteins/*chemistry/*genetics/metabolism; Support, U.S. Gov't, P.H.S.; *Variation (Genetics)
AD Department of Biological Sciences, Laboratory for Molecular Biology, University of Illinois at Chicago, 900 South Ashland Avenue, Chicago, IL 60607, USA
SP englisch
PO England