SUMMARY PARAGRAPH for RNQ1
The [PSI+] prion determinant causes nonsense suppressor phenotype due to a reduced function of the translation termination factor Sup35p (eRF3) polymerized into amyloid fibrils. Prion state of the Rnq1 protein, [PIN+], is required for the [PSI+] de novo generation, but not propagation. Yeast [psi-] [PIN+] cells overproducing Sup35p can exhibit nonsense suppression without generation of a stable [PSI+]. In such cells most of Sup35p is present in amyloid polymers, though remaining Sup35p monomer is sufficient for normal translation termination. Presence of these polymers strictly depends on [PIN+], suggesting that their maintenance relies on efficient generation de novo, rather than inheritance. Sup35p polymers contain Rnq1p, confirming that Rnq1p polymers seed Sup35p polymerization (3).
Last updated: 2005-03-15