Yeast L-A Virus

摘要: The L-A virus of Saccharomyces cerevisiae is a single-segment 4.6 kbp double-stranded (dsRNA) encoding only major coat protein (‘Gag’, with an mRNA-decapping activity) and RNA-dependent RNA polymerase (Pol), made as Gag–Pol fusion using –1 ribosomal frameshift mechanism. has entirely intracellular life cycle conservative replication An internal packaging site, sites at the 3′ end have been defined. supports any several satellite dsRNAs, called M1, M2, M28, secreted toxins (‘killer’ toxins). icosahedral virions 120 Gag molecules, arranged 60 copies asymmetric dimer, 2 molecules. outer virion surface includes activity that transfers 5′ cap structure cellular mRNAs to His154 Gag. This required for normal expression viral which lack polyA structures, probably by making decapped derivatives decoy Xrn1 exoribonuclease specifically degrades uncapped mRNAs. Ski proteins block translation other non-polyA mRNAs, promote their degradation. Mak3p N-acetyltransferase whose modification necessary assembly.