| Brome mosaic virus (BMV), a positive-strand RNA virus that replicates in the yeast Saccharomyces cerevisiae, is a well-established model to study host cell requirements for viral replication. The BMV genome consists of RNAs 1, 2 and 3 that encode 1a, 2a and 3a proteins, respectively. All three RNAs are characterized by a conserved tRNA like structure (TLS) at their 3'ends that is important for translation and for negative strand RNA synthesis. Unknown host factors have been implicated in mediating a 1a-induced switch from translation to replication of viral RNAs. GCD10 protein, a yeast RNA binding subunit of eIF3 that is involved in host cell translation initiation, has in the past been found to be associated with viral RNA-dependent RNA polymerase complexes. When BMV RNA3 is expressed from an inducible promoter in yeast cells, accumulation of RNA3 in the cytoplasm is enhanced with increased levels of GCD10, and co-expression of viral 1a protein further stabilizes RNA3. (Abstract shortened by UMI.)... |
