Mechanism of genome transcription in segmented dsRNA viruses

This chapter discusses the mechanism of genome transcription in segmented double-stranded RNA (dsRNA) viruses. Genome transcription is a critical stage in the life cycle of a virus, as this is the process by which the viral genetic information is presented to the host cell protein-synthesis machinery for the production of the viral proteins needed for genome replication and progeny virion assembly. Viruses with dsRNA genomes face a particular challenge in that host cells do not produce proteins that can transcribe from a dsRNA template. One of the more striking observations about genome transcription in dsRNA viruses is that this process occurs efficiently only when the transcriptionally competent particle is fully intact. This observation suggests that all of the components of the transcriptionally competent particle, including the viral genome, the transcription enzymes, and the viral capsid, function together to produce and release messenger RNA transcripts and that each component has a specific and critical role to play in promoting the efficiency of this process.