VIRION
Non-enveloped capsid presumably with T=2* icosahedral symmetry and composed of 120 protein subunit monomers. The capsid is about 30 nm in diameter.
GENOME
Linear dsRNA genome about 5.3 to 6.6 kb encoding for 2 overlaping ORFs.
GENE EXPRESSION
RdRp may be produced through a fusion protein via a ribosomal frameshift.
ENZYMES
- RNA-directed RNA polymerase [RdRp]
- No capping activity [IRES?]
REPLICATION
CYTOPLASMIC
- Virus penetrates into the cytoplasm.
- Transcription of the dsRNA genome by viral polymerase occurs inside the virion, so that dsRNA is never exposed to the cytoplasm. This plus-strand transcript is used as template for translation.
- (+)RNAs are encapsidated in virion particle, in which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
- Mature virions are transmitted to new cell.