Non-enveloped icosahedral capsid, about 30-35 nm in diameter. Presumably T=1 icosahedral symmetry but has not been determined. The two genomic segments are encapsidated separately.
Segmented dsRNA linear genome: 2 segments encoding potentially for 2 proteins. Segments are about 2.1 kb each, total size about 4 kb.
Each genomic segment is monocistronic.
- 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, inside which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
- Mature are transmitted to new cell during cell division, sporogenesis or cell fusion.