Segmented linear dsRNA genome. Contains 11 or 12 segments coding respectively for 11 or 12 proteins (each segment contains a single ORF). Segments size range from 0.7 to 4.1 kb, genome total size is about 23 kb (CpMYRV-1).
The dsRNA genome is never completely uncoated, to prevent activation of antiviral state by the cell in response to dsRNA. The viral polymerase synthesizes a capped mRNA from each dsRNA segment. This capped mRNA is translocated to the cell cytoplasm where it is translated.
- RNA-dependent RNA polymerase [VP1]
- Cell-type capping:
- Attachment to host receptors probably mediates endocytosis of virus into host cell.
- Particles are partially uncoated in endolysosomes, but not entirely, and penetrate in the cytoplasm.
- Early transcription of the dsRNA genome by viral polymerase occurs inside this sub-viral particle (naked core), so that dsRNA is never exposed to the cytoplasm.
- Full-length plus-strand transcripts from each of the dsRNA segments are synthesized. These plus-strand transcripts are used as templates for translation.
- Viral proteins and genomic RNAs aggregates in cytoplasmic viral factories.
- (+)RNAs are encapsidated in a sub-viral particle, in which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
- The capsid is assembled on the sub-viral particle.
- Mature virions are released presumably following cell death and associated breakdown of host plasma membrane. They can be transmitted to new cell by cytoplasmic exchange, sporogenesis or hyphal anastomosis.