Non enveloped virion, about 40 nm in diameter with a T=4 icosahedral symmetry (240 protein subunits). The capsid precursor is expressed from a subgenomic RNA molecule which, along with genomic RNA, can be packaged into virions.
Linear ssRNA(+) genome of 5.6 kb. The 5' terminus is linked to a VPg protein, and the 3' terminus is not polyadenylated but terminates with a pseudoknot.
The virion RNA is infectious and serves as both the genome and viral messenger RNA. Genomic RNA is translated into a polyprotein which is cleaved presumably by a viral protease into replication proteins. Replication produces a subgenomic RNA which encodes for capsid protein and the 17 kDa protein by RNA termination-reinitiation.
- Virus penetrates into the host cell.
- Uncoating, and release of the viral genomic RNA into the cytoplasm.
- Genomic RNA is translated to produce replication proteins.
- Replication takes place in cytoplasmic viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
- The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
- Expression of the subgenomic RNA encoding the capsid protein.
- Assembly of new virus particles.
- Virion maturation by the viral protease.