VIRION
Non-enveloped, spherical, capsid of about 27-33 nm with icosahedral symmetry. The virion is constructed from two capsid proteins VP1 and VP2.
GENOME
Monopartite, linear, ssRNA(+) genome of 10-11 kb in size, polyadenylated.
GENE EXPRESSION
The virion RNA is infectious and serves as both the genome and viral messenger RNA.
ENZYMES
- RNA-dependent RNA polymerase [RdRp]
- VPG-type capping [VPg]
- NTPase-helicase [Hel]
- Polyprotein major protease (Peptidase C3) [Pro]
REPLICATION
CYTOPLASMIC
- Attachement to host receptors mediates entry into the host cell.
- Uncoating, and release of the viral genomic RNA into the cytoplasm.
- Viral RNA is translated in a polyprotein to produce replication proteins.
- Replication occurs in viral factories made of membrane vesicles derived from the ER. A dsRNA genome is synthesized from the genomic ssRNA(+).
- The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
- Subgenomic RNA translation gives rise to the capsid proteins.
- Assembly of new virus particles.
- Virus release.