VIRION
Non-enveloped, spherical virion about 34 nm in diameter with T=3 icosahedral symmetry composed of 180 CP proteins that make bumps at the surface of the virion.
GENOME
Monopartite, linear, ssRNA(+) genome of 4.4 kb with a stem loop structure at the 3'-end.
GENE EXPRESSION
The virion RNA is infectious and serves as both the genome and viral messenger RNA. ORF1 encodes the replicase and ORF2 encodes the capsid protein.
ENZYMES
- RNA-directed RNA polymerase [RdRp]
- VPG-type capping? [VPg?]
- Polyprotein major protease [Pro]
REPLICATION
CYTOPLASMIC
- Virus penetrates into the host cell.
- Uncoating, and release of the viral genomic RNA into the cytoplasm.
- The viral RNA ORF1 and ORF2 are translated.
- 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.
- Virus assembly.
- Virions accumulate in the host cytoplasm forming a crystalline array.
- Cell lysis and virus release.