VIRION
Non-enveloped, bacilliform with a T=1 icosahedral symmetry, about 50 nm length and 20 nm large.
GENOME
Linear, ssRNA(+) genome of 4 kb. The genome contains four major and three minor ORFs.
GENE EXPRESSION
Genomic RNA serves as both the genome and viral messenger RNA. ORF2 is a polyprotein which is possibly auto-cleaved by the ORF2 viral protease. ORF3 encodes the RNA dependent RNA polymerase and may be translated by ribosomal frameshifting as an ORF2-ORF3 polyprotein. The single capsid protein (ORF4) is translated from a subgenomic RNA.
ENZYMES
REPLICATION
CYTOPLASMIC
- 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 occurs in viral factories. 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 protein precursor.
- Assembly of new virus particles.