VIRION
Non-enveloped, bacilliform, about 150 nm in length and 50 nm in width.
GENOME
Segmented, 2-4 segments, linear, ssRNA(+) genome genomic RNA is capped, and polyadenylated.
GENE EXPRESSION
Genomic RNAs serve as messenger RNAs. RNA1 contains 2 ORFs, the first one encoding the replicase. RNA2 contains 4 ORFs, and may encode a movement proteins.
ENZYMES
- RNA-dependent RNA polymerase [Q1KZ59]
- Polyprotein major protease [Q1KZ59]
- Alpha-type capping [Q1KZ59]
Q1KZ59
REPLICATION
CYTOPLASMIC
- Virus penetrates into the host cell.
- Uncoating, and release of the viral genomic RNA into the cytoplasm.
- The viral RNA is translated to produce the two proteins necessary for RNA synthesis (replication and transcription).
- 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 RNAs (sgRNAs).
- Each segment is encapsidated.
- Viral movement proteins probably mediate virion cell-to-cell transfer.