VIRION
Capsidless virus: No virus particle could be identified, which means that this virus cannot be assigned to the Baltimore classification in the strict sense. This had led to misclassification of this family into the Baltimore group III: dsRNA viruses due to accumulation of dsRNA replication intermediates in infected cells.
None reported. No true capsid. The dsRNA genome is encapsulated along with the viral replicase enzyme.
GENOME
linear ssRNA(+) genome of about 14 kb to 17.6 kb. A site specific break (nick) is found in the coding strand about 1 to 2 kb from the 5' terminus. Some viral genomes are capped.
GENE EXPRESSION
The genome encodes for one ORF potentially cleaved in several polypeptides.
ENZYMES
REPLICATION
CYTOPLASMIC
- Virus penetrates into the host cell.
- The viral RNA is translated as a monocistronic mRNA to produce the RdRp.
- A dsRNA genome is synthesized from the genomic ssRNA(+), possibly in membrane vesicles.
- The dsRNA genome is transcribed/replicated resulting in mRNAs/ssRNA(+) genomes.
- The genomic ssRNA is transmitted to new cell via hyphal anastomosis (fungi) or by spores or seeds (fungi or plants).