Molecular biology
VIRION
Enveloped, spherical, about 50 nm in diameter.
GENOME
Monopartite, linear, ssRNA(+) genome of about 10-12 kb. The virion RNA is infectious and serves as both the genome and the viral messenger RNA.
GENE EXPRESSION
The whole genome is translated in a polyprotein, which is processed co- and posttranslationally by host and viral proteases.
REPLICATION
CYTOPLASMIC
- Virus attaches to host receptors and is endocytosed into vesicles in the host cell.
- Fusion of virus membrane with the vesicle membrane; RNA genome is released into the cytoplasm.
- The positive-sense genomic ssRNA is translated into a polyprotein, which is cleaved into all structural and non structural proteins.
- Replication takes place at the surface of endoplasmic reticulum. A negative-sense complementary ssRNA is synthesized using the genomic RNA as a template.
- New genomic RNA is synthesized using the negative-sense RNA as a template.
- Virus assembly occurs at the endoplasmic reticulum. The virion buds at the endoplasmic reticulum, is transported to the Golgi apparatus, and then bud from the cell membrane.