Molecular biology

VIRION

Non-enveloped, spherical virion about 25nm in diameter with icosahedral symmetry (T=3) composed of 60 trimers of VP1-VP2-VP3 proteins

GENOME

Linear, ssRNA(+) genome about 8.6 kb in size. 3’end is polyadenylated.

GENE EXPRESSION

The virion RNA is infectious and serves as both the genome and viral messenger RNA. The polyprotein is processed presumably by several proteases.

REPLICATION

1. Virus attaches to host receptors.
2. Uncoating, and release of the viral genomic RNA into the cytoplasm possibly through the formation of a pore in the host cell membrane.
3. Genomic RNA is translated into a processed polyprotein.
4. Replication of viral RNA takes place. A negative-sense complementary ssRNA is synthesized using the genomic RNA as a template.
5. New genomic RNA synthesized using the negative-sense RNA as a template is packaged into viral capsids.
6. virus release.