Respiratory Enteric Orphan viruses, i.e. infect the human respiratory and intestinal tracts, usually without disease symptoms. First recognised in 1959 - and previously (wrongly) classified as echoviruses (Picornaviridae). There are >150 species in the family Reoviridae. They are a diverse group, infecting invertebrates, vertebrates and plants, but are unified by their most unique feature - the composition of their genome
The receptor(s) are known to contain sialic acid (haemagglutination, broad cell tropism), but most have not been definitively identified.Particles are internalized and partially uncoated in endolysosomes in the cytoplasm (resistant to protease digestion- if completely uncoated, virus would be destroyed).
Early transcription of the d/s RNA genome by viral polymerase occurs inside this sub-viral particle. The various genome segments are transcribed/translated at different frequencies - the main advantage of a segmented genome? (reassortment?)
RNA is transcribed conservatively - only (-)sense strands are used, resulting in synthesis of (+)sense mRNAs, which are capped inside the core - all this occurs without de novo protein synthesis.
mRNAs leave core and are translated in the cytoplasm.
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