Notes on Genus: Betatetravirus
Type member: Nudaurelia capensis beta virus
This is one of two genera in the family Alphatetraviridae
and consists of those viruses with monopartite genomes.
Virions isometric (icosahedral), not enveloped, about 40 nm in diameter with T=4 icosahedral shell quasi-symmetry.
Monopartite positive sense single-stranded RNA without a 3'-polyA tail and about 6.6kb in length. The subgenomic RNA of about 2.5kb can also be encapsidated.
Genus Genomic Organization
There are two major ORFs, one encoding an RNA polymerase and the other (expressed from a subgenomic RNA) is a coat protein precursor.
Type Member Genomic Organization
The RNA (6625 nts) encodes two proteins:
- Polymerase (216 kDa)
- Coat protein precursor (66 kDa) which is cleaved into two products of 58 and 8 kDa