Notes on Genus: Betatetravirus

icosahedra
icosahedra

Type member: Nudaurelia capensis beta virus

Contents

General Description

This is one of two genera in the family Alphatetraviridae and consists of those viruses with monopartite genomes.

Morphology

Virions isometric (icosahedral), not enveloped, about 40 nm in diameter with T=4 icosahedral shell quasi-symmetry.

Genome

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