Notes on Family: Permutotetraviridae

icosahedra
icosahedra

Contents

General Description

This family consists of ssRNA viruses with 40nm isometric particles and that infect insects. The name is derived from the Greek tettares = four, because of the T=4 symmetry of the virions. All tetraviruses were formerly classified in a single family but this has now been split because of large differences in the types of RNA polymerase and other genome differences. In this family, viruses have highly structured genome terminal sequences and an RdRp domain with a permuted active site and VPg signal similar to members of the family Birnaviridae).

Morphology

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

Genomen

Monopartite positive sense single-stranded RNA of 5.5-6.0 kb without a 3'-polyA tail. There are two major ORFs, one encoding an RNA polymerase and the other a coat protein precursor.

Genera in the Family

There is currently only one genus: