Notes on Family: Alphatetraviridae
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. Most of the species are retained in this family (which has been renamed from
Tetraviridae) but some are now classified in the families
Carmotetraviridae and
Permutotetraviridae.
Morphology
Virions isometric (icosahedral), not enveloped, about 40 nm in diameter with T=4 icosahedral shell quasi-symmetry.
Genomen
Mono- or Bi-partite positive sense single-stranded RNA without 3'-polyA tails. Total genome size less than 8 kb. There are two major ORFs, one encoding an RNA polymerase and the other a coat protein precursor.
Genera in the Family
