Notes on Genus: Spumavirus

enveloped spheres

Type member: Simian foamy virus 1

Contents

Members of this Genus
General Description
Morphology
Electron Micrograph
Genome
Genus Genomic Organization
Genome Map
Type Member Genomic Organization
Curated Sequences

General Description

This is one of the genera in the family Retroviridae. Members are distinguished from those of the other genera by the presence of 6 ORFs, a genome of more than 10 kb, and because they infect mammals.

Morphology

Virions are spherical and enveloped, 80-100 nm in diameter, with suface projections of glycoprotein.

Genome

A dimer of linear, positive sense, ssRNA molecules, each 10.5-13.5 kb long and with a 3'-polyA tail.

Genus Genomic Organization

In addition to the standard 4 genes of the family (gag, pro, pol and env), two other regulatory genes are encoded at the 3'-end of the genome. The pro and the pol are translated from a single spliced mRNA and the other genes downstream are translated from separate spliced mRNAs.

Type Member Genomic Organization

The major genes are
  1. gag: structural polyprotein of 70.7 kDa
  2. pro: protease
  3. pol: polyprotein (pro-pol of 129.9 kDa)
  4. env: envelope proteins (113.3 kDa)
  5. taf: transactivating factor of 33.8 kDa
  6. bet: > 48 kDa