Notes on Genus: Arterivirus

enveloped spheres
enveloped spheres

Type member: Equine arteritis virus


General Description

This is currently the only genus in the family Arteriviridae and is named after the type member, Equine arteritis virus.


Virions enveloped and spherical 45-60 nm in diameter, with a core shell of 25-35nm. There are surface patterns but no obvious spikes.


Monopartite positive sense single-stranded RNA 12-16kb in length and with a 3'-polyA tail.

Genus Genomic Organization

Two large, overlapping ORFs at the 5'-end of the genome encode the major non-structural proteins and are expressed as a fusion protein by ribosomal frameshift. These contain regions with protease, helicase and RNA polymerase motifs. Downstream are up to 9 other genes, most of which encode structural proteins, and these are expressed from a 3'-coterminal nested set of subgenomic RNAs. The major coat protein (N) is at the 3'-end of the genome.

Type Member Genomic Organization

The RNA of 12.7kb is translated into the following products:
  • Replication protein 1a of 187 kDa
  • Polymerase 1b expressed as a fusion protein (345 kDa) with 1a by ribosomal frameshift
  • Small envelope protein E (2a) of 7 kDa
  • Glycoprotein 2b of 26 kDa
  • Glycoprotein 3 of 10 kDa
  • Glycoprotein 4 of 17 kDa
  • Glycoprotein 5 of 29 kDa
  • ORF6 of 18 kDa
  • Coat protein N of 12 kDa