Notes on Genus: Arterivirus
Type member: Equine arteritis virus
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