Notes on Genus: Arterivirus
enveloped spheres
Type member: Equine arteritis virus
Contents
General Description
This is currently the only genus in the family
Arteriviridae and is named after the type member,
Equine arteritis virus.
Morphology
Virions enveloped and spherical 45-60 nm in diameter, with a core shell of 25-35nm. There are surface patterns but no obvious spikes.
Genome
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
