Notes on Genus: Alphamesonivirus

enveloped spheres

Type member: Alphamesonivirus 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

The genus Alphamesonivirus is currently the only genus in the family Mesoniviridae, and contains insect-infecting nidoviruses. The genus (and family) name reflects the fact that the genomes are intermediate (Greek, meso = medium) in size between those of the small nidoviruses in the family Arteriviridae and those of the large nidoviruses in the families Coronaviridae and Roniviridae.

Morphology

Virions are enveloped spheres about 60-80 nm in diameter.

Genome

Monopartite, linear single-stranded RNA, about 20 kb long with a polyA tail at the 3'-terminus.

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. Downstream are at least 4 other genes, mostly or entirely encoding structural proteins, and these are probably expressed from a 3'-coterminal nested set of subgenomic RNAs.

Type Member Genomic Organization

The RNA of 20.2 kb is translated into the following products: