| Nodaviridae | |
|---|---|
| Virus classification | |
| Group: | Group IV ((+)ssRNA) |
| Family: | Nodaviridae |
| Genera | |
|
Alphanodavirus |
|
Nodaviridae is a family of RNA viruses.
Contents |
The virus is not enveloped and has an isocahedral capsid (triangulation number = 3) ranging from 29 to 35 nm in diameter. The capsid is constructed of 32 capsomers.
The genome is linear, positive sense, bipartite (composed of two segments - RNA1 and RNA2) single stranded RNA consisting of 4500 nucleotides with a 5’ terminal methylated cap and a non-polyadenylated 3’ terminal.
RNA1, which is ~3.1 kilobases in length, translates encodes a protein that has multiple functional domains: a mitochondrial targeting domain, a transmembrane domain, an RNA-dependent RNA polymerase (RdRp) domain, a self-interaction domain and an RNA capping domain. In addition, RNA1 encodes a subgenomic RNA3 that translates protein B2, an RNA silencing inhibitor.
RNA2 encodes protein α, a viral capsid protein precursor, which is auto-cleaved into two mature proteins, a 38 kDa β protein and a 5 kDa γ protein, at a conserved Asn/Ala site during virus assembly.
The members of the alphanodoviridae were origianlly isolated from insects while those of the betanodoviridae were isolated from fish. A small number of nodoviruses seem to lie outside either of these clades.
Alphanodovirus:
Betanodovirus:
Other members include:
While NoV remains the type species for this group, Flock House Virus (FHV) is the best studied of the Nodaviruses.