Notes on Family: Picornaviridae
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icosahedra
Contents
- Members of this Family
- General Description
- Morphology
- Genome
- Genera in the Family
- All Known Sequences
- Curated Sequences
General Description
This family consists of viruses that infect vertebrates and which have isometric virions (30 nm) and a monopartite ssRNA genome which encodes a single polyprotein (except in the genus Dicipivirus, where it is split into two sections). It is of interest to plant virolgoists because of its association with the plant virus family Secoviridae within the order Picornavirales. The family Potyviridae is also often considered to be part of the picornavirus "superfamily". The name reflects the small (pico) RNA genome.Morphology
Virions isometric (icosahedral), not enveloped, 30 nm in diameter, made of 60 units (protomers) each consisting of one molecule of each of three surface coat proteins.Genomen
Monopartite positive sense single-stranded RNA 6.7-8.9 kb in length with a genome-linked protein (VPg) at the 5'-terminus and a 3'-polyA tail. It encodes a single polyprotein (two polyproteins in the genus Dicipivirus) that it is subsequently processed into the functional products:| L | Leader protein (absent in some genera; sometimes with protease activity) |
| 1A | Coat protein VP4 (internal capsid protein; absent in some genera) |
| 1B | Coat protein VP2 (surface capsid protein) |
| 1C | Coat protein VP3 (surface capsid protein) |
| 1D | Coat protein VP1 (surface capsid protein) |
| 2A | non-structural protein (sometimes with protease activity; very small in some genera) |
| 2B | non-structural protein |
| 2C | non-structural protein |
| 3A | non-structural protein |
| 3B | Genome-linked protein (VPg) |
| 3C | protease |
| 3D | polymerase |
Genera in the Family
| Genus | 5'-UTR | Leader protein | 1A protein | 2A protein |
| Aphthovirus | >1kb; polyC tract | Protease | + | very small |
| Aquamavirus | 500nt; no polyC tract | None | + | +(2) |
| Avihepatovirus | 620nt; no polyC tract | None | + | +(2) |
| Cardiovirus | 800nt; polyC tract | Not a protease | + | + |
| Cosavirus | >1kb; no polyC tract | None | + | very small |
| Dicipivirus* | >1kb; no polyC tract | None | + | + |
| Enterovirus | 740nt; no polyC tract | None | + | Protease |
| Erbovirus | 900nt; polyC tract | Protease | + | very small |
| Hepatovirus | 700nt; no polyC tract | None | very small | + |
| Kobuvirus | 700nt; no polyC tract | Protease | - | + |
| Megrivirus | 460nt; no polyC tract | None | + | + |
| Parechovirus | 700nt; no polyC tract | None | - | + |
| Sapelovirus | 440nt; no polyC tract | Not a protease | + | Protease |
| Salivirus | 700nt; no polyC tract | Protease? | + | Protease |
| Senecavirus | 700nt; no polyC tract | Not a protease | + | very small |
| Teschovirus | 330nt; polyC tract | Protease | + | very small |
| Tremovirus | 500nt; no polyC tract | None | - | + |
* separate structural and non-structural polyproteins