Notes on Genus: Sapelovirus
icosahedra
Type member: Porcine sapelovirus
Contents
General Description
The genus
Sapelovirus (from
Simian,
Avian and
Porcine
Entero-
Like viruses) is one of the genera in the family
Picornaviridae. Genome organisation is fairly conserved within the family but members of this genus have a 5'-UTR which has no polyC tract, there is a leader protein and the 2A protein is a protease.
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.
Genome
Monopartite positive sense single-stranded RNA 7.5-8.3 kb in length. There is a genome-linked protein (VPg) at the 5'-terminus and a 3'-polyA tail.
Genus Genomic Organization
The RNA encodes a single polyprotein that is subsequently processed into the functional products. The major structural proteins are encoded near the N-terminus.
Type Member Genomic Organization
The genome of about 7,500 nucleotides is translated into a single polyprotein, which is subsequently processed into twelve products:
| L | 9.4 kDa | (Leader protein) |
| 1A | 5.7 kDa | Coat protein VP4 (internal capsid protein) |
| 1B | 26.2 kDa | Coat protein VP2 (surface capsid protein) |
| 1C | 25.9 kDa | Coat protein VP3 (surface capsid protein) |
| 1D | 31.6 kDa | Coat protein VP1 (surface capsid protein) |
| 2A | 26.3 kDa | protease |
| 2B | 11.3 kDa | non-structural protein |
| 2C | 38.2 kDa | non-structural protein |
| 3A | 11.0 kDa | non-structural protein |
| 3B | 2.4 kDa | Genome-linked protein (VPg) |
| 3C | 20.2 kDa | protease |
| 3D | 52.0 kDa | polymerase |
