Notes on Genus: Enterovirus
Type member: Human enterovirus C
The genus Enterovirus
(from the greek enteron
= intestine) 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 no leader protein and the 2A protein is a protease. Species previously classified in the genus Rhinovirus
have recently been moved into this genus.
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 and with a fourth internal capsid protein. The virions have more surface features than most other picornaviruses, with a raised area at the fivefold axis surounded by a groove into which the host cellular receptor binds.
Monopartite positive sense single-stranded RNA 7.3-7.4 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 7,400 nucleotides is translated into a single polyprotein, which is subsequently processed into eleven products:
|1A ||7.5 kDa||Coat protein VP4 (internal capsid protein)|
|1B ||30.0 kDa||Coat protein VP2 (surface capsid protein)|
|1C ||26.4 kDa||Coat protein VP3 (surface capsid protein)|
|1D ||33.5 kDa||Coat protein VP1 (surface capsid protein)|
|2A ||16.7 kDa||protease|
|2B ||10.7 kDa||non-structural protein|
|2C ||37.6 kDa||non-structural protein|
|3A ||9.8 kDa||non-structural protein|
|3B ||2.4 kDa||Genome-linked protein (VPg)|
|3C ||19.7 kDa||protease|
|3D ||52.5 kDa||polymerase|