Notes on Genus: Teschovirus
Type member: Porcine teschovirus 1
The genus Teschovirus
(from the name of teschen disease, caused in pigs by some strains of the type member) is one of the genera in the family Picornaviridae
. Genome organisation is fairly conserved within the family but members of this genus have a comparatively short (<350 nt) 5'-UTR which contains a polyC tract, a leader protease and a very short 2A protein.
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.
Monopartite positive sense single-stranded RNA 7.0-7.2 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, following the self-cleaving leader protease.
Type Member Genomic Organization
The genome of about 8,100 nucleotides is translated into a single polyprotein, which is subsequently processed into twelve products:
|L ||13.6 kDa||Leader protein (protease)|
|1A ||7.4 kDa||Coat protein VP4 (internal capsid protein)|
|1B ||31.1 kDa||Coat protein VP2 (surface capsid protein)|
|1C ||26.8 kDa||Coat protein VP3 (surface capsid protein)|
|1D ||28.9 kDa||Coat protein VP1 (surface capsid protein)|
|2A ||2.1 kDa||non-structural protein|
|2B ||16.4 kDa||non-structural protein|
|2C ||36.8 kDa||non-structural protein|
|3A ||10.8 kDa||non-structural protein|
|3B ||2.8 kDa||Genome-linked protein (VPg)|
|3C ||22.7 kDa||protease|
|3D ||51.2 kDa||polymerase|