Notes on Genus: Avihepatovirus
Type member: Duck hepatitis A virus
The genus Avihepatovirus
(from avian and hepato=liver) is one of the genera in the family Picornaviridae
. Genome organisation is fairly conserved within the family but members of this genus have two separate motifs characteristic of the 2A protein and a longer 3'-UTR than other members of the family.
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 about 8.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 at the N-terminus.
Type Member Genomic Organization
The genome of about 7,300 nucleotides is translated into a single polyprotein, which is subsequently processed into eleven products:
|1B ||28.2 kDa||Coat protein VP0|
|1C ||26.7 kDa||Coat protein VP3|
|1D ||26.4 kDa||Coat protein VP1 |
|2A2 ||32.4 kDa||non-structural protein|
|2B ||13.1 kDa||non-structural protein|
|2C ||38.3 kDa||non-structural protein|
|3A ||10.7 kDa||non-structural protein|
|3B ||3.9 kDa||Genome-linked protein (VPg)|
|3C ||19.7 kDa||protease|
|3D ||51.0 kDa||polymerase|