Notes on Genus: Hepatovirus


Type member: Hepatitis A virus


General Description

The genus Hepatovirus (from the greek hepatos = liver) 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, the internal capsid (1A) protein is extremely small and the 2A protein is not a protease.


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.


Monopartite positive sense single-stranded RNA 7.0-7.5 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 eleven products:
1A  2.5 kDaCoat protein VP4 (internal capsid protein)
1B  24.8 kDaCoat protein VP2 (surface capsid protein)
1C 27.8 kDaCoat protein VP3 (surface capsid protein)
1D 33.2 kDaCoat protein VP1 (surface capsid protein)
2A 22.0 kDanon-structural protein
2B 12.1 kDanon-structural protein
2C 38.5 kDanon-structural protein
3A 8.0 kDanon-structural protein
3B 2.5 kDaGenome-linked protein (VPg)
3C 24.1 kDaprotease
3D 56.3 kDapolymerase