Notes on Genus: Dependovirus
Type member: Adeno-associated virus-2
This is one of the genera in the subfamily Parvovirinae
, the vertebrate pathogens in the family Parvoviridae
. Members are distinguished from those of the other genera by the presence of inverted repeats but not hairpin structures at both ends of the genome, and three mRNA promoters. The name reflects the fact that efficient replication usually depends upon helper adeno- or herpes- viruses.
Virions isometric (icosahedral), not enveloped, 18-26 nm in diameter, made of 60 units of the capsid protein.
Linear, single-stranded monopartite DNA, about 4.4-5.6 kb long with inverted repeats at both ends of the genome and three mRNA promoters. Positive and negative strand DNA occur in the virions in approximately equal proportions.
Genus Genomic Organization
As in other members of the subfamily, there are two major ORFs on the same strand. These encode the non-structural (replication) protein and the capsid protein. mRNA splicing may result in products that differ from those of simple computer predictions but which have not always been experimentally determined. The capsid protein may also undergo proteolytic cleavage.
Type Member Genomic Organization
There are 2 major ORFs in the same orientation and three major protein products:
- Non-structural protein NS1, 70.5 kDa
- Non-structural protein NS2 (60.7 kDa) translated from a spliced mRNA
- Capsid protein VP1 (56.3 kDa)