Dependovirus
| Dependoparvovirus | |
|---|---|
| Virus classification | |
| Group: | Group II (ssDNA) |
| Order: | Unassigned |
| Family: | Parvoviridae |
| Subfamily: | Parvovirinae |
| Genus: | Dependoparvovirus |
| Type species | |
|
Adeno-associated dependoparvovirus A |
|
| Species | |
Dependoparvovirus (formerly Dependovirus or Adeno-associated virus group) is a genus in the virus subfamily Parvovirinae, within the family Parvoviridae; they are Group II viruses according to the Baltimore classification. Some dependoparvoviruses are also known as adeno-associated viruses because they cannot replicate productively in their host cell without the cell being coinfected by a helper virus such as an adenovirus, a herpesvirus, or a vaccinia virus.
There are currently seven recognized species in the genus.
Dependoparvoviruses have an icosahedral shape, measure 22 nm is composed of 60 wedge shaped proteins triangulation number = 1). Three proteins (VP1, VP2 and VP3) are present in each capsomere. Each capsid is made from 5 VP1, 5 VP2, and 50 VP3 proteins. The capsid does not have an envelope.
The genome is a single molecule of single stranded with a length of 4.7 kilobases. It has only two open reading frames. The 3' open reading frame is the structural capsid protein, cap, which can be spliced to form two RNAs, one for virion protein 1 (VP1) and the other goes on to eventually make VP2 and VP3. The second gene, rep, can be spliced into four different, nonstructural, regulatory proteins that all aid in the genome replication. These proteins are named Rep 78, Rep68, Rep 52, and Rep 40 based on their molecular weight.
Due to inverted, complementary long terminal repeats (LTRs) at each end of the genome, a T shaped secondary structure is formed. The complementary areas leave a 3’ hydroxyl group single stranded for the replication to begin. This 3’ hydroxyl group is used as a primer for the leading strand synthesis. Both positive and negative sense strands of DNA are made. Double stranded intermediates are formed throughout the replication; this means the two strands, positive and negative sense, will be matched up.
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