Notes on Genus: Brevidensovirus
Type member: Aedes aegypti densovirus
This is one of the genera in the subfamily Densovirinae
, the insect pathogens in the family Parvoviridae
. Members are distinguished from those of the other genera by genome size (about 4 kb; the smallest in the subfamily), genomic organisation and phylogenetic analysis. The name is from the latin brevis
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 kb long. Both ends have palindromic sequences that can fold to form T-shaped structures. Both plus and minus strand DNAs are encapsidated, but the majority are of the minus strand.
Genus Genomic Organization
The 5' half of the genome has two nested ORFs in different reading frames that encode the non-structural proteins. A single structural ORF in the 3'-half of the genome is translated by a leaky scanning strategy to produce virion proteins of different sizes.
Type Member Genomic Organization
There are 3 major ORFs in the same orientation:
- Non-structural protein NS1, 97.5 kDa
- Non-structural protein NS2, 41.1 kDa
- Capsid protein VP, 40.6 kDa but translated by leaky scanning to produce products of differing length (with the same C-terminus)