| Bidensovirus | |
|---|---|
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Virus classification | |
| (unranked): | Virus |
| Realm: | Monodnaviria |
| Kingdom: | Shotokuvirae |
| Phylum: | Cossaviricota |
| Class: | Mouviricetes |
| Order: | Polivirales |
| Family: | Bidnaviridae |
| Genus: | Bidensovirus |
| Species | |
Bombyx mori bidensovirus | |
Bidensovirus is a genus of single stranded DNA viruses that infect invertebrates. The species in this genus were originally classified in the familyParvoviridae (subfamilyDensovirinae) but were moved to a new genus because of significant differences in the genomes.[1]
There is one species in this genus currently recognised:Bombyx mori bidensovirus.
As the name suggests this virus infectsBombyx mori, the silkworm.[2]
The virions areicosahedral, non enveloped and ~25nanometers in diameter. They contain two structuralproteins.
The genome is bipartite, unique among ssDNA viruses, with two linear segments of ~6 and 6.5 kilobases (kb). These segments and the complementary strands are that are packaged separately giving rise to 4 different types of full particles.
Both segments have an ambisense organization, coding for a structural protein in one sense and the non-structural proteins on the complementary strand.
Theopen reading frame 4 (VD1-ORF4) is 3318 nucleotides (bases) in length and encodes a predicted (3318/3 − 1 =) 1105 amino acid protein which has a conserved DNA polymerase motif. It appears to encode at least 2 other proteins including one of ~53 kDa that forms part of the virion.[3]
Comprehensive analysis of bidnavirus genes has shown that these viruses have evolved from aparvovirus ancestor from which they inherit ajelly-roll capsid protein and asuperfamily 3 helicase.[4] It has been further suggested that the key event that led to the separation of the bidnaviruses from parvoviruses was the acquisition of the PolB gene. A likely scenario has been proposed under which the ancestral parvovirus genome was integrated into a large virus-derived DNAtransposon of thePolinton/Maverick family (polintoviruses)[5] resulting in the acquisition of the polintovirus PolB gene along with terminal inverted repeats. Bidnavirus genes for a minor structural protein (putative receptor-binding protein) and a potential novel antiviral defense modulator were derived from dsRNA viruses (Reoviridae) and dsDNA viruses (Baculoviridae), respectively.[4]