Bacilladnavirus
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''Bacilladnaviridae'' is a family of
single-stranded DNA virus A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and t ...
es that primarily infect
diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...
s.


Characteristics

The genome of these viruses appears to be unique. It consists of a single molecule of covalently closed circular single stranded DNA of 4.5–6 kilobases as well as a segment of linear ssDNA of ~1 kilobase. The linear segment is complementary to a portion of the closed circle creating a partially double stranded region. There are at least three major open reading frames in the genome. Similar to other eukaryotic ssDNA viruses, bacilladnaviruses are likely to replicate their genomes by the rolling-circle mechanism, initiated by the virus-encoded endonuclease (Rep). However, the latter protein of bacilladnaviruses displays unique conserved motifs and in phylogenetic trees forms a monophyletic clade separated from other groups of ssDNA viruses. The capsid protein of bacilladnaviruses has the
jelly-roll fold The jelly roll or Swiss roll fold is a protein fold or supersecondary structure composed of eight beta strands arranged in two four-stranded sheets. The name of the structure was introduced by Jane S. Richardson in 1981, reflecting its resemblanc ...
and is most closely related to the corresponding proteins from members of the family ''
Nodaviridae ''Nodaviridae'' is a family of nonenveloped positive-strand RNA viruses. Vertebrates and invertebrates serve as natural hosts. Diseases associated with this family include: viral encephalopathy and retinopathy in fish. There are nine species in ...
'', which have ssRNA genomes. The virions are about 34 nanometers (nm) in diameter and accumulate in the nucleus. Mature virions are released by lysis of the host cell.


Taxonomy

The following genera are recognized: *'' Diatodnavirus'' *'' Kieseladnavirus'' *'' Protobacilladnavirus''


References


External links

* Yuji Tomaru, Kensuke Toyoda, Hidekazu Suzuki, Tamotsu Nagumo, Kei Kimura & Yoshitake Takao
New single-stranded DNA virus with a unique genomic structure that infects marine diatom ''Chaetoceros setoensis''
In: Nature Sci Rep 3, 3337. 26 November 2013. doi:10.1038/srep03337. Proposal of new species "''Chaetoceros setoensis DNA virus''" (CsetDNAV), ssDNA circular. {{Taxonbar, from=Q52600201 Virus families