Picobirnavirus

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Picobirnaviridae
)

Picobirnavirus
Electron micrograph
of human picobirnavirus particles
Virus classification Edit this classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Pisuviricota
Class: Duplopiviricetes
Order: Durnavirales
Family: Picobirnaviridae
Genus: Picobirnavirus

Picobirnavirus is a genus of

amniotes, especially mammals, were thought to serve as hosts, it has been recently suggested that these viruses might infect bacteria and possibly some other invertebrates. If they do infect bacteria, then they are Bacteriophages.[2][3] There are three species in this genus. Associated symptoms include gastroenteritis in animals and humans, though the disease association is unclear.[4][5]

Etymology

Picobirnavirus is a small (pico,

Latin for two), double-stranded RNA virus. Picobirnaviruses were initially considered to be birna-like viruses, and the name was derived from birnavirus (bisegmented RNA), but the virions are much smaller (diameter 35 nm vs. 65 nm). [6] Picobirnaviruses were first detected in humans and black-footed pigmy rice rats in 1988.[7]

Structure

Viruses in the genus are non-enveloped, with icosahedral geometries, and T=3 symmetry. The diameter is around 35–40 nm.[5][4]

Genome

Genome arrangement of dsRNA1 and dsRNA2 of human picobirnavirus

The

kilobases (kb) in length and a segment 2 which is 1.2–1.9 kb in length. The genome codes for three to four proteins.[4] The capsid protein gene is encoded by the second open reading frame of the larger genomic segment 1.[4]

Picobirnaviruses are divided into two genogroups on the basis of the sequence of segment 2. The

squamates.[8]

Life cycle

viral capsid
.

Picobirnaviruses target intestine tissue. Entry into the host cell is achieved by penetration into the host cell. Once in the host cell, viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. The viruses are released from the cell by budding. Mammals serve as the natural host. Transmission routes are fecal-oral.[5][4]

Taxonomy

Picobirnaviruses were initially thought to belong to the family Birnaviridae, but later were confirmed to differ with respect to host, virion size, capsid, RNA-dependent RNA polymerase, genome size, and organization.[9] The family Picobirnaviridae is now classified distinctly and composed of one genus Picobirnavirus, which has three species:[10]

References

  1. PMID 30484763
    .
  2. PMID 29346073
    .
  3. PMID 29644096
    .
  4. ^ a b c d e "Viral Zone". ExPASy. Retrieved 15 June 2015.
  5. ^ a b c "ICTV Report: Picobirnaviridae".
  6. PMC 6924892
    .
  7. PMID 3053986
    .
  8. PMID 22932227
    .
  9. PMID 25136620
    .
  10. ^ "International Committee on Taxonomy of Viruses (ICTV)". talk.ictvonline.org. Retrieved 8 October 2020.

External links