Bicaudaviridae Explained

Bicaudaviridae is a family of hyperthermophilic archaeal viruses. Members of the genus Acidianus serve as natural hosts. There is only one genus, Bicaudavirus, and one species, Acidianus two-tailed virus, in this family.^{[1] [2] [3]} However, Sulfolobus tengchongensis spindle-shaped viruses 1 and 2 (STSV1 and STSV2) are regarded to belong to this family also.^[4]

Structure

Viruses in Bicaudaviridae are non-enveloped, with lemon-shaped geometries. Genomes are circular dsDNA molecules of around 48–76 kb in length. High-resolution structure was determined by cryo-EM for Sulfolobus monocaudavirus 1 (SMV1) and a lower-resolution structure was determined for Acidianus two-tailed virus (ATV).^[5] Virions of both viruses have helical symmetry, with continuous 7-start helices, composed of the single major capsid protein, forming both the tails and the spindle-shaped body. The major capsid protein structure and virion organization of bicaudaviruses are similar to those of archaeal viruses from the families Fuselloviridae, Thaspiviridae, Halspiviridae and Clavaviridae.

Genus	Structure	Symmetry !	Capsid	Genomic arrangement	Genomic segmentation
Bicaudavirus	Lemon-shaped	Helical (C7)	Non-enveloped	Circular	Monopartite

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the viral proteins to host receptors. DNA-templated transcription is the method of transcription. Diverse species of hyperthermophilic archaea from the order Sulfolobales serve as the natural hosts. Transmission routes are passive diffusion. It has been demonstrated that certain members of the family, namely, STSV2 and Sulfolobus monocaudavirus 1 (SMV1), induce cell gigantism by blocking the expression of the cell division genes and arresting the cell cycle in the S phase.^[6] The diameter of infected cells increases up to 20 times, resulting in 8,000-fold increase in volume compared to noninfected cells.

History

This family was first described by the team led by D. Prangishvili in 2005.^{[7] [8]}

The name is derived from the Latin word 'bi' and 'cauda' meaning 'two-tail'.

External links

• ICTV Report Bicaudaviridae
• Viralzone: Bicaudaviridae

Notes and References

1. Prangishvili . D . Krupovic . M . ICTV Report Consortium . ICTV Virus Taxonomy Profile: Bicaudaviridae . The Journal of General Virology . 99 . 7 . 864–865 . 7 June 2018 . 10.1099/jgv.0.001106 . 29877786. free .
2. Web site: Viral Zone. ExPASy. 12 June 2015.
3. Web site: ICTV Report Bicaudaviridae .
4. Krupovic . M . Quemin . ER . Bamford . DH . Forterre . P . Prangishvili . D . Unification of the globally distributed spindle-shaped viruses of the Archaea . Journal of Virology . 2014 . 88 . 4 . 2354–8 . 10.1128/JVI.02941-13 . 24335300. 3911535 .
5. Wang . F . Cvirkaite-Krupovic . V . Vos . M . Beltran . LC . Kreutzberger . MAB . Winter . JM . Su . Z . Liu . J . Schouten . S . Krupovic . M . Egelman . EH . Spindle-shaped archaeal viruses evolved from rod-shaped ancestors to package a larger genome. . Cell . 2022 . 185 . 8 . 1297–1307.e11 . 10.1016/j.cell.2022.02.019 . 35325592. 9018610 .
6. Liu . J . Cvirkaite-Krupovic . V . Baquero . DP . Yang . Y . Zhang . Q . Shen . Y . Krupovic . M . Virus-induced cell gigantism and asymmetric cell division in archaea. . Proceedings of the National Academy of Sciences of the United States of America . 2021 . 118 . 15 . e2022578118 . 10.1073/pnas.2022578118 . 33782110. 8054024 . free . 2021PNAS..11822578L .
7. Häring M, Vestergaard G, Rachel R, Chen L, Garrett RA and Prangishvili D (2005) Independent virus development outside a host. Nature 436, 1101–1102
8. Prangishvili, D., Vestergaard G, Häring M, Aramayo R, Basta T, Rachel R and Garrett RA (2006) Structural and genomic properties of the hyperthermophilic archaeal virus ATV with an extracellular stage of the reproductive cycle. J. Mol. Biol. 359, 1203–1216