Spiraviridae
Alphaspiravirus | |
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Virus classification | |
(unranked): | Virus |
Family: | Spiraviridae |
Genus: | Alphaspiravirus |
Species | |
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Synonyms | |
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Spiraviridae is a family of
Name
The names Alpaspiravirus and Spiraviridae are both from latin spira for "coil".[4]
Structure
Virions of ACV are non-enveloped and in the shape of hollow cylinders approximately 230±10 by 19±1 nanometers (nm) in size. The cylindrical shape is formed by the coiling of a nucleoprotein filament as a helical spring. This coil-like structure is itself formed by two intertwining halves of a circular, ssDNA molecule in another helical shape that is covered by capsid proteins. Each end of the cylindrical virion has an appendage about 20±2 nm in length protruding from the virion at a 45° angle relative to the axis of the virion.[1] For about 80% of virions, the appendages protrude from the same face of the virion.[3] The virion is flexible, capable of contracting and stiffening upon being dehydrated. Virions have two major proteins with molecular masses of about 23 and 18.5 kilodaltons (kDa) and a few minor proteins with molecular masses of 5–13 kDa.[1] Approximately 40 discs or turns of the helix are distinguishable for the length of the virion.[3] The coil-like morphology of ACV is characteristic of certain archaeal viruses, not being found among bacterial and eukaryotic viruses.[1]
Genome
ACV contains a single molecule of circular, positive-sense, single-stranded DNA ((+)ssDNA) that is 24,893 nucleotides in length. The
Replication
ACV does not encode any identifiable DNA or RNA polymerases, nor does it encode any proteins homologous to known Rep proteins used by most known ssDNA viruses in replication. As such, ACV is likely to replicate in a manner that depends on the host replisome. After replication, virions leave the host cell without the host cell undergoing lysis, or cell death.[1]
Evolution
ACV has no known relation to any other viruses. However, some other archaeal viruses also have coil-shaped virions like ACV, which may indicate such morphology is an ancient form that is not represented among viruses that infect eukaryotes and other prokaryotes.[1]
History
ACV was first isolated from a sample of
References
- ^ PMID 31961791.
- ^ a b "Virus Taxonomy: 2022 Release". International Committee on Taxonomy of Viruses (ICTV). March 2023. Retrieved 19 August 2023.
- ^ PMID 22826255.
- ^ "Proposal 2013.003a-gB.A.v3.Spiraviridae.pdf PDF" (PDF). International Committee on Taxonomy of Viruses (ICTV). Retrieved 19 August 2023.