Narnaviridae
| Narnaviridae | |
|---|---|
| Virus classification | |
| Group: | Group IV ((+)ssRNA) |
| Order: | Unassigned |
| Family: | Narnaviridae |
| Genera | |
Narnaviridae is a family of positive single stranded RNA viruses. Members of this family have no capsid.[1] Fungi serve as natural hosts. There are currently seven species in this family, divided among 2 genera.[2][3]
Virology
The genome of these viruses is unipartate and between 2.3 and 3.5 kilobases in length. It encodes a single gene—the RNA dependent RNA polymerase. This protein is associated with the genome in the cytoplasm of the host.[4] The viruses do not have a capsid or envelop and do not form any infectious viral particles except lipid vesicles.[5]
They infect fungi (including yeast) and oomycetes.[6] Mitovirues appear to be among the most common fungi viruses.[5]
| Genus | Structure | Symmetry | Capsid | Genomic Arrangement | Genomic Segmentation |
|---|---|---|---|---|---|
| Mitovirus | No structural proteins | Non-Enveloped | Linear | Monopartite | |
| Narnavirus | No structural proteins | Non-Enveloped | Linear | Monopartite |
Life Cycle
Viral replication is cytoplasmic. Replication follows the positive stranded RNA virus replication model. Positive-stranded RNA-virus transcription is the method of transcription. The virus exits the host cell by cell to cell movement. Fungi serve as the natural host. Transmission routes are parental and sexual.[2]
| Genus | Host Details | Tissue Tropism | Entry Details | Release Details | Replication Site | Assembly Site | Transmission |
|---|---|---|---|---|---|---|---|
| Mitovirus | Fungi | None | Horizontal; vertical | None | Cytoplasm | Cytoplasm | Horizontal: mating; vertical: parental |
| Narnavirus | Fungi | None | Horizontal; vertical | None | Cytoplasm | Cytoplasm | Horizontal: mating; vertical: parental |
Taxonomy
Two genera have been recognised to date. Mitoviruses infect the mitochondria of fungi while narnaviruses remain within the cytoplasm of the host cell.[5]
Group: ssRNA(+)
- Family: Narnaviridae
- Genus: Mitovirus
- Cryphonectria mitovirus 1
- Ophiostoma mitovirus 4
- Ophiostoma mitovirus 5
- Ophiostoma mitovirus 6
- Ophiostoma mitovirus 3a
- Genus: Narnavirus
- Saccharomyces 20S RNA narnavirus
- Saccharomyces 23S RNA narnavirus
Other proposed members of the Mitovirus are OnuMV1c and OnuMV7.
Their closest relatives among RNA viruses are plant-infecting viruses of genus Ourmiavirus, which, however, have a capsid and a number of other proteins. Other close relatives are bacteriophages of the family Leviviridae.[5]
References
- ↑ Dolja, V. V.; Koonin, E. V. (2012). "Capsid-Less RNA Viruses". ELS. doi:10.1002/9780470015902.a0023269. ISBN 0470016175.
- 1 2 "Viral Zone". ExPASy. Retrieved 15 June 2015.
- 1 2 ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
- ↑ Solorzano A, Rodríguez-Cousiño N, Esteban R, Fujimura T (2000) Persistent yeast single-stranded RNA viruses exist in vivo as genomic RNA. RNA polymerase complexes in 1:1 stoichiometry. J Biol Chem 275(34):26428–35
- 1 2 3 4 Hillman, B. I.; Cai, G. (2013). "The Family Narnaviridae". Mycoviruses. Advances in Virus Research. 86. p. 149. doi:10.1016/B978-0-12-394315-6.00006-4. ISBN 9780123943156.
- ↑ Cai G, Myers K, Fry WE, Hillman BI (2011) A member of the virus family Narnaviridae from the plant pathogenic oomycete Phytophthora infestans. Arch Virol