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Virus classification
Group: Group IV ((+)ssRNA)
Order: Unassigned
Family: Narnaviridae

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]


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[edit]

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


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(+)


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]


  1. ^ Dolja, V. V.; Koonin, E. V. (2012). "Capsid-Less RNA Viruses". ELS. doi:10.1002/9780470015902.a0023269. ISBN 0470016175. 
  2. ^ a b "Viral Zone". ExPASy. Retrieved 15 June 2015. 
  3. ^ a b ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015. 
  4. ^ 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
  5. ^ a b c d 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. 
  6. ^ 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

External links[edit]