Mimiviridae

Mimiviridae
Virus classification
Group: Group I (dsDNA)
Family: Mimiviridae
Genera

Mimiviridae is a family of viruses. Amoeba serve as natural hosts. There are currently only two species in this family, divided among 2 genera.[1][2] Viruses in this family belong to the nucleocytoplasmic large DNA virus clade (NCLDV), a group which includes members of families Asfarviridae, Iridoviridae, Phycodnaviridae and Poxviridae and the genus Dinodnavirus.

History

The first member of this family—the Mimivirus—was discovered in 2003.[3]

Taxonomy

Group: dsDNA

Although only a couple of members of this family have been described in detail it seems likely there are many more awaiting description and assignment.[4][5] These include Chrysochromulina ericina virus 01, Phaeocystis pouchetii virus 01 and Pyramimonas orientalis virus 01. While these virus strains have been isolated they have yet to be fully characterized.

The genus is currently divided into two subfamilies.[2][6] One subfamily (Mimivirus) is divided into three "lineages": A (includes Acanthamoeba polyphaga Mimivirus, Samba virus), B (includes Moumouvirus) and C (includes Courdo7, Courdo 11, LBA111, Megavirus chilensis and Terra1).[7] The vast majority of Mimiviridaes appear to be Mimiviruses.[6] Broad spectrum of mimiviridae virophage allows its isolation using a mimivirus reporter.[7] The second subfamily (Cafeteriavirus) includes the Cafeteria roenbergensis virus. There are at least 17 proposed members of this family, though only two have been officially recognized by the ICTV as of their 2014 release.[2]

Structure

Viruses in Mimiviridae have icosahedral and round geometries, with between T=972 and T=1141, or T=1200 symmetry. The diameter is around 400 nm, with a length of 125 nm. Genomes are linear and non-segmented, around 1200kb in length. The genome has 911 open reading frames.[1]

Genus Structure Symmetry Capsid Genomic Arrangement Genomic Segmentation
MimivirusIcosahedralT=972-1141 or T=1200 (H=19 +/- 1, K=19 +/- 1)LinearMonopartite
CafeteriavirusIcosahedralLinearMonopartite

Life Cycle

Replication follows the DNA strand displacement model. DNA-templated transcription is the method of transcription. Amoeba serve as the natural host.[1]

Genus Host Details Tissue Tropism Entry Details Release Details Replication Site Assembly Site Transmission
MimivirusZooplanktonNoneUnknownUnknownUnknownUnknownPassive diffusion
CafeteriavirusAmoebaNoneUnknownUnknownUnknownUnknownPassive diffusion

Molecular biology

Within the genome of Lentille virus integrated genome of a virophage (Sputnik 2) and a transpoviron—a mobile genetic element—have been reported. Transpovirons are linear DNA elements of about 7 kilobases that encompass six to eight protein coding genes, two of which are homologous to virophage genes.

Clinical

Mimiviruses have been associated with pneumonia but their significance if any is currently unknown.[8] The only virus of this family isolated from a human to date is LBA 111.[9] Mimivirus has also been implicated in rheumatoid arthritis.[10]

See also

Wikispecies has information related to: Mimiviridae

References

  1. 1 2 3 "Viral Zone". ExPASy. Retrieved 15 June 2015.
  2. 1 2 3 ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
  3. ↑ Suzan-Monti M, La Scola B, Raoult D (2006) Genomic and evolutionary aspects of Mimivirus. Virus Res 117(1):145-155
  4. ↑ Ghedin E, Claverie JM (2005) Mimivirus relatives in the Sargasso sea. Virol J. 2:62
  5. ↑ Monier A, Claverie JM, Ogata H (2008) Taxonomic distribution of large DNA viruses in the sea. Genome Biol. 9(7):R106.
  6. 1 2 Colson P, Fournous G, Diene SM, Raoult D (2013) Codon usage, amino acid usage, transfer RNA and amino-acyl-tRNA synthetases in mimiviruses. Intervirology 56(6):364-375. doi: 10.1159/000354557
  7. 1 2 Gaia M, Pagnier I, Campocasso A, Fournous G, Raoult D, La Scola B (2013) PLoS One 8(4):e61912. doi: 10.1371/journal.pone.0061912
  8. ↑ Saadi H, Pagnier I, Colson P, Cherif JK, Beji M, Boughalmi M, Azza S, Armstrong N, Robert C, Fournous G, La Scola B, Raoult D (2013) First isolation of Mimivirus in a patient with pneumonia. Clin Infect Dis
  9. ↑ Yoosuf N, Pagnier I, Fournous G, Robert C, La Scola B, Raoult D, Colson P (2013) Complete genome sequence of Courdo11 virus, a member of the family Mimiviridae. Virus Genes
  10. ↑ Shah, N.; Hulsmeier, A. J.; Hochhold, N.; Neidhart, M.; Gay, S.; Hennet, T. (2013). "Exposure to Mimivirus Collagen Promotes Arthritis". Journal of Virology. 88 (2): 838–45. doi:10.1128/JVI.03141-13. PMC 3911627Freely accessible. PMID 24173233.
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