Mimiviridae
| Mimiviridae | |
|---|---|
| |
| Tupanvirus | |
Virus classification 
| |
| (unranked): | Virus |
| Realm: | Varidnaviria |
| Kingdom: | Bamfordvirae |
| Phylum: | Nucleocytoviricota |
| Class: | Megaviricetes |
| Order: | Imitervirales |
| Family: | Mimiviridae |
| Subfamilies and genera | |
| |
Mimiviridae is a family of
Mimiviridae is the sole recognized member of order Imitervirales.
History
The first member of this family, Mimivirus, was discovered in 2003,[6] and the first complete genome sequence was published in 2004.[7] However, the mimivirus Cafeteria roenbergensis virus[8] was isolated and partially characterized in 1995,[9] although the host was misidentified at the time, and the virus was designated BV-PW1.[8]
Taxonomy
Group: dsDNA
- Family: Mimiviridae
- * Acanthamoeba polyphaga mimivirus
- *
Family Mimiviridae is currently divided into three subfamilies.[2][3][10]
- One subfamily (genus Mimivirus, proposed names: Megavirinae or Megamimivirinae) is divided into three "lineages":
- A — Mimivirus group: includes Acanthamoeba polyphaga Mimivirus, Hirudovirus, Mamavirus, Kroon virus, Lentille virus, Terra2, Niemeyer virus, Samba virus.[11][12]
- B — Moumouvirus group: includes Moumouvirus, Saudi moumouvirus, Moumouvirus goulette, Monve virus (aka Moumouvirus monve), and Ochan virus.[13][11][14][12]
- C — Courdo11 virus group: includes Mont1,[11] Courdo7, Courdo11, Megavirus chilensis, LBA111, Powai lake megavirus and Terra1.[15][16]
- The majority of Mimiviridae appear to belong to this subfamily (Mimiviruses).[10]
- It is sometimes also referred to as Mimiviridae group I.[17]
- The second subfamily (Cafeteriavirus or Mimiviridae group II) includes the Cafeteria roenbergensis virus (CroV).[8]
- The kinetoplastid Bodo saltans.[18]
- Tupanvirus strains have been discussed to comprise a sister group of mimiviruses.[4]
Furthermore, it has been proposed either to extend Mimiviridae by an additional tentative group III (subfamily Mesomimivirinae) or to classify this group as a sister family Mesomimiviridae instead,[19] comprising legacy OLPG (Organic Lake Phycodna Group). This extension (or sister family) may consist of the following:
- Phaeocystis globosa virus (PgV, represented by PgV-16T strain) and Phaeocystis pouchetii virus (PpV, e. g. PpV 01)
- "Organic Lake Phycodnavirus" 1 and 2 (OLV1, OLV2, hosts of Organic Lake virophage)
- "Yellowstone Lake Mimivirus"[12][20] aka "Yellowstone Lake Phycodnavirus" 4 (YSLGV4)
- Chrysochromulina ericina virus (CeV, e. g. CeV 01)
- Aureococcus anophagefferens virus ([21] AaV)
- Pyramimonas orientalis virus (PoV)
- Tetraselmis virus (TetV-1)[22]
This group seems to be closely related to Mimiviridae rather than to
With recognition of new order Imitervirales by the ICTV in March 2020 there is no longer need to extend the Mimiviridae family to comprise a group of viruses of the observed high diversity. Instead, the extension (or at least its main clade) may be referred to as a sister family Mesomimiviridae.[19]
Although only a couple of members of this order have been described in detail it seems likely there are many more awaiting description and assignment[27][28] Unassigned members include Aureococcus anophagefferens virus (AaV), CpV-BQ2 and Terra2.[citation needed]
Structure
[18] 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 | Genomic arrangement | Genomic segmentation |
|---|---|---|---|---|
| Mimivirus | Icosahedral | T=972-1141 or T=1200 (H=19 +/- 1, K=19 +/- 1) | Linear | Monopartite |
| Klosneuvirus | Icosahedral | |||
| Cafeteriavirus | Icosahedral | T=499 | Linear | Monopartite |
| Tupanvirus | Tailed |
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 |
|---|---|---|---|---|---|---|---|
| Mimivirus | Amoeba | None | Unknown | Unknown | Unknown | Unknown | Passive diffusion |
| Klosneuvirus | microzooplankton | None | Unknown | Unknown | Unknown | Cytoplasm | Passive diffusion |
| Cafeteriavirus | microzooplankton | None | Unknown | Unknown | Unknown | Cytoplasm | Passive diffusion |
Molecular biology
Three putative DNA base excision repair enzymes were characterized from Mimivirus.[29] The base excision repair (BER) pathway was experimentally reconstituted using the purified recombinant proteins uracil-DNA glycosylase (mvUDG), AP endonuclease (mvAPE), and DNA polymerase X protein (mvPolX).[29] When reconstituted in vitro mvUDG, mvAPE and mvPolX function cohesively to repair uracil-containing DNA predominantly by long patch base excision repair, and thus these processes likely participate in the BER pathway early in the Mimivirus life cycle.[29]
Clinical
Mimiviruses have been associated with pneumonia but their significance is currently unknown.[30] The only virus of this family isolated from a human to date is LBA 111.[31] At the Pasteur Institute of Iran (Tehran), researchers identified mimivirus DNA in bronchoalveolar lavage (BAL) and sputum samples of a child patient, utilizing real-time PCR (2018). Analysis reported 99% homology of LBA111, lineage C of the Megavirus chilensis.[32] With only a few reported cases previous to this finding, the legitimacy of the mimivirus as an emerging infectious disease in humans remains controversial.[33][34]
Mimivirus has also been implicated in rheumatoid arthritis.[35]
See also
References
- ^ a b c "Viral Zone". ExPASy. Retrieved 15 June 2015.
- ^ a b ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
- ^
- ^ PMID 29487281. Fig. 4 and §Discussion: "Considering that tupanviruses comprise a sister group to amoebal mimiviruses…"
- PMID 16181700.
- S2CID 84298461.
- ^ PMID 20974979.
- .
- ^ PMID 24157883.
- ^ PMID 24747414.
- ^ a b c See also Abrahão & et al. 2018, fig. 4 on p. 5
- PMID 23071316.
- PMID 25042053.
- PMID 23596530.
- ^ For LBA111 and Powai lake megavirus see also Abrahão & et al. 2018, fig. 4 on p. 5
- ^ PMID 26459929.
- ^ PMID 29582753.
- ^ bioRxiv 2018/04/11/299784
- ^ NCBI Complete genomes: Viruses, look for 'Yellowstone Lake'
- PMID 25035289.
- PMID 29649682.
- "A new giant virus found in the waters of Oahu, Hawaii". ScienceDaily (Press release). 3 May 2018.
- PMID 25727355.
- PMID 23557328.
- ^ Blog of Carolina Reyes, Kenneth Stedman: Are Phaeocystis globosa viruses (OLPG) and Organic Lake phycodnavirus a part of the Phycodnaviridae or Mimiviridae?, on ResearchGate, Jan. 8, 2016
- PMID 27965659.
- PMID 16105173.
- PMID 18598358.
- ^ a b c Lad SB, Upadhyay M, Thorat P, Nair D, Moseley GW, Srivastava S, Pradeepkumar PI, Kondabagil K. Biochemical Reconstitution of the Mimiviral Base Excision Repair Pathway. J Mol Biol. 2023 Sep 1;435(17):168188. doi: 10.1016/j.jmb.2023.168188. Epub 2023 Jun 26. PMID: 37380013
- PMID 23709652.
- S2CID 12038772.
- PMID 32946733.
- PMID 15757563.
- PMID 23709652– via Oxford Academic.
- PMID 24173233.
External links
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