Large nuclear-cytoplasmic DNA-containing viruses ( Eng. Nucleocytoplasmic large DNA viruses; NCLDV ) - a group of families of eukaryotic viruses containing DNA . The viruses of this group are distinguished by a large DNA length (from 300 Kb to 2.5 Mb) and large sizes (from 200 nm to 1000 nm) and, thus, are comparable with bacteria in these parameters.
| Virus group | |
|---|---|
 Megaviridae family megavirus , one of the largest known viruses (capsid size 440 nm) | |
| Title | |
| Large nuclear cytoplasmic DNA viruses | |
| Title Status | |
| is being discussed | |
| Scientific name | |
| - | |
| Parent taxon | |
| Domain Viruses ( Viruses [1] ) | |
| Families | |
| |
Classification
The group includes the following families :
- Asfarviridae
- Ascoviridae
- Iridoviridae
- Marseilleviridae
- Megaviridae
- Mimiviridae
- Pandoraviridae
- Phycodnaviridae
- Pithoviridae
- Poxviridae
This genus also includes the genus Dinodnavirus .
NCLDV Features
Viruses of this group have common and unique features of genomic DNA and the structure of the virion . However, it is not known whether these families have a common ancestor or whether these common features arose independently from each other as a result of the recruitment of host genes in the process of virus replication. The general ancestor hypothesis is considered controversial [2] .
Currently, 47 major NCLDV genes have been discovered. They include four key DNA replication and repair proteins: family B DNA polymerase , topoisomerase II A, endonuclease FLAP (5-lipoxygenase-activating protein) and processing factor proliferating cell nuclear antigen. In addition, this includes DNA-dependent RNA polymerase II and transcription factor II B.
Perhaps these viruses arose before the separation of eukaryotes into coronal groups (groups of organisms consisting of the last common ancestor of the group and all living descendants). The precursor genome was complex and consisted of at least 41 genes, including replication genes, up to 4 RNA polymerase subunits, at least 3 transcription factors, cap and polyadenylation enzymes, viral DNA packaging apparatus, and structural components of the icosahedral capsid and viral membrane.
See also
- Viral eukaryogenesis
- Giant viruses
Notes
- ↑ Virus taxonomy (English) on the website of the International Committee on Taxonomy of Viruses (ICTV) .
- ↑ Iyer, LM .; Aravind, L .; Koonin, EV. Common origin of four diverse families of large eukaryotic DNA viruses (Eng.) // J Virol: journal. - 2001 .-- December ( vol. 75 , no. 23 ). - P. 11720-11734 . - DOI : 10.1128 / JVI.75.23.11720-11734.2001 . - PMID 11689653 .
Literature
- Koonin EV, Yutin N .: Origin and evolution of eukaryotic large nucleo-cytoplasmic DNA viruses. Intervirology. 2010; 53 (5): 284-92. PMID 20551680
- Yutin N, Koonin EV .: Hidden evolutionary complexity of Nucleo-Cytoplasmic Large DNA viruses of eukaryotes. Virol J. 2012 Aug 14; 9: 161. PMID 22891861
- Yutin N, Colson P, Raoult D, Koonin EV .: Mimiviridae: clusters of orthologous genes, reconstruction of gene repertoire evolution and proposed expansion of the giant virus family. Virol J. 2013 Apr 4; 10: 106. PMID 23557328
- Yutin N, Wolf YI, Raoult D, Koonin EV .: Eukaryotic large nucleo-cytoplasmic DNA viruses: clusters of orthologous genes and reconstruction of viral genome evolution. Virol J. 2009 Dec 17; 6: 223. PMID 20017929
- Lakshminarayan M. Iyer, L. Aravind, and Eugene V. Koonin: Common Origin of Four Diverse Families of Large Eukaryotic DNA Viruses. J Virol. 2001 December; 75 (23): 11720–11734. PMID 11689653