Mimiviridae | |
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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 viruses. Amoeba and other protists serve as natural hosts. The family contains three subfamilies that contain nine genera. [1] [2] [3] [4] Viruses in this family belong to the nucleocytoplasmic large DNA virus clade (NCLDV), also referred to as giant viruses.
The first member of this family, Mimivirus, was discovered in 2003, [5] and the first complete genome sequence was published in 2004. [6] However, the mimivirus Cafeteria roenbergensis virus [7] was isolated and partially characterized in 1995, [8] although the host was misidentified at the time, and the virus was designated BV-PW1. [7]
The family contains the following subfamilies and genera (-virinae denotes subfamily and -virus denotes genus): [2]
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]
Replication follows the DNA strand displacement model. DNA-templated transcription is the method of transcription. Amoeba serve as the natural host. [1]
Three putative DNA base excision repair enzymes were characterized from Mimivirus. [10] 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). [10] 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. [10]
Mimiviruses have been associated with pneumonia but their significance is currently unknown. [11] The only virus of this family isolated from a human to date is LBA 111. [12] 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. [13] With only a few reported cases previous to this finding, the legitimacy of the mimivirus as an emerging infectious disease in humans remains controversial. [14] [15]
Mimivirus has also been implicated in rheumatoid arthritis. [16]