Iridoviridae
Iridoviridae | |
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TEM micrograph showing a cluster of Iridovirus virions
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Virus classification | |
(unranked): | Virus |
Realm: | Varidnaviria |
Kingdom: | Bamfordvirae |
Phylum: | Nucleocytoviricota |
Class: | Megaviricetes |
Order: | Pimascovirales |
Family: | Iridoviridae |
Subfamilies and genera | |
See text |
Iridoviridae is a family of viruses with double-stranded DNA genomes.[1] Amphibians, fish, and invertebrates such as arthropods serve as natural hosts. There are currently 22 species in this family, divided among two subfamilies and seven genera.[1][2]
Nomenclature
The name is derived from Iris, the Greek goddess of the rainbow. This name was chosen because of the "rainbow-like" iridescence observed in heavily infected insects and pelleted samples of invertebrate iridoviruses. It may refer to any member of the Iridoviridae family or a particular genus within Iridoviridae.[citation needed]
Taxonomy
The following subfamilies and genera are recognized (-virinae denotes subfamily and -virus denotes genus):[citation needed]
Structure
The
The linear genome varies between 150 and 303
Members of this family differ in their degree of genome methylation. The genera Chloriridovirus and Iridovirus lack a highly methylated genome. Members of Lymphocystivirus, Megalocytivirus, and Ranavirus have genomes with about 25% of their cytosine residues methylated by a virally encoded DNA methyltransferase.[citation needed]
Genus | Structure | Symmetry | Genomic arrangement | Genomic segmentation |
---|---|---|---|---|
Lymphocystivirus | Polyhedral | T=189–217 | Linear | Monopartite |
Megalocytivirus | Polyhedral | T=189–217 | Linear | Monopartite |
Ranavirus | Polyhedral | T=133 or 147 | Linear | Monopartite |
Iridovirus | Polyhedral | T=147 | Linear | Monopartite |
Chloriridovirus | Polyhedral | T=189–217 | Linear | Monopartite |
Gene expression
Similar to the herpes viruses, transcription occurs in three stages: immediate-early, delayed-early, and late. Positive induction and negative feedback mechanisms exist in each stage, mediated by products of the other stages.[citation needed]
Replication
Virus particles enter the cell and uncoating occurs. The viral DNA is transported to the host cell nucleus, where it is transcribed by host RNA polymerase II modified by the virus. Meanwhile, host macromolecular synthesis ceases.
Parental DNA produces a genome which is then the template for replication in the
Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
---|---|---|---|---|---|---|---|
Lymphocystivirus | Fish | None | Cell receptor endocytosis | Lysis; budding | Nucleus | Cytoplasm | Unknown |
Megalocytivirus | Fish | None | Cell receptor endocytosis | Lysis; budding | Nucleus | Cytoplasm | Unknown |
Ranavirus | Frogs; snakes | None | Cell receptor endocytosis | Lysis; budding | Nucleus | Cytoplasm | Contact |
Iridovirus | Insects | None | Cell receptor endocytosis | Lysis; budding | Nucleus | Cytoplasm | Contact |
Chloriridovirus | Diptera with aquatic larval stage, mainly mosquitoes | None | Cell receptor endocytosis | Budding | Nucleus | Cytoplasm | Unknown |
DNA repair
Members of the Iridoviridae appear to have the capability to repair DNA damages.[3]
Pathogenesis
Little is known about the
Host range
Members of the Iridoviridae family infect mainly
References
- ^ a b "Iridoviridae". ICTV Online (10th) Report.
- ^ "Viral Zone". ExPASy. Retrieved 15 June 2015.
- ^ Ke F, Zhang QY. ADRV 12L: A Ranaviral Putative Rad2 Family Protein Involved in DNA Recombination and Repair. Viruses. 2022 Apr 27;14(5):908. doi: 10.3390/v14050908. PMID 35632650; PMCID: PMC9146916
MicrobiologyBytes: Iridoviruses, archived from the original on February 24, 2007, retrieved 2007-03-06 Viral Bioinformatics Resource Center & Viral Bioinformatics – Canada, University of Victoria, archived from the original on August 17, 2007, retrieved 2007-03-06