Iridoviridae are a family of viruses all with dsRNA genomes.
Taxonomy
The family contains five genera: Chloriridovirus, Iridovirus, Lymphocystivirus, Megalocytivirus and Ranavirus.
Taxonomy
The family contains five genera: Chloriridovirus, Iridovirus, Lymphocystivirus, Megalocytivirus and Ranavirus.
Virology
The genome is 150-280 kilobases in length. They have icosohedral symmetry. The virion is made up of three domains; an outer proteinaceous capsid, an intermediate lipid membrane, and a central core containing DNA-protein complexes. Some of the viruses also have an outer envelope.
Gene Expression
Like all 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.
[edit] Replication
Final packaging occurs in the cytoplasm but a stage of replication also occurs in the nucleus. Virus particles enter the cell and uncoating occurs. Viral DNA then travels to the host cell nucleus and is transcribed by host RNA polymerase II modified by the virus. Meanwhile host macromolecular synthesis is stopped. Parental DNA produces a genome, which is then the template for replication in the cytoplasm. Large concatemers of viral DNA are formed by recombination in the cytoplasm. The concatamers are then packaged and the virus is released either by budding out of the cell membrane or cell lysis.
[edit] Pathogenesis
Little is known about the pathogenesis of iridoviruses. The pathogenesis is, however, temperature dependent and iridoviruses are thus confined to poikilothermic hosts.
Host range
Members of the Iridoviridae family infect mainly invertebrates, but also some vertebrate species such as fish, amphibians and reptiles.
Taxonomy
The family contains five genera: Chloriridovirus, Iridovirus, Lymphocystivirus, Megalocytivirus and Ranavirus.
Taxonomy
The family contains five genera: Chloriridovirus, Iridovirus, Lymphocystivirus, Megalocytivirus and Ranavirus.
Virology
The genome is 150-280 kilobases in length. They have icosohedral symmetry. The virion is made up of three domains; an outer proteinaceous capsid, an intermediate lipid membrane, and a central core containing DNA-protein complexes. Some of the viruses also have an outer envelope.
Gene Expression
Like all 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.
[edit] Replication
Final packaging occurs in the cytoplasm but a stage of replication also occurs in the nucleus. Virus particles enter the cell and uncoating occurs. Viral DNA then travels to the host cell nucleus and is transcribed by host RNA polymerase II modified by the virus. Meanwhile host macromolecular synthesis is stopped. Parental DNA produces a genome, which is then the template for replication in the cytoplasm. Large concatemers of viral DNA are formed by recombination in the cytoplasm. The concatamers are then packaged and the virus is released either by budding out of the cell membrane or cell lysis.
[edit] Pathogenesis
Little is known about the pathogenesis of iridoviruses. The pathogenesis is, however, temperature dependent and iridoviruses are thus confined to poikilothermic hosts.
Host range
Members of the Iridoviridae family infect mainly invertebrates, but also some vertebrate species such as fish, amphibians and reptiles.
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