Group Group IV ((+)ssRNA) Scientific name Dicistroviridae Rank Family | Order Picornavirales Higher classification Picornavirales | |
Lower classifications Cricket paralysis virus, Drosophila C virus | ||
Dicistroviridae is a family of viruses in the order Picornavirales. Invertebrates, including aphids, leafhoppers, flies, bees, ants, and silkworms, serve as natural hosts. There are currently 15 species in this family, divided among 2 genera. Diseases associated with this family include: DCV: increased reproductive potential. extremely pathogenic when injected with high associated mortality. CrPV: paralysis and death.
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Taxonomy
Although many dicistroviruses were initially placed in the Picornaviridae, they have since been reclassified into their own family. The name (Dicistro) is derived from the characteristic dicistronic arrangement of the genome.
This family is a member of the Order Picornavirales (Comoviridae, Iflavirus, Picornaviridae, Potyviridae, and Sequiviridae). Within this order, the gene order is the gene order of the nonstructural proteins Hel(helicase)-Pro(protease)-RdRp(polymerase). The Dicistroviridae can be distinguished from the members of the taxa by the location of their structural protein genes at the 3' end rather than the 5' end (as found in Iflavirus, Picornaviridae and Sequiviridae) and by having two genomic segments rather than a single one (as in the Comoviridae).
Group: ssRNA(+)
Structure
Viruses in Dicistroviridae are non-enveloped, with icosahedral geometries, and T=pseudo3 symmetry. The diameter is around 30 nm. Genomes are linear and non-segmented, around 8.5-10.2kb in length. The genome has 2 open reading frames.
Life Cycle
Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. Translation takes place by viral initiation, and ribosomal skipping. Invertebrates serve as the natural host. Transmission routes are contamination.
RNA structural elements
Many of the Dicistroviridae genomes contains structured RNA elements. For example, the Cripaviruses have an internal ribosome entry site, which mimics a Met-tRNA and is used in the initiation of translation.