Cripavirus

Cripavirus
Virus classification
Group:	Group IV ((+)ssRNA)
Order:	Picornavirales
Family:	Dicistroviridae
Species
Aphid lethal paralysis virus Black queen cell virus Cricket paralysis virus Drosophila C virus Himetobi P virus Homalodisca coagulata virus 1 Plauti stali intestine virus Rhopalosiphum padi virus Triatoma virus

Cripaviruses are a genus of + sense, single-stranded RNA (ssRNA) viruses. If a ssRNA virus is +sense, it means that the viruses can produce proteins directly from their RNA genome upon entering a cell; and therefore, may not require an RNA polymerase packaged in with it, as this may be produced from the genome after entering the cell.^[1]

The genome is 8500–9500 nucleotides long, and has a VPg (genome linked viral protein) on the 5' end. The 5' end also has a series of C's near it, while the 3' end has a series of A's near it.

These viruses have capsids of 12 capsomers but no envelope, and are round 27–30 nm in diameter with an icosahedral symmetry.

The name of the cripavirus family originates from its most famous member the Cricket Paralysis Virus.^[1] Which was made famous by its rather unique IRES (Internal Ribosome Entry Site): the Cripavirus IRES. The Cripavirus IRES is an RNA element that allows the virus to bind the ribosome and translate without a need for any initiation factors^[2] – as initiation is the most regulated step of translation this allows the virus to avoid many mechanisms to inhibit viral activity.

References

1. ^ ^{a b} International Committee on the Taxonomy of Viruses. [1]
2. ^ "Structure and Function of Regulatory RNA Elements", Biochimica et Biophysica Acta 1789: 542–557, 2009, http://www.ncbi.nlm.nih.gov/pubmed/19632368