Retrovirus
Alpharetrovirus
Betaretrovirus
Gammaretrovirus
Deltaretrovirus
Epsilonretrovirus
Lentivirus
Spumavirus
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A
retrovirus is a
virus which has a
genome consisting of
RNA. It relies on
reverse transcriptase to perform a kind of reverse transcription of its genome from
RNA into
DNA for insertion by
integrase into the host's genome. The virus itself is just a storage form for its RNA; the reverse transcription takes place in the host's
cytosol. A retrovirus' genome integrated into the host's genome is called a
provirus.
The retrovirus genome contains at least three
genes:
- gag codes for core and structural proteins of the virus.
- pol codes for reverse transcriptase, protease and integrase.
- env codes for the virus hull proteins.
Four identified
human retroviruses (
HTLV 1&2,
HIV 1&2) attack
CD4 cells.
Another feature common to all retroviruses is a
lipid envelope surrounding their
capsid. It is essential for their function. This explains why retroviruses can be killed by just washing hands.
Note: In view of current knowledge of retroviruses, the classification into three subfamilies (Oncovirinae, Lentivirinae, and Spumavirinae) is no longer appropriate.
See also
