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
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.
- env codes for the virus hull proteins.
There are three known retrovirus categories :
- Oncovirinae cause sarcomas and leukaemias (e.g., Rous Sarcoma Virus). They contain an onc gene which makes them oncogenic.
- Lentivirinae cause slow progressive degenerative disorders (e.g., HIV).
- Spumavirinae with unknown effects.
All four identified human
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.
- See also: HIV