The full HIV genome is encoded on one long strand of RNA. (In a free virus particle, there are actually two separate strands of RNA, but they're exactly the same!)
This is the form it has when it is a free virus particle. When the virus is integrated into the host's DNA genome (as a provirus) then its information too is encoded in DNA.
The following image shows roughly how the genes are laid out in HIV (remember that HIV-1 and HIV-2 are quite different). Click on a gene's name for more information.
This diagram is based on a fantastic map of the HIV-1, HIV-2, and SIV genomes, available at hiv-web.lanl.gov/content/immunology/pdf/2000/intro/GenomeMaps.pdf
The genes in HIV's genome are as follows:
- gag (coding for the viral capsid proteins)
- pol (notably, coding for reverse transcriptase)(NB. gag and pol together can be expressed in one long strand called "gag-pol")
- env (coding for HIV's envelope-associated proteins) And the regulatory genes:
- tat
- rev
- nef
- vif
- vpr
- vpu (N.B. not present in HIV-2)
- vpx (N.B. not present in HIV-1)
The HIV genome also has a "Long Terminal Repeat" (LTR) at each end of its genome - not quite a gene, but a sequence of RNA/DNA which is the same at either end and which serves some structural and regulatory purposes. |