HIV-1 gag-pol precursor (p160) contains the necessary proteins for viral replication; protease, RNase, reverse transcriptase, and integrase. Naturally, the Gag-pol precursor is generated from a ribosomal frameshift to the pol reading frame 5% of the time. During viral maturation, the virally encoded protease cleaves the Pol polypeptide away from Gag and further digests it to separate the protease (p10), reverse transcriptase (RT; p50), RNase H (p15), and integrase (p31). However, cleavage is not always efficient and a portion of RT may remain attached to RNase H. Gag-Pol may regulate its own translation, by the binding genomic RNA in the 5' untranslated region. At low concentrations, the Gag-Pol polyprotein appears to promote translation, whereas at high concentrations, the polyprotein encapsidates genomic RNA, thus turning off translation.

Protease (Pro) is an aspartyl protease that acts as a dimer. It cleaves viral polyproteins (Gag-Pol, Pol, etc) to yield mature viral proteins during maturation. Pro is most active between shortly before and shortly after budding. It targets host proteins EIF4GI and PABP1 involved in capped cellular mRNA translation to maximize viral gene expression. It also mediates the cleavage of CARD8, thus activating CARD8 inflammasome, leading to clearance of latent HIV-1 in CD4+ T-cells after viral reactivation.

Reverse transcriptase (RT) is a DNA polymerase, which synthesizes double stranded DNA from the single-stranded genomic RNA. RT can act on both RNA and DNA templates.

Ribonuclease H (RNase) cleaves the RNA strand (genomic RNA strand) of RNA-DNA heteroduplexes formed after the initial synthesis of DNA by RT, leaving single-stranded DNA ready for complementary strand synthesis. Two polypurine tracts are left by RNase H to serve as templates for DNA synthesis by RT. After DNA synthesis is initiated, RNase H removes the polyurine tracts.

Integrase (In) catalyzes the integration of viral DNA (provirus) in the host genome. First, an exonuclease activity trims two nucleotides from each 3' end of the linear viral DNA duplex. Then, a double-stranded endonuclease activity cleaves the host DNA at the integration site. Finally, a ligase activity generates a single covalent linkage at each end of the proviral DNA.

For information on the Gag polyprotein, kindly refer to BCH record #116153:
http://bch.cbd.int/database/record.shtml?documentid=116153