Reverse Transcriptase (RT) (heterodimer of p66 (560 amino acids) and p51 (440 amino acids)  
Both subunits are encoded in the pol protein

Reverse transcriptase copies the viral genome to DNA. It carries out both RNA-dependent DNA polymerization and DNA-dependent DNA polymerization.. It also contains an RNase H activity that cleaves the RNA of the RNA/DNA hybrid that is formed after the first round of polymerization. As with all DNA polymerases, RT requires a primer and tRNAlys is packaged in the virus for this purpose. The primer anneals to the primer-binding site (PBS) in the LTR. Other tRNAs can be used if they contain the correct hybridization sequences. It appears that extra nucleotides can be added to the tRNAlys in the virus. After hybridization of tRNAlys, the remainder of the of the RT reactions occur in the cytoplasm after uncoating

Each subunit of RT contains a polymerase domain with four sub-domains (fingers, palm, thumb and connection). The p66 subunit also contains an extra RNaseH domain

For further information see: Alan Frankel and John A. T. Young, HIV-1: Fifteen proteins and an RNA Annual Review of Biochemistry 67: 1-25, 1998