During replicative cycle of retroviruses, the reverse-transcribed viral DNA is integrated into the host chromosome by the viral integrase enzyme. RNase H activity is associated with the reverse transcriptase. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Endonucleolytic cleavage to 5'-phosphomonoester. Binds 8 Mn(2+) or Mg(2+) ions per integrase homotetramer. The integrase forms a homotetramer. The reverse transcriptase forms a heterodimer of alpha and beta subunits (By similarity). The integrase is composed of three domains. The N-terminal domain is a zinc binding domain. The central domain is the catalytic domain. The C-terminal domain is a non-specific DNA binding domain (By similarity). Specific enzymatic cleavages in vivo yield mature proteins. The pol-derived portion of gag-pol precursor is processed to yield the reverse transcriptase beta subunit, which in turn is processed to yield the reverse transcriptase alpha subunit and the integrase (By similarity). This protein is synthesized as a Gag-Pol polyprotein.