Figure 1.

Sequence of events in HIV-1 integration (left) and Tn5 transposition (right). HIV-1: I) donor DNA; II) integrase-catalyzed 3' processing; III) integrase-catalyzed strand transfer; IV) product of strand transfer; V) DNA repair by cellular enzymes. Tn5 transposon: 1) donor DNA; 2) 3'processing; 3–4) 5' processing, consisting of loop formation (3) and generation of blunt-ended DNA (4); 5) strand transfer; 6) repaired strand transfer product. Portions of the donor DNA that become integrated are shown in red. Acceptor DNA is shown in white. Portions of acceptor DNA repaired following the strand transfer reaction are shown in grey.