FIG. 8.
Models for end-joining repair of Ac/Ds excision sites (see text for details). At the top of the figure, the ends of the transposon (dashed lines) have synapsed, TPase cleavage has occurred, and DNA hairpins have formed in the host DNA flanking the transposon. (A) Model showing preferential hairpin opening on the strand that has been attacked to form the DNA hairpin. (B) An alternative model in which hairpins are opened randomly on either strand but subjected to processing by a 5′-to-3′ exonuclease activity. 3′ ends are left as such, and 5′ overhangs are processed into 3′ overhangs that are then resolved through either microhomology-dependent end joining or homologous repair.