Figure 4.

Model of three possible pathways for resolving figure-eight molecules to circles. The figure-eight molecule carrying a 3′-OH is shown above. The two left-hand drawings show circle formation driven by replication from the plasmid origin of replication (left) or from the Tpase-generated 3′-OH (centre). In both cases, replication would generate a double-stranded transposon circle and regenerate the original parental plasmid. Conversion using a recombination/repair pathway is shown on the right. Host-mediated repair would be expected to lead to either destruction or recircularisation of the donor plasmid backbone.