Figure 2.

Mobilization of aac(6′)-Ib. (A) Generic genetic maps of integrons in which an aac(6′)-Ib gene cassette is located immediately following the 5′ conserved region (5′-CR) (top map) or following one or more gene cassettes (gc) inside the variable portion, and followed by other gene cassettes or the 3′ conserved region (3′-CR) (bottom map). The small green ellipse represents attI and the big green ellipses represent attC. (B) Relevant portion of the Tn1331, Tn1331.2, and KQ elements (Tolmasky and Crosa, 1987; Tolmasky et al., 1988; Sarno et al., 2002; Rice et al., 2008). For clarity Tn1332, which has a more complicated structure in its direct repeats (Poirel et al., 2006), is not shown, but it could experience mobilization by homologous recombination as shown. The black dot represents attI1^*. The homologous recombination pathway for generation of an aac(6′)-Ib-containing circular molecule has been proposed by Zong et al. (2009).