FIG. 4.

Effect of MooV-His₆ and Piv-His₆ on IS492 circle formation. IS492 circle formation was examined in E. coli HMS174(DE3) by the PCR assay diagrammed in Fig. 1. The circle junction PCR products after agarose gel electrophoresis are shown. MooV-His₆ and Piv-His₆ (presence or absence is indicated by + or −, respectively) were provided in trans from pAG954 and pAG955, respectively, to the IS492ΔmooV::cam-carrying plasmid, pAG957 (Δ). The levels of MooV-His₆ and Piv-His₆ were varied by using different concentrations of IPTG for induction. The following plasmids in HMS174(DE3) were included as controls: pCR2.1 (− for IS492), pAG949 (+ for IS492), and pAG903 (T, IS492 target site mutant [see Materials and Methods]). Lane M, Promega 1-kb markers.