High-frequency Flp recombinase-mediated inversions of the oriC-containing region of the Pseudomonas aeruginosa genome

The genomes of the two clonally derived Pseudomonas aeruginosa prototypic strains PAO1 and DSM-1707 differ by the presence of a 2.19-Mb inversion including oriC. Integration of two Flp recombinase target sites near the rrn operons containing the inversion endpoints in PAO1 led to Flp-catalyzed inversion of the intervening 1.59-Mb fragment, including oriC, at high frequencies (83%), favoring the chromosome configuration found in DSM-1707. The results indicate that the oriC-containing region of the P. aeruginosa chromosome can readily undergo and tolerate large inversions.