Scheme for the unmarked deletion of a large gene by FLP/FRT recombination. The plasmid pJQFRT with the insertion of the upstream region of the target gene is integrated into the host chromosome by homologous recombination. Next, the plasmid pKFRT/FLP with the insertion of the downstream region of the target gene is integrated into the host chromosome by homologous recombination. As a result, the target gene is sandwiched between the two integrated plasmids. The expression of flp is induced by adding anhydrotetracycline, and then the target region is excised together with the integrated plasmids bracketed by the two FRT sites, leaving a single FRT site.
Ishikawa and Hori BMC Microbiology 2013 13:86 doi:10.1186/1471-2180-13-86