A construct containing a loxP site, FRT site, neo cassette, STOP, FRT site, tetracycline operator (tetO) and loxP site was inserted upstream of the translation initiation site. Flp-mediated recombination removed the neo/STOP cassette and left the tetO operator floxed. In situ hybridization confirmed the rescue of endogenous transcript expression. Western blot analysis confirmed normal protein expression. (J:159353)