A Neo STOP-tetO cassette was inserted just upstream of the translation initiation site. The cassette contained the following elements: a loxP site, an FRT site, a neomycin resistance gene cassette, a transcription and translation STOP cassette, an FRT site, a tetO cassette (the tetracycline operon site and a CMV minimal promoter) and a loxP site. Cre-mediated recombination resulted in the deletion of the flanked regions. (J:242069)