An frt-SD/SA-IRES-LacZ-Neo-frt-loxP (LacZ/Neo) cassette including a reporter (LacZ) and a positive selection marker was inserted 923-bp downstream of exon 2. A loxP sequence was cloned 278-bp upstream of exon 2. FLP-mediated recombination removed the LacZ/Neo cassette in the germline, leaving exon 2 flanked by loxP sites. (J:275512)