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. Cre-mediated recombination of flanking loxP sites resulted in deletino of exon 2 and the lacZ/neo cassette. (J:275512)