A loxP site was inserted 2430 bp upstream of exon 1 and an FRT-flanked neomycin selection cassette and second loxP site were inserted 190 bp downstream of exon 3, resulting in a floxed 4501 bp fragment containing the complete gene. The selection cassette was removed via flp-mediated recombination, leaving exons 1-3 floxed. (J:326708)