A loxP site was inserted at the start codon in exon 3. A loxP site, GFP reporter gene, polyadenylation sequence, and FRT-flanked neomycin resistance cassette were inserted into intron 4. Flp-mediated recombination removed the selection cassette. Cre-mediated recombination removed the coding sequence in exon 3, intron 3 and exon 4. (J:226158)