A loxP site was inserted into intron 1 and an FRT site flanked neomycin resistance gene cassette and a second loxP site into intron 3. The neomycin selection cassette was removed via FLP-mediated recombination. This creates a conditional-ready allele with exons 2 and 3 floxed and without the neomycin selection cassette. (J:241981)