A loxP and FRT flanked neo cassette was inserted in intron 6 and a loxP site was inserted in intron 10 via homologous recombination. Flp mediated recombination removed the neo cassette leaving exons 7 - 10 (1.7 kb) floxed and a single FRT site upstream of the loxP site in intron 6. (J:264168)