An frt-flanked neomycin selection cassette was inserted upstream of exon 10 and loxP sites were inserted to flank exons 1012. FLP-mediated recombination removed the neomycin selection cassette, leaving the loxP sites. Subsequent Cre-mediated recombination resulted in the deletion of the exon 10-12 loxP flanked region. (J:259650)