A loxP site was inserted into intron 7 approximately 500 bp 5' of exon 8, and a second loxP site together with the FRT-PGKneo-FRT cassette was inserted in intron 8 approximately 600 bp 3' of exon 8. Flp-mediated recombination removed the PGKneo cassette, leaving exon 8 floxed. (J:261788)