Using a BAC clone from the C57BL/6J, the Plod2 gene was targeted to insert a loxP site upstream of exon 2 and FRT flanked neo-selection cassette and second loxP site after exon2. The neo-selection cassette was removed by crossing with Flp recombinase expressing mice, leaving the exon 2 flanked by loxP sites. (J:318894)