The Flpo recombinase gene and FRT flanked CAG-Hyg selection cassette were inserted at the first ATG site of the Cyp3a11 gene by targeted transgenesis with homologous recombination such that it is under the control of the Cyp3a11 promoter. The embryonic stem cells (ES) used were established from NOG mice and a clone a5363 bearing Portm1.1Jic was used. (J:336704)