A targeting vector was obtained from the KOMP consortium (project CSD48807, clone HTGRS01006_A_B09) and transfected to V6.5 ES cells. An frt-lacZ-loxP-neomycin selection cassette-frt-loxp construnct was inserted into intron 1 and a single loxP site was inserted into intron 2. (J:264769)