This targeting vector obtained from the Wellcome Trust Sanger Institute KOMP (Knockout Mouse Project) is used to insert a L1L2_Bact_P cassette containing FRT-lacZ-loxP-neo-FRT-loxP upstream of exon 5 (at position 9455699 of Chromosome X; Build GRCm38), and a loxP site downstream of exon 5 (at position 9454892). Flp-mediated recombination removed the FRT-flanked lacZ/neo cassette. (J:245699)