The L1L2_gt2 cassette was inserted at position 89080973 of Chromosome 8 upstream of exon 5 (Build GRCm39). The cassette is composed of an FRT flanked lacZ/neomycin sequence followed by a loxP site. An additional loxP site is inserted downstream of exon 5 at position 89081942. Exon 5 is thus flanked by loxP sites. A "conditional ready" (floxed) allele was created by flp recombinase expression in mice carrying this allele. (J:276819)