The L1L2_gt0 cassette was inserted at position 53422307 of Chromosome 11 upstream of exon 2 (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 2 at position 53423302. A knockout allele was created by flp and cre recombinase expression in mice, removing the lacZ/neomycin sequence and exon 2. Further information on targeting strategies used for this and other IKMC alleles can be found at http://www.informatics.jax.org/mgihome/nomen/IKMC_schematics.shtml.