The L1L2_Bact_P cassette was inserted at position 132388494 of Chromosome 2 upstream of the critical exons, 9 and 10 (Build GRCm39). The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site is followed by a neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site. A third loxP site is inserted downstream of the exon 10 at position 132390080. The critical exons are thus flanked by loxP sites. A "conditional ready" (floxed) allele was be created by flp recombinase recombination of this allele. Subsequent cre expression results in a knockout mouse. 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