The L1L2_Bact_P cassette was inserted at position 54760244 of Chromosome 11 upstream of exon 2 (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 3 at position 54761593. Exons 2 and 3 are thus flanked by loxP sites. Cre mediated recombination without prior flp recombination created a reporter 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