The insertion of the L1L2_Bact_P cassette created a deletion of size 8113 starting at position 121129742 and ending at position 121137855 of Chromosome 2 (Genome Build GRCm39). This deletion results in the removal of functionally critical exon 5. The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site is followed by neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site. Flp-mediated recombination removed the reporter and selection cassette. 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.