The L1L2_Bact_P cassette was inserted at position 81934502 of Chromosome 13 upstream of the critical exon 3 (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 exon 3 at position 81935301. Exon 3 is thus flanked by loxP sites. A null/knockout allele was created by flp and cre recombinase expression in mice carrying this allele to remove the lacZ sequence, neo selection cassette and the loxP-flanked critical exon. 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. In J:275959, immunohistochemistry of retina cryosections confirmed the absence of protein in the connecting cilium and basal bodies of homozygous mutant retinal photoreceptors, indicating that this is a null allele.