The insertion of the L1L2_Bact_P cassette created a deletion of size 4555 starting at position 71197807 and ending at position 71202362 of Chromosome 8 (Genome Build GRCm39). This deletion results in the removal of functionally critical exon(s). The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site was 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, and subsequent Cre-mediated excision deleted the neomycin selection cassette.