The insertion of NorCOMM cassette pGOHANU created a deletion of size 928bp between positions 136320038-136320966 of Chromosome 4 (Build GRCm39). This deletion results in the removal of functionally critical exon(s). The cassette is composed of an F3 site followed by a universal inverse PCR primer site, splice acceptor IRES-lacZ sequence and a loxP site. This first loxP site is followed by deltaTK and neomycin under the control of the human beta-actin promoter / deltaTK / neomycin phosphotransferase (neoR) gene / SV40 polyA and a second loxP site. After the second loxP site is a PhiC31 attP site and a puromycin sequence that is not active unless a promoter is inserted by PhiC31 at the attP site. The cassette is finished with an FRT site. Variations of this allele can be made using PhiC31 docking and subsequent cloning (Nagy et al., 2009. Methods Mol. Biol. 530:365-78).