The insertion of Velocigene cassette ZEN-Ub1 created a deletion of size 4068bp between positions 24336018-24340085 of Chromosome 7 (Build GRCm39). Exons 1-5 were replaced by a beta-galactosidase reporter gene and a neomycin resistance cassette. Immunohistochemical staining of the esophagus confirmed the absence of protein expression in homozygous mutant mice.