The insertion of Velocigene cassette ZEN-Ub1 created a deletion of size 336bp between positions 133396349-133396684 of Chromosome 2 (Build GRCm39). Coding exon 1 is deleted beginning just after the start ATG to the end of coding exon 1, leaving the last 4 bp, and was replaced with a lacZ reporter cassette containing a floxed neomycin resistance gene under the control of the human ubiquitin promoter. (J:136110, J:258535)