The insertion of Velocigene cassette ZEN-Ub1 created a deletion of size 5645bp between positions 121606845-121612489 of Chromosome 9 (Build GRCm39). The coding sequence (excluding the start codon) as well as 23 nucleotides past the stop codon (nucleotides 172-5816 of NCBI reference sequence NC_000075.6) were replaced with a LacZ and neomycin expression cassette. The promoter and the 5' and 3' untranslated regions were left intact allowing for LacZ expression to be driven by the endogenous promoter. qPCR analysis confirmed absence of RNA transcript in quadriceps from P8 homozygous mutant mice.