The insertion of Velocigene cassette ZEN-Ub1 created a deletion of size 8459bp between positions 70290811-70299269 of Chromosome 12 (Genome Build37), and subsequent Cre-mediated excision deleted the neomycin selection cassette. A portion of genomic sequence including exon 1, intron 1 and exon 2, intron 2 and part of exon 3, is thus deleted and replaced with a lacZ reporter gene. RT-PCR analysis confirmed the absence of mRNA expression in homozygous mutant embryos. (J:136110, J:188991, J:278736)