The targeting vector contains a loxP-flanked neomycin cassette introduced to intron 2 and a loxP site in intron 3. Cre-mediated recombination removed exon 3 and the neo cassette. Deletion of exon 3 causes a frameshift mutation and the generation of a stop codon in exon 4. qRT-PCR analysis in adipose tissue shows complete loss of mRNA. (J:245106)