ADAMTS5, the main aggrecanase, is a protein that seems to play a functional role in the development of brown and white adipose tissue (WAT) and browning of WAT. These observations were made using the ADAMTS5-P mice originally generated by Pfizer, in collaboration with Lexicon Genetics (The Woodlands, TX, USA). ADAMTS5-J mice were generated by Deltagen Inc. and are now commercially available through The Jackson Laboratory (Bar Harbor, USA). The targeting construct, containing an IRES-lacZ-neomycin cassette, substituted 134 nucleotides of exon 2.