The 98.6 kb mouse bacterial artificial chromosome (BAC) bMQ353d13 containing the entire Ucp1 gene, was modified by inserting a a luciferase2-T2A-tdTomato reporter cassette into Ucp1 exon 1 at the initiation codon. Luciferase2 is a modified version of firefly luciferase. (J:218083)