Exon 1 was replaced with a CAG promoter, loxP site, neo/stop cassette, loxP2272 site, inverted human TBX2 cDNA, IRES and EGFP cassette, loxP site, and loxP2272 site. Cre-mediated recombination is required to achieve expression of TBX2 and EGFP. (J:181526)