The transgene contains the CAG promoter (CMV-IE enhancer, chicken beta-actin promoter, rabbit beta-globin genomic DNA), E. coli chloramphenicol acetyltransferase (CAT) gene, poly A, mouse Nkx2.5 cDNA, Phage P1 loxP. After cre-mediated excision of the cat gene, the mouse gene is expressed. (J:104881)