The transgene contains the CAG promoter (CMV-IE enhancer, chicken beta-actin promoter, rabbit beta-globin genomic DNA), Phage P1 loxP sites, E. coli chloramphenicol acetyltransferase (CAT) gene, and mouse Dll4 cDNA. The Dll4, Delta-like 4 gene is expressed after excision of the floxed-CAT gene by Cre-mediated recombination. (J:104881)