The transgene contains the CMV enhancer/chicken beta-actin promoter, a floxed Beta-geo reporter/SV40 polyadenylation signal segment, and the human placental alkaline phosphatase gene followed by a rabbit Hbb polyadenylation sequence. In transgenic mice expression of lacZ is widespread, with notable exceptions being erythrocytes, chondrocytes and adipocytes. This expression is observed throughout all embryonic and adult stages.