The transgene consists of a Tagln (transgelin) promoter and a cre gene modified to include translational consensus and nuclear localization signals. The Tagln promoter was used to drive transgene expression in smooth muscle cells. Cre recombinase mRNA expression closely patterns endogenous transgelin expression, with the highest levels detected in the aorta, intestine, and uterus. Low levels of Cre recombinase transcript are detected in all other organs. Recombination occurs in vascular smooth muscle cells of hepatic and pulmonary arteries. No recombination has been detected in non-muscle cells.