RBPJ and Patent ductus arteriosus: Conditional knockout of Jag1 in mouse smooth muscle cells causes defects in the PDA and OFT, with reduced expression of mature smooth muscle cell markers in the OFT; moreover, indomethacin can partially rescue the PDA in these mice.605 Subsequent studies on smooth muscle Rbpj deficiency revealed phenotypes similar to those of Jag1 deficiency, with only a few gene-deficient mice being rescued by indomethacin.606 Another study indicated that Notch2 and Notch3 play crucial roles in promoting vascular smooth muscle cell development and functional closure of the ductus arteriosus.607