The notch signalling pathway in the development of the mouse placenta.

Notch signalling is an evolutionarily conserved pathway taking part in many developmental and cell type specification processes. The development of a functional mouse placenta is a dynamic phenomenon involving a number of different processes: trophoblast cell type specification, branching of the chorion and fetal vascular morphogenesis, as well as formation of a maternal blood circulation. In the placenta several members of the Notch signalling pathway and their regulators are expressed. The analysis of mouse strains with targeted mutations in the Notch2, Notch1/4, Hey1/2, Dll4, RBPJkappa, and Mash2 genes has demonstrated that these genes are indispensable for a proper placental development. Among them Notch1/4, Hey1/2, Dll4 and RBPJkappa have been shown to be crucial for fetal angiogenesis, Notch2 is necessary for formation of maternal blood vessels in the placenta and Mash2 is indispensable for proper trophoblast cell type specification. This review summarizes the current knowledge on the role of the Notch pathway in these various processes happening during placental development.