Vascular expression of Notch pathway receptors and ligands is restricted to arterial vessels

Mice with targeted mutations in genes required for Notch signal transductio n die during embryogenesis, displaying overt signs of hemorrhage due to def ects in their vascular development. Surprisingly, directed expression of a constitutively active form of Notch4 within mouse endothelial cells produce s a similar vascular embryonic lethality. Moreover, patients with mutations in Notch3 exhibit the cerebral vascular disorder, cerebral autosomal domin ant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL ). These findings underscore the importance of Notch signaling in vascular development; however, they do not identify the specific functional defect. Here, we report that Notch1, Notch3, Notch4, Delta4, Jagged1 and Jagged2 ar e all expressed in arteries, but are not expressed by veins. These findings identify an aspect of Notch signaling that could contribute to the mechani sm by which this pathway modulates vascular morphogenesis. (C) 2001 Elsevie r Science Ireland Ltd. All rights reserved.