Notch signaling may be used to control the sprouting pattern of blood vessels during angiogenesis. When cells within a patent vessel are exposed to VEGF signaling, only a restricted number of them initiate the angiogenic process. Vegf is able to induce DLL4 expression. In turn, DLL4 expressing cells down-regulate Vegf receptors in neighboring cells through activation of Notch, thereby preventing their migration into the developing sprout. Likewise, during the sprouting process itself, the migratory behavior of connector cells must be limited to retain a patent connection to the original blood vessel.