The molecular control of angiogenesis, or blood vessel growth, is critical for embryonic development, tissue regeneration, and diseases including cancer and ischemia. The long-term interest of my laboratory is to elucidate the molecular regulators of the cellular processes that occur in endothelial cells lining blood vessel walls. We study these questions through cell-lineage specific, temporally regulatable gene expression and deletion in mice, combined with cellular, molecular, and two-photon in vivo imaging approaches. A key challenge in the study of angiogenesis is the regulation of arterial venous hierarchy. We are currently investigating the function of Notch and ephrin-B2 signaling pathways in arterial venous specification. This work may unravel signaling cascades regulating crucial vascular pathophysiology and facilitate rational design of therapies to treat cardiovascular diseases and cancer.