January 28, 2019—Arteries and veins have different types of endothelium, but it is unclear how these molecular and functional differences are specified during development. To understand more, Ludwig Oxford’s Alice Neal and colleagues from Sarah De Val’s group studied venous development in mice and zebrafish. They found that BMP signalling is required for transcriptional activation of the key venous regulator Ephb4 and subsequent establishment of venous blood vessels. This work, published in Nature Communications, therefore identifies a new potential target for anti-angiogenic therapy to reduce tumour growth.