Animals depend upon epithelial and endothelial tubes to transport gases and liquids in the body, and the sizes of the tubes are critical for their transport function. Tube size must be controlled not only during tube formation but throughout development in order to maintain functionality as the animal grows. For example, the human aorta expands approx. 100-fold between embryonic and adult life ...

The Drosophila tracheal system consists of a stereotyped network of epithelial tubes formed by several tracheal cell types. By the end of embryogenesis, when the general branching pattern is established, some specialised tracheal cells then mediate branch fusion while others extend fine terminal branches. Here evidence is presented that the Notch signalling pathway acts directly in the tracheal...