Organ Size Control: Lessons from Drosophila

Of fundamental interest to biologists is how organs achieve a reproducible size during development. Studies of the developing Drosophila wing have provided many key insights that will help give a conceptual understanding of the process beyond the fly. In the wing, there is evidence for both “top-down” mechanisms, in which signals emanating from small subsets of cells direct global proliferation, and “bottom-up” mechanisms, in which the final size is an emergent property of local cell-cell interactions. Mechanical forces also appear to have an important role along with the Hippo pathway, which may integrate multiple types of inputs to regulate the extent of growth. How do organs achieve a reproducible size during development? Studies of the developing Drosophila wing have provided key insights that will aid conceptual understanding of the process beyond the fly. Top-down and bottom-up mechanisms of size control, along with mechanical forces and Hippo signaling, all contribute to the final structure.