Final Report Summary - CELL SHAPE, FLY (Control of cell shape in the peripodial membrane of the wing disc of Drosophila melanogaster) Drosophila has been broadly used as a model system for studying development. Their short life cycle and genetic tools has made the fly, an ideal model to approach the complexity of the morphogenetic events. In the last decade, the possibility of imaging the live development of the embryo, using reported green fluorescent protein (GFP)-tagged proteins has allow a deeply understanding of the morphogenetic movements. However, little was known about the development movements involved in the metamorphosis. Metamorphosis is major event in Drosophila life cycle; there is a massive rearrangement of tissues responsible of generating from the larval tissues the adult fly. The high dynamicity of the process and the fact that the tissues involved are buried inside of the larva, has made difficult an approach to study in detail this processes. Experiments in the 1970s describe the composition of the media necessary to produce ex vivo the metamorphosis. The hormone responsible of inducing the process is the ecdysone, also known as moulting hormone. We have reproduced these experiments, focusing in the development of the wing, .We have develop a system that allows us to produce ex vivo the metamorphosis of the wing, dissecting the tissue that will develop the wing, known as wing disc, we are able to film its development using confocal technology. This has allow us to describe in cellular detail the complex movements responsible of folding a relatively simple double epithelium sac, the wing discs into a more complex structure, a wing. We analysed what and where are the forces generated in this epithelium sac, responsible of sculpting the tissue; and what is the cellular response of different epithelial cells once their are stretched by this forces. The high conservation between flies and mammal make us confident that the movements described have a homology with mammal development. This ex-vivo model system will allow further studies of other developmental processes such programmed cell death. The culture technique is versatile and could be extended to other tissues, and will allow live imaging of different processes giving a deeper understanding of them.