This project aims at deciphering the various functions of Dystrophin in vivo: muscle contraction, muscle regeneration as well as asymetric divisions of muscle precursors and early muscle development. We will use cell and molecular approaches to investigate the role Dystrophin in cell polarity, fiber integrity and branching, rate of regeneration and how it integrates with alternative cell adhesion system such as integrins. This project will address the role of Dystrophin at different levels of magnitude from subcellular dynamics to tissue level. In short-term, we will compare the function of full length Dystrophin with that of shorter forms of the proteins in order to better understand which protions of the protein are relevant to its various roles. We hope that this project will yield data helping to understand the physiological roles of Dystrophin that may then be used to refine strategies for gene therapy aiming at converting Duchenne muscular dystrophy into a milder Becker dystrophy by reintroducing truncated forms of dystrophin into Duchenne patients. Long-term development of this project will focus on comparing how muscle tissue age in fish model of Duchenne and Becker with a particular interest on tissue fibrosis associated with muscle degeneration and the roles of matrix metalloproteinases in this process.