a pax3dmrt2myf5 regulatory cascade functions at the onset of myogenesispax3dmrt2myf5监管出现肌发生级联功能.pdfVIP

A Pax3/Dmrt2/Myf5 Regulatory Cascade Functions at the Onset of Myogenesis 1 1 ´ 2,3 ´ ´ 2,3 Takahiko Sato , Didier Rocancourt , Luıs Marques , Solveig Thorsteinsdottir , Margaret Buckingham1* ´ ´ 1 Department of Developmental Biology, Centre National de la Recherche Scientifique, Unite de Recherche Associee 2578, Institut Pasteur, Paris, France, 2 Department of Animal Biology and Centre for Environmental Biology, Faculty of Sciences, University of Lisbon, Lisbon, Portugal, 3 Gulbenkian Institute of Science, Oeiras, Portugal Abstract All skeletal muscle progenitor cells in the body derive from the dermomyotome, the dorsal epithelial domain of developing somites. These multipotent stem cells express Pax3, and this expression is maintained in the myogenic lineage where Pax3 plays an important role. Identification of Pax3 targets is therefore important for understanding the mechanisms that underlie the onset of myogenesis. In a microarray screen of Pax3-GFP sorted cells, with analysis on Pax3 gain and loss of function genetic backgrounds, we identify Dmrt2, expressed in the dermomyotome, as a Pax3 target. In vitro gel shift analysis and chromatin immunoprecipitation with in vivo extracts show that Pax3 binds to a conserved 286 bp sequence, situated at 218 kb from Dmrt2. This sequence directs reporter transgene expression to the somite, and this is severely affected when the Pax3 site is mutated in the context of the locus. In Dmrt2 mutant embryos, somite maturation is perturbed and the skeletal muscle of the myotome is abnormal. We now report