MAP5, CNRS UMR 8145, Universitxc3xa9 Paris Descartes, Paris, France.|Institut Curie, CNRS UMR 144, Paris, France.|Unitxc3xa9 de Mathxc3xa9matiques Pures et Appliquxc3xa9es, CNRS UMR 5669 and xc3xa9quipe-projet INRIA NUMED, xc3x89cole Normale Supxc3xa9rieure de Lyon, Lyon, France.|Laboratoire Jean Perrin and Laboratoire de Physique Thxc3xa9orique de la Matixc3xa8re Condensxc3xa9e, UMR 7600 CNRS /UPMC, Paris, France.|Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America.|Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America.|Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America.|Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America.|MAP5, CNRS UMR 8145, Universitxc3xa9 Paris Descartes, Paris, France.