1. Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France and Paris Sciences & Lettres Research University, 75231 Paris Cedex 05, France
2. Institut Jacques Monod, CNRS UMR7592, 75013 Paris, France
3. Department of Genetics and Developmental Biology, CNRS UMR 3215, INSERM U934, Institut Curie, 75005 Paris, France