1. Université de Strasbourg, CNRS, GMGM UMR , 7156 Strasbourg, France
2. RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research , Wako, Saitama 351-0198, Japan
3. Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo , Kashiwa , Chiba 277-8561 , Japan
4. Institut Universitaire de France (IUF) , Paris , France