[1] Barcelona Inst Sci & Technol, Ctr Genom Regulat CRG, Barcelona, Spain
[2] Ist Italiano Tecnol IIT, RNA Syst Biol Lab, Ctr Human Technol, Genoa, Italy
[3] Columbia Univ, Dept Chem, New York, NY 10027 USA
[4] Kings Coll London, 3UK DRI Ctr, Maurice Wohl Inst, Dept Clin & Basic Neurosci, London, England
[5] Barcelona Inst Sci & Technol, ICREA, Barcelona, Spain
[6] Sapienza Univ, Dipartimento Biol & Biotecnol, Rome, Italy