Jesús Gil

Present address: Molecular Oncology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3PX, UK

David Bernard

Present address: Free University of Brussels, Laboratory of Molecular Virology, Faculty of Medicine, Brussels, NULL 1070, Belgium

Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK

Jesús Gil, David Bernard, Dolores Martínez & David Beach

Correspondence to Jesús Gil.