1. Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.
2. Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
3. Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, Cambridge, MA 02142, USA.
4. Department of Cell Biology, John Hopkins University School of Medicine, Baltimore, MD 21205, USA.
5. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, USA.
6. Department of Pathology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
7. Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.