About the Authors
Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
Department of Biological Sciences, Columbia University, New York, New York, United States of America
Friedrich Miescher Institute, Basel, Switzerland
The authors have declared that no competing interests exist.
CPC and KS conceived and designed the experiments and wrote the manuscript. CPC and RMW performed the experiments and analyzed the data. VDP, PC, and KS contributed reagents/materials/analysis tools.