About the Authors
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
Department of Pathology, University of California, San Francisco, San Francisco, California, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: BP. Performed the experiments: OG MJB. Analyzed the data: JH HC BP. Contributed reagents/materials/analysis tools: FLB PAK BP. Wrote the paper: JH GYL JWG PAK BP.