About the Authors
Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: CTT YW VAZ. Performed the experiments: CTT YW AC. Analyzed the data: CTT YW AC. Contributed reagents/materials/analysis tools: CTT YW AC. Wrote the paper: CTT YW AC VAZ.