About the Authors
Department of Biological Sciences and Department of Cell and Developmental Biology, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, United States of America
Department of Cell and Developmental Biology, Seoul National University, Seoul, Republic of Korea
The authors have declared that no competing interests exist.
Conceived and designed the experiments: ND KB. Performed the experiments: ND. Analyzed the data: ND. Contributed reagents/materials/analysis tools: MN SL. Wrote the paper: ND KB.