About the Authors
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
Developmental Biochemistry, Biocentre, University of Wuerzburg, Wuerzburg, Germany
Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: FL. Performed the experiments: XT JC JL CMK S-YL JH CW. Analyzed the data: XT FL. Contributed reagents/materials/analysis tools: KS RK MG. Wrote the paper: XT FL.