1. Department of Cell Biology; Howard Hughes Medical Institute; Kavli Institute for Neuroscience; Program for Cellular Neuroscience, Neurodegeneration, and Repair; and Section of Endocrinology and Metabolism, Department of Internal Medicine; Yale University School of Medicine, New Haven, CT 06510
2. Department of Biochemistry, Yong Loo Lin School of Medicine, and National University of Singapore Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456
3. Department of Embryology, Carnegie Institution, Baltimore, MD 21218