1 Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address: shxu@zju.edu.cn.
2 Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
3 Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.
4 Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA. Electronic address: chisholm@ucsd.edu.