1. State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Datun Road 15, Beijing 100101, China
2. University of Chinese Academy of Sciences, Beijing 100080, China
3. School of Life Sciences, Tsinghua University, Beijing 100084, China
4. Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
5. Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892