1. Department of Cell Biology, School of Basic Medical Sciences, Peking University Stem Cell Research Center, Peking University Health Science Center, Peking University , Beijing 100191 , China
2. State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing 100101 , China
3. Institute for Stem Cell and Regeneration, Chinese Academy of Sciences , Beijing 100101 , China
4. Beijing Institute for Stem Cell and Regenerative Medicine , Beijing 100101 , China
5. MOE Engineering Research Center of Regenerative Medicine, School of Basic Medical Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Peking University Health Science Center and the MOE Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University , Beijing 100191 , China
6. Savaid Medical School, University of Chinese Academy of Sciences , Beijing 101408 , China