1. State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University , Beijing , China
2. Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University , Beijing , China
3. MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University , Beijing , China
4. Centre for Life Sciences, Peking University , Beijing 100871, China