Scientific Reports 4, Article number: 3963 (2014); Published: 4 February 2014; Updated: 4 December 2014

The Acknowledgements section was omitted from the Article. It should read:

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant No. 8140 973, to Dr. Fei Gao), the Fundamental Research Funds for the Central Universities of China (Grant NO. 21614304, to Dr. Fei Gao) and the Medical Scientific Research Foundation of Guangdong Province of China (Grant No. B2014222, to Dr. Fei Gao), the National Natural Science Foundation of China (Grant No. 81172587 and 81372896, to D. Xiao).