1. Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education); College of Chemistry and Molecular Sciences; State Key Laboratory of Virology; The Institute for Advanced Studies and Wuhan Institute of Biotechnology; Wuhan University; Wuhan 430072 P. R. China
2. Section on Molecular Morphogenesis; PCRM, NICHD, NIH; Bethesda MD 20892-5431 USA