BioMed Central Page 1 of 10 (page number not for citation purposes) BMC Microbiology Open Access Research article The expression and antigenicity of a truncated spike-nucleocapsid fusion protein of severe acute respiratory syndrome-associated coronavirus Feng Mu†1, Dongsheng Niu†2, Jingsong Mu†3, Bo He1, Weiguo Han2, Baoxing Fan4, Shengyong Huang1, Yan Qiu5, Bo You1 and Weijun Chen*1 Address: 1Beijing Institute of Genomics, Chinese Academy of Sciences, Airport industry B6, Beijing, 101300, PR China, 2State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Millitary Medical Sciences, Dongdajie Road 20, Beijing, 100071, PR China, 3302 Hospital, Fengtai Road 26, Beijing 100853, PR China, 4301 Hospital, Fuxing Road 28, Beijing 100039, PR China and 5Beijing Red Cross Blood Center, North middle Sanhuan Road 37, Beijing 100088, PR China Email: Feng Mu -