SARS-CoV BJ01株S蛋白基因突变对病毒感染性的影响

Effects of spike gene mutation on infectivity of SARS-CoV BJ01 strain

目的:构建SARS-CoV BJ01株病毒受体结合位点及七肽重复区的突变病毒,为深入探讨SARS-CoV的致病机制及设计抗病毒策略提供理论依据。方法:采取体外突变、分段克隆及拼接策略构建BJ01株突变病毒基因组全长cDNA,经体外转录获取突变病毒,观察突变病毒与原型病毒对细胞感染性的差异。结果:获得了S蛋白不同位点的突变病毒,受体结合位点的突变明显降低了BJ01株病毒对Vero E6细胞的感染性,突变病毒的蚀斑滴度比原型病毒降低3个数量级。结论:SARS-CoV BJ01株S蛋白的受体结合位点及七肽重复区与病毒的毒力及致病性密切相关。

Objective：To construct the mutated viruses targeted receptor-binding domain （RBD） and heptad repeats （HR2） regions of SARS-CoV B J01 strain, and provide evidence for exploration of SARS-CoV pathogenesis and design of new antiviral strategies. Methods： The full-length mutant cDNA of SARS-CoV BJ01 strain was constructed using in vitro mutation and ligation of cDNA fragments. After transcription in vitro and transfection into Vero E6 cells, differences were observed between the mutated viruses and wild-type one. Results and Conclusion： Both RBD mutants induced a mild CPE and the titers of RBD mutants were 3 orders of magnitude lower than those the wild-type virus. The regions of receptor binding and heptad repeats of the spike protein are responsible for virulence and pathogenesis of SARS-CoV.