SARS-CoV由果子狸向人类跨种传播中S蛋白的适应性进化研究  

Adaptive evolution of the Spike Gene of SARS Coronavirus during interspecies transmission from palm civet to human

作　　者：张驰宇[1] 魏继福[2] 

机构地区：[1]江苏大学医学技术学院,江苏镇江212001 [2]江苏省人民医院临床试验研究中心,江苏南京210029

出　　处：《江苏大学学报（医学版）》2006年第5期374-379,共6页Journal of Jiangsu University：Medicine Edition

基　　金：国家自然科学基金资助项目(30600352);江苏省自然科学基金-创新人才启动项目(BK2006550);江苏大学高级人才启动项目(2281270002)

摘　　要：目的:研究SARS-CoV表面S蛋白由动物向人类跨种传播过程中的适应性进化过程。方法:用系统进化树构建和群体遗传学方法,对100个S基因序列进行了分析。这些序列均从GenBank获得,并能反映整个SARS流行期。结果:依据系统进化树和流行病学资料,将SARS病毒分为三个流行群:02-04跨种传播群、03-早中期流行群和03-晚期流行群。它们分别代表SARS-CoV克服种间障碍实现跨种传播阶段、进入人类后的最初适应阶段以及在人类中建立感染后的阶段。在前两个流行群中,S蛋白受到了阳性选择压力,而在03晚期流行群中却遭受了很强的负选择压力。三个流行群选择压力的比较显示,SARS-CoVs从动物向人类跨种传播过程中,S蛋白受到的阳性选择压力依次减小。结论:从最初的阳性选择到最后的负选择,S蛋白经历了变化的自然选择压力。这种变化的选择压力不仅反映了SARS-CoV由动物向人类跨种传播的适应性进化过程,也为研究其他病毒的跨种传播机制提供重要线索。Objective： To investigate the adaptive evolution of spike （S） protein in interspecies transmission of SARS-CoV from animals to human. Methods： A total of 100 S gene sequences were retrieved from the GenBank and analyzed using evolutionary bioinformatics methods. Results： According to phylogenetic tree of S genes and epidemiological investigation, SARS outbreak was divided into three epidemic groups： 02-04 interspecies epidemic, 03-early-mid epidemic, and 03-1ate epidemic groups. Positive selection was detected in former two groups, which represent the course of SARS-CoV interspecies transmission and viral adaptation to human, respectively, whereas demic group. The comparison of selective pressures purifying between selection was detected in 03-1ate phase epithree groups showed that positive selective pressure decreased from 02-04 interspecies epidemic group to 03-1ate epidemic group, suggesting that S protein experiences a step-by-step adaptation process to human cellular receptor. Conclusion： The variation of positive selective pressures from initial positive selection to eventual purifying selection not only represents the adaptive evolution of S protein from animals to human, but also provides a good clue to investigate the interspecies transmission of other viruses.

关 键 词：SARS-COV S蛋白 适应性进化 阳性选择 跨种传播 流行期 

分 类 号：R373.9[医药卫生—病原生物学]