中国台湾地区H6N1禽流感病毒血凝素基因的适应性进化  

Adaptive Evolution of the Hemagglutinin Genes of the H6N1Avian Influenza Virus in Taiwan,China

作　　者：杨建课[1] 朱晓蕾[1] 汪萍[1] 高继光[1] 

机构地区：[1]皖南医学院医学生物学教研室,芜湖241002

出　　处：《病毒学报》2014年第5期529-534,共6页Chinese Journal of Virology

基　　金：省级优秀青年人才基金(WK200921);校重点科研项目(WK2014Z02)

摘　　要：2013年在中国台湾地区发现了第一例人感染H6N1禽流感,研究该地区H6N1病毒血凝素基因(HA)的适应性进化特征和种群动力学,将为人感染H6N1病毒的来源、进化及致病机制的理解提供更多信息,为进一步的研究和防治提供一定帮助。本研究从Flu和GISAID两大数据库中获得中国台湾地区所有已释放的H6N1病毒的HA序列,构建系统发育树和进化动力曲线,并推测其进化速率,分析其适应性进化特征。结果表明中国台湾地区H6N1病毒的HA有五种类型,其中人感染H6N1病毒的HA所属类型为目前当地优势类型;该病毒种群于1971年底第一次扩张,2008年迅速减少,而后又略有增加。同时在长期的进化过程中,3个位点受到正选择作用的影响,增加了病毒的适应能力;89个位点受负选择作用的影响,它们在病毒的复制、流行中可能具有重要的功能;其中剪切位点附近的329位所受负选择作用强烈(PSLAC0.001、PFEL0.000、BFREL137),此位点可能与病毒毒力有关。中国台湾地区H6N1病毒的HA已发生了明显的适应性进化,具有发生疫情的可能性,人们应高度重视,并能及时给与监测和防治。In Taiwan, the first human-infecting H6N1 avian influenza virus was isolated in 2013. To better understand the origin, evolutionary relationship and pathogenesis of the H6N1 virus, we studied the adap- tive evolution and evolutionary dynamics of the hemagglutinin （HA） genes of the H6N1 virus in Taiwan. We felt that such studies woud contribute to the further study and control of the virus. Datasets were gained from the Flu and Global Initiative on Sharing All Influenza Data （GISAID） databases. Then, phy- logenetic trees and evolutionary dynamics were reconstructed. The evolutionary rate and characterization of adaptive evolution were analyzed by bioinformatic methods. Results indicated that the HA genes of H6N1 in Taiwan were divided into at least five types, and that the new types that the infected human H6N1 be- longed to could be local advantage type at present. Evolutionary dynamics revealed the viral population ex- panded first at the end of 1971, reduced sharply in 2008, and then increased slightly. Three sites were i- dentified under positive selection, suggesting that various sites might increase the adaptive ability of the vi- rus. Eighty-nine sites were under negative selection, revealing that these sites might play an important role in the replication and epidemiology of the virus. Interestingly, site 329 upstream from the cleavage site was also under negative selection, suggesting that this site might be associated with the virulence of H6N1. These data suggest that the HA genes of the Taiwan Residents H6N1 virus have been undergoing adaptive evolu- tion, and that an outbreak may occur again. Hence, more attention should be paid to the identified sites, to enable timely monitoring and control of a future epidemic.

关 键 词：人感染H6N1禽流感病毒 适应性进化 进化动力学 血凝素 生物信息学方法 

分 类 号：R373.9[医药卫生—病原生物学]