Molecular evolution of West Nile virus in a northern temperate region: Connecticut, USA 1999-2008.
Molecular evolution of West Nile virus in a northern temperate region: Connecticut, USA 1999-2008.
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西尼罗河病毒在北部温带地区的分子进化：美国康涅狄格州，1999- 2008年。
DOI：
10.1016/j.virol.2011.06.006
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发表时间：
2011-08-15
期刊：
影响因子：
3.7
通讯作者：
Henn MR
中科院分区：
文献类型：
--
作者：
Armstrong PM;Vossbrinck CR;Andreadis TG;Anderson JF;Pesko KN;Newman RM;Lennon NJ;Birren BW;Ebel GD;Henn MR
西尼罗河病毒(WNV)已经在美国东北部站稳脚跟，自1999年进入北美以来，每年夏天都会重新出现。为了确定西尼罗河病毒是在当地越冬还是每年补种，我们通过系统发育分析检查了康涅狄格州连续10个传播季节的病毒谱系持续和替换模式。此外，我们还比较了不同西尼罗河病毒分离株的全长蛋白质编码序列，以寻找趋同和适应性进化的证据。从康涅狄格州采集的病毒通过隔离一年被分离到许多得到良好支持的亚分支中，很少有分支持续≥2年。相似的病毒株分散在该州的不同地点，而在一个传播季节内，同一地点出现了不同的病毒株，这意味着病毒的广泛移动和快速定植。在人群中出现了许多氨基酸替换，但只有一个变化，即包膜蛋白第159位的V→A永久固定。在独立的谱系中发现了几个平行进化的例子，包括NS4A蛋白中似乎被积极选择的一个氨基酸变化。我们的结果表明，西尼罗河病毒的每年重新出现是由病毒的重新传入和局部越冬共同驱动的。尽管西尼罗河病毒正在进化，但大多数氨基酸变异发生的频率很低，在病毒群体中是短暂的。
West Nile virus (WNV) has become firmly established in northeastern U.S., reemerging every summer since its introduction into North America in 1999. To determine whether WNV overwinters locally or is reseeded annually, we examined the patterns of viral lineage persistence and replacement in Connecticut over 10 consecutive transmission seasons by phylogenetic analysis. In addition, we compared the full protein coding sequence among WNV isolates to search for evidence of convergent and adaptive evolution. Viruses sampled from Connecticut segregated into a number of well-supported subclades by year of isolation with few clades persisting ≥2 years. Similar viral strains were dispersed in different locations across the state and divergent strains appeared within a single location during a single transmission season, implying widespread movement and rapid colonization of virus. Numerous amino acid substitutions arose in the population but only one change, V→A at position 159 of the envelope protein, became permanently fixed. Several instances of parallel evolution were identified in independent lineages, including one amino acid change in the NS4A protein that appears to bepositively selected. Our results suggest that annual reemergence of WNV is driven by both reintroduction and local-overwintering of virus. Despite ongoing evolution of WNV, most amino acid variants occurred at low frequencies and were transient in the virus population.