Specificity and functional interplay between influenza virus PA-X and NS1 shutoff activity.
Specificity and functional interplay between influenza virus PA-X and NS1 shutoff activity.
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DOI：
10.1371/journal.ppat.1007465
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发表时间：
2018-11
期刊：
影响因子：
6.7
通讯作者：
Takimoto T
中科院分区：
文献类型：
--
作者：
Chaimayo C;Dunagan M;Hayashi T;Santoso N;Takimoto T
甲型流感病毒调节宿主抗病毒反应以促进病毒生长和致病性。通过病毒PA-X和NS 1蛋白，病毒能够抑制宿主蛋白质合成，称为“宿主关闭”。虽然这两种蛋白质是已知的诱导一般关闭，特异性的靶基因和它们的功能相互作用，在介导主机关闭没有完全阐明。在这项研究中，我们产生了四种重组流感A/加州/04/2009（pH 1 N1）病毒，其中含有影响活性PA-X和NS 1表达的突变。我们分析了病毒的生长，一般关闭活动，特异性的mRNA目标，和病毒基因表达。我们的研究结果表明，PA-X是减少病毒感染细胞中一般宿主蛋白表达的主要贡献者。有趣的是，我们对感染的人气道A549细胞的转录组分析表明，具有关闭活性的NS 1特异性靶向与干扰素（IFN）信号传导途径和细胞因子释放相关的宿主mRNA。靶mRNA的特异性在PA-X中不太明显，尽管它优先降解与细胞蛋白质代谢和蛋白质修复相关的基因。有趣的是，在存在关闭活性NS 1的情况下，PA-X也降解病毒mRNA，尤其是NS片段。表达关闭活性NS 1且PA-X表达量减少的病毒最有效地抑制人细胞中的抗病毒和先天免疫应答，表明流感病毒需要优化这两种关闭蛋白的贡献以规避宿主应答以实现其最佳生长。病毒感染诱导广泛的宿主防御反应，如先天免疫反应和炎症。一些病毒表达辅助蛋白以诱导宿主蛋白质合成的全面关闭，这是病毒对抗宿主抗病毒活性和免疫应答的主要策略之一。甲型流感病毒表达两种蛋白质，NS 1和PA-X，以诱导一般关闭。它们的作用机制不同; NS 1与CPSF 30相互作用并阻断宿主前体mRNA的3 '端加工，而PA-X通过其内切酶结构域降解靶mRNA。重要的是，NS 1和PA-X活性在病毒分离株之间存在差异，表明这两种蛋白质之间存在功能性相互作用。在这项研究中，我们拯救并表征了2009年大流行的H1N1突变病毒与各种NS 1和PA-X关闭活动。我们的数据表明，PA-X是宿主蛋白质合成全面关闭的主要贡献者，而NS 1特异性靶向参与宿主先天反应和细胞因子反应的基因。我们的数据还表明，病毒的mRNA，特别是NS基因可以PA-X诱导的降解的目标，如果NS 1关闭活性是活跃的。这项研究表明NS 1和PA-X蛋白之间的功能相互作用，这是最佳病毒生长所必需的。
Influenza A viruses modulate host antiviral responses to promote viral growth and pathogenicity. Through viral PA-X and NS1 proteins, the virus is capable of suppressing host protein synthesis, termed “host shutoff.” Although both proteins are known to induce general shutoff, specificity of target genes and their functional interplay in mediating host shutoff are not fully elucidated. In this study, we generated four recombinant influenza A/California/04/2009 (pH1N1) viruses containing mutations affecting the expression of active PA-X and NS1. We analyzed viral growth, general shutoff activity, specificity of mRNA targets, and viral gene expressions. Our results showed that PA-X was the major contributor in reducing general host protein expression in the virus-infected cells. Intriguingly, our transcriptomic analysis from infected human airway A549 cells indicate that shutoff-active NS1 specifically targeted host mRNAs related to interferon (IFN) signaling pathways and cytokine release. Specificity of target mRNAs was less evident in PA-X, although it preferentially degraded genes associated with cellular protein metabolism and protein repair. Interestingly, in the presence of shutoff-active NS1, PA-X also degraded viral mRNAs, especially NS segments. The virus expressing shutoff-active NS1 with reduced amount of PA-X expression most efficiently suppressed antiviral and innate immune responses in human cells, indicating that influenza virus needs to optimize the contribution of these two shutoff proteins to circumvent host responses for its optimum growth. Virus infection induces a wide range of host defense responses, such as the innate immune response and inflammation. Some viruses express accessory proteins to induce general shutoff of host protein synthesis, which is one of the major viral strategies to counteract host antiviral activity and immune response. Influenza A virus expresses two proteins, NS1 and PA-X, to induce general shutoff. Their mechanism of action is different; NS1 interacts with CPSF30 and blocks the 3’end processing of host pre-mRNAs, while PA-X degrades target mRNAs through its endonuclease domain. Importantly, the NS1 and PA-X activities differ among the virus isolates, suggesting a functional interplay between these two proteins. In this study, we rescued and characterized 2009 pandemic H1N1 mutant viruses with various NS1 and PA-X shutoff activities. Our data showed that PA-X was the major contributor of general shutoff of host protein synthesis, while NS1 specifically targeted genes involved in host innate response and cytokine response. Our data also suggest that viral mRNAs, especially the NS gene can be the target of PA-X induced degradation if NS1 shutoff activity is active. This study indicates a functional interplay between NS1 and PA-X proteins, which is required for optimum viral growth.
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DOI：
10.1038/nri3665
发表时间：
2014-05
期刊：
Nature reviews. Immunology
影响因子：
--
作者：
通讯作者：
--
影响因子：
64.5
作者：
Fauci AS
通讯作者：
Fauci AS
流感A/香港/156/1997（H5N1）病毒NS1基因突变F103L和M106I都会增加IFN拮抗，毒力和细胞质定位，但与RIG-I和CPSF30的结合有所不同。
影响因子：
4.8
作者：
Dankar SK;Miranda E;Forbes NE;Pelchat M;Tavassoli A;Selman M;Ping J;Jia J;Brown EG
通讯作者：
Brown EG
影响因子：
5.4
作者：
Hayashi, Tsuyoshi;MacDonald, Leslie A.;Takimoto, Toru
通讯作者：
Takimoto, Toru
影响因子：
5.4
作者：
Hayashi, Tsuyoshi;Chaimayo, Chutikarn;Takimoto, Toru
通讯作者：
Takimoto, Toru