Influenza A/Hong Kong/156/1997(H5N1) virus NS1 gene mutations F103L and M106I both increase IFN antagonism, virulence and cytoplasmic localization but differ in binding to RIG-I and CPSF30.
Influenza A/Hong Kong/156/1997(H5N1) virus NS1 gene mutations F103L and M106I both increase IFN antagonism, virulence and cytoplasmic localization but differ in binding to RIG-I and CPSF30.
复制标题
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。
DOI：
10.1186/1743-422x-10-243
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发表时间：
2013-07-25
期刊：
影响因子：
4.8
通讯作者：
Brown EG
中科院分区：
文献类型：
--
作者：
Dankar SK;Miranda E;Forbes NE;Pelchat M;Tavassoli A;Selman M;Ping J;Jia J;Brown EG
甲型流感病毒从禽类到哺乳动物宿主转换的遗传基础在很大程度上是未知的。从家禽传播的人A/HK/156/1997 （H5N1）病毒具有NS1基因突变F103L + M106I，这是肺炎小鼠模型的毒力决定因素；然而，他们各自的角色尚未确定。新兴的A/Shanghai/patient1/2013（H7N9）样病毒也具有这些突变，这可能有助于其毒性和切换物种的能力。通过反向遗传和定点诱变技术，构建了NS1突变病毒。小鼠感染评估了毒力、病毒产量、组织感染和IFN诱导。评估NS1蛋白的亚细胞分布、IFN拮抗（小鼠和人）、CPSF30和RIG-I结构域结合、宿主转录（微阵列）特性；评估103L和106I突变体的自然流行率。F103L和M106I突变通过介导肺泡组织感染，使>的感染量增加100倍，分别将致死剂量降低了800倍和3200倍，从而增加了毒力。106I NS1突变体失去了CPSF结合，而103L突变体保持了CPSF结合，这与宿主基因在人类细胞中普遍表达的增加减少有关，而在小鼠细胞中没有。每个突变都正向调节小鼠细胞中IFN诱导的抑制和人类细胞中IFN-β启动子的激活，但在人类细胞中没有组合，表明负上位性。F103L和M106I突变恢复了小鼠细胞中H5N1 NS1细胞质定位的缺陷。人H1N1和H3N2 NS1蛋白结合到CARD、解旋酶和RD RIG-I结构域，而具有相同共识的103F和106M突变的H5N1 NS1不结合这些结构域，分别被M106I或F103L突变完全或部分恢复。H5N1 NS1蛋白的F103L和M106I突变各自增加了IFN的拮抗作用，并介导了小鼠的间质性肺炎，这与细胞质定位增加和宿主因子结合改变有关。这些突变可能有助于以前的高致病性H5N1和最近的低致病性H7N9和H6N1 （NS1-103L+106M）病毒转换宿主并在人类中引起疾病。
The genetic basis for avian to mammalian host switching in influenza A virus is largely unknown. The human A/HK/156/1997 (H5N1) virus that transmitted from poultry possesses NS1 gene mutations F103L + M106I that are virulence determinants in the mouse model of pneumonia; however their individual roles have not been determined. The emergent A/Shanghai/patient1/2013(H7N9)-like viruses also possess these mutations which may contribute to their virulence and ability to switch species. NS1 mutant viruses were constructed by reverse genetics and site directed mutagenesis on human and mouse-adapted backbones. Mouse infections assessed virulence, virus yield, tissue infection, and IFN induction. NS1 protein properties were assessed for subcellular distribution, IFN antagonism (mouse and human), CPSF30 and RIG-I domain binding, host transcription (microarray); and the natural prevalence of 103L and 106I mutants was assessed. Each of the F103L and M106I mutations contributes additively to virulence to reduce the lethal dose by >800 and >3,200 fold respectively by mediating alveolar tissue infection with >100 fold increased infectious yields. The 106I NS1 mutant lost CPSF binding but the 103L mutant maintained binding that correlated with an increased general decrease in host gene expression in human but not mouse cells. Each mutation positively modulated the inhibition of IFN induction in mouse cells and activation of the IFN-β promoter in human cells but not in combination in human cells indicating negative epistasis. Each of the F103L and M106I mutations restored a defect in cytoplasmic localization of H5N1 NS1 in mouse cells. Human H1N1 and H3N2 NS1 proteins bound to the CARD, helicase and RD RIG-I domains, whereas the H5N1 NS1 with the same consensus 103F and 106M mutations did not bind these domains, which was totally or partially restored by the M106I or F103L mutations respectively. The F103L and M106I mutations in the H5N1 NS1 protein each increased IFN antagonism and mediated interstitial pneumonia in mice that was associated with increased cytoplasmic localization and altered host factor binding. These mutations may contribute to the ability of previous HPAI H5N1 and recent LPAI H7N9 and H6N1 (NS1-103L+106M) viruses to switch hosts and cause disease in humans.