Differential nucleocytoplasmic shuttling of the nucleoprotein of influenza a viruses and association with host tropism
Differential nucleocytoplasmic shuttling of the nucleoprotein of influenza a viruses and association with host tropism
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甲型流感病毒核蛋白的差异核细胞质穿梭及其与宿主向性的关联
DOI：
10.1111/cmi.12692
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发表时间：
2017-05-01
影响因子：
3.4
通讯作者：
Liu, Wenjun
中科院分区：
文献类型：
--
作者：
Li, Jing;Zheng, Weinan;Liu, Wenjun
甲型流感病毒的核蛋白（NP）在病毒复制、感染性和宿主适应中起着至关重要的作用。作为病毒核糖核蛋白复合物（viral ribonucleoprotein complex，vRNP）的主要组成部分，NP可启动vRNP在宿主细胞的细胞核和细胞质之间穿梭。然而，从H1N1甲型流感病毒的核质穿梭的特点仍然不清楚。本研究对H1N1流感病毒核蛋白的亚细胞定位及相关关键残基进行了鉴定和评价。流感病毒A/WSN/33（H1N1; WSN）的NP在核内聚集较A/Anhui/1/2013（H7N9; AH）和A/chicken/Shandong/lx 1023/2007（H9 N2; SD）明显。来自WSN NP的位于NLS 1中的NP残基K4和位于NES 3中的残基F253在H7N9和H9 N2中不保守，它们分别编码Q4和I253。重要的是，这些残基通过与CRM 1和importin-α相互作用参与NP核质穿梭的调节。此外，253位残基在病毒复制中也起重要作用，导致vRNP聚合酶活性增加，以及小鼠细胞嗜性和致病性的改变。目前的数据显示，与WSN-NP中的K4和F253残基相比，来自H7N9的NP的Q4和I253残基在增强NP和vRNP活性的细胞质积累中具有关键作用。此外，WSN NP中的F253 I取代改变了感染小鼠的存活率和感染禽源细胞（DF-1）的生长曲线。目前的数据表明，F253 I突变导致病毒在小鼠中的致病性减弱，细胞嗜性改变。本研究证明了H1N1病毒WSN和其他甲型流感病毒株之间的亚细胞NP运输过程的差异，以及揭示了负责这种差异的机制。
The nucleoprotein (NP) of influenza A virus plays a crucial role in virus replication, infectivity, and host adaptation. As a major component of the viral ribonucleoprotein complexes (vRNP), NP initiates vRNP shuttling between the nucleus and cytoplasm in the host cell. However, the characteristics of the nucleocytoplasmic shuttling of NP from H1N1 influenza A virus still remain unclear. In the present study, the subcellular localization and the related key residues of the H1N1 influenza virus NP were identified and evaluated. The NP of influenza virus A/WSN/33 (H1N1; WSN) displayed a more obvious nuclear accumulation than A/Anhui/1/2013 (H7N9; AH) and A/chicken/Shandong/lx1023/2007 (H9N2; SD). NP residue K4, located in NLS1, and residue F253, located in NES3, from WSN NP are not conserved in H7N9 and H9N2, which instead encode Q4 and I253, respectively. Crucially, these residues are involved in the regulation of NP nucleocytoplasmic shuttling through interactions with CRM1 and importin‐α. Moreover, residues at position 253 also play important roles in the replication of the virus, resulting in an increase in vRNP polymerase activity and an alteration of the cell tropism and pathogenicity in mice. The present data revealed a pivotal role of the Q4 and I253 residues of NP from H7N9 in enhancing the cytoplasmic accumulation of NP and vRNP activity compared to the K4 and F253 residues in WSN‐NP. In addition, an F253I substitution in the NP of WSN altered the survival ratio of infected mice and the growth curve in infected avian‐origin cells (DF‐1). The current data indicate that the F253I mutation results in attenuated pathogenicity of the virus in mice and altered cell tropism. The present study demonstrated the dissimilarity in subcellular NP transport processes between H1N1 virus WSN and other influenza A virus strains, as well as uncovered the mechanism responsible for this difference.