Nucleolin Promotes IRES-Driven Translation of Foot-and-Mouth Disease Virus by Supporting the Assembly of Translation Initiation Complexes
Nucleolin Promotes IRES-Driven Translation of Foot-and-Mouth Disease Virus by Supporting the Assembly of Translation Initiation Complexes
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核仁素通过支持翻译起始复合物的组装来促进 IRES 驱动的口蹄疫病毒翻译
DOI：
10.1128/jvi.00238-21
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发表时间：
2021-07-01
影响因子：
5.4
通讯作者：
Guo, Huichen
中科院分区：
文献类型：
--
作者：
Han, Shichong;Wang, Xiaojia;Guo, Huichen
核仁素（NCL）是一种应激反应性RNA结合蛋白，参与了含有内部核糖体进入位点（IRES）的mRNA的翻译，该mRNA编码参与细胞增殖、致癌和病毒感染（I型IRES）的蛋白质。然而，NCL参与IRES驱动的翻译的机制的细节迄今尚未被描述。在这里，我们确定了NCL作为一种蛋白质，与口蹄疫病毒（FMDV）的IRES相互作用，这是一种II型IRES。我们还在体外绘制了FMDV IRES和NCL内的相互作用区域。我们发现，NCL作为口蹄疫病毒IRES驱动的翻译，但不是散装细胞或水泡性口炎病毒帽依赖性翻译的实质性调节剂。NCL还调节Seneca Valley病毒（III型样IRES）和经典猪瘟病毒（III型IRES）的翻译和感染，这表明其功能在不相关的含IRES的病毒中是保守的。我们还表明，NCL通过直接调节病毒蛋白质的产生和间接调节FMDV RNA的合成来影响病毒复制。重要的是，我们观察到在FMDV感染期间NCL的细胞质再定位是病毒IRES驱动的翻译的实质性步骤，并且NCL通过将翻译起始复合物募集到病毒IRES来特异性地促进翻译过程的起始阶段。最后，证实了NCL在FMDV致病性中的功能重要性。综上所述，我们的研究结果demonstrate一个特定的功能，NCL在选择性mRNA翻译，并确定了一个目标的发展，一个广谱类的抗病毒interventions.IMPORTANCE口蹄疫篡夺细胞翻译机器启动病毒蛋白质合成通过IRES元件驱动的机制。它允许病毒关闭大量的细胞翻译，同时为其自身的基因表达提供优势。由于其自身基因组的编码能力有限，FMDV已经进化出一种机制来劫持宿主蛋白质以促进宿主翻译机器的募集，这一过程仍然没有得到很好的理解。在这里，我们确定了核仁素（NCL）作为一个积极的调节器的IRES驱动的翻译FMDV。我们的研究支持了一个模型，其中NCL从细胞核重新定位到细胞质的过程中的FMDV感染，其中细胞质NCL促进FMDV IRES驱动的翻译，通过桥接翻译起始复合物与病毒IRES。我们的研究证实了NCL在含IRES病毒的翻译起始中的一个先前未表征的作用，这对广泛的抗病毒干预措施的发展具有重要意义。
Nucleolin (NCL), a stress-responsive RNA-binding protein, has been implicated in the translation of internal ribosome entry site (IRES)-containing mRNAs, which encode proteins involved in cell proliferation, carcinogenesis, and viral infection (type I IRESs). However, the details of the mechanisms by which NCL participates in IRES-driven translation have not hitherto been described. Here, we identified NCL as a protein that interacts with the IRES of foot-and-mouth disease virus (FMDV), which is a type II IRES. We also mapped the interactive regions within FMDV IRES and NCL in vitro. We found that NCL serves as a substantial regulator of FMDV IRES-driven translation but not of bulk cellular or vesicular stomatitis virus cap-dependent translation. NCL also modulates the translation of and infec-tion by Seneca Valley virus (type III-like IRES) and classical swine fever virus (type III IRES), which suggests that its function is conserved in unrelated IRES-containing viruses. We also show that NCL affects viral replication by directly regulating the production of viral proteins and indirectly regulating FMDV RNA synthesis. Importantly, we observed that the cytoplas-mic relocalization of NCL during FMDV infection is a substantial step for viral IRES-driven translation and that NCL specifically promotes the initiation phase of the translation process by recruiting translation initiation complexes to viral IRES. Finally, the functional importance of NCL in FMDV pathogenicity was confirmed in vivo. Taken together, our findings demon -strate a specific function for NCL in selective mRNA translation and identify a target for the development of a broad-spectrum class of antiviral interventions.IMPORTANCE FMDV usurps the cellular translation machinery to initiate viral protein synthesis via a mechanism driven by IRES elements. It allows the virus to shut down bulk cellular translation, while providing an advantage for its own gene expression. With limited coding capacity in its own genome, FMDV has evolved a mechanism to hijack host proteins to promote the recruitment of the host translation machinery, a process that is still not well understood. Here, we identified nucleolin (NCL) as a pos-itive regulator of the IRES-driven translation of FMDV. Our study supports a model in which NCL relocalizes from the nucleus to the cytoplasm during the course of FMDV infection, where the cytoplasmic NCL promotes FMDV IRES-driven translation by bridging the translation initiation complexes with viral IRES. Our study demonstrates a previously uncharacterized role of NCL in the translation initiation of IRES-contain-ing viruses, with important implications for the development of broad antiviral interventions.