RPLP1 and RPLP2 Are Essential Flavivirus Host Factors That Promote Early Viral Protein Accumulation
RPLP1 and RPLP2 Are Essential Flavivirus Host Factors That Promote Early Viral Protein Accumulation
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DOI：
10.1128/jvi.01706-16
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发表时间：
2017-02-01
影响因子：
5.4
通讯作者：
Bradrick, Shelton S.
中科院分区：
文献类型：
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作者：
Campos, Rafael K.;Wong, Benjamin;Bradrick, Shelton S.
黄病毒属包含多种节肢动物传播的病毒，对全球健康构成威胁，包括登革热病毒（DENV）、黄热病病毒（YFV）和寨卡病毒（ZIKV）。为了了解这些病毒如何在人类细胞中复制，我们之前进行了基因组规模的RNA干扰筛选，以确定候选宿主因子。在这些筛选中，我们确定核糖体蛋白 RPLP1 和 RPLP2 (RPLP1/2) 是 DENV 和 YFV 感染所需的最关键的推定宿主因子之一。 RPLP1/2 是通过与另一种核糖体蛋白 RPLP0 相互作用结合核糖体的磷蛋白，形成称为核糖体茎的结构。 RPLP1/2 被验证为两种人类细胞系（A549 肺腺癌细胞和 HuH-7 肝癌细胞）中 DENV、YFV 和 ZIKV 感染的重要宿主因子，以及埃及伊蚊的有效 DENV 感染的重要宿主因子。根据代谢标记确定，RPLP1/2 的耗尽对整体蛋白质合成造成中等程度的细胞系特异性影响。在 A549 细胞中，整体翻译增加，而在 HuH-7 细胞中则减少，尽管这两种影响都很温和。相比之下，RPLP1/2 敲除强烈减少早期 DENV 蛋白积累，表明病毒翻译中需要 RPLP1/2。此外，RPLP1/2 的敲除降低了外源转基因表达的 DENV 结构蛋白的水平。我们假设这些核糖体蛋白是通过病毒开放阅读框有效翻译延伸所必需的。总之，这项工作将 RPLP1/2 确定为翻译所需的关键黄病毒宿主因子。 重要性 黄病毒会引起人类的重要疾病。蚊子传播的黄病毒的例子包括登革热、黄热病和寨卡病毒。病毒需要大量的细胞因子来感染细胞，而核糖体在所有病毒感染中发挥着重要作用。核糖体是由RNA和蛋白质组成的复杂大分子机器，负责蛋白质的合成。我们鉴定了黄病毒感染人类细胞和蚊子所严格需要的两种特定核糖体蛋白：RPLP1 和 RPLP2 (RPLP1/2)。这些蛋白质是核糖体茎结构的一部分，有助于协调翻译的延伸阶段。我们发现黄病毒特别依赖于 RPLP1/2 的功能。我们的研究结果表明，核糖体组成是病毒翻译的重要因素，可能代表特定细胞 mRNA 翻译的调节层。
The Flavivirus genus contains several arthropod-borne viruses that pose global health threats, including dengue viruses (DENV), yellow fever virus (YFV), and Zika virus (ZIKV). In order to understand how these viruses replicate in human cells, we previously conducted genome-scale RNA interference screens to identify candidate host factors. In these screens, we identified ribosomal proteins RPLP1 and RPLP2 (RPLP1/2) to be among the most crucial putative host factors required for DENV and YFV infection. RPLP1/2 are phosphoproteins that bind the ribosome through interaction with another ribosomal protein, RPLP0, to form a structure termed the ribosomal stalk. RPLP1/2 were validated as essential host factors for DENV, YFV, and ZIKV infection in two human cell lines: A549 lung adenocarcinoma and HuH-7 hepatoma cells, and for productive DENV infection of Aedes aegypti mosquitoes. Depletion of RPLP1/2 caused moderate cell-line-specific effects on global protein synthesis, as determined by metabolic labeling. In A549 cells, global translation was increased, while in HuH-7 cells it was reduced, albeit both of these effects were modest. In contrast, RPLP1/2 knockdown strongly reduced early DENV protein accumulation, suggesting a requirement for RPLP1/2 in viral translation. Furthermore, knockdown of RPLP1/2 reduced levels of DENV structural proteins expressed from an exogenous transgene. We postulate that these ribosomal proteins are required for efficient translation elongation through the viral open reading frame. In summary, this work identifies RPLP1/2 as critical flaviviral host factors required for translation.IMPORTANCE Flaviviruses cause important diseases in humans. Examples of mosquito-transmitted flaviviruses include dengue, yellow fever and Zika viruses. Viruses require a plethora of cellular factors to infect cells, and the ribosome plays an essential role in all viral infections. The ribosome is a complex macromolecular machine composed of RNA and proteins and it is responsible for protein synthesis. We identified two specific ribosomal proteins that are strictly required for flavivirus infection of human cells and mosquitoes: RPLP1 and RPLP2 (RPLP1/2). These proteins are part of a structure known as the ribosomal stalk and help orchestrate the elongation phase of translation. We show that flaviviruses are particularly dependent on the function of RPLP1/2. Our findings suggest that ribosome composition is an important factor for virus translation and may represent a regulatory layer for translation of specific cellular mRNAs.