Infectious Bursal Disease Virus Hijacks Endosomal Membranes as the Scaffolding Structure for Viral Replication
Infectious Bursal Disease Virus Hijacks Endosomal Membranes as the Scaffolding Structure for Viral Replication
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DOI：
10.1128/jvi.01964-17
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发表时间：
2018-06-01
影响因子：
5.4
通讯作者：
Ruth Delgui, Laura
中科院分区：
文献类型：
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作者：
Cecilia Gimenez, Maria;Adriana Zanetti, Flavia;Ruth Delgui, Laura
双链RNA病毒是双链RNA（dsRNA）病毒组的非常规成员，其特征在于缺乏转录活性内核。相反，双RNA病毒颗粒将其基因组组织在由dsRNA片段、dsRNA结合VP 3蛋白和病毒编码的RNA依赖性RNA聚合酶（RdRp）组成的核糖核蛋白复合物（RNP）中。这种和其他结构特征表明双RNA病毒可能遵循与呼肠孤病毒科成员完全不同的复制程序，支持双RNA病毒是单链阳性RNA（+ssRNA）和dsRNA病毒之间进化联系的假设。在这里，我们证明了传染性法氏囊病病毒（IBDV），双RNA病毒科的一个典型成员，劫持感染细胞的内体膜通过相互作用的病毒蛋白，VP 3，与这些隔间的胞质小叶上的磷脂复制。采用突变方法，我们证明VP 3结构域PATCH 2（P2）介导VP 3与内体膜的结合。为了确定VP 3 P2在病毒复制周期中的作用，我们使用稳定过表达VP 3 P2的禽类细胞用于IBDV感染。重要的是，在稳定过表达VP 3 P2的细胞中，细胞内和细胞外病毒产量以及VP 2病毒衣壳蛋白的细胞内水平显著降低。总之，我们的结果表明，VP 3与内体的关联在IBDV复制周期中具有相关作用。这份报告提供了直接的实验证据，膜室，如内体所需的dsRNA病毒复制。这些结果也支持了先前提出的双RNA病毒作为+ssRNA和dsRNA病毒之间进化联系的作用。传染性法氏囊病（IBD;也称为Gumboro病）是一种急性、高度传染性的免疫抑制疾病，影响雏鸡并在全球范围内传播。IBD的病原体是传染性法氏囊病病毒（IBDV）。该病毒破坏中枢免疫器官（法氏囊），导致免疫抑制和鸡对疫苗的反应降低，从而增加其对其他病原体的易感性。IBDV属于双核糖核酸病毒科（Birnaviridae），由双链RNA病毒的非常规成员组成，其复制策略的研究很少。在这份报告中，我们表明，IBDV劫持感染细胞的内体，通过核糖核蛋白复合物组分VP 3与内体膜的胞质小叶中的磷脂的关联建立病毒复制复合物。我们表明，这种相互作用是由VP 3 PATCH 2结构域介导的，并证明其在病毒感染的背景下的相关作用。
Birnaviruses are unconventional members of the group of double-stranded RNA (dsRNA) viruses that are characterized by the lack of a transcriptionally active inner core. Instead, the birnaviral particles organize their genome in ribonucleoprotein complexes (RNPs) composed by dsRNA segments, the dsRNA-binding VP3 protein, and the virally encoded RNA-dependent RNA polymerase (RdRp). This and other structural features suggest that birnaviruses may follow a completely different replication program from that followed by members of the Reoviridae family, supporting the hypothesis that birnaviruses are the evolutionary link between single-stranded positive RNA (+ssRNA) and dsRNA viruses. Here we demonstrate that infectious bursal disease virus (IBDV), a prototypical member of the Birnaviridae family, hijacks endosomal membranes of infected cells through the interaction of a viral protein, VP3, with the phospholipids on the cytosolic leaflet of these compartments for replication. Employing a mutagenesis approach, we demonstrated that VP3 domain PATCH 2 (P2) mediates the association of VP3 with the endosomal membranes. To determine the role of VP3 P2 in the context of the virus replication cycle, we used avian cells stably overexpressing VP3 P2 for IBDV infection. Importantly, the intra- and extracellular virus yields, as well as the intracellular levels of VP2 viral capsid protein, were significantly diminished in cells stably overexpressing VP3 P2. Together, our results indicate that the association of VP3 with endosomes has a relevant role in the IBDV replication cycle. This report provides direct experimental evidence for membranous compartments such as endosomes being required by a dsRNA virus for its replication. The results also support the previously proposed role of birnaviruses as an evolutionary link between +ssRNA and dsRNA viruses. IMPORTANCE Infectious bursal disease (IBD; also called Gumboro disease) is an acute, highly contagious immunosuppressive disease that affects young chickens and spreads worldwide. The etiological agent of IBD is infectious bursal disease virus (IBDV). This virus destroys the central immune organ (bursa of Fabricius), resulting in immunosuppression and reduced responses of chickens to vaccines, which increase their susceptibility to other pathogens. IBDV is a member of Birnaviridae family, which comprises unconventional members of dsRNA viruses, whose replication strategy has been scarcely studied. In this report we show that IBDV hijacks the endosomes of the infected cells for establishing viral replication complexes via the association of the ribonucleoprotein complex component VP3 with the phospholipids in the cytosolic leaflet of endosomal membranes. We show that this interaction is mediated by the VP3 PATCH 2 domain and demonstrate its relevant role in the context of viral infection.