Matrix-glycoprotein interactions required for budding of a plant nucleorhabdovirus and induction of inner nuclear membrane invagination
Matrix-glycoprotein interactions required for budding of a plant nucleorhabdovirus and induction of inner nuclear membrane invagination
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植物核弹状病毒出芽和诱导内核膜内陷所需的基质-糖蛋白相互作用
DOI：
10.1111/mpp.12699
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发表时间：
2018
影响因子：
4.9
通讯作者：
Li Zhenghe
中科院分区：
文献类型：
--
作者：
Sun Kai;Zhou Xin;Lin Wenye;Zhou Xueping;Jackson Andrew O.;Li Zhenghe
核habdovirus （nucleorhabdovirus， SYNV）在植物细胞的细胞核内复制，并在核膜（inner nuclear membrane， IM）上进行形态发生。成熟颗粒被认为是通过基质(M)蛋白-核衣壳复合物通过宿主IMs出芽而形成的，以获取宿主磷脂和表面糖蛋白(G)。为了解决核habdovirus出芽的机制，我们产生了含有截断氨基末端（NT）或羧基末端（CT）结构域的重组SYNV G突变体。电镜和蔗糖梯度离心分析表明，CT结构域对病毒粒子形态发生至关重要，而NT结构域也是有效出芽所必需的。SYNV感染引起内陷，这被认为为病毒出芽提供了膜位点。我们发现，在病毒感染的情况下，M蛋白与膜锚定G蛋白的CT结构域的相互作用介导M蛋白易位和IM内陷。有趣的是，无论是通过跨膜G蛋白CT结构域的共表达，还是通过与G蛋白膜靶向序列的人工融合，将M蛋白系在细胞膜上，都会诱导未感染细胞的IM内陷。支持G - M相互作用在病毒出芽中的功能的进一步证据来自于对SYNV诱导的IM内陷和病毒感染的主要负面影响，这是由可溶性G蛋白CT结构域的表达引起的。基于这些数据，我们提出协同G - M相互作用促进高效的SYNV出芽。
Nucleorhabdoviruses such asSonchus yellow net virus(SYNV) replicate in the nuclei and undergo morphogenesis at the inner nuclear membrane (IM) in plant cells. Mature particles are presumed to form by budding of the Matrix (M) protein‐nucleocapsid complexes through host IMs to acquire host phospholipids and the surface glycoproteins (G). To address mechanisms underlying nucleorhabdovirus budding, we generated recombinant SYNV G mutants containing a truncated amino‐terminal (NT) or carboxyl‐terminal (CT) domain. Electron microscopy and sucrose gradient centrifugation analyses showed that the CT domain is essential for virion morphogenesis whereas the NT domain is also required for efficient budding. SYNV infection induces IM invaginations that are thought to provide membrane sites for virus budding. We found that in the context of viral infections, interactions of the M protein with the CT domain of the membrane‐anchored G protein mediate M protein translocation and IM invagination. Interestingly, tethering the M protein to endomembranes, either by co‐expression with a transmembrane G protein CT domain or by artificial fusion with the G protein membrane targeting sequence, induces IM invagination in uninfected cells. Further evidence to support functions of G‐M interactions in virus budding came from dominant negative effects on SYNV‐induced IM invagination and viral infections that were elicited by expression of a soluble version of the G protein CT domain. Based on these data, we propose that cooperative G‐M interactions promote efficient SYNV budding.