Herpes Simplex Virus Transmission Across Cell Junctions

描述（由申请人提供）：单纯疱疹病毒（HSV）和其他α-疱疹病毒具有惊人的先天能力，可以非常迅速地从感染细胞传播到邻近细胞，特别是在生物学上重要的上皮和神经元组织中。这种细胞间传播的过程涉及专门的病毒机制：i）将病毒颗粒引导到细胞之间形成的连接处，ii）允许病毒穿过细胞连接处并进入相邻细胞。HSV糖蛋白gE/gl在病毒细胞间传播的这两个方面都起重要作用，但显著地，在细胞外病毒颗粒进入上皮细胞的顶端表面中不起作用。因此，gE/gl是研究疱疹病毒细胞间传播的重要分子手段。gE/gl的胞质结构域影响糖蛋白向细胞的跨高尔基体网络（trans-Golgi network，TGN）的分选，并且在病毒进入胞质膜中起重要作用。TGN是极化细胞中基底外侧/顶端分选的主要位点，并且gE/gl促进新生病毒体特异性地分选到细胞的基底外侧表面和细胞连接处。此外，我们有两个新的证据表明，gE/gl的胞外结构域结合到细胞连接的组件，细胞受体，这促进了相邻细胞的感染。首先，gE胞外结构域的突变显著减少了细胞间的扩散。第二，gE/gl在细胞中的反式表达干扰细胞间的扩散。的 本报告提出的研究目标是：i）更好地理解gE/gl的细胞内运输以及这如何决定新生病毒体向细胞连接的分选，ii）表征gE/gl和其他HSV糖蛋白在核衣壳的细胞质表达中的贡献，iii）表征gE/gl的胞外结构域在介导病毒穿过细胞连接并进入相邻细胞中的运动中的作用，和iv）检测gE/gl突变对角膜中HSV传播的影响。这些研究将有助于阐明疱疹病毒细胞间传播的这一鲜为人知的过程，也将扩大我们对疱疹病毒如何通过粘膜上皮和神经系统内移动的知识。

DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) and other alpha-herpesviruses possess the amazing innate ability to spread very rapidly from infected cells to neighboring cells, especially in biologically important epithelial and neuronal tissues. This process of cell-to-cell spread involves specialized virus machinery that: i) directs virus particles to junctions formed between cells and ii) allows the virus to cross cell junctions and enter neighboring cells. HSV glycoprotein gE/gl plays an important role in both these facets of virus cell-to-cell spread but, significantly, does not play a role in entry of extracellular virus particles at the apical surfaces of epithelial cells. As such gE/gl is an important molecular handle to study herpesvirus cell-to-cell spread. The cytoplasmic domain of gE/gl affects sorting of the glycoprotein to trans-Golgi network (TGN) of cells and plays an important role in virus envelopment into cytosolic membranes. The TGN is the major site of basolateral/apical sorting in polarized cells and gE/gl promotes sorting of nascent virions specifically to basolateral surfaces of cells and cell junctions. Moreover, we have two new pieces of evidence that the extracellular domain of gE/gl binds to components of cell junctions, cellular receptors, and that this promotes infection of adjacent cells. First, mutations in the extracellular domain of gE significantly diminish cell-to-cell spread. Second, expression of gE/gl in cells, in trans, interferes with cell-to cell spread. The aims of the research proposed here are to: i) better understand the intracellular traffic of gE/gl and how this determines sorting of nascent virions to cell junctions, ii) to characterize the contribution of gE/gl and other HSV glycoproteins in cytoplasmic envelopment of nucleocapsids, iii) to characterize the extracellular domains of gE/gl in mediating movement of viruses across cell junctions and into adjacent cells, and iv) to examine the effects of gE/gl mutations on HSV spread in the cornea. These studies will help elucidate this poorly understood process of herpesvirus cell-to-cell spread, and will also expand our knowledge of how a herpesvirus moves through mucosal epithelium and within the nervous system.