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，可以从感染细胞迅速传播到邻近细胞，特别是在生物学上重要的上皮和神经组织中。这种细胞间传播的过程涉及到专门的病毒机制：1)将病毒颗粒引导到细胞间形成的连接处；2)允许病毒穿过细胞连接处进入邻近细胞。HSV糖蛋白gE/gl在病毒细胞间传播的这两个方面都起着重要作用，但值得注意的是，它在细胞外病毒颗粒进入上皮细胞的顶端表面时不起作用。因此，gE/gl是研究疱疹病毒细胞间传播的重要分子手柄。gE/gl的胞质结构域影响糖蛋白向细胞反式高尔基网络（TGN）的分选，并在病毒包膜进入细胞质膜中起重要作用。TGN是极化细胞基底外侧/根尖分选的主要位点，gE/gl促进新生病毒粒子特异性地向细胞基底外侧表面和细胞连接分选。此外，我们有两个新的证据表明，gE/gl的细胞外结构域与细胞连接的成分，细胞受体结合，并促进邻近细胞的感染。首先，gE细胞外结构域的突变显著减少细胞间传播。其次，细胞中gE/gl的表达，反过来，会干扰细胞间的扩散。这个

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.