EBV BMRF-2 Protein in Infection of Oral Epithelial Cells

描述：最初的EB病毒(EBV)感染是通过口咽粘膜发生的，但EBV进入上皮细胞的机制尚不清楚。利用极化的口咽上皮细胞，我们发现EBV通过两条不依赖于CD21的途径进入这些细胞：顶端上皮细胞膜与EBV感染的淋巴细胞直接细胞接触，以及无细胞EBV病毒粒子通过基底膜进入。我们的数据表明，EBV BMRF-2糖蛋白和β1整合素之间的相互作用在病毒粒子无细胞进入过程中起着关键作用。我们发现，子代病毒从感染细胞到未感染细胞的细胞间传播发生在侧膜上。BMRF-2的氨基酸序列揭示了几个潜在的基侧分选信号，我们已经证明它被运输到基侧膜上。我们推测BMRF-2可能参与将细胞内的子代病毒粒子靶向到基底膜，并可能促进病毒粒子跨细胞间连接的转移。本研究的目的是研究BMRF-2/β1整合素相互作用的分子机制及其在EBV感染和在单层极化和多层复层口咽上皮细胞传播中的功能意义。本研究的具体目的是：1)研究EBV BMRF-2在病毒粒子附着和进入口咽上皮细胞中的作用；2)确定BMRF-2的分选信号，调控其转运到极化的口咽上皮细胞的基侧膜；以及3)研究BMRF-2蛋白在EBV在口咽上皮细胞间传播中的作用。这些数据将极大地促进对口咽上皮细胞EBV感染机制的了解，并可能对设计新的预防初始EBV感染的方法有价值。

DESCRIPTION: Initial Epstein-Barr virus (EBV) infection occurs via the oropharyngeal mucosa, but mechanisms of EBV entry into epithelial cells are poorly understood. Using polarized oropharyngeal epithelial cells, we showed that EBV enters these cells through two CD21-independent pathways: direct cell-to-cell contact of apical epithelial cell membranes with EBV-infected lymphocytes, and entry of cell-free EBV virions through basolateral membranes. Our data show that interaction between the EBV BMRF-2 glycoprotein and beta1 integrin play a key role in cell-free virion entry. We showed that cell-to-cell spread of progeny versions from infected into uninfected cells occurs across lateral membranes. The amino acid sequence of BMRF-2 reveals several potential basolateral-sorting signals, and we have shown that it is transported to basolateral membranes. We posit that BMRF-2 may be involved in targeting of intracellular progeny virions to the basolateral membrane and may facilitate translocation of virions across lateral intercellular junctions. The goal of this study is to characterize molecular mechanisms of BMRF-2/beta1 integrin interactions and their functional significance in EBV infection and dissemination in single-layer polarized and multi-layer stratified oropharyngeal epithelial cells. The Specific Aims of the study are: 1) To investigate the role of EBV BMRF- 2 in virion attachment and entry in oropharyngeal epithelial cells; 2) To identify the sorting signals of BMRF-2 that govern its transport to the basolateral membranes of polarized oropharyngeal epithelial cells; and 3) To study the functions of the BMRF-2 protein in EBV cell-to-cell spread in oropharyngeal epithelium. These data will greatly advance knowledge of the mechanisms of EBV infection of oropharyngeal epithelial cells and may be of value to design new approaches to prevention of initial EBV infection.