EBV gB Function in Viral Fusion, Entry, and Egress

EB病毒进入靶细胞和病毒粒子的分子基础 贩运受感染的细胞是Lonanecker实验室的长期目标。我们期待着这些发现 与EB病毒进入和病毒粒子形态形成有关的感染细胞将在发展中起重要作用。 治疗人类宿主中EBV相关癌症的治疗。我们的总体假设推动了我们的 研究重点是EBV gb与特定的细胞表面受体相互作用，促进病毒融合和 进入EBV靶细胞。此外，EBV gB的细胞质尾巴与宿主和病毒蛋白相互作用 这种相互作用对调节融合很重要，但也是EBV衣壳正确排出所必需的。 被感染的细胞。EBV在体内的组织嗜性很大程度上限于上皮或淋巴样来源的细胞。 EBV进入靶B细胞所需的细胞和病毒因素已经被很好地描述了。这个 主要病毒包膜糖蛋白350/220(gp350/220)与大量表达的CR2/CD21结合 B细胞。随后，GP42与HLAII类分子结合，触发Gb和Gh/gl介导的融合。几个细节 关于EBV诱导的膜融合和病毒进入上皮细胞的机制是已知的。 很明显，其他受体在上皮细胞中起作用，因为CD21和人类白细胞抗原II类通常不是 在上皮细胞上表达。Lindsey Hutt-Fletcher提供了令人信服的证据表明EBV 与B细胞相比，上皮细胞的进入在机制上是不同的。在我们的初步研究中，我们 研究表明，与需要GP42、Gb和Gh/gl才能有效融合细胞的B细胞不同，上皮细胞 细胞只需要Gb和Gh/Gl，当使用Gb的突变形式时，高效细胞只需要Gb 融合提示gB可能是上皮细胞的主要融合蛋白，而特异性上皮细胞 Gb受体可能存在。这份建议书将分析： 1-通过鉴定重要的gB功能，探讨gB在EB病毒进入上皮细胞和B细胞中的作用 通过定点特定突变和随机突变获得结构域。 2-gB胞质尾巴在调节融合和介导病毒粒子形态发生中的作用以及 结合gb尾巴的几种细胞蛋白的功能将被确定。 3-将研究一种新的GB受体的存在。 阐明EBV与靶细胞之间的相互作用对于理解EBV的趋向性是至关重要的 人类宿主中的感染。EBV致病机制及病毒和细胞因子的知识 上皮细胞和B细胞的进入和复制将提供对宿主易感性的洞察，并将允许 治疗或根除EB病毒相关疾病的治疗方法的发展。

The understanding of the molecular basis of Epstein-Barr virus (EBV)entry into target cells and virion trafficking in infected cells is the long-term goal of the Lonanecker Laboratory. We anticipate that discoveries related to EBV entry and virion morphogenesis in infected cells will be important for the development of therapeutics to treat EBV-associated cancers in the human host. Our overall hypothesis that drives our research focus is that EBV gB interacts with specific cell surface receptors that facilitate viral fusion and entry into EBV target cells. In addition, the cytoplasmic tail of EBV gB interacts with host and viral proteins and this interaction is important for regulating fusion, but also required for proper egress of EBV capsids from infected cells. The tissue tropism for EBV in vivo is largely limited to cells of epithelial or lymphoid origin. The cellular and viral factors required for EBV entry of target B cells has been fairly well described. The major viral envelope glycoprotein 350/220 (gp350/220) binds to CR2/CD21 that is abundantly expressed on B cells. Subsequently, gp42 binds to HLA Class II triggering fusion mediated by gB and gH/gL. Few details are known in regard to the mechanism of EBV induced membrane fusion and viral entry into epithelial cells. It is apparent that other receptors function in epithelial cells since CD21 and HLA Class II are not typically expressed on epithelial cells. Lindsey Hutt-Fletcher has provided compelling evidence to suggest that EBV entry of epithelial cells when compared to B cells is mechanistically different. In our preliminary studies, we have shown that in contrast to B cells, which require gp42, gB, and gH/gL for efficient cell fusion, epithelial cells require only gB, and gH/gL and when a mutant form of gB is used, only gB is required for efficient cell fusion indicating that gB may be the major fusion protein for epithelial cells and that a specific epithelial receptor for gB may exist. This proposal will analyze: 1 - The role of gB in EBV entry of epithelial and B cells by the identification of important gB functional domains by site-specific and random mutation. 2 - The role of the gB cytoplasmic tail in regulating fusion and mediating virion morphogenesis as well as the function of several cellular proteins that bind the gB tail will be determined. 3 - The existence of a novel gB receptor will be investigated. Clarifying the interactions between EBV and target cells is essential for understanding the tropism of EBV infections in the human host. Knowledge of the mechanism and viral and cellular factors required for EBV entry and replication in epithelial and B cells will provide insight into host susceptibility and will allow for the development of therapeutics for the treatment or eradication of EBV-associated diseases.