EBV gB Function in Viral Fusion, Entry, and Egress

EBV gB 在病毒融合、进入和排出中的功能

• 批准号: 7215035
• 负责人: Richard M Longnecker
• 金额: $ 36.32万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-15 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7215035
• 关键词: AIDS-Related Opportunistic Infections; Acquired Immunodeficiency Syndrome; Antibodies; B-Lymphocytes; Binding; Biological Assay; Capsid; Cell Surface Receptors; Cell fusion; Cell surface; Cells; Chimeric Proteins; Class; Complement 3d Receptors; Cytoplasmic Tail; Cytoskeleton; Development; Disease; EBV-associated disease; Epithelial; Epithelial Cells; Epithelial Receptor Cell; Epstein-Barr Virus Infections; Expression Library; Family; Glycoproteins; Goals; Golgi Apparatus; Green Fluorescent Proteins; Guanine; Guanine Nucleotide Exchange Factors; Herpesviridae; Human; Human Herpesvirus 4; Immune; Immunoprecipitation; Infection; Knowledge; Laboratories; Lymphoid; Maintenance; Malignant - descriptor; Malignant Neoplasms; Mediating; Molecular; Monitor; Monoclonal Antibodies; Morphogenesis; Mutation; Patients; Peripheral; Phenotype; Predisposition; Process; Property; Protein Binding; Proteins; Recombinants; Regulation; Research; Role; Screening procedure; Simplexvirus; Site; Specificity; Tail; Therapeutic; Tissues; Tropism; Viral; Viral Proteins; Virion; Virus; Virus-Induced Membrane Fusion; Work; Yeasts; base; cDNA Expression; cell type; in vivo; insight; mutant; novel; ras-Related G-Proteins; receptor; receptor function; research study; tissue tropism; tool; trafficking; yeast two hybrid system

DESCRIPTION (provided by applicant): 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 Longnecker 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.

描述(由申请人提供)：了解EB病毒(EBV)进入目标细胞的分子基础和病毒粒子在感染细胞中的运输是朗纳克实验室的长期目标。我们预计，与EBV进入和感染细胞中病毒粒子形态形成相关的发现将对开发治疗人类宿主中EBV相关癌症的疗法具有重要意义。推动我们研究重点的总体假设是，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，这种相互作用对于调节融合是重要的，但也是EBV衣壳从感染细胞中正确排出所必需的。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。主要的病毒包膜糖蛋白350/220(gp350/220)与在B细胞上大量表达的CR2/CD21结合。随后，GP42与HLAII类分子结合，触发Gb和Gh/gl介导的融合。关于EBV诱导的膜融合和病毒进入上皮细胞的机制还知之甚少。很明显，其他受体在上皮细胞中发挥作用，因为CD21和人类白细胞抗原II类通常不在上皮细胞上表达。Lindsey Hutt-Fletcher提供了令人信服的证据，表明与B细胞相比，上皮细胞的EBV进入机制是不同的。在我们的初步研究中，我们已经表明，与B细胞不同，B细胞需要GP42、Gb和Gh/gl来进行有效的细胞融合，而上皮细胞只需要Gb和Gh/gl，当使用突变形式的Gb时，只需要Gb就可以进行有效的细胞融合，这表明Gb可能是上皮细胞的主要融合蛋白，并且可能存在Gb的特异性上皮受体。这项建议将分析：1-通过定点突变和随机突变识别重要的GB功能结构域，从而分析GB在上皮细胞和B细胞进入EBV中的作用。2-GB细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。弄清EBV与靶细胞之间的相互作用对于了解EBV感染在人类宿主中的趋向性至关重要。了解EBV进入上皮细胞和B细胞所需的机制以及病毒和细胞因子将有助于深入了解宿主的易感性，并将有助于开发治疗或根除EBV相关疾病的疗法。