Low pH-mediated HSV fusion and entry

 描述（由申请方提供）：单纯疱疹病毒（HSV）可导致人类终身潜伏感染。它是造成重大疾病的原因，从唇疱疹和生殖器感染到失明和致命的脑炎。该项目的长期目标是了解单纯疱疹病毒进入宿主细胞的分子机制。疱疹病毒学中的一个新兴概念是宿主细胞的内体pH是病毒进入所需的，通常以细胞类型特异性方式。然而，低pH值在疱疹病毒进入中所起的机制作用尚不清楚。HSV利用低pH、内吞途径感染上皮细胞， 进入人类宿主的主要门户和复发感染的部位。HSV gB属于III类病毒融合蛋白家族，其成员还驱动其他几种重要的包膜病毒进入。III类融合机制仍不明确。该建议的重点是描绘HSV介导的低pH膜融合的机制。根据以前的结果和我们新的初步研究，我们制定了三个具体目标。在具体目标# 1，我们将阐明由低pH值引发的HSV膜融合的病毒和细胞参数。我们将揭示融合蛋白gB的关键区域，并定义细胞受体在由低pH值引发的细胞-细胞融合中的作用。在目标2中，我们将描绘一个新的HSV包膜蛋白的作用，而不是以前与融合和进入。我们将阐明其重要性，为目的3，我们将确定HSV的gH/gL和gB之间的相互作用的功能后果，在低pH值的融合和进入的背景下，由酸性pH值引发的构象变化。我们的实验设计采用了分子病毒学、生物化学和细胞生物学技术。实现这些目标将填补关于疱疹病毒的复杂融合机制如何由生理相关细胞类型中的宿主囊内pH触发的关键知识空白。这些结果将代表我们对III类融合机制的理解的重大进展，并可能有助于开发新的抗病毒干预措施。

 DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) causes lifelong latent infections in humans. It is responsible for significant disease, ranging from cold sores and genital infections to blindness and fatal encephalitis. The long- term goal of this project is to understand the molecular mechanisms that HSV uses to gain entry into host cells. An emerging concept in herpesvirology is that endosomal pH of the host cell is required for viral entry, often in a cell type specific manner. However, the mechanistic role that low pH plays in herpes viral entry is not clear. HSV utilizes a low pH, endocytic pathway for infection of epithelial cells, the primary portal of entry into the human host and the site of recurrent infection. HSV gB belongs to the class III viral fusion protein family, whose members also drive the entry several other important enveloped viruses. The class III fusion mechanism remains poorly defined. The focus of this proposal is the delineation of the mechanism of low pH membrane fusion mediated by HSV. Based on previous results and our new preliminary studies, we have formulated three specific aims. In Specific Aim # 1, we will elucidate viral and cellular parameters of HSV membrane fusion triggered by low pH. We will reveal critical regions of the fusion protein gB and define the roles of cellular receptors in cell-cell fusion triggered by low pH. In Aim 2, we will delineate a novel role for an HSV envelope protein, not previously associated with fusion and entry. We will elucidate its importance for conformational changes triggered by acidic pH. For Aim 3, we will determine the functional consequences of the interaction between HSV gH/gL and gB in the context of low pH fusion and entry. Our experimental design employs techniques of molecular virology, biochemistry and cell biology. Achieving these aims will fill critical knowledge gaps about how the complex fusion mechanism of herpesviruses is triggered by host intravesicular pH in physiologically relevant cell types. The results will represent significant advances in our understanding of class III fusion mechanisms, and may aid in development of novel, antiviral interventions.