Low pH-mediated HSV fusion and entry

 描述(申请人提供)：单纯疱疹病毒(HSV)会导致人类终身潜伏感染。它是重大疾病的罪魁祸首，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概念是，宿主细胞的内体pH是病毒进入所需的，通常是以细胞类型特有的方式。然而，低pH值在疱疹病毒侵入中所起的作用机制尚不清楚。HSV利用低pH的内吞途径感染上皮细胞， 进入人类宿主和反复感染的部位的主要入口。HSV gb属于III类病毒融合蛋白家族，其成员还驱动着其他几种重要的囊膜病毒的进入。III类融合机制仍然没有明确的定义。这一建议的重点是描述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。在特定的目标#1中，我们将阐明低pH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，并确定细胞受体在低pH引发的细胞-细胞融合中的作用。在目标2中，我们将为HSV包膜蛋白描绘一个新的角色，以前不与融合和进入相关。我们将阐明它对酸性pH引发的构象变化的重要性。对于目标3，我们将确定HSV Gh/g1和GB在低pH融合和进入的背景下相互作用的功能后果。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复杂融合机制如何由宿主生理相关细胞类型的囊泡内pH触发的关键知识空白。这一结果将代表着我们对III类融合机制的理解取得了重大进展，并可能有助于开发新型的抗病毒干预措施。

 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.