Elucidating the Entry Mechanism of Ebola Viruses

描述（由申请人提供）：埃博拉和马尔堡病毒属于丝状病毒科，可引起致命的出血热，其特征是广泛的组织破坏。出于安全考虑，这些病毒被指定为生物安全4级制剂。在阐明埃博拉病毒进入机制和发病机制方面的进展受到阻碍，部分原因是安全问题。然而，基于病毒假分型技术的各种替代系统已经建立，以研究埃博拉病毒的进入机制。在这个应用中，我们证明埃博拉糖蛋白（GP）可以有效地结合到HIV病毒颗粒上，并且假型病毒粒子具有高度传染性，正如其他人所报道的那样。更重要的是，我们表明我们可以使用这个系统作为一个强大的进入实验来阐明埃博拉病毒的进入机制。我们的初步结果清楚地说明了我们如何使用这种伪型系统来剖析埃博拉GP的两个亚基（GP1和GP2）在受体识别和病毒进入中的作用。本应用将侧重于以下具体目的：(1)表征GP2发夹的带电残基在埃博拉病毒入境中的作用。(2)埃博拉病毒入境GP1受体结合区分析。(3)潜在埃博拉病毒受体的鉴定和表征。这些研究将提供关于埃博拉GP如何与细胞受体相互作用以及埃博拉GP如何介导有效的膜融合和病毒进入的重要信息。此外，阐明GP1和GP2在埃博拉病毒进入中的作用将有助于我们设计有效的埃博拉病毒进入抑制剂，从而提供针对埃博拉感染和疾病的治疗方法。因此，本应用中提出的研究工作不仅对于阐明埃博拉病毒的基本进入机制具有重要意义，而且对于开发潜在的强大治疗方法来对抗这种致命病原体也具有重要意义。

DESCRIPTION (provided by applicant): Ebola and Marburg viruses belong to the family Filoviridae and can cause fatal hemorrhagic fevers characterized by widespread tissue destruction. Because of the safety concerns, these viruses are designated as the bio-safety level 4 agents. Progress in elucidation of the mechanisms of Ebola entry and pathogenesis has been hampered partly due to the safety concern. However, various surrogate systems based on the viral pseudotyping technique have been established to investigate the entry mechanism of Ebola viruses. In this application, we demonstrate that Ebola glycoprotein (GP) can be efficiently incorporated onto HIV viral particles, and the pseudotyped virions are highly infectious, as reported by others. More importantly, we show that we can use this system as a powerful entry assay to elucidate the entry mechanism of Ebola viruses. Our preliminary results clearly illustrate how we can use this pseudotyped system to dissect the roles of both subunits (GP1 and GP2) of Ebola GP in receptor recognition and viral entry. This application will focus on the following specific aims: (1) Characterization of the roles of the charged residues of the GP2 hairpin in Ebola entry. (2) Analysis of the receptor binding region of GP1 in Ebola entry. (3) Identification and characterization of the potential Ebola receptor(s). These studies will provide important information regarding how Ebola GP interacts with the cellular receptor(s) and how Ebola GP mediates efficient membrane fusion and viral entry. Furthermore, elucidation of the roles of GP1 and GP2 in Ebola entry will help us design effective Ebola entry inhibitors which may provide therapeutic treatments against Ebola infection and disease. Therefore, the research work proposed in this application is not only important for elucidating the basic entry mechanism of Ebola viruses, but also important for developing potentially powerful treatments to combat this deadly pathogen.