Dissecting the alphavirus entry receptor NRAMP

描述（由申请人提供）：甲病毒与细胞受体的相互作用可能在决定病毒的趋向性和驱动病毒诱导的疾病中起主要作用。然而，介导甲病毒进入的病毒受体知之甚少。利用Sindbis病毒进行基因组宽筛选，鉴定出NRAMP是昆虫细胞中潜在的甲病毒进入受体。其他研究表明，NRAMP也是委内瑞拉马脑炎病毒的一种进入受体。此外，在哺乳动物细胞中，普遍表达的同源物NRAMP2可以介导这些甲病毒的感染。我们的长期目标是剖析NRAMPs在甲病毒的感染性和发病机制中的作用，以制定对抗这些病原体的策略。我们将从病毒及其不同宿主的角度研究这种重要的相互作用，包括确定是否有其他甲型病毒使用NRAMP作为受体，以及确定介导NRAMP结合的病毒糖蛋白区域。由于哺乳动物有两个同源基因，NRAMP1和NRAMP2，我们还将测试NRAMP1和NRAMP2是否可以在功能上相互替代作为甲病毒的进入受体，并测试来自不同谱系的原代细胞和体内的甲病毒感染是否需要这两个分子中的一个或两个。我们将利用我们已经开发的强大的检测方法来研究甲病毒在昆虫和哺乳动物细胞中的进入和感染，并将这些研究扩展到小鼠和成年果蝇，以探索NRAMPs在病毒发病和传播中的作用。我们的中心假设是，解剖这些医学上重要的虫媒病毒与其受体的相互作用，将揭示有助于开发针对这些未被充分研究的病原体的抗病毒治疗的机制，这些病原体没有疫苗或治疗方法。

DESCRIPTION (provided by applicant): Alphavirus interactions with cellular receptors are likely to play a major role determining viral tropism and driving virus-induced disease. However, the viral receptors that mediate alphavirus entry are poorly understood. A genome wide screen using Sindbis virus identified NRAMP as a potential alphavirus entry receptor in insect cells. Additional studies suggest that NRAMP is also an entry receptor for Venezuelan Equine Encephalitis virus. Furthermore, in mammalian cells the ubiquitously expressed homolog, NRAMP2, can mediate infection of these alphaviruses. Our long-term goal is to dissect the role of NRAMPs in infectivity and pathogenesis of alphaviruses with the goal of developing strategies to combat these pathogens. We will study this important interaction from both the perspective of the viruses and their varied hosts, including studies to determine whether additional alphaviruses use NRAMP as a receptor and to define the regions of the viral glycoproteins that mediate NRAMP binding. Since mammals have two homologous genes, NRAMP1 and NRAMP2, we will also test whether NRAMP1 and NRAMP2 can functionally substitute for one another as alphavirus entry receptors and test whether one or both of these molecules is required for alphavirus infection in primary cells from diverse lineages and in vivo. We will take advantage of powerful assays that we have developed to study alphavirus entry and infection both in insect and mammalian cells and extend these studies to mice and adult flies to explore the role of NRAMPs in viral pathogenesis and spread. Our central hypothesis is that dissecting the interactions of these medically important arboviruses with their receptor will reveal mechanisms that will aid in the development of antiviral treatments against these understudied pathogens for which there are no vaccines or therapeutics.