The Role of US28 During HCMV Latency

 描述(申请人提供)：人类巨细胞病毒(HCMV)在美国是一个重要的公共卫生问题。最重要的是病毒对发育中的胎儿和免疫功能受损的人的影响，在这些人中，它会导致从轻微到危及生命的各种病理情况。由于世界上50%-90%的成年人口中HCMV以持久性或潜伏性形式存在，因此鉴定有助于建立和维持潜伏感染的Virl基因产物是一个紧张而重要的研究领域。人巨细胞病毒编码包括US28在内的4种G蛋白同源物，在感染人巨细胞病毒的成纤维细胞中表现出结构性和激动剂依赖性的G蛋白信号转导活性。尽管US28表现出高水平的信号转导，但它不是裂解病毒复制所必需的，因此它在病毒发病机制中的作用尚不清楚。有趣的是，US28的mRNAs在潜伏感染的造血祖细胞和单核细胞中表达，这引发了人们对US28在潜伏的CMV感染中的潜在作用的疑问。我们令人兴奋的初步数据表明，US28促进了成功的潜伏感染，因为US28缺失病毒自发进入造血细胞的裂解阶段，在那里野生型病毒建立了潜伏感染。因此，我们假设US28在HCMV感染的造血祖细胞中引导信号导致潜伏期的建立和/或维持。为了探索这一假设，我们将利用一个新构建的US28突变病毒小组和最近建立的方法来检查HCMV感染细胞中的US28信号。在目标1中，我们将研究US28利用病毒重组在原代造血祖细胞中驱动潜伏期的生物学参数，在目标2中，我们将检测US28的分子信号特性，并确定哪些途径有助于建立和/或维持潜伏期。最后，本申请中提出的那些实验对于我们理解CMV GPCRs在病毒发病中的作用至关重要，并将为开发专门针对病毒感染的潜在储存库的独特抗病毒药物开辟新的研究途径。

 DESCRIPTION (provided by applicant): Human cytomegalovirus (HCMV) is a significant public health concern in the United States. Most important are the effects of the virus on developing fetuses and immunocompromised individuals where it causes a variety of pathological conditions ranging in severity from mild to life-threatening. Since HCMV is present in a persistent or latent form in 50-90% of the world's adult population, the identification of virl gene products that contribute to the establishment and maintenance of a latent infection is an intense and important area of investigation. HCMV encodes 4 GPCR homologs including US28, which has been shown to exhibit both constitutive and agonist-dependent G-protein signaling activities in HCMV infected fibroblasts. Although US28 exhibits high level signaling, it is not essential for lytic viral replication and therefore its function in viral pathogenesis remains unclear. Interestingly, US28 mRNAs are expressed in latently infected hematopoietic progenitors and monocytes, prompting questions regarding the potential role of US28 during latent CMV infections. Our exciting preliminary data indicates that US28 promotes a successful latent infection as US28 null viruses spontaneously enter the lytic phase in hematopoietic cells where wild type virus establishes a latent infection. Therefore, we hypothesize that US28 directed signaling in HCMV infected hematopoietic progenitors leads to the establishment and/or maintenance of latency. To explore this hypothesis, we will take advantage of a newly constructed panel of US28 mutant viruses and recently established methodologies to examine US28 signaling in HCMV infected cells. In Aim 1, we will examine the biological parameters by which US28 drives latency using viral recombinants in primary hematopoietic progenitor cells, and in Aim 2 we will examine the molecular signaling properties of US28 and determine which pathways contribute to the establishment and/or maintenance of latency. Finally, experiments like those proposed in this application are essential for our understanding of the role of CMV GPCRs in viral pathogenesis and will open novel avenues of research for the development of unique antivirals that specifically target the latent reservoir of virus infection.