CAPSID STRUCTURE AND ASSEMBLY IN KSHV

卡波西肉瘤（KS），一种混合性多中心血管生成性肿瘤， 细胞性，是获得性缺乏症患者的主要肿瘤 综合症（艾滋病）。目前的分子和血清流行病学数据表明， KS相关疱疹病毒（KSHV），也称为人疱疹病毒8（HHV 8），是一种 KS的感染性病因。在大多数感染病例中， 免疫反应可能会破坏绝大多数活跃的细胞， 复制病毒相反，免疫抑制可以使这种平衡发生倾斜 从这种主要的潜伏状态转变为病毒的重新激活， 推广和广泛传播。这种致病过程取决于， 部分原因是KSHV产量增加。最引人注目的前病毒体 病毒复制开始后出现的结构是内部结构， 衣壳-二十面体对称的粒子，填充细胞核，当 完全成熟，携带线性病毒基因组鲜明对比 成功地研究了病毒衣壳的结构和组装 α-和β-疱疹病毒（如单纯疱疹病毒1和 巨细胞病毒，分别），试图探讨这些方面的 γ疱疹病毒（如EB病毒）的研究进展甚微。的 我们在提案中描述的研究的长期目标是 了解KSHV的结构和装配，与其他成员相比 疱疹病毒亚科，并把这些发现的背景下，KS 发病机制最近，我们已经设计出方法来纯化结构完整的 KSHV衣壳。在本申请中，我们建议： 1.纯化和鉴定裂解KSHV过程中形成的不同衣壳种类 使用生物化学和物理分离技术生长。 2.用生物化学的方法来表征这些衣壳的结构成分， 电子显微镜和质谱方法。 3.利用计算机辅助确定衣壳的三维结构 电子低温显微镜图像的分析。 4.研究KSHV衣壳组装。 了解衣壳结构和组装的细节，在KSHV复制的早期和必要的步骤，可以同时确定新的潜在的治疗干预的目标。

Kaposi's sarcoma (KS), a multicentric angiogenic tumor of mixed cellularity, is the leading neoplasm of patients with acquired deficiency syndrome (AIDS). Current molecular- and seroepidemiologic data demonstrate that KS-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is the infectious cause of KS. In most cases of infection, a healthy cellular immune response likely destroys the vast majority of cells that harbor actively replicating virus. In contrast, immunosuppression can tilt this equilibrium away from this predominantly latent state to one of viral reactivation, replication and widespread dissemination. This pathogenic progression depends, in part, on high levels of KSHV production. The most remarkable pre-virion structures to appear after the initiation of viral replication are the inner capsid--the icosahedrally symmetric particles that fill the nucleus and, when fully mature, harbor the linear viral genome. In stark contrast to the successful investigations into the structure and assembly of the capsids of alpha- and betaherpesviruses, (such as herpes simplex virus 1 and cytomegalovirus, respectively), attempts to explore these aspects in the gammaherpesviruses (such as Epstein-Barr virus) have made little progress. The long-term objectives of the research we describe in the proposal are to understand KSHV structure and assembly in comparison to members of the other herpesvirus subfamilies and to place these findings into the context of KS pathogenesis. Recently, we have devised methods to purify structurally intact KSHV capsids. In this application, we propose to: 1.Purify and identify the distinct capsid species formed during lytic KSHV growth using biochemical and physical separation techniques. 2.Characterize the structural components of these capsids with biochemical, electron microscopic and mass spectrometric approaches. 3.Determine the three-dimensional structure of the capsids using computer-aided analyses of electron cryomicroscopic images. 4.Investigate KSHV capsid assembly. Understanding the details of capsid structure and assembly, an early and essential step in KSHV replication, may simultaneously identify new potential targets for therapeutic intervention.