VIRUS CHROMOSOME STRUCTURE--ROLE IN DEVELOPMENT

描述：组装大型DNA病毒包括一系列步骤 包装病毒基因组。病毒DNA首次被识别为包装 通过包装蛋白质，然后被加工并转移到一个空的 蛋白质壳(前额)。移位是DNA最鲜为人知的阶段 包装。已知转运的能量是三磷酸腺苷的水解，但是 其机制尚不清楚。在这项提案中，给出了一种 利用噬菌体Lambda对易位复合体的分子鉴定 作为一个模范系统。基因实验将确定这些部分的 直接参与易位的易位复合体 进程。最初，这些遗传学研究将集中在大亚基上。 终止酶，病毒蛋白参与识别、处理和 易位。在易位研究的同时，一系列 将进行结构研究，以确定ATP结合中心 终止符。终止酶的球状结构域的位置也将是 已确认身份。结构研究，加上易位研究 将提供更多关于终止酶在易位中的作用的信息，以及 这将是第一次对易位机制进行如此详细的研究。 复制lambda DNA产生端到端的lambda多聚体 染色体。多聚体前体DNA由终止酶处理，该终止酶 引入交错的缺口来产生病毒DNA的粘性末端。 因为外壳突变体对DNA处理是有缺陷的，所以DNA处理 反应在某种程度上是由外壳控制的。这种外壳控制还 观察致病疱疹病毒。对模型的测试 介绍了壳牌实现这一点的方法。有三个相邻的地点用于 基因实验将详细研究 包装蛋白与这些位点之间的相互作用。这些研究是 旨在了解包装蛋白质如何与DNA相互作用 解释了包装蛋白质的主要重组发生在 DNA包装。

DESCRIPTION: Assembly of a large DNA virus includes a series of steps for packaging the viral genome. The viral DNA is first recognized for packaging by a packaging protein, then is processed and translocated into an empty protein shell (prohead). Translocation is the least understood stage of DNA packaging. The energy for translocation is known to be ATP hydrolysis, but the mechanism is unclear. In this proposal, experiments are presented for a molecular characterization of the translocation complex, using phage lambda as a model system. Genetic experiments will identify those parts of the translocation complex that are directly involved in the translocation process. Initially these genetic studies will focus on the large subunit of terminase, the viral protein involved in recognition, processing, and translocation. In parallel with the translocation studies, a series of structural studies will be carried out to identify ATP binding centers of terminase. The locations of globular domains of terminase will also be identified. The structural studies, coupled with the translocation studies will give much information about the role of terminase in translocation, and will be the first such detailed studies on the mechanism of translocation. Replication of lambda DNA produces end-to-end multimers of lambda chromosomes. The multimeric precursor DNA is processed by terminase, which introduces staggered nicks to produce the cohesive ends of virion DNA. Because shell mutants are defective for DNA processing, the DNA processing reaction is controlled somehow by the shell. Such shell control is also observed for the pathogenic herpes viruses. Tests of models for how the shell achieves this are presented. There are three adjacent sites used for recognition and processing; genetic experiments will examine in detail the interactions between packaging proteins and these sites. These studies are directed at understanding how packaging protein interactions with DNA account for the major reconfiguring of packaging proteins that occurs during DNA packaging.