VIRUS CHROMOSOME STRUCTURE--ROLE IN DEVELOPMENT

描述：大型DNA病毒的组装包括一系列步骤， 包装病毒基因组。 病毒DNA首先被识别为包装 通过包装蛋白质，然后被加工并转移到空的 蛋白质外壳（prohead）。 易位是DNA最不为人所知的阶段 包装. 转运的能量已知是ATP水解，但 其机制尚不清楚。 在这个建议中，实验提出了一个 使用λ噬菌体的易位复合物的分子表征 作为一个模型系统。 基因实验将确定这些部分的 直接参与易位的易位复合体 过程 最初，这些遗传学研究将集中在 末端酶，参与识别，加工和 易位 在易位研究的同时， 将进行结构研究，以确定ATP结合中心的 末端酶。 终止酶的球状结构域的位置也将是 鉴定 结构研究，再加上易位研究 将提供更多关于末端酶在易位中的作用的信息， 将是第一次对易位机制进行如此详细的研究。 λ DNA的复制产生λ的端到端多聚体 染色体 多聚体前体DNA被末端酶加工，末端酶 引入交错切口以产生病毒体DNA的粘性末端。 由于壳突变体在DNA加工方面有缺陷， 反应是由外壳控制的。 这样的壳控也是 观察致病性疱疹病毒。 模型的测试， Shell实现了这一点。 有三个相邻的网站用于 识别和处理;遗传实验将详细研究 包装蛋白和这些位点之间的相互作用。 这些研究 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， 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.