Virus Chromosome Structure: Role in Development

描述（申请人提供）：噬菌体Lambda是研究大型DNA病毒（包括疱疹病毒、痘病毒和腺病毒）病毒粒子组装的优秀模型系统。这些病毒组装空的蛋白质外壳，将病毒染色体包装在里面。此外，在许多小体噬菌体和疱疹病毒的DNA包装过程中，病毒DNA的长端到端聚合物在特定位点被切割以产生单位长度的分子。从包含宿主序列的DNA池中选择病毒DNA进行包装。这种识别是由病毒包装蛋白与病毒DNA上的一组蛋白质结合位点的相互作用所控制的。蛋白质- dna的相互作用如何协调包装是最好的理解。我们建议进一步定义这些DNA-蛋白质相互作用，这对病毒DNA识别具有广泛的意义。我们也试图了解组装催化剂的机制，以帮助识别步骤。虽然病毒DNA包装酶，即终止酶的功能已被广泛研究，但壳的作用，特别是壳的入口顶点的作用尚未得到广泛研究。我们提出了关于门户在包装中的作用的实验，并试图定义门户的终止酶结合位点。作为这项工作的一部分，我们计划研究几种参与壳组装的蛋白质的作用。这项工作将产生纯化的包装蛋白和适合结构分析的组合。包装蛋白的结构信息对于了解丰富的遗传信息和协助设计进一步研究这些蛋白质的功能至关重要。在任何病毒系统中，DNA如何转移到外壳的机制都不为人所知。我们提出分子研究的一系列突变，有缺陷的DNA包装，包括DNA易位。我们还将研究端酶移动DNA的能力，并对端酶的功能域进行结构分析。

DESCRIPTION (provided by applicant): Bacteriophage Lambda is an excellent model system for studying virion assembly for the large DNA viruses, including the herpes, pox and adenoviruses. These viruses assemble empty protein shells into which the viral chromosome is packaged. In addition, during DNA packaging of many lambdoid phages and the herpes viruses, long end-to-end polymers of viral DNA are cut at specific sites to generate unit-length molecules.Viral DNA is selected for packaging from a DNA pool that also includes host sequences. This recognition is governed by the interactions of viral packaging proteins with a set of protein binding sites on the viral DNA. How protein-DNA interactions orchestrate packaging is best understood for . We propose to further define these DNA-protein interactions, which have broad implications for virus DNA recognition. We also seek to understand the mechanism of an assembly catalyst that aids recognition steps.While the functioning of the viral DNA packaging enzyme, terminase, has been extensively studied, the role of the shell, especially the shell's portal vertex, has not. We propose experiments on the portal's role in packaging, and seek to define the portal's binding site for terminase. As part of this work we plan to examine the roles of several proteins involved in shell assembly. This work will generate purified packaging proteins and assemblages suitable for structural analysis. Structural information about packaging proteins is crucial for understanding the wealth of genetic information and to assist in design of further studies on the functioning of these proteins.The mechanism of how DNA is translocated into the shell is not understood in any virus system. We propose molecular studies on a series of mutants that have defects in DNA packaging, including DNA translocation. We will also look at the ability of terminase to move DNA, and to pursue a structural analysis of functional domains of terminase.