VIRUS CHROMOSOME STRUCTURE: ROLE IN DEVELOPMENT

实验提出了关于病毒染色体是如何 在组装过程中选择和包装。 使用的系统是噬菌体 λ，强大的遗传和生物化学分析方法， available. 染色体识别的一个方面， 是识别DNA粘性末端位点（cos）的基础 通过末端酶产生称为复合物I的ω-末端酶复合物。 所提出的实验将定义参与的终止酶结构域， 切割位点的切割，cosN。 cosN点突变将产生 关于特定cosN碱基对在 通过末端酶识别。 终止酶与蛋白质的初始相互作用 结合位点，cosB，将被研究和宿主因子的作用 阐明。 在cosN和cosB之间有一段DNA， 未知的意义 实验将测试这一部分是否是 参与与包装蛋白的特异性相互作用， 仅仅是一个间隔物。 参与与片段相互作用的蛋白质 将被识别。 将研究宿主因子IHF在21末端酶作用中的作用。 将检查21个IHF依赖性突变体（HER）的宿主因素 要求. 在λ宿主因子（HF）中缺陷的突变体将是 寻找和研究。 复合物II与前体结合所涉及的相互作用也将 接受检查。 一个重要的目标是鉴定出 在复合物II形成过程中与末端酶结合。 辅助蛋白gpFI的作用将被研究，以了解它是如何 改变细胞内环境，使包装可以发生。 的 gpFI与噬菌体编码的ben核酸内切酶以及与宿主的相互作用 将对这些因素进行研究。 这项工作对病毒生物学具有普遍意义， 包括致病病毒。 DNA-蛋白质的基本信息 相互作用、组装机制和病毒-宿主相互作用。

Experiments are proposed to ask questions about how virus chromosomes are selected and packaged during assembly. The system used is bacteriophage lambda, for which powerful genetic and biochemical methods of analysis are available. One aspect of chromosome recognition that is poorly understood is the basis for the recognition of the cohesive end site (cos) of the DNA by terminase which generates the cos-terminase complex called complex I. The proposed experiments will define the terminase domain involved in cleavage of the cutting site, cosN. cosN point mutations will give detailed information about the role of specific cosN base pairs in recognition by terminase. The initial interaction of terminase with the binding site, cosB, will be studied and the role of the host factor elucidated. There is a segment of DNA between cosN and cosB that is of unknown significance. Experiments will test whether this segment is involved in specific interactions with packaging proteins or whether it is simply a spacer. The protein(s) involved in interaction with the segment will be identified. The role of the host factor IHF in 21 terminase action will be examined. IHF-dependent mutants (her) of 21 will be examined for host factor requirements. Mutants defective in the Lambda host factor (HF) will be sought and studied. Interactions involved in the binding of the prohead by complex II will also be examined. One important goal is to identify the prohead protein that binds to terminase during complex II formation. The role of the accessory protein gpFI will be studied to understand how it alters the intracellular environment so that packaging can occur. The interaction of gpFI with the phage-coded ben endonuclease, and with host factor(s) will be studied. The proposed work will be of general significance for virus biology, including pathogenic viruses. Fundamental information on DNA-protein interactions, assembly mechanisms and virus-host interactions will result.