VIRUS CHROMOSOME STRUCTURE: ROLE IN DEVELOPMENT

人们建议进行实验，以询问病毒染色体是如何 在组装过程中进行选择和包装。所使用的系统是噬菌体 Lambda，其强大的遗传和生化分析方法是 可用。人们对染色体识别知之甚少的一个方面 是识别DNA的粘合末端(Cos)的基础 通过终止酶产生称为复合体I的辅酶末端酶复合体。 拟议的实验将定义参与其中的终止酶结构域 切割部位的裂解，CoSN。CoSN点突变将给 有关特定CoSN碱基对在 终止酶识别。终止酶与细胞因子的初始相互作用 将研究结合位点、COSB和宿主因子的作用 已澄清。在CoSN和COSB之间有一段DNA是 未知的意义。实验将测试此数据段是否 参与与包装蛋白的特定相互作用或它是否 只是一个间隔器。与片段相互作用的蛋白质(S) 将会被确认。 将研究宿主因子IHF在21末端酶作用中的作用。 将对21个IHF依赖突变体(HER)进行宿主因子检查 要求。在Lambda宿主因子(HF)方面有缺陷的突变株将 寻找和研究。 参与络合物II与前体素结合的相互作用也将 接受检查。一个重要的目标是确定前头蛋白 在形成复合体II的过程中与终止酶结合。 将研究辅助蛋白GPFI的作用，以了解它是如何 改变细胞内环境，使包装得以发生。这个 GPFI与噬菌体编码的Ben内切酶及其与宿主的相互作用 因素(S)将被研究。 这项拟议的工作将对病毒生物学具有普遍意义， 包括致病病毒。关于DNA-蛋白质的基本信息 将产生相互作用、组装机制和病毒与宿主的相互作用。

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.