The Characterization of the Methanothermobacter Thermautotrophicus Origin of Replication and its Associated Proteins

每一个增殖的细胞都必须准确地复制其遗传信息，并且在每个细胞周期中只能复制一次。任何福尔斯低于或超过这些限制的过程都会导致细胞死亡或异常增殖。该研究计划的长期目标是了解真核细胞中DNA复制的机制，该研究项目将特别关注复制起点，复制起始的染色体上的特定位置。尽管DNA复制在细菌、病毒和噬菌体中已被很好地表征，但真核生物中该过程的许多方面，特别是在起始阶段，仍然是未知的。复杂的真核细胞周期从起源识别的第一步到细胞分裂的最后一步需要许多调节信号和因子，使得难以研究单个组分和事件。有一种生物可能有助于规避真核生物复制的某些复杂性，它是一种具有真核生物样复制过程的原核生物，即古菌嗜热甲烷杆菌（Methanothermobacter thermautotrophicus，Mth）。细胞DNA复制似乎更类似于真核生物而不是细菌的过程。然而，古细菌DNA复制装置似乎需要更少的蛋白质和复合物。因此，古生菌可能提供一个很好的模型系统，了解真核生物复制的酶学。该研究将集中在Mth的DNA复制的启动机制。野生型和突变重组蛋白将用于体外实验，旨在：1）分离和鉴定的起源结合蛋白，2）了解如何识别和起始蛋白结合的起源;和3）确定在古细菌起源的功能基序。一个长期的目标是开发一个体外复制系统的Mth，从这些生化研究中获得的信息将直接适用于这样的系统。

Every proliferating cell must duplicate its genetic information accurately and only once per cell cycle. Any process that falls short of or exceeds these limits results in cell death or abnormal proliferation. The long-term goal of this research program is to understand the mechanisms governing DNA replication in eukarya, and this research project will focus specifically on the origin of replication, a specific location on the chromosome where replication initiates. Whereas DNA replication has been well characterized in bacteria, viruses and bacteriophages, many aspects of the process in eukarya, particularly in the initiation phase, are still unknown. The complex eukaryotic cell cycle entails numerous regulatory signals and factors from the first step of origin recognition to the final step of cell division, making it difficult to study individual components and events. An organism that may help to circumvent some of the complexity of eukaryotic replication is a prokaryote with eukaryotic-like replication processes,the archaeon Methanothermobacter thermautotrophicus (Mth). Archaeal DNA replication appears to be more similar to the eukaryal rather than the bacterial process. However, the archaeal DNA replication apparatus appears to require fewer proteins and complexes. Thus, archaea may provide a good model system for understanding the enzymology of eukaryotic replication. The research will focus on the mechanisms of the initiation of DNA replication in Mth.Both wild-type and mutant recombinant proteins will be used in in vitro experiments designed to:1) isolate and identify the origin binding proteins,2)understand how the origin is recognized and bound by the initiation proteins; and 3) identify the functional motifs in the archaeal origin. A long-term goal is to develop an in vitro replication system for Mth; the information gained from these biochemical studies will be directly applicable to such a system.