INITIATION OF DNA REPLICATION OF YEAST CHROMOSOMES

描述：基因组的及时和准确复制是必不可少的， 所有真核细胞的正常增殖因此， DNA复制与细胞周期的进程密切相关。 本提案的长期目标是确定选择 DNA复制的位点并激活起始过程。起源 识别复合物（ORC）是控制这些事件的关键因素。ORC是 只有S。已知的酿酒蛋白特异性识别所有的酵母来源， 复制的一旦与这些位点结合，ORC就会招募其他复制 复制的起源。在这个提议中，贝尔博士将利用 他最近在理解ORC的生化功能方面的进展， 确定这些功能是如何机械地耦合到复制 启动过程。贝尔博士将：确定DNA的机制 与ORC的结合以及该事件如何改变细胞中ORC的功能。这些 研究将提供有关选择机制的关键信息， 复制的起源确定ORC在复制过程中的功能 在复制起点的复杂组装和激活。同时使用 复制因子相互作用的生化分析和遗传筛选 新的ORC突变体，这些研究将确定所需的关键事件， 基本复制复合物的组装。确定的影响 核小体对ORC和起源功能的影响。利用核小体组装反应， 一种新的全基因组测定，用于确定ORC结合位点，贝尔博士 将剖析核小体和染色质对DNA复制的影响。的 真核生物DNA复制的高度保守性强烈表明， 对真核生物DNA复制基本机制的新认识 将很容易地转化为我们对同一过程的理解， 人体细胞在S.酿酒厂使它成为一个 进行这些研究的理想生物。对这些蛋白质的新认识 将导致抗真菌化合物的强有力的候选靶标， 用于识别癌细胞的标记物。此外，对酵母的了解 在这些研究中获得的复制蛋白将指导研究， 这些蛋白质的人类类似物的抑制剂，其代表重要的 新型化疗化合物的靶点。

DESCRIPTION: The timely and accurate replication of the genome is essential to the normal proliferation of all eukaryotic cells. Accordingly the initiation of DNA replication is carefully coordinated with the progress of the cell cycle. The long-term objective of this proposal is to determine the events that select the sites of DNA replication and activate the initiation process. The origin recognition complex (ORC) is a key factor controlling these events. ORC is the only S. cerevisiae protein known to specifically recognize all yeast origins of replication. Once bound to these sites, ORC acts to recruit other replication factors to the origin of replication. In this proposal, Dr. Bell will exploit his recent advances in understanding the biochemical functions of ORC to determine how these functions are mechanistically coupled to the replication initiation process. Specifically Dr. Bell will: Determine the mechanism of DNA binding by ORC and how this event alters the function of ORC in the cell. These studies will provide critical information concerning the mechanisms that select origins of replication. Determine the function of ORC during replication complex assembly and activation at origins of replication. Using both biochemical analysis of replication factor interaction and a genetic screen for novel ORC mutants, these studies will define key events required for the assembly of essential replication complexes. Determine the influence of nucleosomes on ORC and origin function. Using nucleosome assembly reactions and a novel genome-wide assay for determining the sites of ORC binding, Dr. Bell will dissect the impact of nucleosomes and chromatin on DNA replication. The highly conserved nature of eukaryotic DNA replication strongly argues that any new understanding of the fundamental mechanisms of eukaryotic DNA replication in yeast will be readily translated to our understanding of the same process in human cells. The rapid progress that can be made in S. cerevisiae make it an ideal organism to perform these studies. New understanding of these proteins will lead to strong candidate targets for anti-fungal compounds and potential markers to identify cancer cells. In addition, the understanding of the yeast replication proteins gained in these studies will direct studies to identify inhibitors of the human analogs of these proteins, which represent important targets for novel chemotherapeutic compounds.