The Completion of DNA Replication

染色体复制精确完成的机制还不清楚。为了在复制过程中保持基因组的完整性，细胞必须有能力识别复制区域，限制正在进行的复制过程，并在DNA序列加倍的精确点连接聚合的子链。 尽管存在这些复杂性，但这一过程的效率非常高（在人类细胞中每次分裂发生数千次），并且是基因组精确复制的基础。它似乎是许多癌细胞中失调的共同点，并且被病毒故意靶向灭活以诱导复制的裂解期（其中病毒快速繁殖）。 本项目将确定细胞如何感知复制区域，并在模式生物大肠杆菌和酿酒酵母的精确倍增点准确完成这一过程。 在本项目期间接受培训的学生将有资格在学术界和工业界从事研究，生物技术和医学的职业。该项目还将扩大参与该地区研究中心研究经验的本科生人数，并扩大公立学校系统K-8学生的数学和科学机会。大肠杆菌似乎涉及在多余区域被切开、切除和连接之前叉会聚的区域的瞬时过度复制。 通过监测在E.该研究将确定准确完成复制能力受损的突变体。 使用质粒微型染色体，2D和1D琼脂糖凝胶分析的组合，然后将用于确定在野生型和突变细胞中完成复制过程中出现的结构中间体。最后，该研究将通过检查酵母中的同源突变体来确定完成机制是否在真核生物中保守，以确定在复制叉会聚的地方是否观察到真核染色体上的类似异常。

The mechanism by which chromosome replication is accurately completed is not well understood. To maintain genomic integrity during replication, cells must have an ability to recognize replicated regions, limit the ongoing replication process, and join converging daughter strands at the precise point at which the DNA sequence has doubled. Despite these complexities, this process occurs with remarkable efficiency (occurring thousands of times per division in human cells) and is fundamental to the accurate duplication of the genome. It appears to be a common point of deregulation in many cancer cells and is deliberately targeted for inactivation by viruses to induce the lytic phase of replication (wherein the virus multiplies rapidly). This project will determine how cells sense replicated regions and accurately complete the proess at the precise doubling point in the model organisms, Escherichia coli and Saccharomyces cerevisiae. Students trained during this project will be qualified for careers in research, biotechnology and medicine in both academia and industry. The project will also expand the number of undergraduates who participate in research experiences at research centers in the region and expand the math and science opportunities for K-8 students in the public school system.Completion of replication in E. coli appears to involve a transient over-replication of the region where forks converge before the excess regions are incised, resected, and joined. By monitoring the copy number of DNA sequences where completion occurs in E. coli, the research will identify mutants that have an impaired ability to accurately complete replication. Using plasmid minichromosomes, a combination of 2D and 1D agarose gel analysis will then be used to identify the structural intermediates that arise during the completion of replication in both wild type and mutant cells. Finally, the research will determine if the completion mechanism is conserved in eukaryotes, by examining the homologous mutants in yeast to identify whether similar abnormalities on eukaryotic chromosomes are observed where replication forks converge.