Roles for Mismatch Repair Proteins in Maintaining Genome Stability

项目摘要 DNA错配修复（MMR）系统用于切除DNA复制期间发生的错误掺入错误。 在真核生物中，MSH蛋白在碱基-碱基和插入/缺失的背景下识别这些错误 错配并募集MLH复合物，形成与复制因子和Exo 1一起工作的三元复合物 通过错配位点切除新复制的DNA链。接下来是DNA重新合成 步MMR因子还识别在同源染色体中链侵入步骤期间形成的错配。 它们募集解旋酶复合物，解旋（拒绝）重组中间体，并允许重组。 新的同源性搜索。悉尼罗森的夏季研究旨在了解决策步骤， 当DNA序列中发生双链断裂时， 使用含有低水平序列差异的供体序列进行修复（项目3在父母资助 R35GM134872）。更具体地说，她有兴趣了解动力学和亚核 同源重组的位置。当使用相同的供体序列时， 作为修复的模板与不同的供体模板。她计划跟踪和测量修复的时间 通过参与同源重组的荧光标记蛋白（Rad 52）诱导DSB 作为核孔组分。她的假设是，不同序列之间的重组将导致 修复速度较慢以及修复位置可能存在差异。从这个时间过程的结果将提供一个更好的 了解排斥决定是如何促进的，以及染色体重排如何导致 疾病悉尼对攻读博士学位表示了浓厚的兴趣。在分子生物学方面， 从康奈尔大学毕业她将成为经验丰富的转化面包酵母和分析转化体 使用蛋白质印迹分析和荧光和共聚焦显微镜。她还将学习适当的 对她的每个实验进行统计分析。她的导师将每天与她会面，讨论她的研究 并计划未来的实验。她已经是小组会议和期刊俱乐部的积极参与者， 发表研究摘要和正式报告。今年夏天，悉尼将加入我们部门的 夏季研究经验的本科生（REU）计划，她将获得经验介绍 她以书面和口头形式工作。

Project Summary DNA mismatch repair (MMR) systems act to excise misincorporation errors that occur during DNA replication. In eukaryotes MSH proteins recognize these errors in the context of base-base and insertion/deletion mismatches and recruit MLH complexes to form ternary complexes that work with replication factors and Exo1 to excise the newly replicated DNA strand through the mismatch site. This is followed by DNA re-synthesis steps. MMR factors also recognize mismatches that form during strand invasion steps in homologous recombination; they recruit a helicase complex that unwinds (rejects) recombination intermediates and allows a new homology search. Sydney Rosen's summer research is aimed at understanding the decision steps that take place during homologous recombination when a double-strand break occurring in a DNA sequence is repaired using a donor sequence containing low levels of sequence divergence (Project 3 in parent grant R35GM134872). More specifically, she is interested in understanding how the kinetics and subnuclear location(s) of homologous recombination in S. cerevisiae compare when an identical donor sequence is used as a template for repair versus a divergent donor template. She plans to track and measure the timing of repair of an induced DSB via a fluorescence-marked protein involved in homologous recombination (Rad52) as well as nuclear pore components. Her hypothesis is that recombination between divergent sequences will result in slower repair and possibly differences in repair location. Results from this time course will provide a better understanding of how the rejection decision is facilitated, and how chromosomal rearrangements can lead to disease. Sydney has expressed strong interest in entering a Ph.D. program in molecular biology after graduating from Cornell. She will become experienced transforming baker's yeast and analyzing transformants using western blot analysis and fluorescence and confocal microscopy. She will also learn the appropriate statistical analyses for each of her experiments. Her mentors will meet with her daily to discuss her research progress and plan future experiments. She is already an active participant in group meeting and journal club, presenting research summaries and formal presentations. Over the summer Sydney will join our department's summer Research Experience for Undergraduates (REU) program where she will gain experience presenting her work in written and oral formats.