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复制过程中发生的错配错误。 在真核生物中，MSH蛋白在碱基和插入/缺失的背景下识别这些错误 错配和招募MLH复合体形成与复制因子和Exo1共同作用的三元复合体 通过错配位置切除新复制的DNA链。这之后是DNA的重新合成 台阶。MMR因子还识别在同源基因的链侵袭步骤中形成的错配 重组；他们招募解旋酶复合体来解开(拒绝)重组中间体，并允许 新的同源搜索。西德尼·罗森的夏季研究旨在了解 当DNA序列中发生双链断裂时，在同源重组期间发生 使用含有低水平序列分歧的供体序列修复(父母赠款中的项目3 R35GM134872)。更具体地说，她感兴趣的是如何理解动力学和亚核 用相同供体序列比较酿酒酵母中同源重组的位置(S) 作为修复的模板而不是发散的供体模板。她计划跟踪和测量维修的时间 通过参与同源重组的荧光标记蛋白诱导的DSB(RAD52) 作为核孔成分。她的假设是，不同序列之间的重组将导致 维修速度较慢，维修地点可能存在差异。这一时间进程的结果将提供更好的 了解排斥决定是如何促成的，以及染色体重排如何导致 疾病。悉尼对进入分子生物学博士项目表现出了强烈的兴趣， 从康奈尔大学毕业。她将成为转化面包师酵母和分析转化子的经验丰富的人 采用免疫印迹分析、荧光和共聚焦显微镜观察。她还将学习适当的 对她的每一个实验进行了统计分析。她的导师每天都会和她见面，讨论她的研究 进展和计划未来的实验。她已经是小组会议和日记俱乐部的积极参与者， 介绍研究总结和正式报告。今年夏天，西德妮将加入我们部门的 本科生暑期研究经验(REU)项目，在那里她将获得演讲经验 她的作品有书面和口头形式。

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.