Mismatch repair in Bacillus subtilis

智力优势：DNA错配修复识别并修复在基因组复制过程中合并的DNA聚合酶错误。关于细菌错配修复的绝大多数研究工作都致力于研究革兰氏阴性菌大肠杆菌中的错配修复途径。大肠杆菌使用DNA甲基化依赖的修复途径来检测新合成的DNA链，这是罕见的，主要局限于大肠杆菌及其近亲。最近的证据表明，错配修复的一种更普遍的机制在大多数细菌和所有真核系统中发挥作用。在革兰氏阳性菌枯草芽孢杆菌中的错配修复途径是甲基化不依赖的，并与大多数其他系统中存在的错配修复途径高度保守，包括甲基化独立修复的标志要求，一种含有核酸内切酶的蛋白质MutL。它的错配修复系统与真核生物和大多数其他细菌的错配修复系统相似，再加上它的众多遗传、细胞生物学和生化工具，使枯草杆菌成为了解错配修复的普遍机制的理想平台，这些机制在整个生物学中都是保守的。这项研究调查了错配修复与枯草杆菌DNA复制机制相结合的机制。最近，PI的实验室发现错配修复蛋白MutS和MutL直接结合DNA复制机制，这表明错配修复蛋白与DNA复制机制之间的特定接触对修复的几个步骤至关重要。这个项目将描述与DNA复制复合体协调错配修复的机制，从而了解在缺乏甲基化指导的修复系统的生物体中识别和修复错配所需的保守步骤。此外，这项研究项目将影响和推动DNA修复、DNA复制和突变领域的信息。广泛影响：该项目将影响大学和社区的教育。首先，将教授一门为本科生评估初级文学的高级课程，同时还将有机会了解国际文学联合会的实验室是如何进行实践最先进的研究的。这一经历将培养一个独特而有效的学习环境，促进科学发展，让学生充分参与学习。其次，在现代科学中，研究生和本科生迫切需要研究一个完整的系统，而不是孤立地学习各个组成部分。这个项目的一个组成部分是用一种科学的方法培训研究生和本科生，这种方法考虑到多种细胞成分如何共同发挥作用。此外，研究生和本科生将参与跨学科研究计划的所有方面。第三，PI和PI实验室的成员将参与社区外联活动，其中将包括参观当地的高中和中学，并在实验室接待学生，向他们教授包括活细胞成像技术在内的尖端微生物科学。

Intellectual Merit: DNA mismatch repair recognizes and repairs DNA polymerase errors that are incorporated during genome replication. The vast majority of research efforts on bacterial mismatch repair have been devoted to the study of the pathway in the Gram-negative bacterium Escherichia coli. E. coli uses a DNA methylation-dependent repair pathway to detect the newly synthesized DNA strand, which is rare and mostly restricted to E. coli and its close relatives. Recent evidence suggests that a more universal mechanism of mismatch repair operates in most bacteria and all eukaryotic systems. The mismatch repair pathway in the Gram-positive bacterium Bacillus subtilis is methylation-independent and shows a high level of conservation with the mismatch repair pathway present in most other systems, including the hallmark requirement of methylation-independent repair, an endonuclease-containing protein, MutL. The similarity of its mismatch repair system to those of eukaryotes and most other bacteria, together with its numerous genetic, cell biological, and biochemical tools, makes B. subtilis an ideal platform for understanding universal mechanisms of mismatch repair that are conserved throughout biology. This research investigates the mechanisms that couple mismatch repair to the DNA replication machinery in B. subtilis. Recently, the PI's laboratory found that mismatch repair proteins MutS and MutL directly bind the DNA replication machinery, suggesting that specific contacts between mismatch repair proteins and the DNA replication machinery are critical for several steps in repair. This project will characterize the mechanisms that coordinate mismatch repair with the DNA replication complex, leading to an understanding of conserved steps required for the identification and repair of mismatches in organisms that lack a methylation-directed repair system. Furthermore, this research project will impact and advance information in the fields of DNA repair, DNA replication and mutagenesis.Broader Impacts: This project will impact education at the university and in the community. First, an upper level course for undergraduates evaluating the primary literature will be taught along with an opportunity to learn how hands-on state-of-the-art research is conducted in the PI's laboratory. This experience will foster a unique and effective learning environment that will advance science and fully engage students in learning. Second, in modern science there is a critical need for graduate and undergraduate students to study an intact system as opposed to components in isolation. An integral part of this project is to train graduate and undergraduate students in a scientific approach that takes into account how multiple cellular components function together. Furthermore, graduate and undergraduate students will be involved in all aspects of the interdisciplinary research program. Third, the PI and members of the PI's laboratory will participate in community outreach, which will include visiting local high schools and middle schools, and hosting students in the lab to teach them cutting-edge microbial sciences including live cell imaging techniques.