Processing and Repair of DNA Crosslinks

项目摘要 DNA交联，包括链间交联（ICL）和DNA-蛋白质交联（DPC）是DNA的形式， DNA中不断出现的内源性和自然来源的损伤。它们必须被移除 以允许精确的基因组复制和基因表达。许多化疗药物诱导ICLs 包括氮芥和衍生物（美法仑、苯丁酸氮芥）、青霉烯类、丝裂霉素C、铂- 基于化合物如顺铂和亚硝基脲如BCNU。确定和今后的发展 与ICL修复能力相关的生物标志物将促进个体患者的精确医疗。 患者尽管交联在癌症病因学和治疗中的重要性，但DNA交联的机制 维修只知道轮廓，许多步骤只是假设。一种综合的方案办法 涉及四个研究项目和两个服务核心，将根据 联合国教科文组织将继续支持该计划，并单独和协同地为这一主题做出贡献。每个整体 目标/具体目标由每个项目使用独特和互补的方法独立参与。 该计划项目围绕三个目标组织，代表项目的目标： 目的1：确定如何使用或协调不同的交联修复途径。该计划将 调查有关不同交联修复途径知识的主要差距，包括核酸酶或 复合物/组件被招募并用于不同的情况，在不同的情况下， 细胞周期，交联修复的作用，在不同配置的模型停滞复制叉，是否ICL 不同损伤的修复不同，以及无错误和致突变交联修复的机制不同。目标二： 了解新发现的和很少研究的交联修复组件的功能。一个街区到达 在理解ICL修复方面取得的进展是，已知有一组成分参与ICL的修复 在交联修复中，但其中机械作用未指定或仅表面上已知。在这个项目中， 调查人员将合作确定其职能。主要未知组件包括SLX4IP（ 与SLX4相关）; HMGB1、HMGB2和HMGB3 DNA结合蛋白; MSH2-MSH3复合物 （其结合DNA畸变）;和UHRF 1（假定为用于递送核酸酶的替代支架）。 目的3：探讨DNA-蛋白质交联的修复机制。很可能有几条路线 DPC修复和公差。将进行实验以确定不同的处理模式。主要 知识的差距包括范可尼贫血（FA）通路蛋白参与修复以及如何 FA的特征可以通过DPC修复中的缺陷来解释。我们会调查复制人是否参与了 旁路（跨损伤DNA合成）耐受DNA-肽交联（蛋白水解处理的模型 DPC）。我们还将探索防止或诱导DPC诱变的途径。

PROJECT SUMMARY DNA crosslinks, including interstrand crosslinks (ICLs) and DNA-protein crosslinks (DPCs) are forms of DNA damage that arise continuously in DNA from endogenous and natural sources. They must be removed in order to allow accurate genome duplication and gene expression. Many chemotherapeutic agents induce ICLs including nitrogen mustards and derivatives (melphalan, chlorambucil), psoralens, mitomycin C, platinum- based compounds such as cisplatin, and nitrosoureas such as BCNU. Identification and future development of biomarkers associated with ICL repair proficiency will facilitate precision medical treatment for individual patients. Despite the importance of crosslinks in cancer etiology and treatment, mechanisms of DNA crosslink repair are known only in outline, and many steps are simply assumed. An integrated, programmatic approach involving four Research Projects and two service Cores will conduct experimental investigations under the auspices of the Program and contribute, both individually and synergistically, to this theme. Each Overall Goal/Specific Aim is independently engaged by each project using distinct and complementary approaches. The Program Project is organized around three aims, representing goals of the project: Aim 1: Determine how different pathways of crosslink repair are used or coordinated. The program will investigate major gaps in knowledge about different crosslink repair pathways, including how nucleases or complexes/components are recruited and used in different situations, variations of crosslink repair during the cell cycle, action of crosslink repair at different configurations of model stalled replication forks, whether ICL repair differs for different lesions, and the mechanism of error-free and mutagenic crosslink repair. Aim 2: Understand functions of newly discovered and little-studied crosslink repair components. One block to progress in understanding repair of ICLs is that there are a group of components that are known to be involved in crosslink repair, but where mechanistic roles are unassigned or known only superficially. In this program the investigators will cooperate to determine their functions. Major unknown components include SLX4IP (which associates with SLX4); the HMGB1, HMGB2 and HMGB3 DNA binding proteins; the MSH2-MSH3 complex (which binds DNA distortions); and UHRF1 (postulated as an alternative scaffold for delivery of nucleases). Aim 3: Investigate the mechanisms of repair of DNA-protein crosslinks. There are likely to be several routes of DPC repair and tolerance. Experiments will be undertaken to determine different modes of processing. Major gaps in knowledge include the involvement of Fanconi anemia (FA) pathway proteins in repair and how features of FA might be explained by defects in DPC repair. We will investigate involvement of replicative bypass (translesion DNA synthesis) in tolerance of DNA-peptide crosslinks (modeling proteolytically processed DPCs). We will also explore pathways that prevent or induce mutagenesis by DPCs.