Inflammation as a Mediator of Dynamic DNA Mutations

炎症作为动态 DNA 突变的中介

基本信息

批准号：
8272599
负责人：
Sarah Delaney
金额：
$ 37.9万
依托单位：
BROWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-22 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8272599
关键词：
7,8-dihydro-8-oxoguanine 8-hydroxyguanosine Adopted Aflatoxin B Aflatoxin B1 Area Binding Biological Biological Assay Cells Chemicals Chromatin Chronic Complex DNA DNA Damage DNA Packaging DNA Repair Enzymes DNA Sequence Data Diet Diet Modification Disease Disease Progression Environmental Carcinogens Environmental Exposure Epidemiology Event Excision Family Gene Mutation Generations Genes Genetic Anticipation Goals Hepatitis B Hepatitis B Virus Hot Spot Human Huntington Disease In Vitro Individual Infectious Agent Inflammation Inflammatory Inflammatory Response Intervention Knowledge Laboratories Lead Length Link Location Malignant Neoplasms Malignant neoplasm of liver Mediating Mediator of activation protein Methods Modeling Modification Molecular Molecular Conformation Mutation Neurodegenerative Disorders Nitrates Nitric Oxide Nucleosome Core Particle OGG1 gene Oligonucleotides Pathway interactions Patients Pattern Peroxonitrite Play Polymerase Primer Extension Process Proteins Reaction Relative (related person)Relative Risks Research Risk Role Source Structure Superoxides Testing Tissues Trauma Trinucleotide Repeats Work base cytokine design environmental agent experience human Huntingtin protein human disease macrophage mouse model nucleobase oxidation oxidative DNA damage oxidative damage prevent public health relevance repaired research study synergism therapy design

项目摘要

DESCRIPTION (provided by applicant): The goal of this work is to define the mechanism by which DNA damage resulting from an inflammatory response or other environmental sources of damage contribute to dynamic DNA mutations. Dynamic mutations are characterized by the expansion of a triplet repeat sequence such as (CAG)n/(CTG)n and are known to be the primary pathogenic signature of several neurodegenerative disorders. As one example, 5-35 repeats are present in the huntingtin gene of normal individuals but there are more than 40 repeats in Huntington's disease (HD) patients. Using a mouse model of HD, recent work from other laboratories has implicated the oxidative DNA damage product 7,8-dihydro-8-oxoguanine (8-oxoG) in dynamic mutations. Furthermore, the DNA repair enzyme OGG1, which is known to remove 8-oxoG from DNA duplexes, has also been linked to dynamic mutations. Our central hypothesis is based on our preliminary data that (CAG)n and (CTG)n sequences adopt non-B conformations that are hyper-susceptible to DNA damage relative to duplex, including the formation of 8-oxoG. In addition to containing hot spots for DNA damage we have also found that these non-B conformations are not efficiently repaired by OGG1. We postulate that formation of an OGG1- DNA misrepair complex stabilizes the non-B conformation and the DNA is then misreplicated and polymerase incorporates excess triplet repeats. This proposal outlines four specific aims to test our hypothesis. First, studies are proposed to identify the conformation of a family of repetitive CAG/CTG sequences that are prone to dynamic mutations. These experiments will be performed both with oligonucleotide substrates and also DNA in nucleosome core particles (NCP) which model the packaging of DNA in chromatin. Second, the patterns of damage in the triplet repeat DNA will be established using peroxynitrite as the damaging agent. Peroxynitrite is the reactive species produced during inflammation and is known to convert G to 8-oxoG. Third, the OGG1-mediated repair of 8-oxoG-containing DNA substrates, both oligonucleotide and NCP, will be characterized. The final aim of this proposal is to define the processing of damage-containing CAG/CTG sequences by the replication machinery and elucidate the role of OGG1 in modulating replication fidelity. PUBLIC HEALTH RELEVANCE: The goal of this research is to define how the DNA damage derived from an inflammatory response or other environmental sources contribute to dynamic DNA mutations. In particular, this work will describe how the DNA damage product 7,8-dihydro-8-oxoguanine contributes to disease-initiating dynamic mutations. This knowledge is expected to provide the information needed to rationally design interventions to prevent or delay the onset of multiple diseases that are caused by dynamic mutations.

描述（由申请人提供）：这项工作的目的是定义由炎症反应或其他损伤造成的DNA损伤的机制，从而导致动态DNA突变。动态突变的特征是三胞胎重复序列（例如（CAG）n/（ctg）n）的扩展，已知是几种神经退行性疾病的主要致病性特征。一个例子，正常个体的亨廷顿基因中存在5-35个重复，但亨廷顿氏病（HD）患者有40多个重复。使用HD的小鼠模型，来自其他实验室的最新工作暗示了动态突变中的氧化DNA损伤产物7,8-二氢-8-氧气（8-oxog）。此外，已知可以从DNA双链体中去除8-oxog的DNA修复酶也与动态突变有关。我们的中心假设是基于我们的初步数据，即（CAG）N和（CTG）N序列采用非B构象，这些构象相对于DNA损伤，相对于双链体，包括8-oxog的形成，对DNA损伤具有非常敏感性。除了含有用于DNA损伤的热点外，我们还发现这些非B构象没有通过OGG1有效地修复。我们假设OGG1-DNA虚假络合物的形成稳定了非B构象，然后将DNA稳定下来，然后将DNA混杂，聚合酶结合了多余的三重态重复序列。该提案概述了四个特定的目的旨在检验我们的假设。首先，提出了研究以确定容易发生动态突变的重复CAG/CTG序列的构象。这些实验将用寡核苷酸底物和核小体核心颗粒（NCP）中的DNA进行，该实验将模拟DNA在染色质中的包装。其次，将使用过氧亚硝酸盐作为损害剂建立三重态重复DNA中损伤的模式。过氧亚硝酸盐是炎症过程中产生的反应性物种，已知将G转换为8-oxog。第三，将表征OGG1介导的8-氧基DNA底物（寡核苷酸和NCP）的修复。该提案的最终目的是通过复制机制来定义处理含损害的CAG/CTG序列的处理，并阐明OGG1在调节复制保真度中的作用。公共卫生相关性：这项研究的目的是定义从炎症反应或其他环境来源造成的DNA损伤如何有助于动态DNA突变。特别是，这项工作将描述DNA损伤产物如何7,8-二氢-8-氧气氨酸有助于疾病引发动态突变。预计该知识将提供理性设计干预措施所需的信息，以防止或延迟由动态突变引起的多种疾病的发作。