c-myc DNA breaks and c-myc-IgH locus translocations: roles of AID and oxidation

c-myc DNA 断裂和 c-myc-IgH 基因座易位：AID 和氧化的作用

基本信息

批准号：
8097530
负责人：
Janet M. Stavnezer
金额：
$ 24.43万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
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：
2010-07-01 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8097530
关键词：
Acetylcysteine Address Affect Amino Acids Antibodies B-Cell Lymphomas B-Lymphocytes Bacterial Toxins Cells Chromosomal translocation Cytidine Deaminase DNA DNA Double Strand Break DNA lesion DNA repair protein Deaminase Deamination Event Frequencies Generations Genes Genetic Recombination Glutathione IGH@ gene cluster IgE Immunoglobulin A Immunoglobulin Class Switching Immunoglobulin G Immunoglobulin Genes Immunoglobulin M Immunoglobulin Somatic Hypermutation Immunoglobulin Switch Recombination Immunoglobulins Lead Lesion Ligation MYC gene Malignant Neoplasms Mediating Mitochondria Multiple Myeloma Mus Mutation Oncogenes Process Proteins Publishing Reaction Reactive Oxygen Species Recruitment Activity Respiration Role Signal Transduction Site activation-induced cytidine deaminase c-myc Genes cell transformation improved oxidation pathogen public health relevance repaired response variable region gene

项目摘要

DESCRIPTION (provided by applicant): Antibody (immunoglobulin, Ig) class switch causes B lymphocytes to switch from producing IgM to producing IgG, IgA or IgE, which improves the ability of the antibody to remove pathogens and bacterial toxins from the body. Class switching occurs by an intrachromosomal DNA recombination event that must be carefully controlled in order to avoid aberrant recombination with other chromosomes (translocations). However, occasional translocations do occur. Sometimes they result in B lymphomas or myelomas due to translocations of the Ig genes to a chromosomal site encoding an oncogene, e.g. c-myc, which induces aberrant expression of the c-myc gene. This application proposes to investigate how DNA double-strand breaks (DSBs) are introduced into the mouse c-myc gene and the role of activation-induced cytidine deaminase (AID) in the process of c-myc-IgH translocations. In Aim 1, we will investigate the hypothesis that reactive oxygen species (ROS) induce DNA lesions that lead to DSBs in the c-myc gene, and also stimulate the deamination activity of AID, as deamination occurs by an oxidation reaction. In Aim 2, we will investigate whether AID has additional activities besides its deaminase activity that contribute to creating c- myc-IgH translocations. In Aim 3, we will investigate the role of the 10 amino acids at the C terminus of AID, which is required for class switch recombination but not for somatic hypermutation, and has been shown to repress c-myc-IgH translocations. We will examine the hypothesis that DNA repair proteins involved in switch recombination are recruited by the C terminus. PUBLIC HEALTH RELEVANCE: This project investigates the events that initiate the generation of B cell lymphomas and myelomas. We will study how DNA breaks are introduced into the c-myc oncogene when normal mouse B cells are induced to undergo the normal process of antibody class switching in response to activation signals. These DNA breaks can result in translocations of the c-myc oncogene to the immunoglobulin (Ig) heavy (H) chain gene locus, which increases expression of the c-myc gene, and this can lead to cell transformation and malignancy. We will study whether the protein that is required for initiating DNA break formation in the IgH genes during antibody class switching (activation-induced cytidine deaminase, AID) is required for introducing DNA breaks into the c-myc gene, and whether AID has additional roles that lead to the translocations between the IgH genes and c-myc genes. We will also investigate the function of AID itself during normal class switching, as this affects translocations between the c-myc gene and the IgH locus.

描述（申请人提供）：抗体（免疫球蛋白，Ig）类别转换导致B淋巴细胞从产生IgM转变为产生IgG、IgA或IgE，从而提高抗体清除体内病原体和细菌毒素的能力。类别转换是通过染色体内 DNA 重组事件发生的，必须仔细控制该重组事件，以避免与其他染色体发生异常重组（易位）。然而，偶尔也会发生易位。有时，由于 Ig 基因易位至编码癌基因的染色体位点，例如 B 淋巴瘤或骨髓瘤，它们会导致 B 淋巴瘤或骨髓瘤。 c-myc，它诱导 c-myc 基因的异常表达。本申请旨在研究 DNA 双链断裂 (DSB) 如何被引入小鼠 c-myc 基因中，以及激活诱导的胞苷脱氨酶 (AID) 在 c-myc-IgH 易位过程中的作用。在目标 1 中，我们将研究这样的假设：活性氧 (ROS) 会诱导 DNA 损伤，导致 c-myc 基因中出现 DSB，并且还会刺激 AID 的脱氨活性，因为脱氨是通过氧化反应发生的。在目标 2 中，我们将研究 AID 除了其脱氨酶活性之外是否还具有有助于产生 c-myc-IgH 易位的其他活性。在目标 3 中，我们将研究 AID C 末端 10 个氨基酸的作用，这是类转换重组所必需的，但不是体细胞超突变所必需的，并且已被证明可以抑制 c-myc-IgH 易位。我们将检验以下假设：参与开关重组的 DNA 修复蛋白是由 C 末端招募的。公共健康相关性：该项目调查引发 B 细胞淋巴瘤和骨髓瘤产生的事件。我们将研究当正常小鼠 B 细胞响应激活信号而被诱导经历抗体类别转换的正常过程时，DNA 断裂如何被引入到 c-myc 癌基因中。这些 DNA 断裂可导致 c-myc 癌基因易位至免疫球蛋白 (Ig) 重 (H) 链基因位点，从而增加 c-myc 基因的表达，从而导致细胞转化和恶性肿瘤。我们将研究抗体类别转换过程中 IgH 基因中启动 DNA 断裂形成所需的蛋白质（激活诱导胞苷脱氨酶，AID）是否需要将 DNA 断裂引入 c-myc 基因，以及 AID 是否具有其他作用导致 IgH 基因和 c-myc 基因之间的易位。我们还将研究 AID 本身在正常类别转换过程中的功能，因为这会影响 c-myc 基因和 IgH 基因座之间的易位。