Alternative End-Joining in DNA Repair and Chromosomal Translocations

DNA 修复和染色体易位中的选择性末端连接

基本信息

批准号：
9099801
负责人：
Vipul Kumar
金额：
$ 3.16万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-01 至 2019-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9099801
关键词：
Antibodies Antigen Receptors B-Cell Lymphomas B-Lymphocytes BCL2 gene Biological Assay CRISPR/Cas technology Cell Cycle Cell Death Cell Line Cell Survival Cell division Cells Chemicals Chimeric Proteins Chromosomal Breaks Chromosomal Rearrangement Chromosomal translocation Chromosome Deletion Clustered Regularly Interspaced Short Palindromic Repeats Complex Cytogenetics DNA DNA Damage DNA Double Strand Break DNA Repair DNA Sequence Rearrangement Data Detection Double Strand Break Repair Embryo Exons G1 Arrest G22P1 gene Gene Mutation Gene Silencing Generations Genome Genome Stability Glucocorticoid Receptor Health Heavy-Chain Immunoglobulins Immunoglobulin Class Switching Immunoglobulin Constant Region Immunoglobulin Switch Recombination Immunoglobulin Variable Region J segment gene Lead Ligation Lymphocyte Activation Lymphomagenesis Malignant Neoplasms Mature B-Lymphocyte Mediating Mus Mutant Strains Mice Nonhomologous DNA End Joining Oncogenes Oncogenic Pathway interactions Phase Phosphotransferases Poly(ADP-ribose) Polymerases Proteins Publishing Reporter Role Site Southern Blotting System Testing Transgenes V(D)J Recombination XRCC1 gene XRCC4 gene XRCC5 gene abl Oncogene activation-induced cytidine deaminase ataxia telangiectasia mutated protein base endodeoxyribonuclease SceI endonuclease genome-wide homologous recombination insight interest nuclease p53-binding protein 1 repaired research study sensor

项目摘要

DESCRIPTION (provided by applicant): Improperly repaired DNA double-strand breaks (DSBs) can lead to cell death or chromosomal rearrangements that contribute to oncogenic transformation. The two major mammalian DSB repair pathways are homologous recombination (HR), which is active in post-replicative (S/G2) cells, and classical non-homologous end joining (C-NHEJ), which predominates in pre-replicative (G1) cells. For C-NHEJ, the Ku70/Ku80 heterodimer ("Ku") recognizes DSBs and the XRCC4/Ligase4 (Lig4) complex joins them. During V(D)J recombination in developing B lymphocytes, RAG endonuclease generated DSBs at V, D, and J gene segments are joined exclusively by C-NHEJ to assemble exons encoding antigen receptor/antibody variable regions. During immunoglobulin (Ig) heavy chain (IgH) class switch recombination (CSR) in activated mature B lymphocytes, activation-induced cytidine deaminase (AID)-initiated DSBs in IgH switch (S) regions are fused, predominantly by C-NHEJ, to exchange expressed IgH constant region exons. Aberrant joining of V(D)J- or CSR-associated DSBs can lead to chromosomal translocations that fuse antigen receptor loci to oncogenes, and, thereby, contribute to lymphomagenesis. In the absence of C-NHEJ, RAG- or AID-initiated IgH DSBs can be joined to form such oncogenic chromosomal translocations by an alternative end-joining (A-EJ) pathway (or pathways). In addition, CSR is carried out relatively robustly by A-EJ in the absence of Lig4, Ku, or both. Based on substantial preliminary data, we propose the A-EJ in the absence of Lig4 is distinct from that which occurs in the absence of Ku (or Ku plus Lig4). We refer to these two A-EJ pathways as "Lig4-independent" and "Ku- independent" A-EJ, respectively. We propose to elucidate DSB recognition and joining components of the two A-EJ pathways, their relative activity in the G1 cell cycle, and their relative contributions to normal versus aberrant end-joining that promotes chromosomal translocations. Specifically, we propose to 1) Identify factors that mediate Lig4- and/or Ku-independent A-EJ during CSR and 2) Assess potential roles of Lig4- and/or Ku- independent A-EJ in G1-arrested pro-B lines.

描述（由申请人提供）：修复不当的 DNA 双链断裂 (DSB) 可导致细胞死亡或染色体重排，从而导致致癌转化。哺乳动物 DSB 修复的两种主要途径是同源重组 (HR)，其在复制后 (S/G2) 细胞中活跃，以及经典的非同源末端连接 (C-NHEJ)，其在复制前 (G1) 细胞中占主导地位细胞。对于 C-NHEJ，Ku70/Ku80 异二聚体 (“Ku”) 识别 DSB，并且 XRCC4/连接酶 4 (Lig4) 复合物将它们连接起来。在发育中的 B 淋巴细胞中进行 V(D)J 重组期间，RAG 核酸内切酶在 V、D 和 J 基因片段上生成 DSB，并通过 C-NHEJ 专门连接，以组装编码抗原受体/抗体可变区的外显子。在激活的成熟 B 淋巴细胞中的免疫球蛋白 (Ig) 重链 (IgH) 类别转换重组 (CSR) 过程中，IgH 转换 (S) 区域中激活诱导的胞苷脱氨酶 (AID) 启动的 DSB 主要通过 C-NHEJ 融合，交换表达IgH恒定区外显子。 V(D)J 或 CSR 相关 DSB 的异常连接可导致染色体易位，使抗原受体基因座与癌基因融合，从而导致淋巴瘤发生。在 C-NHEJ 不存在的情况下，RAG 或 AID 引发的 IgH DSB 可以通过替代末端连接 (A-EJ) 途径（或多种途径）连接形成此类致癌染色体易位。此外，在 Lig4、Ku 或两者均不存在的情况下，A-EJ 可以相对稳健地执行 CSR。基于大量初步数据，我们认为缺乏 Lig4 时的 A-EJ 与缺乏 Ku（或 Ku 加 Lig4）时发生的情况不同。我们将这两条 A-EJ 途径分别称为“Lig4 独立”和“Ku 独立”A-EJ。我们建议阐明 DSB 识别和连接两条 A-EJ 途径的组成部分、它们在 G1 细胞周期中的相对活性，以及它们对促进染色体易位的正常末端连接与异常末端连接的相对贡献。具体来说，我们建议 1) 确定在 CSR 过程中介导 Lig4 和/或 Ku 独立 A-EJ 的因素，以及 2) 评估 Lig4 和/或 Ku 独立 A-EJ 在 G1 阻滞的 pro-B 系中的潜在作用。