The Role of Mono-ADP-Ribosylation by PARP14 in Radioresistance

PARP14 的单 ADP 核糖基化在放射抗性中的作用

基本信息

批准号：
10594033
负责人：
George Lucian Moldovan
金额：
$ 37.95万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-02-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10594033
关键词：
ADP ribosylation Affect BRCA deficient BRCA1 Protein BRCA2 Protein Binding Biochemical Biological Assay Cell physiology Cells Chemotherapy and/or radiation Chromosomal translocation Clinic Clinical Complex DNA DNA Damage DNA Double Strand Break DNA Repair DNA biosynthesis DNA lesion DNA replication fork Development Double Strand Break Repair EXO1 gene Excision Family Genome Genome Stability Genomic DNA Genomic Instability Goals Health Human Knowledge Lesion Measures Mediating Mutagenesis Pathway interactions Process Proteins Radiation Radiation Tolerance Resistance Role Single-Stranded DNA Sister Chromatid Site Structure Testing Tumor Markers Tumor Suppression cancer risk cancer therapy carcinogenesis cell type chemotherapy environmental agent genotoxicity homologous recombination inhibitor member mutant novel novel marker nuclease radiation resistance radiation response recruit response risk prediction translocase tumor

项目摘要

Project Summary DNA double stranded breaks (DSBs) interfere with cellular viability, but also initiate chromosomal translocations resulting in genomic instability and promoting carcinogenesis. BRCA1 and BRCA2 proteins are essential for homologous recombination (HR)-mediated repair of DSBs. Understanding the mechanisms of the BRCA pathway has broad implications for human health. When replication forks encounter damaged DNA, they arrest and unless properly processed, they collapse leading to DNA breaks and genomic instability. To avoid their collapse, stalled forks can be reversed by annealing the two nascent strands to each other, in a process catalyzed by DNA translocases such as ZRANB3. The BRCA proteins load RAD51 on reversed forks to protect the DNA ends against degradation by the nuclease MRE11. The ability to protect forks against degradation corelates with DNA damage sensitivity. Thus, replication fork protection is essential for DNA repair and genomic stability. However, how protection of stalled replication forks against nucleolytic degradation is achieved represents a major knowledge gap. The PARP family at least 17 members, with various and lesser understood functions than the founding member PARP1. PARP14 has been associated with multiple cellular processes, but mechanistic details are generally sparse. We previously showed that PARP14 loss reduces HR efficiency and sensitizes cells to radiation. Recently, we have identified a novel role of PARP14 in promoting replication fork degradation, genomic instability and DNA damage sensitivity, which is the focus on this application. For this application, our goal is to understand how PARP14 promotes fork degradation, resulting in DNA damage sensitivity of BRCA-deficient cells. Our overall hypothesis is that PARP14 interferes with the RAD51-MRE11 mechanism of control of DNA resection at reversed replication forks to trigger nascent strand degradation, thus enhancing DNA damage sensitivity in BRCA-deficient cells. Aim 1 is to reveal the impact of PARP14 on RAD51-mediated protection of stalled replication forks. We hypothesize that PARP14 interferes with BRCA-independent stabilization of RAD51 on reversed forks, to enhance their degradation. Aim 2 is to uncover how PARP14 engages MRE11 for nucleolytic degradation of damaged forks. We hypothesize that PARP14 binds to stalled replication forks in BRCA-deficient cells and recruits MRE11 to initiate nucleolytic degradation of nascent DNA at these structures. Aim 3 is to elucidate the role of KU in fork protection against nucleolytic resection by EXO1 and MRE11. We hypothesize that KU binding to reversed forks protects them against EXO1-mediated degradation, but enables nascent strand resection by the MRE11-PARP14 complex. Since DNA damaging agents promote genomic instability by inducing nascent strand degradation, potentially underlying their carcinogenesis, successful accomplishment of these Specific Aims would reveal a new mechanism of genome stability and tumor suppression, centered on PARP14. It may also reveal PARP14 as a biomarker for the tumor response to radiation and genotoxic chemotherapy, in the context of the BRCA status.

项目概要 DNA 双链断裂 (DSB) 会干扰细胞活力，但也会启动染色体易位导致基因组不稳定并促进癌变。 BRCA1 和 BRCA2 蛋白是对于同源重组 (HR) 介导的 DSB 修复至关重要。了解其机制 BRCA 通路对人类健康具有广泛的影响。当复制叉遇到受损的DNA时，它们会停滞，除非经过适当处理，否则它们会崩溃，导致 DNA 断裂和基因组不稳定。到为了避免它们的崩溃，可以通过将两条新生链相互退火来逆转停滞的叉，该过程由 ZRANB3 等 DNA 转位酶催化。 BRCA 蛋白将 RAD51 装载在反向叉上保护 DNA 末端免受核酸酶 MRE11 的降解。保护货叉的能力降解与 DNA 损伤敏感性相关。因此，复制叉保护对于 DNA 修复至关重要和基因组稳定性。然而，如何保护停滞的复制叉免受溶核降解？所取得的成就代表着重大的知识差距。 PARP家族至少有17名成员，成员种类繁多，数量较少。比创始成员 PARP1 更了解功能。 PARP14 与多种细胞相关过程，但机械细节通常很少。我们之前表明 PARP14 损失会降低 HR 效率并使细胞对辐射敏感。最近，我们发现了 PARP14 在促进复制叉降解、基因组不稳定性和DNA损伤敏感性是本次研究的重点应用。对于此应用程序，我们的目标是了解 PARP14 如何促进分叉降解，从而导致 BRCA 缺陷细胞的 DNA 损伤敏感性。我们的总体假设是 PARP14 干扰 RAD51-MRE11 控制反向复制叉 DNA 切除以触发新生链的机制降解，从而增强 BRCA 缺陷细胞的 DNA 损伤敏感性。目标 1 是揭示影响 PARP14 对 RAD51 介导的停滞复制叉的保护。我们假设 PARP14 干扰与 BRCA 无关的 RAD51 在反向叉上的稳定性，以增强其降解。目标 2 是揭示 PARP14 如何与 MRE11 结合以对受损叉进行溶核降解。我们假设 PARP14 与 BRCA 缺陷细胞中停滞的复制叉结合，并招募 MRE11 启动溶核这些结构中新生 DNA 的降解。目标 3 是阐明 KU 在前叉保护中的作用 EXO1 和 MRE11 进行溶核切除。我们假设 KU 与反向叉的结合可以保护它们对抗 EXO1 介导的降解，但能够通过 MRE11-PARP14 复合物切除新生链。由于 DNA 损伤剂通过诱导新生链降解而促进基因组不稳定，因此可能在其致癌作用的基础上，成功实现这些具体目标将揭示一个新的以PARP14为中心的基因组稳定性和肿瘤抑制机制。它还可能揭示 PARP14 作为在 BRCA 状态的背景下，肿瘤对放射和基因毒性化疗反应的生物标志物。