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.

项目摘要 DNA双链断裂（DSB）干扰细胞活力，但也启动染色体易位导致基因组不稳定性并促进致癌作用。 BRCA1和BRCA2蛋白是 DSB的同源重组（HR）介导的修复必不可少的。了解 BRCA途径对人类健康具有广泛的影响。当复制叉遇到损坏的DNA时，它们逮捕并除非经过适当的处理，否则它们会崩溃，导致DNA断裂和基因组不稳定。到避免它们倒塌，可以通过在一个彼此中退火两条新生的束缚来颠倒叉子由DNA易位酶（例如Zranb3）催化的过程。 BRCA蛋白在反向叉上负载RAD51 为了保护DNA末端免受核酸酶MRE11的降解。保护叉子免受的能力与DNA损伤敏感性的降解结合。因此，复制叉保护对于DNA修复至关重要和基因组稳定性。但是，如何保护停滞的复制叉对核酸溶解降解的保护是如何的实现代表了一个主要的知识差距。 PARP家族至少有17名成员，有各种各样的成员比创始成员PARP1所理解的功能。 PARP14与多个细胞有关过程，但机械细节通常很少。我们先前表明PARP14损失减少了HR 效率并使细胞对辐射敏感。最近，我们确定了PARP14在促进中的新作用复制叉降解，基因组不稳定性和DNA损伤敏感性，这是对此的重点应用。对于此应用，我们的目标是了解PARP14如何促进分叉退化，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干扰了 RAD51-MER11控制DNA切除的机理在反向复制叉上触发新生链的机理降解，从而增强了BRCA缺陷细胞中的DNA损伤敏感性。目标1是揭示 RAD51介导的停滞复制叉的保护。我们假设PARP14干扰 RAD51在反向叉上不依赖BRCA的稳定，以增强其降解。目标2是发现PARP14如何使MRE11与受损的叉子的核解降解。我们假设这一点 PARP14与BRCA缺陷型细胞中停滞的复制叉结合，并募集MRE11启动核酸化在这些结构上新生DNA的降解。目标3是阐明KU在叉子保护中的作用 exo1和Mre11核解切除术。我们假设KU结合了反向叉子保护它们反对exo1介导的降解，但可以通过MRE11-PARP14复合物进行新生的链切除。由于DNA损伤剂通过诱导新生链降解促进基因组不稳定性，因此可能癌变的基本，成功完成这些特定目标将揭示一个新的基因组稳定性和肿瘤抑制的机制，以PARP14为中心。它也可能揭示PARP14作为一个在BRCA状态的背景下，肿瘤对放射线和遗传毒性化疗的反应的生物标志物。