Understanding DNA break repair pathway choice regulation by the cNHEJ inhibitor CYREN

了解 cNHEJ 抑制剂 CYREN 的 DNA 断裂修复途径选择调节

基本信息

批准号：
10397557
负责人：
Jan Karlseder
金额：
$ 43.13万
依托单位：
SALK INSTITUTE FOR BIOLOGICAL STUDIES
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-06 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10397557
关键词：
Affect Alleles Alternative Splicing Amino Acids Applications Grants Binding Cell Cycle Cell Cycle Deregulation Cell Cycle Regulation Cell Cycle Stage Cell Survival Cell physiology Cells Complex DNA DNA Damage DNA Double Strand Break DNA Repair DNA Repair Pathway Dominant-Negative Mutation Double Strand Break Repair Ensure Essential Amino Acids Event Excision Exposure to G2 Phase G22P1 gene Generations Genome Genome Stability Genomic Instability Genotoxic Stress Goals Human Human Genome Infection Invaded Lead Learning Lesion Lysine Maintenance Malignant Neoplasms Maps Metabolism Modeling Modification Mutagens Mutate Nature Neoplastic Cell Transformation Nonhomologous DNA End Joining Open Reading Frames Pathway interactions Pharmaceutical Preparations Play Point Mutation Predisposition Proteasome Inhibition Protein Isoforms Proteins Regulation Role S phase Sister Chromatid Site System Therapeutic Intervention Translating XRCC5 gene base brca gene cancer cell design experimental study genetic information genome integrity genotoxicity homologous recombination inhibitor mutant novel overexpression p53-binding protein 1 polypeptide preservation prevent public health relevance repaired telomere

项目摘要

Project Summary DNA double stranded breaks (DSBs) are deleterious lesions that require rapid repair to avoid the loss of genetic information, genomic instability, neoplastic transformation and cancer formation. In human systems, the two predominant pathways for double stranded DNA break repair are canonical non-homologous end joining (cNHEJ) and homologous recombination (HR). The cNHEJ machinery recognizes breaks, indiscriminately joins them independent of sequence context and is therefore considered error prone and potentially genotoxic. HR relies on resection of the 5’ strand with the generation of single stranded 3’ overhangs, which invade homologous sister chromatids to promote error-free break repair. Choice between HR and cNHEJ depends primarily on the cell cycle stage and the nature of the break. During G1 of the cell cycle HR is inhibited by RIF1 and 53BP1, which prevent the required BRCA1/2 complex assembly and end resection for HR initiation. During S and G2, when sister chromatids are available as a template for HR, both cNHEJ and HR pathways can be employed and compete to repair DSBs. End resection is activated by CtIP in S and G2 phases and promotes HR, but it is unclear how the abundant and efficient cNHEJ machinery is suppressed in S and G2 to allow resection at break sites and commencement of HR, thereby ensuring error- free repair of lesions to preserve genome integrity. CYREN (Cell cYcle REgulator of NHEJ) was originally identified in a screen for potential modulators of retroviral infection. Later, an alternatively spliced isoform of CYREN, CYREN-2, was found as short open reading frame translated polypeptide and shown to interact with the Ku70/80 heterodimer, pointing at a potential role in cNHEJ. Here it is proposed to investigate the discovery that CYREN modulates the cell cycle dynamics of cNHEJ and that the small protein is a direct cell cycle regulator of cNHEJ. In three specific aims it is proposed to investigate the mechanism of how CYREN inhibits cNHEJ through the CYREN interaction with the Ku heterodimer complex (AIM 1), how CYREN is cell cycle regulated and controls the cell cycle regulation of DSB repair pathway choice (AIM2) and finally what the effects of CYREN deletion and overexpression are, how the deregulation of cell cycle control of cNHEJ influences genome maintenance and genome instability and whether cells that lack CYREN are sensitive to DNA damage causing agents (AIM 3). In summary, this grant proposal focuses on CYREN, a novel regulator of DNA repair pathway choice, the mechanism of how CYREN is regulated and controls cNHEJ, whether lack of CYREN causes genome instability and whether CYREN targeting can be exploited to sensitize cancer cells to treatment with genotoxic agents.

项目摘要 DNA双链断裂（DSB）是删除的病变，需要快速修复以避免丢失遗传信息，基因组不稳定性，肿瘤转化和癌症形成。在人类系统中，双链DNA断裂修复的两种主要途径是规范的非理论端加入（CNHEJ）和同源重组（HR）。 CNHEJ机械识别休息，偶然地加入它们独立于序列上下文，因此被认为容易出错，并且潜在的遗传毒性。人力资源依赖于5'链的切除，产生了单链3' 悬垂，侵略同源姐妹染色单体以促进无错误的断裂修复。之间的选择 HR和CNHEJ主要取决于细胞周期阶段和断裂的性质。在细胞的G1期间循环HR被RIF1和53BP1抑制，这阻止了所需的BRCA1/2复合组件和结束人力资源倡议的切除。在S和G2期间，当姐妹染色单体作为HR的模板可用时，两者都可以 CNHEJ和人力资源途径可以雇用并竞争维修DSB。终端切除被CTIP激活 S和G2阶段并促进了人力资源在S和G2中被抑制以允许在休息地点切除并开始HR，从而确保错误 - 免费修复病变以保留基因组完整性。 Cyren（NHEJ的细胞周期调节剂）最初是在屏幕上鉴定出逆转录病毒感染的潜在调节剂。后来，替代剪接的同工型发现Cyren，Cyren-2，是简短的开放式阅读框翻译的多肽，并证明与之相互作用 KU70/80异二聚体指向CNHEJ中的潜在作用。在这里建议调查发现 Cyren调节CNHEJ的细胞周期动力学，而小蛋白是直接的细胞周期 CNHEJ的监管者。在三个特定的目标中，提出了研究Cyren如何抑制的机制通过Cyren与KU异二聚体复合物的相互作用（AIM 1），Cyren如何为细胞周期调节并控制DSB修复途径选择的细胞周期调节（AIM2），最后是什么 Cyren缺失和过表达的影响是CNHEJ细胞周期控制的放松管制影响基因组维持和基因组不稳定性，以及缺乏Cyren的细胞是否敏感 DNA损伤导致剂（AIM 3）。总而言之，该赠款提案的重点是Cyren，这是一个新型的监管机构 DNA修复途径的选择，Cyren的调节方式和控制CNHEJ的机制是否缺乏 Cyren引起基因组不稳定性以及是否可以探索Cyren靶向以感知癌细胞用遗传毒性药物治疗。