Repair of DNA ends with adducts

用加合物修复 DNA 末端

基本信息

批准号：
10587000
负责人：
SANG EUN LEE
金额：
$ 31万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-03-15 至 2027-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10587000
关键词：
APEXL2 Gene Address Aging Alleles Antineoplastic Agents BRCA deficient BRCA1 gene BRCA2 gene Base Excision Repairs Binding Proteins Biochemical Biochemical Genetics Biochemistry Biological Biological Assay Biological Models Biological Process Camptothecin Cell Death Cell physiology Cells Chemicals Chromatin Collaborations Complex DNA DNA Adduction DNA Adducts DNA Damage DNA Repair DNA Repair Pathway DNA lesion DNA replication fork DNA-(apurinic or apyrimidinic site) lyase DNA-Directed DNA Polymerase DNA-Directed RNA Polymerase DNA-protein crosslink Deoxyribonucleases Development Disease Disease Resistance Environmental Pollutants Enzymes Etiology Excision Exposure to Formaldehyde Foundations Gene Expression Genetic Genetic Recombination Genome Genomic Instability Genomics Growth Histones Homologous Gene Human Interruption Investigation Laboratories Lymphopoiesis Maintenance Malignant neoplasm of liver Malignant neoplasm of ovary Modeling Molecular Genetics Motor Neuron Disease Movement Mus Mutagenesis Mutation Nerve Degeneration Nucleotide Excision Repair Nucleotides Pathway interactions Patients Peptide Hydrolases Peptides Periodicity Physiological Process Property Proteins Proteolysis Reaction Regulation Repair Complex Repetitive Sequence Research Resistance Ribonucleotides Role Single Strand Break Repair Stress Symptoms Tail Technical Expertise Testing Therapeutic Topoisomerase Toxin Type I DNA Topoisomerases Tyrosine Ubiquitin Ubiquitination Yeasts adduct anti-cancer cancer cell crosslink environmental chemical genetic approach homologous recombination human disease innovation inorganic phosphate malignant breast neoplasm multicatalytic endopeptidase complex mutant nuclease prevent protein complex receptor reconstitution repaired response seal therapy resistant

项目摘要

Project Summary Environmental pollutants and anti-cancer chemicals induce DNA–protein crosslinks (DPCs, also known as protein adducts) of topoisomerases and other proteins that obstruct almost every chromatin transaction and lead to mutations, genome instability and cell death if not removed quickly. Cells thus possess multiple mechanisms to remove DPCs: homologous recombination, nucleotide excision repair and proteolytic repair that involves proteolysis of bound proteins and nucleolytic cleavage of peptide-DNA bonds. Among these, proteolytic DPC repair is poorly defined and there are many questions about this unique collaboration between protease and nuclease and their substrate recognition. Using genetic and biochemical approaches, we have discovered that Apn2, the evolutionarily conserved back-up AP endonuclease, possesses an enzymatic activity unblocking DNA ends with various 3’ adducts including 2’,3’-cyclic phosphate, monophosphate and tyrosine DNA conjugates. We also found that Apn2 removes DNA-topoisomerase I crosslinks, the flagship DPC at 3' termini. The results might explain several puzzling symptoms in mice deleted for APE2, the metazoan Apn2 homolog, including dys-lymphopoiesis and growth retardation. The results also underscore the importance of 3’ blocked termini processing for genome maintenance and reveal unique challenges in removing these toxic DNA lesions in a tractable model system. Nevertheless, our results also raise a new set of questions about the regulation of Apn2 and APE2 in 3' adduct repair. For instance, we aim to determine how Apn2 recognizes a wide range of 3’ termini with different structural features and how such activities are regulated under unique cellular and functional contexts. We also want to elucidate the biological significance of Apn2 and human APE2-dependent Top1cc repair in cellular physology exposed to chemotherapeutics. Furthermore, we plan to define the roles of Apn2 and its interacting protease(s) in the removal of toxic DNA protein complexes (DPCs) that form via environmental pollutants and chemicals. The current proposal will address these important questions using innovative genetic and biochemical assays and shed light on the fundamental mechanisms of 3’ DNA adduct repair, mutagenesis and maintenance of chromosomal integrity. Emerging evidence suggests that accumulated DPCs cause aging, neurodegeneration and liver cancers. The human homolog of Apn2 is also essential for the viability of BRCA-deficient breast and ovarian cancer cells. The functional conservation in Top1cc and DPC repair between yeast and human further underscores the value of the proposed research in setting the foundation for analyzing the equivalent processes in human. Information gained from our proposed research plan will not only solve one of the fundamental questions in biological processes associated with mutagenesis, DNA repair, and genome maintenance, but will also impinge directly on the management and treatment of patients suffering from several devastating diseases with no clear treatment option.

项目概要环境污染物和抗癌化学物质会诱导 DNA-蛋白质交联（DPC、拓扑异构酶和其他蛋白质的蛋白质加合物）几乎阻碍了所有如果不去除染色质交换，会导致突变、基因组不稳定和细胞死亡因此，细胞拥有多种机制来去除 DPC：同源重组、核苷酸切除修复和蛋白水解修复，涉及结合蛋白的蛋白水解和其中，蛋白水解 DPC 修复效果较差。定义，并且关于蛋白酶和核酸酶及其底物识别。使用遗传和生化方法，我们发现 Apn2，即进化上的保守的备用 AP 核酸内切酶，具有解锁 DNA 末端的酶活性与各种 3' 加合物，包括 2',3'-环磷酸盐、单磷酸盐和酪氨酸 DNA 我们还发现 Apn2 消除了 DNA 拓扑异构酶 I 交联，这是旗舰 DPC。该结果可能解释了 APE2 缺失小鼠中的一些令人费解的症状。后生动物 Apn2 同源物，包括淋巴细胞生成障碍和生长迟缓。强调 3' 封闭末端处理对于基因组维护的重要性并揭示在易于处理的模型系统中去除这些有毒 DNA 损伤是一项独特的挑战。尽管如此，我们的结果也提出了一系列有关 Apn2 和 APE2 监管的新问题例如，在 3' 加合物修复中，我们的目标是确定 Apn2 如何识别各种 3' 加合物。具有不同结构特征的终点站以及这些活动如何在独特的条件下受到监管我们还想阐明 Apn2 和的生物学意义。暴露于化疗药物的细胞生理学中人类 APE2 依赖性 Top1cc 修复。此外，我们计划定义 Apn2 及其相互作用的蛋白酶在去除由环境污染物和化学物质形成的有毒 DNA 蛋白质复合物 (DPC)。当前的提案将利用创新的遗传和生化技术解决这些重要问题分析并阐明 3' DNA 加合物修复、诱变和维持染色体完整性。新出现的证据表明，累积的 DPC 会导致衰老、神经退行性疾病和 Apn2 的人类同源物对于 BRCA 缺陷的生存能力也至关重要。乳腺癌和卵巢癌细胞中 Top1cc 和 DPC 修复之间的功能保守性。酵母和人类进一步强调了拟议研究在奠定基础方面的价值用于分析从我们提出的研究中获得的人类的等效过程。计划不仅将解决与生物过程相关的基本问题之一诱变、DNA 修复和基因组维护，但也会直接影响对患有多种严重疾病且尚无明确证据的患者进行管理和治疗治疗选择。