Role of BRCA1 phosphorylation in DNA DSB repair and genome stability maintenance

BRCA1 磷酸化在 DNA DSB 修复和基因组稳定性维持中的作用

• 批准号: 9753187
• 负责人: YANFEN HU
• 金额: $ 37.96万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9753187
• 关键词: Assessment tool; BRCA1 Mutation; BRCA1 gene; Basal Cell; Biological; Cell Culture System; Cell Culture Techniques; Cell Cycle; Cell Line; Cell Lineage; Cells; Clinical; DNA Damage; DNA Double Strand Break; DNA Repair; Data; Development; Double Strand Break Repair; Epithelium; Etiology; Event; Excision; G2 Phase; Genes; Genetic; Genetic Transcription; Genetically Engineered Mouse; Genome Stability; Genomic Segment; Genomics; Human; Investigation; Ionizing radiation; Knowledge; Laboratories; Licensing; Licensing Factor; Light; Maintenance; Malignant Neoplasms; Mammary Gland Parenchyma; Mammary Neoplasms; Modeling; Modification; Mus; Mutation; Pathway interactions; Phosphorylation; Phosphotransferases; Physiological; Play; Positioning Attribute; Radiation Tolerance; Risk Assessment; Role; Sampling; Scaffolding Protein; Scientist; Signal Transduction; Site; Stem cells; Stromal Cells; Testing; Time; Tissues; Tumor Suppression; Tumor Suppressor Proteins; Ubiquitination; Work; anticancer research; base; cancer prevention; clinically relevant; experimental study; homologous recombination; in vitro activity; in vivo; innovation; malignant breast neoplasm; multidisciplinary; mutation carrier; novel; nuclease; recombinational repair; recruit; response; tumor; ubiquitin-protein ligase

The tumor suppressor BRCA1 plays an important role in the homologous recombination (HR) pathway of DNA double strand break (DSB) repair. From a mechanistic perspective, BRCA1 facilitates recruitment of nucleases required for end resection, the commitment step in HR repair, yet paradoxically, BRCA1 has been shown to inhibit the nuclease activity in vitro. It is unclear how nuclease-recruiting and -inhibiting activities of BRCA1 can be reconciled in HR repair. From a cancer pathophysiological perspective, most BRCA1- associated breast tumors are basal-like but they originate from luminal progenitor cells, so-called cells of origin. This poses an important and largely unaddressed question: does BRCA1 influence HR repair and genome stability in a cell lineage- and genomic locus-preferred manner? Our preliminary data indicate that BRCA1 modifications signal its timely departure from DSBs and thus effectively neutralize its nuclease-inhibiting activity at DSB. Using clinical samples, we also found that luminal cells from BRCA1 mutation carriers are particularly radiosensitive and prone to accumulation of DSB precursors at specific genomic loci. Based on these compelling preliminary data, we hypothesize that BRCA1 modifications are part of a licensing mechanism that confines the commitment step of HR to S/G2 phase. We further propose that BRCA1 HR repair activity is particularly important for genetic integrity at luminal genes in luminal cells of the breast tissue. Our multidisciplinary team of laboratory and clinician scientists will combine cell culture systems with mouse genetics and human samples to test this novel hypothesis. Our proposed work seeks to validate a previously unrecognized role of BRCA1 in licensing the commitment step in HR, thus challenging the current view of BRCA1 merely as a scaffolding protein. Furthermore, by interrogating BRCA1 HR function in the clinically relevant cell lineage and genomic regions, our work represents a significant departure from traditional cell line-focused mechanistic studies. Our proposed work helps fill a critical knowledge gap between mechanistic investigation of BRCA1 and etiology of tissue/cell lineage-specific BRCA1-associated tumor development, thus substantially advancing BRCA1-related breast cancer research.

抑癌基因 BRCA1 在同源重组 (HR) 途径中发挥重要作用 DNA 双链断裂 (DSB) 修复。从机制角度来看，BRCA1 促进了 末端切除所需的核酸酶，HR 修复的承诺步骤，但矛盾的是，BRCA1 已被 在体外显示出抑制核酸酶活性。目前尚不清楚核酸酶招募和抑制活性如何 BRCA1 可以在 HR 修复中得到协调。从癌症病理生理学的角度来看，大多数 BRCA1- 相关的乳腺肿瘤是基底细胞样的，但它们起源于管腔祖细胞，即所谓的起源细胞。 这就提出了一个重要且很大程度上尚未解决的问题：BRCA1 是否影响 HR 修复和基因组 细胞谱系和基因组位点首选方式的稳定性？ 我们的初步数据表明，BRCA1 修饰标志着其及时脱离 DSB，因此 有效中和其 DSB 核酸酶抑制活性。使用临床样本，我们还发现管腔 BRCA1 突变携带者的细胞对放射线特别敏感，容易积累 DSB 特定基因组位点的前体。基于这些令人信服的初步数据，我们假设 BRCA1 修改是许可机制的一部分，该机制将 HR 的承诺步骤限制在 S/G2 阶段。我们 进一步提出 BRCA1 HR 修复活性对于管腔基因的遗传完整性特别重要 乳腺组织的管腔细胞。我们的实验室和临床科学家的多学科团队将结合起来 具有小鼠遗传学和人类样本的细胞培养系统来测试这一新假设。 我们提出的工作旨在验证 BRCA1 在许可中的先前未被认识的作用 HR 中的承诺步骤，从而挑战了目前 BRCA1 仅作为支架蛋白的观点。 此外，通过探究临床相关细胞谱系和基因组区域中的 BRCA1 HR 功能， 我们的工作与传统的以细胞系为中心的机制研究有很大不同。我们提出的 这项工作有助于填补 BRCA1 机制研究和组织/细胞病因学之间的关键知识空白 谱系特异性 BRCA1 相关肿瘤的发展，从而显着促进 BRCA1 相关乳腺的发展 癌症研究。