Regulation of DNA repair by histone ADP-ribosylation

组蛋白 ADP 核糖基化调节 DNA 修复

• 批准号: MR/W017350/1
• 负责人: Nicholas Lakin
• 金额: $ 86.32万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FW017350%2F1
• 关键词: Regulation; DNA; repair; histone; ADP

DNA is continually being exposed to a variety of agents that induce DNA damage. As such, a set of pathways known as the DNA damage response (DDR) detect DNA damage when it occurs and activate mechanisms for its repair. These pathways are critical for our health and their dysfunction leads to a variety of pathologies including increased cancer risk, neurodegeneration, congenital abnormalities and premature ageing. Therefore, understanding how cells repair DNA damage will provide information about the underlying causes of these conditions and, importantly, how they can be treated.This strategy is exemplified by inhibition Poly(ADP-ribose)-polymerases (PARPs), a class of enzymes that promote DNA repair by attaching ADP-ribose units onto proteins through a process known as ADP-ribosylation. Inhibitors of PARPs are being used to treat breast and ovarian cancers and have the potential to treat other pathologies associated with DDR defects. However, despite their potential as therapeutic targets, our knowledge of how PARPs regulate DNA repair is limited. For example, the proteins ADP-ribosylated in response to DNA damage and how this regulates repair are ill-defined. This situation is epitomized by histones, the proteins that package DNA into the nucleus of the cell. Histones are major targets for PARPs, particularly at serine amino acids that also have the potential to be modified by phosphorylation. Given phosphorylation regulates a variety of processes, including cell growth and division, this raises the possibility that interplay between ADP-ribosylation and phosphorylation may coordinate DNA repair with a variety of pathways. However, the functional significance of these relationships remains to be tested due to difficulties in manipulating histone genes in human cells. There is therefore a need for an experimental system where histone genes can be easily manipulated to test how histone ADP-ribosylation regulates DNA repair.Our current MRC-funded work provided key advances to these questions by developing a robust experimental pipeline in the amoeba Dictyostelium that allowed us to manipulate histone genes to assess how histone ADP-ribosylation regulates DNA repair. Our previous work pioneered the use of this system to study human DNA repair mechanisms lost in other genetic model organisms, including ADP-ribosylation. By exploiting the unique ability to manipulate histone ADP-ribosylation sites in this organism, we identified that interplay between histone ADP-ribosylation and phosphorylation is critical to maintain genome integrity by coordinating DNA repair with cell division. This provides a paradigm shift for how ADP-ribosylation integrates with other post-translational modifications to regulate the DDR and the ability to identify novel regulatory mechanisms that can be extended to human cells. The proposed work will build on these key technical and conceptual advances in Dictyostelium to identify how histone ADP-ribosylation couples DNA repair with cell cycle progression and extend these findings to human cells. In addition to providing an increased understanding of how cells promote DNA repair to prevent mutagenesis, these studies will provide information to facilitate the design of therapeutic agents that target DNA repair pathways to treat pathologies associated with a defective DDR.

DNA 不断暴露于各种诱发 DNA 损伤的物质中。因此，一组称为 DNA 损伤反应 (DDR) 的途径会在 DNA 损伤发生时检测到它并激活其修复机制。这些通路对我们的健康至关重要，它们的功能障碍会导致各种病理，包括癌症风险增加、神经退行性变、先天性异常和过早衰老。因此，了解细胞如何修复 DNA 损伤将提供有关这些疾病的根本原因的信息，更重要的是，提供有关如何治疗这些疾病的信息。这种策略以抑制聚（ADP-核糖）聚合酶（PARP）为例，这是一类通过称为 ADP-核糖基化的过程将 ADP-核糖单元附着到蛋白质上来促进 DNA 修复的酶。 PARP 抑制剂被用于治疗乳腺癌和卵巢癌，并有可能治疗与 DDR 缺陷相关的其他病理。然而，尽管它们具有作为治疗靶点的潜力，但我们对 PARP 如何调节 DNA 修复的了解仍然有限。例如，针对 DNA 损伤而进行 ADP 核糖基化的蛋白质以及它如何调节修复尚不明确。这种情况以组蛋白为代表，组蛋白是将 DNA 包装到细胞核中的蛋白质。组蛋白是 PARP 的主要靶标，尤其是丝氨酸氨基酸，这些氨基酸也有可能被磷酸化修饰。鉴于磷酸化调节多种过程，包括细胞生长和分裂，这提出了 ADP-核糖基化和磷酸化之间的相互作用可能通过多种途径协调 DNA 修复的可能性。然而，由于在人类细胞中操纵组蛋白基因存在困难，这些关系的功能意义仍有待测试。因此，需要一个可以轻松操纵组蛋白基因的实验系统，以测试组蛋白 ADP-核糖基化如何调节 DNA 修复。我们目前由 MRC 资助的工作通过在变形虫盘基网柄菌中开发强大的实验管道，为这些问题提供了关键进展，使我们能够操纵组蛋白基因来评估组蛋白 ADP-核糖基化如何调节 DNA 修复。我们之前的工作开创性地使用该系统来研究其他遗传模型生物中丢失的人类 DNA 修复机制，包括 ADP-核糖基化。通过利用这种生物体中操纵组蛋白 ADP-核糖基化位点的独特能力，我们发现组蛋白 ADP-核糖基化和磷酸化之间的相互作用对于通过协调 DNA 修复与细胞分裂来维持基因组完整性至关重要。这为 ADP-核糖基化如何与其他翻译后修饰整合以调节 DDR 提供了范式转变，并提供了识别可扩展到人类细胞的新型调节机制的能力。拟议的工作将建立在盘基网柄菌的这些关键技术和概念进展的基础上，以确定组蛋白 ADP-核糖基化如何将 DNA 修复与细胞周期进程结合起来，并将这些发现扩展到人类细胞。除了加深对细胞如何促进 DNA 修复以防止突变的理解之外，这些研究还将提供信息，以促进针对 DNA 修复途径的治疗药物的设计，以治疗与 DDR 缺陷相关的病理。

项目成果

C16orf72/HAPSTR1/TAPR1 functions with BRCA1/Senataxin to modulate replication-associated R-loops and confer resistance to PARP disruption.

• DOI: 10.1038/s41467-023-40779-9
• 发表时间: 2023-08-17
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Sharma, Abhishek Bharadwaj;Ramlee, Muhammad Khairul;Kosmin, Joel;Higgs, Martin R.;Wolstenholme, Amy;Ronson, George E.;Jones, Dylan;Ebner, Daniel;Shamkhi, Noor;Sims, David;Wijnhoven, Paul W. G.;Forment, Josep;Gibbs-Seymour, Ian;Lakin, Nicholas D.
• 通讯作者: Lakin, Nicholas D.