Role of HELB in the Replication Stress Response

HELB 在复制压力响应中的作用

• 批准号: 10669294
• 负责人: Alicia K. Byrd
• 金额: $ 31.6万
• 依托单位: ARKANSAS CHILDREN'S HOSPITAL RES INST
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-11 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10669294
• 关键词: ATAC-seq; Aging; Binding Sites; Biochemical; Cell Cycle; Cells; Centers of Research Excellence; ChIP-seq; Childhood; Chromatin; DNA; DNA lesion; DNA replication fork; Data; Defect; Development; Disease; Doctor of Philosophy; EXO1 gene; Epigenetic Process; Event; Excision; Fragile X Syndrome; G-Quartets; Genes; Genome; Genome Stability; Genomic DNA; Genomics; Goals; HELB gene; Human; Individual; Maintenance; Malignant Neoplasms; Mental Retardation; Molecular; Pediatric Research; Phosphorylation; Population; Post-Translational Protein Processing; Process; Proliferating; Proteins; Recombinants; Recovery; Regulation; Replication Initiation; Research; Research Project Grants; Resources; Role; Site; Structure; Testing; assault; biological adaptation to stress; developmental disease; epigenomics; experimental study; genome integrity; genome-wide; helicase; homologous recombination; insight; knock-down; new therapeutic target; nuclease; preservation; protein protein interaction; proteogenomics; repaired; replication stress; therapeutic target

Summary Accurate and complete replication of the genome is essential for both proliferation and genomic stability. Genomic DNA is constantly under assault from both exogenous and endogenous agents. The resulting DNA lesions can cause stalling of the replication fork and activation of the replication stress response (RSR). This activates a group of proteins that protect and restart the replication fork so that genomic integrity is maintained. Incorrect repair can lead to cancer and aging, and defects in the RSR predispose individuals to develop cancer. Our overall goal is to define the molecular mechanisms that protect the genome during replication stress. We have discovered that DNA Helicase B (HELB) protects stalled replication forks from aberrant degradation by nucleases and promotes replication restart. This is consistent with data showing reduced recovery from replication stress with HELB knockdown; however, the mechanism by which HELB promotes recovery from replication stress is unknown. In addition, we have found that HELB enhances replication through G-quadruplex (G4) structures, suggesting that HELB may enable the replication fork to progress through difficult to replicate sites. Since replication stalling can result in epigenetic instability, HELB may be involved in epigenetic maintenance in addition to genomic maintenance. HELB has also been implicated in initiation of DNA replication and regulation of end resection in homologous recombination (HR). Due to its varied roles in multiple processes, regulation of HELB activity is likely required. Indeed, we have evidence that HELB activity is regulated by post- translational modifications (PTMs). We hypothesize that HELB maintains genomic and epigenetic integrity by protecting nascent DNA from degradation, aiding in replication restart, and assisting in replication through difficult sites. We will test this hypothesis through the following Specific Aims: (1) Ascertain the role of HELB in protection and restart of stalled DNA replication forks, (2) Determine the function of HELB in replication through difficult to replicate regions of the genome, and (3) Delineate the role of HELB PTMs and protein-protein interactions (PPIs) in the replication stress response.

概括 基因组的准确和完整复制对于增殖和基因组稳定性至关重要。 基因组 DNA 不断受到外源和内源因素的攻击。所得DNA 损伤可能导致复制叉停滞和复制应激反应（RSR）激活。这 激活一组保护并重新启动复制叉的蛋白质，从而维持基因组完整性。 不正确的修复会导致癌症和衰老，而 RSR 缺陷会使个体容易患上癌症。 我们的总体目标是定义在复制应激期间保护基因组的分子机制。我们 发现 DNA 解旋酶 B (HELB) 通过以下方式保护停滞的复制叉免遭异常降解： 核酸酶并促进复制重新启动。这与显示恢复减少的数据一致 HELB 敲低带来的复制压力；然而，HELB 促进恢复的机制 复制压力未知。此外，我们发现HELB通过G-四链体增强复制 (G4) 结构，表明 HELB 可能使复制叉能够通过难以复制的过程 网站。由于复制停滞会导致表观遗传不稳定，HELB 可能参与表观遗传 除了基因组维护之外的维护。 HELB 也与 DNA 复制的启动有关 以及同源重组（HR）中末端切除的调节。由于其在多个流程中的不同作用， 可能需要对 HELB 活动进行监管。事实上，我们有证据表明 HELB 活性受到后调节 翻译修饰（PTM）。我们假设 HELB 通过以下方式维持基因组和表观遗传完整性： 保护新生 DNA 免遭降解，帮助复制重新启动，并协助复制度过困难时期 网站。我们将通过以下具体目标来检验这一假设： (1) 确定 HELB 在保护中的作用 并重新启动停滞的DNA复制叉，（2）通过难以确定的方法确定HELB在复制中的功能 复制基因组区域，以及 (3) 描述 HELB PTM 和蛋白质-蛋白质相互作用 (PPI) 的作用 在复制应激反应中。