Role of HELLS chromatin remodeler in genome maintenance

HELLS 染色质重塑剂在基因组维护中的作用

• 批准号: 10629966
• 负责人: Wioletta Czaja
• 金额: $ 1.21万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2022-10-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10629966
• 关键词: Alkylating Agents; Alkylation; Animal Model; Area; Biological Assay; Cause of Death; Cell Death; Cell Survival; Cells; Centromere; Chromatin; Chromosomal Breaks; Chromosomal Rearrangement; Chromosome abnormality; Cytoprotection; DNA; DNA Alkylation; DNA Damage; DNA Methylation; DNA Repair; DNA Repair Pathway; DNA replication fork; Data; Development; Diagnosis; Disease; Etiology; Eukaryota; Event; Exhibits; Exposure to; Face; Gametogenesis; Genetic; Genome; Genome Stability; Genomic Instability; Genomic approach; Genomics; Genotoxic Stress; Goals; HELLS gene; Heterochromatin; Human; Hypersensitivity; Immune system; Immunofluorescence Immunologic; Immunologic Deficiency Syndromes; Knowledge; Link; Maintenance; Malignant Neoplasms; Measures; Mediating; Metabolism; Modeling; Molecular; Mus; Mutagens; Mutation; Neurospora; Neurospora crassa; Nonhomologous DNA End Joining; Organism; Pathway interactions; Phenotype; Play; Proteins; Proteomics; Regulation; Reporter; Research; Role; Toxic effect; base; chromatin remodeling; disorder prevention; epigenomics; genome-wide; genomic locus; human disease; immunodeficiency-centromeric instability-facial anomalies syndrome; insight; member; mutant; novel; novel strategies; prevent; repaired; response

Project Summary Robust and tightly regulated DNA repair is critical to maintain genome stability and prevent disease development. Eukaryotic DNA is packaged into chromatin that has a profound, yet not well understood regulatory influence on DNA repair, replication and genome maintenance. There is a fundamental gap in understanding how DNA repair pathways are regulated and coordinated within structurally diverse chromatin, and across the heterogeneous genomic landscape. The HELLS (Helicase Lymphoid Specific) is a poorly understood chromatin-associated protein, with an emerging new role in genome maintenance. Mouse HELLS is essential for gametogenesis and proper development of the immune system. Mutations in human HELLS cause severe immunodeficiency syndrome ICF (Immunodeficiency Centromeric Instability Facial anomalies). Despite substantial progress in understanding the molecular functions of the mammalian HELLS in DNA methylation and chromatin remodeling, its role in DNA repair and genome maintenance is poorly understood and remains elusive. The unresolved questions remain whether HELLS regulates multiple DNA repair pathways, and whether it has specialized roles in the repair and maintenance of a distinct genomic loci or domains. We have established and validated fungal model, Neurospora crassa to advance the fundamental understanding of HELLS-mediated mechanisms of genome stability. Our studies reveal a new, previously unrecognized link between HELLS proteins and cellular responses to DNA alkylation damage in fungal and human cells. We hypothesize that HELLS protects cells form alkylation-induced toxicity and plays important roles in the repair and stability of the constitutive heterochromatin domains. This hypothesis is founded based on a strong preliminary data in the fungal model Neurospora and in human cells demonstrating that cells deficient in HELLS exhibit sensitivity to DNA alkylation damage and are deficient in the repair of the constitutive heterochromatin. In addition, we discovered that loss of fungal WDR76 protein in HELLS mutant cells leads to the synthetic rescue of the alkylation sensitivity phenotype, implying that WDR76 acts as genetic suppressor of HELLS deficiency. In Aim 1 we will determine the role of fungal and human HELLS remodelers in the repair of alkylation DNA damage. In Aim 2 we will define precise genomic and chromatin contexts that depend on HELLS for genome maintenance. In Aim 3 we will determine the functional relationship between HELLS and WDR76, a WD40 protein implicated in response to DNA alkylation. Successful completion of the proposed research will define HELLS-mediated mechanisms of genome maintenance, and identify additional regulators and pathways cooperating with HELLS in protecting the cells from detrimental consequences of genotoxic stress. These studies will provide important insights into the origin of the disease- causing chromosomal rearrangements and breaks found in many human diseases, including the ICF syndrome.

项目摘要 稳健和严格调节的DNA修复对于维持基因组稳定性和预防疾病发展至关重要。 真核DNA被包装成染色质，具有深刻但尚未充分了解的调节性影响 DNA修复，复制和基因组维持。了解DNA如何维修存在根本的差距 途径在结构上多样化的染色质内，并在异质上进行调节和协调 基因组景观。地狱（解旋酶特异性）是一种鲜为人知的染色质相关的 蛋白质，在基因组维持中具有新的作用。鼠标地狱对于配子发生至关重要 免疫系统的适当发展。人类地狱中的突变会导致严重的免疫缺陷 ICF综合征（免疫缺陷丝粒不稳定性面部异常）。尽管取得了长足的进步 了解哺乳动物地狱在DNA甲基化和染色质重塑中的分子功能， 它在DNA修复和基因组维持中的作用知之甚少，并且仍然难以捉摸。未解决的 问题仍然是地狱是否规范多个DNA维修途径，以及它是否具有专业角色 在修复和维护不同的基因组基因局或结构域中。我们已经建立和验证了真菌 模型，Neurospora crassa，以促进对地狱介导的机制的基本理解 基因组稳定性。我们的研究揭示了地狱蛋白与细胞之间的新的，以前无法识别的联系 对真菌和人类细胞中DNA烷基化损伤的反应。我们假设地狱保护细胞形式 烷基化引起的毒性，并在构成异染色质的修复和稳定性中起重要作用 域。该假设是基于真菌模型Neurospora和In中的强大初步数据建立的 人类细胞表明，地狱缺乏细胞对DNA烷基化损伤表现出敏感性，并且是 构成异染色质的修复缺乏。此外，我们发现了真菌WDR76的损失 地狱突变细胞中的蛋白质会导致烷基化敏感性表型的合成营养，这意味着 WDR76充当地狱缺乏症的遗传抑制剂。在AIM 1中，我们将确定真菌和人类的作用 地狱重塑烷基化DNA损伤中的重塑。在AIM 2中，我们将定义精确的基因组和 染色质环境取决于基因组维持的地狱。在AIM 3中，我们将确定功能 地狱与WDR76之间的关系，这是一种与DNA烷基化有关的WD40蛋白。成功的 拟议研究的完成将定义地狱介导的基因组维持机制，并 确定其他调节器和与地狱合作的途径，以保护细胞免受有害 遗传毒性应激的后果。这些研究将为疾病的起源提供重要的见解 - 引起许多人类疾病（包括ICF综合征）中发现的染色体重排和断裂。