The molecular basis of RECQ4-associated genetic disorders and cancer predispositi

RECQ4相关遗传性疾病和癌症易感性的分子基础

• 批准号: 8101561
• 负责人: Yilun Liu
• 金额: $ 8.4万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2011-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8101561
• 关键词: Aging-Related Process; Alleles; Amino Acids; Bacteria; Binding; Biochemical; CDC45L gene; Catalytic Domain; Cell Cycle; Cell Extracts; Cell Proliferation; Cell Survival; Cells; Chromatin; Chromosomes; Circadian Rhythms; Cisplatin; Complex; Cyclin-Dependent Kinases; DNA; DNA Binding; DNA Damage; DNA Repair; DNA Replication Factor; DNA Structure; DNA biosynthesis; Data; Defect; Development; Disease; Dissociation; Eukaryota; Evolution; Family; G1 Phase; Genes; Genome; Genomic Instability; Genomics; Genotoxic Stress; Goals; Health; Hereditary Disease; Homologous Gene; Human; In Vitro; Individual; Ionizing radiation; Knowledge; Lead; Lesion; Link; Lymphoma; MCM10 gene; MCM2 gene; Maintenance; Malignant Neoplasms; Maps; Metabolism; Methods; Molecular; Mutagenesis; Mutation; Organism; Outcome; Pathogenesis; Patients; Phenotype; Phosphorylation; Predisposition; Premature aging syndrome; Process; Prokaryotic Cells; Property; Protein Family; Proteins; RECQL4 gene; Regulation; Replication Initiation; Replication Origin; Reporting; Role; Set protein; Sister Chromatid; Tumor Suppressor Proteins; Vertebrates; Work; Yeasts; arm; base; biological adaptation to stress; cancer prevention; cancer therapy; cell growth; clinical phenotype; cohesion; helicase; in vitro activity; in vivo; metaplastic cell transformation; mouse model; osteosarcoma; polypeptide; prevent; protein complex; protein protein interaction; repaired; tumorigenesis

DESCRIPTION (provided by applicant): Functional machineries to prevent and repair DNA damages are required for maintaining genome integrity and preventing tumourigenesis. A set of proteins belonging to the RecQ family is among the cancer suppressors linked to repairing lesions caused by DNA damaging agents, such as ionizing radiation and cisplatin. During the course of evolution, RecQ genes appear to have been amplified and diverged from a single copy of the RecQ gene in bacteria and yeast to five RecQ homologs in humans. The clinical phenotypes caused by mutations in different RECQ proteins in humans and mouse models indicate that they have important and non-overlapping roles in maintaining genomic integrity and cancer prevention. Since RECQ helicases are highly interactive proteins and form large protein complexes in vivo, the unique functions of each of the RECQ proteins are likely defined and regulated by the specific protein-protein interactions they form in cells. To understand how the mammalian RECQ proteins act as tumor suppressors and caretakers for our genome, it is crucial to understand the unique functions of each of the RECQ protein complexes. Recently, our lab has several breakthroughs in the study of human RECQ4 helicase. First, we successfully reported ATP-dependent RECQ4 helicase activity in vitro. Surprisingly, domain analyses uncovered two distinct ATP binding and DNA unwinding activities within the RECQ4 protein. Secondly, we report the identification of a highly purified chromatin bound RECQ4 complex from human cell extracts. We found that essential replisome factors MCM10, MCM2-7 helicase, CDC45 and GINS are the primary interaction partner proteins of human RECQ4. Moreover, circadian proteins, TIMELESS and TIPIN important for cohesion establishment and DNA replication progression are part of the RECQ4 complex. Importantly, complex formation and the association of RECQ4 with the replication origin are cell cycle regulated. Our studies allow us to conclude that RECQ4 is an integral component of the MCM replicative helicase complex participating in DNA replication in human cells. Based on our work, the goal of this proposal is to define the exact function of RECQ4 complex in DNA replication, cohesion establishment and cancer avoidance. The Specific Aims are: (1) dissecting the role of human RECQ4 in DNA replication initiation; (2) Establishing the functional relationship between RECQ4 and TIM-TIPIN heterodimer in replication fork progression, genotoxic stress response and cohesion establishment; and (3) Analysis of the cancer-associated RECQ4 (c.1390+2delT) mutation. PUBLIC HEALTH RELEVANCE: DNA replication is essential for cell growth, and abnormal DNA synthesis can result in genome instability, mutagenesis and tumorigenesis. Therefore, elucidation of the mechanisms that regulate DNA replication and the molecular functions of the involved proteins, such as RECQ4, are fundamental to our understanding of the cancer development. Crucially, our detailed knowledge on the DNA replication factors will aid in the discovery of new cancer therapy treatments, since inhibiting DNA replication factors effectively prevents cell proliferation.

描述(由申请人提供)：防止和修复DNA损伤的功能机器是维持基因组完整性和防止肿瘤发生所必需的。一组属于RecQ家族的蛋白质是与修复DNA损伤剂(如电离辐射和顺铂)造成的损伤有关的癌症抑制因子之一。在进化过程中，RecQ基因似乎已经被扩增，并从细菌和酵母中的RecQ基因的一个副本分化为人类的五个RecQ同源物。在人类和小鼠模型中，不同的RecQ蛋白突变引起的临床表型表明，它们在维持基因组完整性和癌症预防方面具有重要且不重叠的作用。由于RecQ解旋酶是高度相互作用的蛋白质，并在体内形成大型蛋白质复合体，因此每个RecQ蛋白质的独特功能可能由它们在细胞中形成的特定蛋白质-蛋白质相互作用来定义和调节。要了解哺乳动物的RecQ蛋白如何作为我们基因组的肿瘤抑制者和看守者，了解每个RecQ蛋白复合体的独特功能是至关重要的。最近，我们实验室在人类RECQ4解旋酶的研究上取得了几项突破。首先，我们成功地报道了依赖于ATP的RECQ4解旋酶的体外活性。令人惊讶的是，结构域分析发现RECQ4蛋白中有两种不同的ATP结合和DNA解离活性。其次，我们报道了从人类细胞提取物中鉴定出一个高纯度的染色质结合RECQ4复合体。我们发现基本复制体因子MCM10、MCM2-7解旋酶、CDC45和GINS是人RECQ4的主要相互作用伙伴蛋白。此外，昼夜节律蛋白质是RECQ4复合体的一部分，它们对凝聚力的建立和DNA复制进程至关重要，是永恒的和关键的。重要的是，复合体的形成和RECQ4与复制起点的关联是细胞周期调节的。我们的研究使我们得出结论，RECQ4是参与人类细胞DNA复制的MCM复制型解旋酶复合体的组成部分。基于我们的工作，这项建议的目标是确定RECQ4复合体在DNA复制、凝聚力建立和癌症预防中的确切功能。其具体目的是：(1)剖析人类RECQ4在DNA复制启动中的作用；(2)建立RECQ4和Tim-tipin异二聚体在复制分叉进展、遗传毒性应激反应和凝聚力建立中的功能关系；以及(3)分析与癌症相关的RECQ4(c.1390+2delT)突变。 与公共卫生相关：DNA复制对细胞生长至关重要，DNA合成异常可能导致基因组不稳定、突变和肿瘤形成。因此，阐明调控DNA复制的机制和相关蛋白的分子功能，如RECQ4，对于我们理解癌症的发展是至关重要的。至关重要的是，我们对DNA复制因子的详细了解将有助于发现新的癌症治疗方法，因为抑制DNA复制因子有效地阻止了细胞增殖。