Regulation of Homologous Recombination in Human Cells

人类细胞同源重组的调控

• 批准号: 8906781
• 负责人: Nathan A. Ellis
• 金额: $ 31.28万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8906781
• 关键词: ATP phosphohydrolase; Affect; Affinity; Amino Acids; Binding; Binding Proteins; Binding Sites; Biochemical; Bloom Syndrome; Catalysis; Cells; Characteristics; Chromosomal Instability; DNA; DNA Damage; DNA Repair; DNA biosynthesis; Data; Defect; Development; Double Strand Break Repair; Exhibits; Failure; Genes; Genetic Recombination; Genomic Instability; Human; In Vitro; Joints; Laboratories; Lead; Lysine; Malignant Neoplasms; Mediating; Modeling; Molecular; Molecular Cytogenetics; Mutate; Normal Cell; Pathway interactions; Phenotype; Process; Recombinant Proteins; Recruitment Activity; Regulation; Research; Role; Site; Speed; Testing; Ubiquitin; Work; base; cancer cell; cancer therapy; design; genome integrity; helicase; homologous recombination; in vivo; insight; mutant; overexpression; prevent; recombinase; recombinational repair; repaired; research study; response; therapeutic target; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Homologous recombination (HR) is an essential mechanism that maintains genomic integrity in cells by repairing double-strand breaks and repairing damaged replication forks. The RAD51 recombinase catalyzes the central step in the HR pathway, forming joint molecules through homology-dependent strand invasion. The BLM helicase, which is the gene mutated in Bloom's syndrome (BS), regulates RAD51. BLM can promote RAD51 function, for example by generating substrate for RAD51 binding, or it can inhibit RAD51 function by unwinding the products of RAD51 catalysis, which prevents the accumulation of toxic recombination intermediates. Thus, through its regulation of RAD51, BLM has both pro- and anti-recombinogenic functions in HR. We have shown that BLM is modified by small ubiquitin-related modifiers (SUMOs) and that BLM SUMOylation regulates BLM's functions at stalled replication forks, stimulating HR repair. In addition, RAD51 is SUMO-binding, and BLM SUMOylation stimulates BLM's interaction with RAD51 in vitro. Our findings support a model in which BLM SUMOylation controls a switch between BLM's anti- recombinogenic and pro-recombinogenic functions. To test this hypothesis, we have four specific aims: (1) characterization of the role of BLM SUMOylation in stabilization of replication forks; (2) characterization of the role of RAD51 SUMO binding in replication fork stability and HR repair; (3) analysis of the effects of BLM SUMOylation on BLM's biochemical activities and RAD51 function; and (4) analysis of the effects of BLM SUMOylation and RAD51 SUMO binding in genomic integrity. Our studies will elucidate the molecular mechanisms that regulate HR at damaged replication forks, providing insights into the dynamic functions of BLM and RAD51 in HR repair and leading to a deeper understanding of how these functions are regulated by the SUMO pathway. Because HR repair mechanisms are often dysregulated in cancer cells, our work will lead to a better understanding of genomic instability in cancer and will facilitate the exploitation of this instability in cancer treatments.

描述（由申请人提供）：同源重组（HR）是一种基本机制，它通过修复双链断裂并修复受损的复制叉来维持细胞中的基因组完整性。 RAD51重组酶催化HR​​途径中的中心步骤，通过依赖同源性的链浸入形成关节分子。 BLM解旋酶是Blo​​om综合征（BS）中突变的基因，调节RAD51。 BLM可以通过生成用于RAD51结合的底物来促进RAD51功能，或者可以通过放松RAD51催化的产物来抑制RAD51功能，从而防止有毒重组中间体的积累。因此，通过其对RAD51的调节，BLM在HR中具有促和抗染色性功能。我们已经证明，BLM通过小型泛素相关的修饰剂（SUMOS）进行了修改，并且BLM Sumoylation在停滞的复制叉处调节BLM的功能，从而刺激HR修复。另外，rad51是相邻的结合，而BLM Sumoylation刺激了BLM与Rad51体外的相互作用。我们的发现支持了一个模型，其中BLM Sumoylation控制BLM的抗重组和促造成重组功能之间的切换。为了检验这一假设，我们有四个具体的目的：（1）BLM Sumoylation在复制叉稳定中的作用的表征； （2）表征Rad51 Sumo结合在复制叉稳定性和HR修复中的作用； （3）分析BLM Sumoylation对BLM生化活动和RAD51功能的影响； （4）分析BLM Sumoylation和Rad51 Sumo结合在基因组完整性中的影响。我们的研究将阐明在损坏的复制叉处调节HR的分子机制，从而提供对HR修复中BLM和RAD51的动态功能的见解，并更深入地了解这些功能如何受SUMO途径调节。由于HR修复机制通常在癌细胞中失调，因此我们的工作将使人们对癌症的基因组不稳定性有更好的了解，并促进这种不稳定性在癌症治疗中的剥削。

项目成果

BLM Sumoylation Is Required for Replication Stability and Normal Fork Velocity During DNA Replication.

• DOI: 10.3389/fmolb.2022.875102
• 发表时间: 2022
• 期刊: Frontiers in molecular biosciences
• 影响因子: 5