Mitochondrial translesion DNA synthesis

线粒体跨损伤 DNA 合成

• 批准号: 10587813
• 负责人: Yuhui Yin
• 金额: $ 38.87万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-28 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10587813
• 关键词: Active Sites; Aging; Base Pairing; Binding; Binding Sites; Bioinformatics; Biophysics; Bypass; Cell Aging; Cell Nucleus; Cells; Code; Complex; Cryoelectron Microscopy; Cyclobutanes; DNA; DNA Primers; DNA biosynthesis; DNA-Directed DNA Polymerase; Dermis; Elasticity; Electron Transport; Energy Metabolism; Energy Supply; Enzyme Kinetics; Enzymes; Evolution; Exhibits; Family; Foundations; Genes; Health; Human; Introns; Investigation; Ions; Kinetics; Knowledge; Lesion; Location; Longevity; Maintenance; Manganese; Mediating; Memory; Metabolism; Metals; Methods; Mitochondria; Mitochondrial DNA; Mutation; Nuclear; Nucleotide Excision Repair; Nucleotides; Nutrient; Organism; Oxidative Phosphorylation; Oxidative Stress; Physiological; Polymerase; Proliferating; Property; Proteins; Pyrimidine Dimers; Role; Skin; Solid; Specific qualifier value; Structure; Sun Exposure; Testing; Tissues; Ultraviolet Rays; Work; X-Ray Crystallography; biophysical techniques; blind; dimer; genome integrity; human disease; in vivo; insight; magnesium ion; member; mitochondrial genome; postmitotic; public health relevance; repaired; replicase; response; skin disorder; stoichiometry; ultraviolet damage; ultraviolet lesions

ABSTRACT Mitochondrial DNA (mtDNA) integrity is critical for metabolism and cellular energy supply and human health and longevity. Due to lack of repair mechanism and specified translesion synthesis (TLS) polymerase, mtDNA contains higher contents of UV lesions. The high-fidelity mitochondrial DNA polymerase (Pol g) will unavoidably encounter the UV lesions during mtDNA replication. Unlike other high-fidelity DNA polymerases that lack TLS activity, we found Pol g possesses a metal regulated TLS activity. In the presence of magnesium ion, Pol g exhibits no TLS activity, however, in the presence of physiological concentrations of manganese ion alone or Mg/Mn mixture, Pol g can synthesize cross UV lesion cyclobutane dimer with efficiency near that on the non-damaged DNA. We also discovered that Pol g has an extensive lesion recognition network that can sense an upstream lesion as far as 10 base pairs in the presence of Mg2+, but completely ignores the lesion with Mn2+. We hypothesize that Manganese ion can alter the elasticity of Pol g to be able to accommodate bulky lesions for translesion synthesis. we will test the hypothesis by completing the Specific Aims 1) Mechanism of Pol g integrated lesion bypassing, extension, and replication activities, 2) Investigation of Pol g long-range lesion sensing and 3) Biophysical basis for metal-directed Pol g TLS. The proposed studies will illustrate how mitochondrial replicase utilizing the essential metal ions to maintain genome integrity under UV radiation.

摘要 线粒体DNA（mtDNA）的完整性对于代谢和细胞能量供应以及人类的健康至关重要。 健康和长寿。由于缺乏修复机制和特定的跨损伤合成（TLS）聚合酶， 线粒体DNA中紫外线损伤含量较高。高保真线粒体DNA聚合酶（Pol g）将 在mtDNA复制过程中不可避免地遇到紫外线损伤。与其他高保真DNA聚合酶不同 在缺乏TLS活性的细胞中，我们发现Pol g具有金属调节的TLS活性。在镁的存在下 在生理浓度的锰离子存在下，Pol g没有TLS活性 单独或Mg/Mn混合物，Pol g可以合成交叉紫外损伤环丁烷二聚体，其效率接近于 未受损的DNA我们还发现Pol g有一个广泛的病变识别网络， 在Mg ~（2+）存在下，上游损伤远达10个碱基对，但完全忽略Mn ~（2+）的损伤。 我们假设锰离子可以改变Pol g的弹性，使其能够适应大体积病变， 跨损伤合成我们将通过完成具体目标1）Pol g的机制来验证假设 综合病变旁路、扩展和复制活动，2）研究Pol g长距离病变 3）金属导向的Pol g TLS的生物物理基础。拟议的研究将说明如何 线粒体复制酶利用必需的金属离子在UV辐射下维持基因组完整性。