超氧化物歧化酶Sod在维持基因组稳定性中的作用机制研究

Superoxide dismutase (Sod) is an important member of cellular antioxidant system, whose functional defect is associated with neurological diseases such as ALS, chronic inflammation and cancer. Our proposal intends to explore the effect of Sod activity on genomic stability by multiple omics and molecular genetic techniques in Saccharomyces cerevisiae. The research contents include: (1) using yeast chromosome homologous recombination screening system and customized SNP microarray, the effect of intracellular Sod activity on DNA breaks and recombination will be determined; (2) whether and how Sod defect would induce genomic instability (point mutation, loss of heterozygosity, recombination and chromosome aberration) will be investigated at a whole genome level;(3) the genomic binding sites and targeted genes of Sod1 will be revealed using RNA-Seq and ChIP-Seq technology. Our findings can not only further clarify the function of Sod protein in oxidative stress response and maintaining genomic stability, but also provide useful reference for elucidating the pathogenesis of Sod functional defect induced diseases.

超氧化物歧化酶Sod是细胞抗氧化系统的重要成员，其功能缺陷是诱发神经系统疾病肌萎性侧索硬化（ALS）、慢性炎症和肿瘤等疾病的重要因素之一。本项目拟以酿酒酵母为模型，运用多种组学和分子遗传操作技术探究Sod活性变化对细胞应激DNA氧化损伤和基因组稳定性的影响机制。具体研究内容包括：（1）运用酵母染色体同源重组筛选系统和定制的SNP芯片分析胞内Sod活性变化影响染色体DNA断裂和重组的分子机制；（2）全基因组测序阐释Sod功能缺陷诱导基因组不稳定性（点突变、杂合性丢失、染色体重组和畸变）的模式和规律；和（3）利用RNA-Seq和ChIP-Seq技术揭示Sod1在多种条件下与基因组DNA的结合位点和靶基因。该项目的实施不仅可以进一步明确Sod蛋白在细胞应激氧化胁迫信号传导途径和维持基因组稳定性中的功能，对阐明Sod功能缺陷相关疾病的发生机理也具有重要的理论指导意义。

氧化压力是生物细胞最常见的胁迫因子之一，超氧化物歧化酶在所有需氧生物中都存在，在维持细胞氧化还原平衡和遗传物质稳定性中发挥重要作用。本项目揭示了Sod1功能缺陷与基因组不稳定的关系，解析了Sod1缺失诱导的基因组变异的规律，为阐明超氧化物岐化酶在生物进化中的作用提供了新见解。同时课题对直接的氧自由基H2O2和能间接引起DNA氧化损伤的博来霉素和糠醛的遗传毒性进行了阐明，发现这些化合物均能造成特征性的基因组变异模式。并比较分析了Sod1功能缺陷与其它几种氧化压力下突变的差异的原因主要与碱基切除修复和易错DNA聚合酶的活性不同相关。