Abstract：
While that ROS causes DNA damage is well documented, there has been limited investigation into whether DNA damages and their repair processes can conversely induce oxidative stress. By generating a site-specific DNA double strand break (DSB) via I-SceI endonuclease expression in S. cerevisiae without damaging other cellular components, this study demonstrated that DNA repair does trigger oxidative stress. Deleting genes participating in the initiation of the resection step of homologous recombination (HR), like the MRX complex, resulted in stimulation of ROS. In contrast, deleting genes acting downstream of HR resection suppressed ROS levels. Additionally, blocking non-homologous end joining (NHEJ) also suppressed ROS. Further analysis identified Rad53 as a key player that relays DNA damage signals to alter redox metabolism in an HR-specific manner. These results suggest both HR and NHEJ can drive metabolism changes and oxidative stress, with NHEJ playing a more prominent role in ROS stimulation. Further analysis revealed a correlation between DSB-induced ROS increase and enhanced activity of NADPH oxidase Yno1 and various antioxidant enzymes. Deleting the antioxidant gene SOD1 induced synthetic lethality in HR-deficient mutants like mre11Δ and rad51Δ upon DSB induction. These findings uncover a significant interplay between DNA repair mechanisms and cellular metabolism, providing insights into understanding the side effects of genotoxic therapies and potentially aiding development of more effective cancer treatment strategies.
摘要：
虽然ROS导致DNA损伤是有据可查的，关于DNA损伤及其修复过程是否可以相反诱导氧化应激的研究有限。通过在酿酒酵母中通过I-SceI内切核酸酶表达产生位点特异性DNA双链断裂（DSB）而不损害其他细胞成分，这项研究表明，DNA修复确实会引发氧化应激。删除参与同源重组（HR）切除步骤起始的基因，就像MRX复合体一样，导致ROS的刺激。相比之下,删除作用于HR切除下游的基因抑制了ROS水平。此外,阻断非同源末端连接（NHEJ）也抑制了ROS。进一步的分析确定Rad53是以HR特异性方式传递DNA损伤信号以改变氧化还原代谢的关键参与者。这些结果表明，HR和NHEJ都可以驱动代谢变化和氧化应激，NHEJ在ROS刺激中起着更突出的作用。进一步的分析表明，DSB诱导的ROS增加与NADPH氧化酶Yno1和各种抗氧化酶的活性增强之间存在相关性。在DSB诱导后，删除抗氧化剂基因SOD1在HR缺陷型突变体如mre11Δ和rad51Δ中诱导合成致死性。这些发现揭示了DNA修复机制和细胞代谢之间的重要相互作用。提供深入了解基因毒性疗法的副作用，并可能帮助开发更有效的癌症治疗策略。
