EEPD1 promotes repair of oxidatively-stressed replication forks.
EEPD1 promotes repair of oxidatively-stressed replication forks.
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未修复的氧化应激复制叉可导致染色体不稳定和肿瘤转化或细胞死亡。为了应对这些挑战，细胞已经进化出一种强大的机制，通过碱基切除修复（BER）途径修复氧化基因组DNA损伤，但对复制叉处氧化损伤的修复知之甚少。我们发现EEPD1的缺失或基因缺失会降低DNA氧化损伤后的克隆形成细胞存活率。我们表明，EEPD1被招募到复制叉强调氧化损伤诱导H2O2和EEPD1促进复制叉修复和重新启动，并减少染色体异常后，这样的损害。EEPD 1结合到脱碱基DNA结构，并促进氧化应激后基因组脱碱基位点的解析。我们进一步观察到，通过表达载体转染恢复EEPD 1的表达可恢复细胞存活，并抑制EEPD 1缺失细胞中由氧化应激诱导的染色体异常。与此一致，我们发现EEPD1通过防止氧化应激的未修复的叉融合来保持复制叉的完整性，从而减少染色体不稳定性和有丝分裂异常。我们的研究结果表明EEPD1在氧化应激过程中复制叉保存和染色体稳定性维护中的新作用。
Unrepaired oxidatively-stressed replication forks can lead to chromosomal instability and neoplastic transformation or cell death. To meet these challenges cells have evolved a robust mechanism to repair oxidative genomic DNA damage through the base excision repair (BER) pathway, but less is known about repair of oxidative damage at replication forks. We found that depletion or genetic deletion of EEPD1 decreases clonogenic cell survival after oxidative DNA damage. We demonstrate that EEPD1 is recruited to replication forks stressed by oxidative damage induced by H2O2 and that EEPD1 promotes replication fork repair and restart and decreases chromosomal abnormalities after such damage. EEPD1 binds to abasic DNA structures and promotes resolution of genomic abasic sites after oxidative stress. We further observed that restoration of expression of EEPD1 via expression vector transfection restores cell survival and suppresses chromosomal abnormalities induced by oxidative stress in EEPD1-depleted cells. Consistent with this, we found that EEPD1 preserves replication fork integrity by preventing oxidatively-stressed unrepaired fork fusion, thereby decreasing chromosome instability and mitotic abnormalities. Our results indicate a novel role for EEPD1 in replication fork preservation and maintenance of chromosomal stability during oxidative stress.