OGG1-DNA interactions facilitate NF-κB binding to DNA targets.
OGG1-DNA interactions facilitate NF-κB binding to DNA targets.
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OGG1-DNA 相互作用促进 NF-κB 与 DNA 靶标结合
DOI：
10.1038/srep43297
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发表时间：
2017-03-07
影响因子：
4.6
通讯作者：
Ba X
中科院分区：
文献类型：
--
作者：
Pan L;Hao W;Zheng X;Zeng X;Ahmed Abbasi A;Boldogh I;Ba X
DNA修复蛋白对抗氧化启动子损伤可能调节基因表达。氧化DNA碱基被活性氧（ROS）修饰，主要是7,8 -二氢-8-氧-2 ' -脱氧鸟苷（8-oxoG），在碱基切除修复（BER）途径中被8-氧鸟嘌呤DNA糖基化酶1 （OGG1）修复。由于细胞对氧化挑战的反应伴随着DNA损伤的修复，我们测试了OGG1的修复是否与转录因子结合和基因表达兼容。我们使用源自Cxcl2基因启动子的野生型序列和相同的序列，在特定的5 ‘或3 ’鸟嘌呤上含有单个合成的8-oxoG，以模拟鸟嘌呤的氧化作用，进行了电泳迁移试验（EMSA）。我们发现肿瘤坏死因子α (TNFα)暴露细胞的核提取物中NF-κB的DNA占用依赖于OGG1和8-oxoG的位置，重要的是，OGG1抵消共识基序外的8-oxoG对纯化的NF-κB与DNA的结合有深远的影响。此外，在8-oxoG从DNA中切除之前，OGG1对于NF-κB依赖性基因的表达至关重要。这些观察结果表明，在由ROS引起的OGG1启动的BER过程中，预切除步骤促进了NF-κB DNA的占据和基因表达。
DNA repair protein counteracting oxidative promoter lesions may modulate gene expression. Oxidative DNA bases modified by reactive oxygen species (ROS), primarily as 7, 8-dihydro-8-oxo-2′-deoxyguanosine (8-oxoG), which is repaired by 8-oxoguanine DNA glycosylase1 (OGG1) during base excision repair (BER) pathway. Because cellular response to oxidative challenge is accompanied by DNA damage repair, we tested whether the repair by OGG1 is compatible with transcription factor binding and gene expression. We performed electrophoretic mobility shift assay (EMSA) using wild-type sequence deriving from Cxcl2 gene promoter and the same sequence bearing a single synthetic 8-oxoG at defined 5′ or 3′ guanine in runs of guanines to mimic oxidative effects. We showed that DNA occupancy of NF-κB present in nuclear extracts from tumour necrosis factor alpha (TNFα) exposed cells is OGG1 and 8-oxoG position dependent, importantly, OGG1 counteracting 8-oxoG outside consensus motif had a profound influence on purified NF-κB binding to DNA. Furthermore, OGG1 is essential for NF-κB dependent gene expression, prior to 8-oxoG excised from DNA. These observations imply that pre-excision step(s) during OGG1 initiated BER evoked by ROS facilitates NF-κB DNA occupancy and gene expression.