OGG1-DNA interactions facilitate NF-κB binding to DNA targets

• DOI: 10.1038/srep43297
• Publication Date: 2017-03-07T10:35:04Z
• Authors: Lang Pan; Wenjing Hao; Xu Zheng; Xianlu Zeng; Adeel Ahmed Abbasi; Istvan Boldogh; Xueqing Ba
• Keywords: 0303 health sciences; DNA Repair; NF-kappa B; Deoxyguanosine; Electrophoretic Mobility Shift Assay; DNA; Article; Cell Line; DNA Glycosylases; Mice; 03 medical and health sciences; 8-Hydroxy-2'-Deoxyguanosine; Animals; Protein Binding

AbstractDNA 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.