Genome-wide mapping of 8-oxo-7,8-dihydro-2-deoxyguanosine reveals accumulation of oxidatively-generated damage at DNA replication origins within transcribed long genes of mammalian cells
Genome-wide mapping of 8-oxo-7,8-dihydro-2-deoxyguanosine reveals accumulation of oxidatively-generated damage at DNA replication origins within transcribed long genes of mammalian cells
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DOI：
10.1093/nar/gky1152
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发表时间：
2019-01-10
影响因子：
14.9
通讯作者：
Majello, Barbara
中科院分区：
文献类型：
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作者：
Amente, Stefano;Di Palo, Giacomo;Majello, Barbara
8-氧代-7，8-二氢-2-脱氧鸟苷（8-oxodG）是主要的DNA修饰之一，并且是易于与2-脱氧腺苷（dA）错配的有效的前致突变损伤。数千个8-oxodG残基组成型产生于哺乳动物细胞的基因组中，但其基因组分布尚未完全表征。在这里，通过使用OxiDIP-Seq，一种高灵敏度的方法，使用免疫沉淀与有效的抗8-oxodG抗体结合高通量测序，我们报告了8-oxodG在人类非致瘤性上皮乳腺细胞（MCF 10A）和小鼠胚胎成纤维细胞（MEF）中的全基因组分布。OxiDIP-Seq揭示了在转录的长基因的基因体内，特别是在其中包含的DNA复制起点处，8-oxodG积累与H2 AX ChIP-Seq信号重叠的位点。我们建议，持久的单链DNA的存在下，作为在这些网站的转录-复制冲突的结果，决定了当地的脆弱性，DNA氧化和/或其缓慢修复。这种氧化性损伤可能与其他类型的损伤结合，可能有助于DNA双链断裂的形成和DNA损伤反应的激活。
8-Oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is one of the major DNA modifications and a potent pre-mutagenic lesion prone to mispair with 2-deoxyadenosine (dA). Several thousand residues of 8-oxodG are constitutively generated in the genome of mammalian cells, but their genomic distribution has not yet been fully characterized. Here, by using OxiDIP-Seq, a highly sensitive methodology that uses immuno-precipitation with efficient anti-8-oxodG antibodies combined with high-throughput sequencing, we report the genome-wide distribution of 8-oxodG in human non-tumorigenic epithelial breast cells (MCF10A), and mouse embryonic fibroblasts (MEFs). OxiDIP-Seq revealed sites of 8-oxodG accumulation overlapping with H2AX ChIP-Seq signals within the gene body of transcribed long genes, particularly at the DNA replication origins contained therein. We propose that the presence of persistent single-stranded DNA, as a consequence of transcription-replication clashes at these sites, determines local vulnerability to DNA oxidation and/or its slow repair. This oxidatively-generated damage, likely in combination with other kinds of lesion, might contribute to the formation of DNA double strand breaks and activation of DNA damage response.