Augmented oxidative stress increases 8-oxoguanine preferentially in the transcriptionally active genomic regions
Augmented oxidative stress increases 8-oxoguanine preferentially in the transcriptionally active genomic regions
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DOI：
10.1080/10715762.2020.1733548
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发表时间：
2020-04-16
影响因子：
3.3
通讯作者：
Toyokuni, Shinya
中科院分区：
文献类型：
--
作者：
Akatsuka, Shinya;Li, Guang Hua;Toyokuni, Shinya
8-氧鸟嘌呤 (8-oxoG) 是哺乳动物基因组中最常见的 DNA 碱基修饰，与氧化应激相关。在这里，我们分析了使用次氮基三乙酸铁（Fe-NTA）作为肾近曲小管氧化应激诱导剂导致氧化应激升高之前和之后整个小鼠基因组中 8-oxoG 分布的变化。我们通过免疫沉淀从小鼠基因组中分离出含有 8-oxoG 的 DNA 片段，并通过 PCR 扩增它们，以便使用基于微阵列的比较基因组杂交进行分布分析。分布图显示，8-oxoG 的频率沿着染色体以 1-10 Mb 为周期波动，并且在施用 Fe-NTA 后波动幅度减小。在对照和氧化应激条件下，8-oxoG 在整个基因组中的分布与基因密度呈负相关，但与核纤层蛋白 B1 相互作用呈正相关，后者对应于核纤层相关结构域。小鼠基因组的这些结果与我们之前报道的大鼠基因组的结果一致。我们进一步发现 8-oxoG 的分布与基因组转录活性之间存在负相关。最后，比较 Fe-NTA 施用前后的分布表明，8-oxoG 是为了响应氧化应激的增加而优先在转录活性基因组区域产生的，而在对照条件下，该区域 8-oxoG 的积累较少。
8-Oxoguanine (8-oxoG) is the most common DNA base modification in the mammalian genome, associated with oxidative stress. Here we analysed the alterations in the distribution of 8-oxoG across the entire murine genome, before and after an elevation of oxidative stress by the use of ferric nitrilotriacetate (Fe-NTA) as an oxidative stress inducer in the renal proximal tubules. We isolated DNA fragments containing 8-oxoGs with immunoprecipitation from the murine genome, and amplified them by PCR for a distribution analysis with microarray-based comparative genomic hybridisation. The distribution profiles revealed that frequencies of 8-oxoG fluctuated with a cycle of 1-10 Mb along the chromosomes and the amplitude of the fluctuation was reduced after Fe-NTA administration. The distributions of 8-oxoG along the entire genome in the control and oxidatively stressed conditions were negatively correlated with that of gene density but positively correlated with that of Lamin B1 interaction, which corresponds to lamina-associated domains. These results on the murine genome were consistent with those on the rat genome we previously reported. We further discovered a negative correlation between the distributions of 8-oxoG and transcriptional activity along the genome. Finally, a comparison of the distributions before and after Fe-NTA administration suggested that 8-oxoGs are generated in response to the augmented oxidative stress preferentially in the transcriptionally active genomic regions, where 8-oxoGs have been less accumulated in the control condition.