LINE-1 methylation status of endogenous DNA double-strand breaks
LINE-1 methylation status of endogenous DNA double-strand breaks
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DOI：
10.1093/nar/gkn261
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发表时间：
2008-06-01
影响因子：
14.9
通讯作者：
Mutirangura, Apiwat
中科院分区：
文献类型：
--
作者：
Pornthanakasem, Wichai;Kongruttanachok, Narisorn;Mutirangura, Apiwat
DNA甲基化和DNA双链断裂修复是维持基因组完整性的重要过程。虽然DSB可以由许多试剂产生，但它们也作为内源性DSB（EDSB）自发发生。在这项研究中，我们评估了EDSB的甲基化状态，以确定DNA甲基化和EDSB之间是否存在联系。我们利用散布的重复序列聚合酶链反应（PCR），连接介导的PCR和结合亚硫酸氢盐限制性内切酶分析，以检查EDSB的程度和甲基化在长散布的核元件-1（LINE-1）序列附近的EDSB。我们测试了正常的白色血细胞和几种来自上皮癌和白血病的细胞系。在所有细胞类型中均可检测到显著水平的EDSB。在复制和非复制细胞中也发现EDSB。我们发现EDSB含有比细胞基因组更高水平的甲基化。这种超甲基化是复制无关的，并且甲基化存在于基因组中DNA DSB之前的位置。EDSB和基因组其余部分之间甲基化水平的差异表明，EDSB通过产生、末端修饰或修复进行差异加工，这取决于DNA甲基化状态。
DNA methylation and the repair of DNA double-strand breaks (DSBs) are important processes for maintaining genomic integrity. Although DSBs can be produced by numerous agents, they also occur spontaneously as endogenous DSBs (EDSBs). In this study, we evaluated the methylation status of EDSBs to determine if there is a connection between DNA methylation and EDSBs. We utilized interspersed repetitive sequence polymerase chain reaction (PCR), ligation-mediated PCR and combined bisulfite restriction analysis to examine the extent of EDSBs and methylation at long interspersed nuclear element-1 (LINE-1) sequences nearby EDSBs. We tested normal white blood cells and several cell lines derived from epithelial cancers and leukemias. Significant levels of EDSBs were detectable in all cell types. EDSBs were also found in both replicating and non-replicating cells. We found that EDSBs contain higher levels of methylation than the cellular genome. This hypermethylation is replication independent and the methylation was present in the genome at the location prior to the DNA DSB. The differences in methylation levels between EDSBs and the rest of the genome suggests that EDSBs are differentially processed, by production, end-modification, or repair, depending on the DNA methylation status.