The effects of cytosine methylation on general transcription factors.
The effects of cytosine methylation on general transcription factors.
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胞嘧啶甲基化对一般转录因子的影响
DOI：
10.1038/srep29119
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发表时间：
2016-07-07
影响因子：
4.6
通讯作者：
Su XD
中科院分区：
文献类型：
--
作者：
Jin J;Lian T;Gu C;Yu K;Gao YQ;Su XD
CpG位点上的DNA甲基化是最常见的表观遗传修饰。最近，发现非CPG环境中的甲基化广泛发生在基因组DNA上。此外，非CPG位点的甲基化是一个高度控制的过程，其水平在细胞发育过程中可能会有所不同。为了研究非CPG甲基化对DNA/蛋白质相互作用的影响，我们选择了三个人类转录因子（TFS）：糖皮质激素受体（GR），脑和肌肉类似ARNT类似于1（BMAL1） - 昼夜节律型kaput（bmal1） - 使用甲基甲基化的蛋白酶和甲基化的dna dna d.量热测定。结果表明，与它们的同源DNA序列相比，这些TF与具有不同作用的甲基化DNA相互作用。非CPG甲基化对转录调控的影响通过基于细胞的荧光素酶测定在蛋白质水平上验证。通过晶体学分析和分子动力学模拟研究了影响DNA-蛋白相互作用的非CPG甲基化的机制。在HEK-293T细胞中的Bischip-Seq分析中，我们发现GR可以识别细胞中染色质中高度甲基化的位点。因此，我们得出结论，DNA的非CPG甲基化可以通过直接影响TF的结合来提供调节基因表达的机制。
DNA methylation on CpG sites is the most common epigenetic modification. Recently, methylation in a non-CpG context was found to occur widely on genomic DNA. Moreover, methylation of non-CpG sites is a highly controlled process and its level may vary during cellular development. To study non-CpG methylation effects on DNA/protein interactions, we have chosen three human transcription factors (TFs): glucocorticoid receptor (GR), brain and muscle ARNT-like 1 (BMAL1) - circadian locomotor output cycles kaput (CLOCK) and estrogen receptor (ER) with methylated or unmethylated DNA binding sequences, using single-molecule and isothermal titration calorimetry assays. The results demonstrated that these TFs interact with methylated DNA with different effects compared with their cognate DNA sequences. The effects of non-CpG methylation on transcriptional regulation were validated by cell-based luciferase assay at protein level. The mechanisms of non-CpG methylation influencing DNA-protein interactions were investigated by crystallographic analyses and molecular dynamics simulation. With BisChIP-seq assays in HEK-293T cells, we found that GR can recognize highly methylated sites within chromatin in cells. Therefore, we conclude that non-CpG methylation of DNA can provide a mechanism for regulating gene expression through directly affecting the binding of TFs.