CpG methylation prevents YY1-mediated transcriptional activation of the vimentin promoter
CpG methylation prevents YY1-mediated transcriptional activation of the vimentin promoter
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DOI：
10.1016/j.bbrc.2011.09.155
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发表时间：
2011-11-04
影响因子：
3.1
通讯作者：
Homma, Yoshimi
中科院分区：
文献类型：
--
作者：
Sekimata, Masayuki;Murakami-Sekimata, Akiko;Homma, Yoshimi
Vimentin表现出复杂的组织特异性和发育调控表达模式，但复杂转录调控的机制仍然知之甚少。在这里，我们研究了vimentin的表达是否可以通过vimentin启动子的CpG甲基化来调节。用（C6vim+）和不含（C6vim-） vimentin分别建立了大鼠C6胶质瘤细胞亚克隆。亚硫酸氢盐基因组测序显示，在C6vim-细胞中，vimentin启动子内的转录起始位点附近高度甲基化，而在C6vim+细胞中则没有。用去甲基化剂5-aza-2'-脱氧胞苷处理C6vim-细胞，恢复了vimentin的表达，这表明启动子区域的高甲基化与vimentin基因的转录沉默相关。电泳迁移迁移试验（EMSA）和瞬时转染实验表明，YY1是调节vimentin表达的关键转录激活因子，CpG甲基化足以阻止YY1与vimentin启动子结合。这些数据表明，YY1无法进入高甲基化启动子可能是介导vimentin下调的机制之一。(C) 2011爱思唯尔公司版权所有。
Vimentin exhibits a complex pattern of tissue-specific and developmentally regulated expression, but the mechanisms underlying the complex transcriptional regulation remain poorly understood. Here we examined whether vimentin expression can be regulated by CpG methylation of the vimentin promoter. Two subclones of the rat C6 glioma cells were established with (C6vim+) and without (C6vim-) vimentin. Bisulfite genomic sequencing revealed that the vicinity of the transcription start site within the vimentin promoter is highly methylated in C6vim- cells but not in C6vim+ cells. Treatment of C6vim- cells with a demethylating agent, 5-aza-2'-deoxycytidine, restored vimentin expression, indicating that hypermethylation of the promoter region correlates with transcriptional silencing of the vimentin gene. Electrophoretic mobility shift assay (EMSA) and transient transfection experiments demonstrated that YY1 is a key transcriptional activator regulating vimentin expression and that CpG methylation is sufficient to prevent the binding of YY1 to the vimentin promoter. These data suggest that the inability of YY1 to access the hypermethylated promoter may be one of the mechanisms that mediate vimentin downregulation. (C) 2011 Elsevier Inc. All rights reserved.