Insulin gene expression is regulated by DNA methylation.
Insulin gene expression is regulated by DNA methylation.
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DOI：
10.1371/journal.pone.0006953
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发表时间：
2009-09-09
期刊：
影响因子：
3.7
通讯作者：
Ferreri K
中科院分区：
文献类型：
--
作者：
Kuroda A;Rauch TA;Todorov I;Ku HT;Al-Abdullah IH;Kandeel F;Mullen Y;Pfeifer GP;Ferreri K
胰岛素是代谢控制的关键组成部分，因此，胰岛素基因表达一直是广泛研究的焦点。调节胰岛素基因转录和大多数调节因子的 DNA 序列已经被确定。然而，直到最近才对胰岛素基因表达的其他组成部分进行了研究，在这项研究中，我们研究了 DNA 甲基化在小鼠和人类胰岛素基因表达调节中的作用。来自多个组织的基因组 DNA 样本经过亚硫酸氢盐处理并测序，结果表明小鼠 Ins2 和人 INS 启动子中的胞嘧啶-鸟苷二核苷酸 (CpG) 位点在产生胰岛素的胰腺 β 细胞中独特地去甲基化。这些 CpG 位点的甲基化将胰岛素启动子驱动的报告基因活性抑制了近 90%，而单独启动子中 cAMP 响应元件 (CRE) 中 CpG 位点的特异性甲基化则将胰岛素启动子活性抑制了 50%。甲基化在体外并不直接抑制因子与CRE的结合，但在体内抑制ATF2和CREB的结合，并相反增加甲基CpG结合蛋白2（MeCP2）的结合。对小鼠胚胎干细胞培养物中 Ins2 基因的检查表明，它是完全甲基化的，并且随着细胞在体外分化为胰岛素表达细胞而变得去甲基化。我们的研究结果表明，胰岛素启动子 CpG 去甲基化可能在 β 细胞成熟和组织特异性胰岛素基因表达中发挥至关重要的作用。
Insulin is a critical component of metabolic control, and as such, insulin gene expression has been the focus of extensive study. DNA sequences that regulate transcription of the insulin gene and the majority of regulatory factors have already been identified. However, only recently have other components of insulin gene expression been investigated, and in this study we examine the role of DNA methylation in the regulation of mouse and human insulin gene expression. Genomic DNA samples from several tissues were bisulfite-treated and sequenced which revealed that cytosine-guanosine dinucleotide (CpG) sites in both the mouse Ins2 and human INS promoters are uniquely demethylated in insulin-producing pancreatic beta cells. Methylation of these CpG sites suppressed insulin promoter-driven reporter gene activity by almost 90% and specific methylation of the CpG site in the cAMP responsive element (CRE) in the promoter alone suppressed insulin promoter activity by 50%. Methylation did not directly inhibit factor binding to the CRE in vitro, but inhibited ATF2 and CREB binding in vivo and conversely increased the binding of methyl CpG binding protein 2 (MeCP2). Examination of the Ins2 gene in mouse embryonic stem cell cultures revealed that it is fully methylated and becomes demethylated as the cells differentiate into insulin-expressing cells in vitro. Our findings suggest that insulin promoter CpG demethylation may play a crucial role in beta cell maturation and tissue-specific insulin gene expression.
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DOI：
10.1016/j.bbaexp.2007.01.005
发表时间：
2007-02-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA-GENE STRUCTURE AND EXPRESSION
影响因子：
--
作者：
Hay, Colin W.;Ferguson, Laura A.;Docherty, Kevin
通讯作者：
Docherty, Kevin
影响因子：
3.2
作者：
Lukowiak, B;Vandewalle, B;Pattou, F
通讯作者：
Pattou, F
影响因子：
7.7
作者：
Evans-Molina, Carmella;Garmey, James C.;Mirmira, Raghavendra G.
通讯作者：
Mirmira, Raghavendra G.
影响因子：
4.8
作者：
Abu, M;Waters, TR
通讯作者：
Waters, TR
影响因子：
4.8
作者：
Francis, J;Chakrabarti, SK;Mirmira, RG
通讯作者：
Mirmira, RG