Role and Regulation of DNA Methylation in Cellular Reprogramming

DNA 甲基化在细胞重编程中的作用和调节

• 批准号: 66270595
• 负责人: Professor Dr. Heinrich Leonhardt
• 金额: --
• 依托单位: Arbeitsgruppe Humanbiologie und Bioimaging
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/66270595?language=en
• 关键词: Role; Regulation; DNA; Methylation; Cellular

DNA methyltransferases (Dnmts) play a central role in the maintenance and modification of epigenetic information. There is evidence that changes of DNA methylation correlate with cellular reprogramming but little is known about the underlying mechanisms. We now have shown that DNA methylation plays a minor role in controlling gene expression in pluripotent stem cells but is required for efficient and stable silencing of pluripotency genes during differentiation and its absence facilitates re-activation of the oct4 promoter. Last year, the discovery of 5-hydroxymethylcytosine (hmC), a potential de-methylation intermediate, and the corresponding enzymes (Tet1-3) opened an entirely new perspective on epigenetic reprogramming. We have developed new tools to quantify and map this new DNA modification and now want to study its genome-wide distribution by chromatin immuno-precipitation and specific nucleases in combination with deep sequencing. In addition, we want to determine the subcellular distribution of hmC with respect to different chromatin domains and other epigenetic marks by super-resolution microscopy. To test the role of this novel modification we will manipulate Tet activity and test its effect on demethylation and reprogramming. This project should help elucidate the role and regulation of DNA (de-)methylation during cellular reprogramming and to improve its efficiency.

DNA甲基转移酶（Dnmts）在表观遗传信息的维持和修饰中起着核心作用。有证据表明，DNA甲基化的变化与细胞重编程相关，但对其潜在机制知之甚少。我们现在已经证明，DNA甲基化在控制多能干细胞的基因表达中起着次要作用，但在分化过程中，DNA甲基化对于多能基因的有效和稳定沉默是必需的，而DNA甲基化的缺失有助于oct4启动子的重新激活。去年，一种潜在的去甲基化中间体5-羟甲基胞嘧啶（hmC）和相应的酶（Tet1-3）的发现为表观遗传重编程开辟了一个全新的视角。我们已经开发了新的工具来量化和绘制这种新的DNA修饰，现在希望通过染色质免疫沉淀和特异性核酸酶结合深度测序来研究其全基因组分布。此外，我们希望通过超分辨率显微镜确定hmC在不同染色质结构域和其他表观遗传标记方面的亚细胞分布。为了测试这种新修饰的作用，我们将操纵Tet活性并测试其对去甲基化和重编程的影响。该项目将有助于阐明DNA（去）甲基化在细胞重编程中的作用和调控，并提高其效率。