Role and Regulation of DNA Methylation in Cellular Reprogramming

点击翻译按钮获取中文摘要

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.