GSE65836
The Histone Deacetylase Sirt6 Controls Embryonic Stem Cell Fate Via Tet-Mediated Production of 5-Hydroxymethylcytosine
How embryonic stem cells (ESC) commit to specific cell lineages and ultimately yield all cell types of a fully formed organism remains a major question. ESC differentiation is accompanied by large-scale histone and DNA modifications, but the relations between these two categories of epigenetic changes are not understood. Here we demonstrate the hierarchical interplay between the histone deacetylase, sirtuin 6 (Sirt6), which targets acetylated histone H3 at lysines 9 and 56 (H3K9ac and H3K56ac), and the Tet (Ten-eleven translocation) enzymes, which convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC). ESCs derived from Sirt6 knocSirt6 KOut (S6Sirt6 KO) mice are skewed towards neuroectoderm development. This phenotype is associated with derepression of Oct4, Sox2 and Nanog, which in turn causes an upregulation of Tet enzymes and elevated production of 5hmC. Genome-wide analysis revealed an upregulation of neuroectoderm genes marked with 5hmC in S6Sirt6 KO ESCs, thereby implicating Tet enzymes in the neuroectoderm-skewed differentiation phenotype of S6Sirt6 KO ESCs, which is fully rescued upon knockdown of Tets. We demonstrate a new role for Sirt6 as a chromatin regulator safeguarding the balance between pluripotency and differentiation through Tet-dependent regulation of 5hmC levels. Overall design: ChIP-Seq experiments to examine two different histone modifications (H3K9ac and H3K56ac) and Sirt6 binding in Sirt6 wild type (WT) and knock-out (Sirt6 KO) mouse embryonic stem cells with and without treatment using differentiating agent retonic acid (RA). CMS-IP 5-Hydroxymethylation mapping in wild type (WT, 129 mouse strain) and Sirt6 knockout (S6KO, 129 mouse strain) mouse embryonic stem cells.