GSE65838
Dnmt3a and Dnmt3b associate with enhancers to regulate human epidermal stem cell homeostasis
Here, we show that Dnmt3a and Dnmt3b show non-overlapping and unique patterns of genomic localization in human epidermal stem cells and their differentiated counterparts. Dnmt3a, but not Dnmt3b, binds to the TSSs of a cohort of genes required for the interaction of stem cells with their underlying stroma. Unexpectedly, TSSs bound by Dnmt3a are highly transcribed and are devoid of DNA-methylation. Conversely, Dnmt3b specifically decorates the genebody of genes that establish the stem cell and differentiated signatures. Genic occupation by Dnmt3b correlates with high levels of DNA-methylation, broad domains of histone H3K4me3 8, and robust transcription. Intriguingly, both proteins also bind to the most active subset of enhancers, and are required for the production of their associated bidirectional enhancer RNAs 9. We show that typical and super-enhancers are very dynamically regulated during the linear transition of epidermal stem cells to differentiated keratinocytes. Interestingly, Dnmt3a and Dnmt3b show a strong preference for the super-enhancers that define the ectodermal lineage, but importantly, that also establish the functional traits associated to the stem cell and differentiated states. These enhancers contain very low levels of DNA-methylation, but high amounts of DNA-hydroxymethylation. Depletion of either protein completely impairs human epidermal stem cell self-renewal by inducing their spontaneous differentiation. Overall design: Examination of genome wide localization of Dnmt3A and Dnmt3B and their overlap within genomic regulatory regions in a DNA-methylation dependent and independent manner. Genome wide total RNA quantification of Wild Type Human EpiSC and its Differentiated counterparts.