Control of embryonic stem cell identity by BRD4-dependent transcriptional elongation of super-enhancer-associated pluripotency genes.
Bottom Line: Transcription factors and chromatin-remodeling complexes are key determinants of embryonic stem cell (ESC) identity.BRD4 maintains transcription of core stem cell genes such as OCT4 and PRDM14 by occupying their super-enhancers (SEs), large clusters of regulatory elements, and recruiting to them Mediator and CDK9, the catalytic subunit of the positive transcription elongation factor b (P-TEFb), to allow Pol-II-dependent productive elongation.Our study describes a mechanism of regulation of ESC identity that could be applied to improve the efficiency of ESC differentiation.
Affiliation: Department of Pathology, New York University School of Medicine, and Perlmutter Cancer Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA. Electronic address: email@example.com.Show MeSH
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Mentions: We next investigated whether BRD4 inhibition results in ESC differentiation together with suppression of stem cell genes and loss of self-renewal capacity. Compound treatment of ESCs modulated the expression of genes involved in epithelialto-mesenchymal transition (EMT) (Figures 3A and 3B), a defining feature of ESCs undergoing differentiation. Accompanying the emergence of an EMT signature, we observed an enrichment of neuroectodermal differentiation markers (e.g., NES, NCAD, and SOX1) relative to markers of other lineages in both hESCs (Figures 3B and 3C) and mESCs (Figures S4A and S4B), indicating lineage specificity associated with BET inhibition. Consistently, individual silencing of BRD4 mimicked the preferential regulation of EMT and neuroectodermal markers over other line-ages observed following pharmacologic BET inhibition in human (Figure 3D) and mouse ESCs (Figure S4C). BET inhibitor treat ment of ESCs significantly affected both the number and morphology of embryoid bodies (EBs) (Figures S5A and S5B), indicating that BRD4 activity is required for the formation of tridimensionally organized EBs. Moreover, BET inhibition resulted in suppression of stem cell genes (Figure S5C) and induction of neuroectodermal lineage genes over genes of other lineages in EBs formation assay (Figure S5D), highlighting the specific line-age commitment following BET inhibition.
Affiliation: Department of Pathology, New York University School of Medicine, and Perlmutter Cancer Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Stem Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA. Electronic address: firstname.lastname@example.org.