title: A double take on bivalent promoters.
abstract: Histone modifications and chromatin-associated protein complexes are crucially involved in the control of gene expression, supervising cell fate decisions and differentiation. Many promoters in embryonic stem (ES) cells harbor a distinctive histone modification signature that combines the activating histone H3 Lys 4 trimethylation (H3K4me3) mark and the repressive H3K27me3 mark. These bivalent domains are considered to poise expression of developmental genes, allowing timely activation while maintaining repression in the absence of differentiation signals. Recent advances shed light on the establishment and function of bivalent domains; however, their role in development remains controversial, not least because suitable genetic models to probe their function in developing organisms are missing. Here, we explore avenues to and from bivalency and propose that bivalent domains and associated chromatin-modifying complexes safeguard proper and robust differentiation.
authors.affiliation: Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.
authors.forename: Philipp
authors.initials: P
authors.lastname: Voigt
authors.forename: Wee-Wei
authors.initials: WW
authors.lastname: Tee
authors.forename: Danny
authors.initials: D
authors.lastname: Reinberg
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics; D053595:Embryonic Stem Cells / Q000166:cytology; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*
keywords: Polycomb; Trithorax; bivalent domains; chromatin; embryonic stem cells