Genome wide nucleosome specifity and function of chromatin remodellers in embryonic stem cells [Chd9]

How various ATP-dependent chromatin remodellers bind to nucleosomes to regulate transcription is not well defined in mammalian cells. Here, we present genome-wide remodeller-interacting nucleosome profiles for Chd1, Chd2, Chd4, Chd6, Chd8, Chd9, Brg1 and Ep400 in mouse embryonic stem (ES) cells. These remodellers bind to nucleosomes at specific positions, either at one or both nucleosomes that flank each side of nucleosome-free promoter regions (NFRs), at enhancer elements, or within gene bodies. At promoters, bidirectional transcription commonly initiates on either side of remodeller-bound nucleosomes. Transcriptome analysis upon remodeller depletion reveals reciprocal mechanisms of transcriptional regulation by remodellers. At active genes, certain remodellers are positive regulators of transcription, whereas others act as repressors. At bivalent genes, which are bound by repressive Polycomb complexes, the same remodellers act in the opposite way. Together, these findings reveal how remodellers integrate promoter nucleosomal architecture to regulate ES cell transcription programs. 6 samples analysed