Project description:Precise control of gene expression plays fundamental roles in brain development, but the roles of chromatin regulators in neuronal connectivity have remained poorly understood. Here, we find that depletion of the nucleosome remodeling and deacetylation (NuRD) complex in the cerebellar cortex by in vivo RNAi in rats and conditional knockout of the core NuRD subunit Chd4 in mice profoundly impairs the establishment of granule neuron parallel fiber/Purkinje cell synapses. In RNA-Seq analyses of Chd4 conditional knockout mice, we identify a set of nearly 200 genes that are repressed by the NuRD complex in the cerebellum in vivo. Genome-wide ChIP-Seq analyses reveal that the NuRD complex selectively decommissions the promoters of NuRD-repressed genes in the cerebellum in vivo by inducing the deacetylation of histone H3K9/14 and H3K27 and demethylation of H3K4 at these genes. Importantly, temporal control of promoter decommissioning and repression of NuRD target genes upon maturation of the cerebellum requires the NuRD complex. Finally, in a targeted in vivo RNAi screen of NuRD-repressed target genes, we identify the transcription factor Nhlh1, the RNA-binding protein Elavl2, and the presynaptic regulator Cplx3 as negative regulators of presynaptic differentiation in the cerebellar cortex. Together, these findings define NuRD-dependent promoter decommissioning as a developmentally regulated programming mechanism that releases the brake on presynaptic differentiation and thereby drives synaptic connectivity in the mammalian brain. Three distinct histone modifications using postnatal day 6 or day 22 cerebella from wild type (WT) or Chd4 conditional knockout (cKO) mice were examined in duplicate using libraries prepared with the Illumina ChIP-Seq DNA Sample Prep Kit and sequenced on the Illumina HiSeq 2000 platform.
Project description:Precise control of gene expression plays fundamental roles in brain development, but the roles of chromatin regulators in neuronal connectivity have remained poorly understood. Here, we find that depletion of the nucleosome remodeling and deacetylation (NuRD) complex in the cerebellar cortex by in vivo RNAi in rats and conditional knockout of the core NuRD subunit Chd4 in mice profoundly impairs the establishment of granule neuron parallel fiber/Purkinje cell synapses. In RNA-Seq analyses of Chd4 conditional knockout mice, we identify a set of nearly 200 genes that are repressed by the NuRD complex in the cerebellum in vivo. Genome-wide ChIP-Seq analyses reveal that the NuRD complex selectively decommissions the promoters of NuRD-repressed genes in the cerebellum in vivo by inducing the deacetylation of histone H3K9/14 and H3K27 and demethylation of H3K4 at these genes. Importantly, temporal control of promoter decommissioning and repression of NuRD target genes upon maturation of the cerebellum requires the NuRD complex. Finally, in a targeted in vivo RNAi screen of NuRD-repressed target genes, we identify the transcription factor Nhlh1, the RNA-binding protein Elavl2, and the presynaptic regulator Cplx3 as negative regulators of presynaptic differentiation in the cerebellar cortex. Together, these findings define NuRD-dependent promoter decommissioning as a developmentally regulated programming mechanism that releases the brake on presynaptic differentiation and thereby drives synaptic connectivity in the mammalian brain.
Project description:Dynamic changes of histone epigenetic modifications and chromatin structure represent an universal mechanism by which cells adapt their transcriptional response to rapidly changing environmental conditions. During neuronal development, extensive chromatin remodeling takes place allowing the transition of pluripotent cells into differentiated neurons. Here we report that the ATP-dependent chromatin remodeling complex NuRD, which couples ATP-dependent nucleosome sliding with histone deacetylase activity, is a major remodeling complex in embryonic brain and plays an instructive role during mouse neuronal development. Importantly, the ATPase subunits of NuRD complex CHD3, CHD4 and CHD5 undergo a functional switch, thereby regulating distinct aspects of neuronal differentiation and migration in a sequential and mostly non-overlapping manner. We conclude that the recruitment of NuRD complexes containing specific CHDs to gene promoters and enhancers plays an instructive role in brain development. Gene expression analysis was performed in the mouse embryonic cortex at three developmental stages: E12.5, E15.5 and E18.5 using total RNA obtained from four embryos for each time point.
Project description:Activity-dependent transcription influences neuronal connectivity, but the roles and mechanisms of inactivation of activity-dependent genes have remained poorly understood. Genome-wide analyses in the mouse cerebellum revealed that the nucleosome remodeling and deacetylase (NuRD) complex deposits the histone variant H2A.z at promoters of activity-dependent genes, thereby triggering their inactivation. Purification of translating mRNAs from synchronously developing granule neurons (Sync-TRAP) showed that conditional knockout of the core NuRD subunit Chd4 impairs inactivation of activity-dependent genes when neurons undergo dendrite pruning. Chd4 knockout or expression of NuRD-regulated activity genes impairs dendrite pruning. Imaging of behaving mice revealed hyperresponsivity of granule neurons to sensorimotor stimuli upon Chd4 knockout. Our findings define an epigenetic mechanism that inactivates activity-dependent transcription and regulates dendrite patterning and sensorimotor encoding in the brain.
Project description:Maintenance of chromatin structure is essential to eukaryotic life; dysregulation is known to be causal for aberrant development and disease. The Mi-2/nucleosome remodeling and histone deacetylase (NuRD) complex is a multiprotein machine proposed to regulate chromatin structure by nucleosome remodeling and histone deacetylation activities. We identified the localization of MBD3, a component of Mi-2/NuRD complex, in two breast cancer cell lines (MCF7 and MDA-MB-231) using ChIP-Seq. MBD3 showed cell-type specific localization with overlap across cell lines being less than 50%. MBD3 localized across gene bodies, peaking around the transcription start site (TSS). Contrary to existing models, MBD3 preferentially associated with CpG rich promoters marked by H3K4me3. These data suggest that MBD3, and by extension the Mi-2/NuRD complex, may have roles in fine tuning expression for active genes. These data represent an important first step in defining regulatory mechanisms by which Mi-2/NuRD complex controls chromatin structure and gene expression. DamID experiment was performed in human breast cancer cell lines (MCF-7 and MDA-MB-231) in duplicate. Samples were hybridized to Nimblegen 2.1M Deluxe promoter array. MBD3-Dam material was hybridized over Dam-only control.
Project description:Activity-dependent transcription influences neuronal connectivity, but the roles and mechanisms of inactivation of activity-dependent genes have remained poorly understood. Genome-wide analyses in the mouse cerebellum revealed that the nucleosome remodeling and deacetylase (NuRD) complex deposits the histone variant H2A.z at promoters of activity-dependent genes, thereby triggering their inactivation. Purification of translating mRNAs from synchronously developing granule neurons (Sync-TRAP) showed that conditional knockout of the core NuRD subunit Chd4 impairs inactivation of activity-dependent genes when neurons undergo dendrite pruning. Chd4 knockout or expression of NuRD-regulated activity genes impairs dendrite pruning. Imaging of behaving mice revealed hyperresponsivity of granule neurons to sensorimotor stimuli upon Chd4 knockout. Our findings define an epigenetic mechanism that inactivates activity-dependent transcription and regulates dendrite patterning and sensorimotor encoding in the brain. One or two replicates of the histone modifications (H3K27me3 and H2A.z), total histone proteins (H2A.z and H3), and ATPase Chd4 using postnatal day 22 cerebella from wild type (WT) or Chd4 conditional knockout (cKO) mice were examined using libraries prepared with the Illumina ChIP-Seq DNA Sample Prep Kit. Four replicates of total RNA were extracted from postnatal day 27-28 cerebella from rotarod-trained or control homecage mice, or Chd4 cKO or WT mice using Trizol and reverse-transcribed with oligo-dT priming. Three replicates of immunoprecipitated Sync-TRAP RNA or the input control using postnatal day 12 Chd4 cKO or WT cerebella were purified and amplified with Ovation RNA-Seq System V2 (NuGEN). All samples were sequenced on the Illumina HiSeq 2000 platform.
Project description:Connectivity webs mediate the unique biology of mammalian brain. Yet while cell and gene circuit maps are increasing in resolution, knowledge of the molecular interaction networks of the brain is limited. Here, we applied multidimensional biochemical fractionation with precision mass spectrometry to survey endogenous macromolecules in adult mouse brain. We defined a global ‘interactome’ landscape consisting of hundreds of multi-protein complexes, most never reported before. Brain selective assemblies exhibit distinctive biophysical and functional attributes, including enrichment for synaptic, RNA-binding and other evolutionarily conserved proteins showing tissue-, regional- and cell-type specificity. Strikingly, many macromolecules have links to diverse neurological disorders and disease variants, illustrating the broad pathophysiological relevance of the network. We validated a putative 15-member complex associated with Amyotrophic Lateral Sclerosis using reciprocal pulldowns and a transgenic rodent model, establishing balancing functions in alternative splicing and disease progression. This resource facilitates exploration of the mechanistic basis of neuronal function, synaptic plasticity and diseases of the central nervous system.
Project description:Molecular functions of the Nucleosome Remodeling and Deacetylation (NuRD) complex in the control of gene expression were investigated using an inducible system to direct its assembly in embryonic stem cells. This dataset maps time-resolved DNA association of NuRD complex members, pluripotency factors, components of the RNA polymerase II machinery and changes to histone modifications.
Project description:Molecular functions of the Nucleosome Remodeling and Deacetylation (NuRD) complex in the control of gene expression were investigated using an inducible system to direct its assembly in embryonic stem cells. This dataset profiles nascent RNA transcription in response to NuRD induction.