Project description:We mapped the binding sites of Chd7 in cerebellar granule cells, and compared with the pattern of H3K27ac. To examine the impact of Chd7 loss to Top2b binding, we mapped the binding sites of Top2b in control and Chd7 mutant cells
Project description:We performed array-based expression profiling to determine genes regulated by Chd7 and Top2b in CGNs. Our data show Chd7 and Top2b coregulate a common set of neuronal genes. Furthermore, we compared the gene expession in proliferating and postmitotic granule cells.
Project description:Regulation of chromatin plays fundamental roles in the normal development of the brain. Haploinsufficiency of the chromatin remodeling enzyme CHD7 causes CHARGE syndrome, a genetic disorder that prominently affects the development of the cerebellum. However, how CHD7 controls chromatin states in the cerebellum remains incompletely understood. Using conditional knockout of CHD7 in granule cell precursors in the mouse cerebellum, we find that CHD7 robustly promotes the accessibility and activity of enhancers in granule cell precursors. Remarkably, in vivo profiling of genome architecture reveals that CHD7 operates locally to stimulate enhancer activation, thereby driving the expression of topologically-interacting genes. Genome and gene ontology studies show that CHD7-regulated enhancers are associated prominently with genes that control brain tissue morphogenesis. Accordingly, conditional knockout of CHD7 triggers a striking phenotype of cerebellar polymicrogyria, which we have also found in a case of CHARGE syndrome. Finally, we uncover a CHD7-dependent switch in the preferred orientation of granule cell precursor division in the developing cerebellum, providing a cellular basis for the cerebellar polymicrogyria phenotype upon loss of CHD7. Collectively, our findings define CHD7 function in the regulation of the epigenome in granule cell precursors and identify a surprising link of CHD7 to the control of cerebellar cortical morphogenesis, with potential implications for our understanding of CHARGE syndrome.
Project description:Mutation of the gene encoding the ATP-dependent chromatin remodeler CHD7 causes CHARGE syndrome. The mechanisms underlying the neurodevelopmental deficits associated with the syndrome, which include cerebellar hypoplasia, developmental delay, coordination problems and autistic features, are not known. CHD7 is expressed in neural stem and progenitor cells, but its role in neurogenesis during brain development remains unknown. Here we show that deletion of Chd7 from cerebellar granule cell precursors (GCps) in the mouse results in reduced GCp proliferation, cerebellar hypoplasia, developmental delay and motor deficits. Genome-wide expression profiling revealed downregulated Reln gene expression in Chd7-deficient GCps. Recessive RELN mutations is associated with severe cerebellar hypoplasia in humans. We provide molecular and genetic evidence that reduced Reln expression contributes substantially to the GCp proliferative defect and cerebellar hypoplasia in GCp-specific Chd7 mouse mutants. Finally, we show that CHD7 is necessary for the maintenance of an open, accessible chromatin state at the Reln locus. Taken together, this study shows that Reln gene expression is regulated by chromatin remodeling, identifies CHD7 as a previously unrecognized upstream regulator of Reln and provides the first evidence that a mammalian CHD protein controls brain development by modulating chromatin accessibility in neuronal progenitors in vivo.
Project description:We analysed genes upregulated or down regulated by double deletion of Rac1 and Rac3 (Rac1/Rac3-DKO) in cerebellar granule neurons compared with control, using the external granule layer (EGL) dissected from Rac1/Rac3-DKO cerebellum at P6. Rac1-KO mouse is an inducible knockout, in which Rac1 is specifically deleted in cerebellar granule neurons under control of Atoh1 (also called Math1) promoter. In contrast, Rac3-KO mouse is a conventional/simple KO, in which Rac3 is deleted in all cells in the body. Total RNA from the medial portion of the EGL of Rac1/Rac3-DKO and control cerebella at P6 was extracted using TRIzol (Invitrogen). The quality and quantity of RNA were determined using the Agilent 2100 BioAnalyzer.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
Project description:To establish a new model system with which to study cerebellar granule lienage development and disease, human hbNES cells were differentiated to cerebellar granule neurons over a 56 day period.
