Establishment of oligodendrocyte identity is crucial for subsequent events of myelination in the CNS. Here, we demonstrate that activation of ATP-dependent SWI/SNF chromatin-remodeling enzyme Smarca4/Brg1 at the differentiation onset is necessary and sufficient to initiate and promote oligodendrocyte lineage progression and maturation. Genome-wide multistage studies by ChIP-seq reveal that oligodendrocyte-lineage determination factor Olig2 functions as a prepatterning factor to direct Smarca4/Br ...[more]
Project description:We investigate the role of Brg1 and Olig2 during oligodendrocyte differentiation by combining gene conditional knockout and next generation sequencing technology. We generate genome-wide maps of RNA polymerase II (RPolII), Brg1 (Smarca4), Olig2 and histone modifications in primary rat oligodendrocyte precursor cells (iOLs), differentiating oligodendrocytes and mature oligodendrocytes.We found that Brg1 is intensely regulated by RPolII at the initiation of oligodedrocyte differentiation. The genomic distribution of Brg1 in differentiating oligodendrocytes is pre-directed by Olig2 in iOLs. The dynamic interaction of Brg1 and chromatin is correlate with the distinct stages of gene expression during maturation. Finally, we show that Brg1 and Olig2 localization predict critical genes controling CNS myeliantion. Our study represents the first detailed analysis of genomic landscape during the oligodendrocyte development and provides a framework for further understanding of molecular mechanisms underlying oligodendrocyte lineage progression. Genomic distribution of Brg1, Olig2, RPolII and three different histone modifications in three oligodendrocyte developemtal stages were examined using primary cells by ChIP-sequencing. Spinal cord mRNA profiles of 14-day old control and Brg1c/c;Olig1-Cre mice were generated by RNA-sequencing.
Project description:Establishment and maintenance of CNS glial cell identity ensures proper brain development and function, yet the epigenetic mechanisms underlying glial fate control remain poorly understood. Here we show that the histone deacetylase Hdac3 controls oligodendrocyte-specification gene Olig2 expression, and functions as a molecular switch for oligodendrocyte and astrocyte lineage determination. Our data suggest that Hdac3 cooperates with p300 to prime and maintain oligodendrogenic programs while inhibiting Stat3-mediated astrogliogenesis, and thereby regulate phenotypic commitment at the point of oligodendrocyte-astrocytic fate decision. Examination of Hdac3 and p300 genomewide occupancy in differentiating oligodendrocytes
Project description:We performed genome-wide profiling of Tcf7l2 occupancy during oligodendrocyte differentiation and identified the key enzymes involved in cholesterol metabolism and essential for CNS myelination. Examination of Tcf7l2 chIP-seq in oligodendrocyte progenitor cell and 2 differentiation oligodendrocytes.
Project description:Myelination by oligodendrocytes in the central nervous system (CNS) is essential for proper brain function, yet the molecular determinants that control this process remain poorly understood. The basic helix-loop-helix transcription factors Olig1 and Olig2 promote myelination, whereas bone morphogenetic protein (BMP) and Wnt/β-catenin signaling inhibit myelination. Here we show that these opposing regulators of myelination are functionally linked by the Olig1/2 common target Smad-interacting protein-1 (Sip1). We demonstrate that Sip1 is an essential modulator of CNS myelination. Sip1 represses differentiation inhibitory signals by antagonizing BMP receptor-activated Smad activity while activating crucial oligodendrocyte-promoting factors. Importantly, a key Sip1-activated target, Smad7, is required for oligodendrocyte differentiation and partially rescues differentiation defects caused by Sip1 loss. Smad7 promotes myelination by blocking the BMP- and β-catenin-negative regulatory pathways. Thus, our findings reveal that Sip1-mediated antagonism of inhibitory signaling is critical for promoting CNS myelination and point to new mediators for myelin repair. ChIP-seq was performed to identify Olig2 direct target genes in oligodendrocytes during oligodendrocyte differentiation.
Project description:We report maps of H3K4me3 and H3ac - activiting expression histone modifications in C6 rat glioma cells. The data was obtained using whole genome high throughput technology. The sequencing was performed on HiSeq Ilumina platform. Examination of H3K4me3 histone modification and H3ac histone modification in C6 rat glioma cell line
Project description:We report a map of H3K4me3 - an activiting expression histone modification in C6 rat glioma cells. The data was obtained using whole genome high throughput technology. The sequencing was performed on Solid 5500xl platform. Examination of H3K4me3 histone modification in C6 rat glioma cell line
Project description:Explore DNA methylation in chronic epilepsy and its relationship to gene expression. Examination of methylation changes in pilocarpine-treated rats compared to controls and pilocarpine-treated rats on a ketogenic diet.
Project description:Transcriptome remodeling in heart disease occurs through the coordinated actions of transcription factors, histone modifications and other chromatin features at pathology-associated genes. It remains unknown the extent to which genome-wide chromatin reorganization also contributes to the pathologic gene expression. We examined the roles of two chromatin structural proteins, CTCF (CCCTC-binding factor) and HMGB2 (high mobility group protein B2), in regulating pathologic transcription and chromatin remodeling. Our data demonstrate a reciprocal relationship between HMGB2 and CTCF in controlling aspects of chromatin structure and gene expression. Both proteins regulate each other’s expression as well as transcription in cardiac myocytes: however, only HMGB2 does so in a manner that involves global reprogramming of chromatin accessibility. We demonstrate that the actions of HMGB2 on local chromatin accessibility are conserved across genomic loci, whereas the effects on transcription are loci-dependent and emerge in concert with histone modification and other chromatin features. Lastly, while both proteins share gene targets, HMGB2 and CTCF neither bind these genes simultaneously nor do they physically co-localize in myocyte nuclei. Our study uncovers a previously unknown relationship between these two ubiquitous chromatin proteins and provides a mechanistic explanation for how HMGB2 regulates gene expression and cellular phenotype. Furthermore, we demonstrate direct evidence for hierarchical remodeling of chromatin on a genome-wide scale in the setting of cardiac disease. Examination of a chromatin structural protein, HMGB2 in basal and agonist-treated cells.