Project description:The submitted files contain ChIP-seq data for the MyoD and myogenin muscle regulatory factors in diffrentiated C2C12 cells as well as two different sonicated input samples (one from a regular 1% formaldehyde fixation and one from a dual 1%FA + 1.5 mM EGS fix). Characterization of genome-wide MyoD and myogenin binding in C2C12 cells
Project description:The submitted files contain ChIP-seq data for the MyoD and myogenin muscle regulatory factors in diffrentiated C2C12 cells as well as two different sonicated input samples (one from a regular 1% formaldehyde fixation and one from a dual 1%FA + 1.5 mM EGS fix).
Project description:The enhancer regions of the myogenic master regulator MyoD give rise to at least two enhancer RNAs. CEeRNA regulates transcription of the adjacent MyoD gene while DRReRNA affects expression of Myogenin in trans. We found that DRReRNA is recruited at the Myogenin locus where it colocalizes with Myogenin nascent transcripts. DRReRNA associates with the Cohesin complex and such association correlates with its transactivating properties. Despite being expressed in undifferentiated cells, Cohesin is not loaded on Myogenin until the cells start expressing DRReRNA, which is then required for Cohesin chromatin recruitment and maintenance. Functionally, depletion of either Cohesin or DRReRNA reduces chromatin accessibility, prevents Myogenin activation, and hinders muscle cell differentiation. Thus, DRReRNA ensures spatially appropriate Cohesin loading in trans to regulate gene expression.
Project description:While skeletal myogenesis is tightly coordinated by myogenic regulatory factors including MyoD and myogenin, chromatin modifications have emerged as vital mechanisms of myogenic regulation. We have previously established that bexarotene, a clinically approved agonist of retinoid X receptor, promotes the specification and differentiation of skeletal muscle lineage. Here, we examine a genome-wide impact of rexinoids on myogenic differentiation through integral RNA-seq and ChIP-seq analyses. We found that bexarotene promotes myoblast differentiation through the coordination of exit from the cell cycle and the activation of muscle-related genes. We uncovered a new mechanism of rexinoid action which is mediated by the nuclear receptor and largely reconciled through a direct regulation of MyoD gene expression. In addition, we determined a rexinoid-responsive residue-specific histone acetylation at a distinct chromatin state associated to MyoD and myogenin. Thus, we provide novel molecular insights into the interplay between retinoid X receptor signaling and chromatin states pertinent to myogenic programs in early myoblast differentiation.
Project description:In skeletal myogenesis, the transcription factor MyoD activates distinct transcriptional programs in progenitors compared to terminally differentiated cells. Using ChIP-seq and gene expression analyses, we show that in primary myoblasts, Snail-HDAC1/2 repressive complex bind and exclude MyoD from its targets. Notably, Snail binds E-box motifs that are G/C-rich in their central dinucleotides, and such sites are almost exclusively associated with genes expressed during differentiation. By contrast, Snail does not bind the A/T-rich E-boxes associated with MyoD targets in myoblasts. Thus, Snai1-HDAC1/2 prevents MyoD occupancy on differentiation-specific regulatory elements and the change from Snail- to MyoD-binding often results in enhancer switching during differentiation. Furthermore, we show that a regulatory network involving Myogenic Regulatory Factors (MRFs), Snail/2, miR-30a and miR-206 acts as a molecular switch that controls entry into myogenic differentiation. Together, these results reveal a regulatory paradigm that directs distinct gene expression programs in progenitors versus terminally differentiated cells. Genome wide binding sites of various transcription factors and chromatin modifiers in muscle cells
Project description:While skeletal myogenesis is tightly coordinated by myogenic regulatory factors including MyoD and myogenin, chromatin modifications have emerged as vital mechanisms of myogenic regulation. We have previously established that bexarotene, a clinically approved agonist of retinoid X receptor, promotes the specification and differentiation of skeletal muscle lineage. Here, we examine a genome-wide impact of rexinoids on myogenic differentiation through integral RNA-seq and ChIP-seq analyses. We found that bexarotene promotes myoblast differentiation through the coordination of exit from the cell cycle and the activation of muscle-related genes. We uncovered a new mechanism of rexinoid action which is mediated by the nuclear receptor and largely reconciled through a direct regulation of MyoD gene expression. In addition, we determined a rexinoid-responsive residue-specific histone acetylation at a distinct chromatin state associated to MyoD and myogenin. Thus, we provide novel molecular insights into the interplay between retinoid X receptor signaling and chromatin states pertinent to myogenic programs in early myoblast differentiation.