Project description:The spatial and temporal control of gene expression during development requires the concerted actions of sequence-specific transcriptional regulators and epigenetic chromatin modifiers, which are thought to function within precise nuclear compartments. However, how these activities are coordinated within the dynamic context of the nuclear environment is still largely unresolved. Here we show that transcriptional repression by the Msx1 homeoprotein coordinates recruitment of Polycomb to genomic targets with localization to the nuclear periphery. Using genome-wide ChIP-Seq analyses to identify genomic binding sites for Msx1, we find that repressed target genes are enriched at the nuclear periphery in myoblast cells. We further show that the interaction of Msx1 with the Polycomb repressive complex PRC2 is required for transcriptional repression and regulation of myoblast differentiation, and promotes increased tri-methylation of lysine 27 on histone H3 (H3K27me3) at Msx1 target genes. Furthermore, Msx1 genomic binding promotes the dynamic spatial redistribution of the H3K27me3 repressive mark to the nuclear periphery in developing embryos in vivo. Thus, our findings suggest a hitherto unappreciated spatial coordination of transcription factor binding, Polycomb recruitment, and subnuclear localization in regulation of developmentgene expression programs. In order to identify genes regulated by Msx1, we infected C2C12 myoblast cells with a retrovirus expressing a tamoxifen-regulated Msx1 protein, Msx1-ER (or with empty vector as a control), followed by induction with 0.2 nM of tamoxifen or vehicle (DMSO) for 6 hours. Regulated genes were identified as those that changed in expression upon tamoxifen induction of the Msx1-ER protein but did not change in the empty vector control. Experiments were performed in triplicate for each of the four experimental conditions (Msx1-ER + tamoxifen, Msx1-ER - tamoxifen, empty vector control + tamoxifen, empty vector control - tamoxifen), for a total of 12 independent array samples. This submission represents the transcriptome component of the study.
Project description:The spatial and temporal control of gene expression during development requires the concerted actions of sequence-specific transcriptional regulators and epigenetic chromatin modifiers, which are thought to function within precise nuclear compartments. However, how these activities are coordinated within the dynamic context of the nuclear environment is still largely unresolved. Here we show that transcriptional repression by the Msx1 homeoprotein coordinates recruitment of Polycomb to genomic targets with localization to the nuclear periphery. Using genome-wide ChIP-Seq analyses to identify genomic binding sites for Msx1, we find that repressed target genes are enriched at the nuclear periphery in myoblast cells. We further show that the interaction of Msx1 with the Polycomb repressive complex PRC2 is required for transcriptional repression and regulation of myoblast differentiation, and promotes increased tri-methylation of lysine 27 on histone H3 (H3K27me3) at Msx1 target genes. Furthermore, Msx1 genomic binding promotes the dynamic spatial redistribution of the H3K27me3 repressive mark to the nuclear periphery in developing embryos in vivo. Thus, our findings suggest a hitherto unappreciated spatial coordination of transcription factor binding, Polycomb recruitment, and subnuclear localization in regulation of developmentgene expression programs. In order to identify genes regulated by Msx1, we infected C2C12 myoblast cells with a retrovirus expressing a tamoxifen-regulated Msx1 protein, Msx1-ER (or with empty vector as a control), followed by induction with 0.2 nM of tamoxifen or vehicle (DMSO) for 6 hours. Regulated genes were identified as those that changed in expression upon tamoxifen induction of the Msx1-ER protein but did not change in the empty vector control.
Project description:The spatial and temporal control of gene expression during development requires the concerted actions of sequence-specific transcriptional regulators and epigenetic chromatin modifiers, which are thought to function within precise nuclear compartments. However, how these activities are coordinated within the dynamic context of the nuclear environment is still largely unresolved. Here we show that transcriptional repression by the Msx1 homeoprotein coordinates recruitment of Polycomb to genomic targets with localization to the nuclear periphery. We used genome-wide ChIP-Seq analyses to identify genomic binding sites for Msx1 in C2C12 murine myoblast cells. C2C12 myoblast cells were seeded at a density of 2.5 x 10^5 cells / 10-cm plate one day prior to infection, and infected with a retrovirus containing a Flag-Msx1 construct for two consecutive days. The resulting cells were then crosslinked with formaldehyde, and DNA was enriched by chromatin immunoprecipitation (ChIP) with an anti-Flag antibody and analyzed by Solexa sequencing. Enriched regions were identified using a Poissonian background model, and were further compared to an additional background of sequences from a sample of Flag-immunoprecipitated DNA from C2C12 cells infected with an empty vector to determine enrichment. ChIP was performed using an antibody against the Flag epitope (Sigma M2, F3165).
Project description:The spatial and temporal control of gene expression during development requires the concerted actions of sequence-specific transcriptional regulators and epigenetic chromatin modifiers, which are thought to function within precise nuclear compartments. However, how these activities are coordinated within the dynamic context of the nuclear environment is still largely unresolved. Here we show that transcriptional repression by the Msx1 homeoprotein coordinates recruitment of Polycomb to genomic targets with localization to the nuclear periphery. We used genome-wide ChIP-Seq analyses to identify genomic binding sites for Msx1 in C2C12 murine myoblast cells.
Project description:We screened for long intergenic non-coding RNAs (lincRNAs) that are highly and specifically expressed in the murine myoblast cell line C2C12 during the differentiation process.
Project description:Analysis of C2C12 myoblast induced with tetracycline to enhance integrin alpha7 expression. Integrin alpha7 is the major laminin binding integrin in muscle cells. Enhancing its expression has been demonstrated to alleviate pathology in a murine model of Duchenne muscular dystrophy. Results of this study provide insights into the effects of increasing integirn alpha7 expression on muscle cells and possible side effects associate with enhancing integrin alpha7 in muscle cells. Experiment Overall Design: Triplicate biological smaples for each condition(induced and non-induced) C2C12 myoblast were used.
Project description:Synovial sarcoma is a rare malignancy characterized by the presence of a specific chromosomal translocation t(X;18) that results in the formation of a fusion protein SYT-SSX. Because it is believed that synovial sarcoma arises from mesenchymal stem or progenitor cells, we wanted to determine the changes in gene expression caused by SYT-SSX2 in untransformed mesenchymal progenitor cells - murine C2C12 myoblasts in this experiment. In 2 independent experiments, C2C12 myoblasts were infected with retrovirus carrying either control vector (pOZ) or SYT-SSX2 expression vector. Total cellular RNA was extracted 48 hours post-infection and utilized for microarray analysis on Affymetrix arrays.
Project description:The TEAD (1-4) transcription factors comprise the conserved TEA/ATTS DNA binding domain recognising the MCAT element in the promoters of muscle-specific genes. Despite extensive genetic analysis, the function of TEAD factors in muscle differentiation has proved elusive due to redundancy amongst the family members. Expression of the TEA/ATTS DNA binding domain that acts a dominant negative repressor of TEAD factors in C2C12 myoblasts inhibits their differentiation, while selective shRNA knockdown of TEAD4 results in abnormal differentiation characterised by the formation of shortened myotubes. Chromatin immunoprecipitation coupled to array hybridisation (ChIP-chip) shows that TEAD4 occupies 867 promoters including those of myogenic miRNAs. We show that TEAD factors cooperate with MYOD1 to directly induce Myogenin, CDKN1A and Caveolin 3 expression to promote myoblast differentiation and fusion. RNA-seq identifies a novel set of TEAD4 target genes encoding muscle structural and regulatory proteins and those required for the unfolded protein response. In contrast, TEAD4 represses expression of the growth factor CTGF and Cyclin D1 to promote differentiation. Together these results show that TEAD factor activity is essential for C2C12 cell differentiation and define a novel and nonredundant role for TEAD4 in regulating the unfolded protein response. C2C12 cells were infected with retrotiviral vector expressing Flag-HA-Tagged TEAD4 or with empty control vector and selected in the continouos presence of puromycin. Infected cell populations were then differentiated for 5 days in DMEM medium with 2% horse serum and fixed in 0.4% formaldehyde.