Project description:In this work we compare the molecular functions of Myf5 and MyoD, two highly related bHLH transcription factors that regulate skeletal muscle specification and differentiation. We find MyoD and Myf5 bind the same sites genome-wide but have distinct functions: Myf5 induces histone acetylation without Pol II recruitment or robust gene activation, whereas MyoD induces histone acetylation, recruits PolII and robustly activates gene transcription. RNA-Seq profiling of MyoD and Myf5
Project description:In this work we compare the molecular functions of Myf5 and MyoD, two highly related bHLH transcription factors that regulate skeletal muscle specification and differentiation. We find MyoD and Myf5 bind the same sites genome-wide but have distinct functions: Myf5 induces histone acetylation without Pol II recruitment or robust gene activation, whereas MyoD induces histone acetylation, recruits PolII and robustly activates gene transcription. Chip-seq profiling of MyoD, Myf5, Histone H4 acetylation (H4Ac), and Pol II in MyoD-/-; Myf5-/- MEFs (M&M MEFs)
Project description:We used a combination of genome-wide and promoter-specific DNA binding and expression analyses to assess the functional roles of Myod and Myog in regulating the program of skeletal muscle gene expression. Our findings indicate that Myod and Myog have distinct regulatory roles at a similar set of target genes. At genes expressed throughout the program of myogenic differentiation, Myod can bind and recruit histone acetyltransferases. At early targets, Myod is sufficient for near full expression; whereas, at late expressed genes Myod initiates regional histone modification but is not sufficient for gene expression. At these late genes, Myog does not bind efficiently without Myod, however, transcriptional activation requires the combined activity of Myod and Myog. Therefore, the role of Myog in mediating terminal differentiation is, in part, to enhance expression of a subset of genes previously initiated by Myod. Mouse embryonic fibroblasts isolated from Myod-/-Myf-/- mice were tranduced with either MDER or MDER+Myog. MDER was activated by the addition of beta-estradiol. Cells were induced to differentiate for various times, and triplate samples were collected from the indicated time points.
Project description:MyoD and NeuroD2 are master regulators of myogenesis and neurogenesis and bind to a "shared" E-box sequence (CAGCTG) and a "private" sequence (CAGGTG or CAGATG, respectively). To determine whether private-site recognition is sufficient to confer lineage-specification, we generated a MyoD-mutant with the DNA binding specificity of NeuroD2. Our results demonstrate that redirecting MyoD binding from MyoD-private sites to NeuroD2-private sites, despite preserved binding to the MyoD/NeuroD2-shared sites, is sufficient to change MyoD from a master regulator of myogenesis to a master regulator of neurogenesis. RNA-seq profiling of mouse P19 cells transfected with MyoD, NeuroD2 and chimera mutants. The chimeric mutants are MyoD with the bHLH domain replaced with the NeuroD2 bHLH domain.
Project description:Gene expression changes induced by MyoD or Myf5 were examined in a double-knockout fibroblast cell line lacking endogenous functional myoD or myf5 genes. Use of this cell line precluded the possibility of auto- or cross-activation of endogenous myoD or myf5. Myogenin or hrGFP were expressed in parallel samples as controls. Following infection with retrovirus - expressing the relevant myogenic regulatory factor (MRF) from the viral LTR promoter and hrGFP through an IRES element in the same mRNA transcript - GFP+ cells were sorted by FACS and harvested for total RNA. Experiment Overall Design: this experiment include 4 samples and 12 replicates
Project description:During reprogramming of fibroblasts into cardiomyocyte-like cells by overexpression of transcription factors, GATA4, Hand2, Mef2C and Tbx5 (GHMT), H3K4Me2, an active histone code, shifts from fibroblast-exclusive peaks to cardiomyocyte-exclusive peaks. Important cardiac genes are gradually marked by this active histone marker. Mouse embryonic fibroblasts (MEFs) and neonatal mouse ventricular cardiomyocytes (NMVMs) represent fibroblasts and cardiomyocytes, respectively. Chromatins harvested from MEFs infected with retroviruses carrying GHMT at day 3, day 5, day 7 post-viral infection were prepared for immunoprecipitation.
Project description:Fibroblasts can be reprogrammed into cardiomyocyte-like cells by overexpressing transcription factors, GATA4, Hand2, Mef2C and Tbx5 (GHMT). A83-01, an inhibitor of ALK4, ALK5 and ALK7 and two microRNA, miR-1 and miR-133 increase the efficiency of cardiac reprogramming. RNA_Seq was performed to anyalyze effects of these factors on gene expression. Total RNAs were prepared from mouse embryonic fibroblasts (MEFs); Reprogramming fibroblasts including MEFs transduced with retroviruses encoding GHMT, MEFs transduced with with retroviruses encoding GHMT plus miR-1 and miR-133 (GHMT2m), MEFs transduced with with retroviruses encoding GHMT2m treated with A83-01, at day 7 after viral transduction; and neonatal mouse cardiomyocytes (NMCMs).
Project description:In order to identify gene-expression patterns in mesenchymal stem cells associated with different birth weights and intrauterine growth parameters, we conducted comparative microarray gene expression experiments prior and post acute insulin stimulation Mesenchymal stem cells (MSC) were extracted from the Wharton's jelly of the umbilical cord of normal and SGA babies. The MSCs were expended in culture. The MSCs were subjected to acute insulin treatment for various time points. The RNA of these cells were collected for gene-expression study.