Myogeneic differentiation in Rb1 or Kdm5a/Jarid1a/Rbp2 deficient mouse embryonic fibroblasts.
ABSTRACT: Cells lacking Rb1 are deficient in differentiation. Loss of Kdm5a rescues myogenic differentiation, as judged by appearance of morphologically normal myotubes that display expression of late markers of differentiation. In order to better understand how Kdm5a loss rescues differentiation, we induced mouse embryonic fibroblasts (MEFs) of different genotypes to undergo myogenic differentiation and analyzed gene expression changes in wild-type, Kdm5a-/-, Rb1-/- and Kdm5a-/-; Rb1-/- cells. Rb1-/- cells stained single nucleated, did not exhibit morphological changes and increased expression of the myogenic marker MYHC. Except for Rb1-/- cells, all other cells were undergoing successful convertion into aligned multinucleated myotubes and were MYHC-positive. We obtained purified populations of myotubes for the wild-type and Kdm5a-/-; Rb1-/- cells. RNA-seq analysis of gene expression in Rb1 or Kdm5a deficient MEFs that were induced for myogenic differentiation.
Project description:Genome-wide gene expression analysis of MyoD-infected DMD-specific iPSCs (GM05112-M5.1) on days 0 (untreated), day 3 and day 8 post Dox treatment, human primary myoblasts (undifferentiated and as differentiated myotubes), and undifferentiated iPSCs from healthy donors (iPSCs-1 and iPSCs-2). DMD-specific iPSCs were infected with lentivirus expressing MyoD under the control of Tet-inducible promoter and another lentivirus expressing the transactivator. To initiate myogenic differentiation, iPSCs were treated with 1µg/ml Dox. RNA was isolated 0, 3 and 8 days later and gene expression analysis was performed.
Project description:A number of microRNAs have been shown to regulate skeletal muscle development and differentiation. MicroRNA-222 is downregulated during myogenic differentiation and its overexpression leads to alteration of muscle differentiation process and specialized structures. By using RNA induced silencing complex (RISC) pulldown followed by RNA sequencing, combined with in silico microRNA target prediction, we have identified two new targets of microRNA-222 involved in the regulation of myogenic differentiation, Ahnak and Rbm24. Specifically, the RNA binding protein Rbm24 is a major regulator of muscle specific alternative splicing and its downregulation by microRNA-222 results in defective exon inclusion impairing the production of muscle-specific isoforms of Coro6, Fxr1 and NACA transcripts. Reconstitution of normal levels of Rbm24 in cells overexpressing microRNA-222 rescues muscle-specific splicing. In conclusion, we have identified a new function of microRNA-222 leading to alteration of myogenic differentiation at the level of alternative splicing, and we provide evidence that this effect is mediated by Rbm24 protein. We built linear models using 2 different experiments and two conditions (miR222 over expression (n=1) and control siRNA(n=2)) with the linear formula (~condition + experiment).
Project description:Skeletal muscle contains long multinucleated and contractile structures known as muscle fibers, which arise from the fusion of myoblasts into nucleated myotubes during myogenesis. The myogenic regulatory factor (MRF) MYF5 is the earliest to be expressed during myogenesis and functions as a transcription factor in muscle progenitor cells (satellite cells) and myocytes. In mouse C2C12 myocytes, MYF5 is implicated in the initial steps of myoblast differentiation into myotubes. Ribonucleoprotein immunoprecipitation (RIP) analysis showed that MYF5 bound a subset of myoblast mRNAs; prominent among them was Ccnd1 mRNA, which encodes the key cell cycle regulator CCND1 (Cyclin D1). Biotin-RNA pulldown, UV-crosslinking, and gel shift experiments indicated that MYF5 was capable of binding the 3' untranslated region (UTR) and the coding region (CR) of Ccnd1 mRNA. MYF5 silencing in proliferating growing myoblasts revealed that and MYF5 promoted CCND1 translation, and it also modestly increased transcription of Ccnd1 mRNA. Importantly, silencing MYF5 reduced myoblast growth as well as differentiation of myoblasts into myotubes, while overexpressing MYF5 in C2C12 cells upregulated CCND1 expression. We propose that MYF5 enhances early myogenesis in part by coordinately elevating Ccnd1 transcription and Ccnd1 mRNA translation. Four replicates were utilized from either Control (IgG) or MYF5-immunoprecipitated RNA samples from C2C12 cells growing in either growth medium (GM) or differentiation medium (DM) for a total of sixteen samples.
Project description:Synthetic transcription factors can be applied to many areas of biotechnology, medicine, and basic research. Currently, the most common method for engineering synthetic transcription factors has been based on programmable DNA-binding domains of zinc finger proteins, Transcription Activator-Like Effectors (TALEs), and most recently the CRISPR/Cas9 system. These transcription factor platforms consist of the DNA-binding domain fused to potent transcriptional activation domains, most commonly the tetramer of the minimal transactivation domain of the VP16 protein from herpes simplex virus, referred to as VP64. Although many applications are well-suited for the targeted activation of a single gene, genetic reprogramming requires the coordinated regulation of many nodes of natural gene networks as is typically performed by naturally occurring reprogramming factors. Thus we sought to combine principles from each of these approaches by attaching potent transcriptional activation domains to a natural reprogramming factor to increase the efficiency and/or rate of cell fate conversion. In this study, we evaluated the effects of fusing potent activation domains to the transcription factor MyoD, the master regulator of the skeletal myoblast lineage. In certain non-myogenic lineages, MyoD overexpression causes upregulation of the myogenic gene network and conversion to a myoblast phenotype including cell fusion into multinucleated myotubes. Compared to wild-type MyoD, the VP64-MyoD fusion protein induced greater overall reprogramming of global gene expression. This simple approach for increasing the potency of natural reprogramming factors circumvents the need for screening engineered proteins and leads to a more robust cellular reprogramming compared to treatment with the wild type transcription factor. Human dermal fibroblasts were transduced with a single tet inducible lentivirus that expresses either WT-MyoD or VP64-MyoD in response to treatment with doxycycline. Untreated human dermal fibroblast served as the negative control. Gene expression was measured using mRNA-seq, and differential expression was calculated using DESeq. All experiments were performed in biological duplicates.
Project description:Gene expression profiles of Immortalized KDM5A-/- MEFs with re-introduction of wild-type KDM5A or KDM5A-H483A mutant. Overall design: Duplicate total RNA samples were isolated from subconfluent MEFs using RNeasy mini kit with on-column DNase digestion (Qiagen). Gene-expression profiling was performed using Affymetrix mouse M430 2.0 chip.
Project description:We generated the human ES lines, in which the genome-wide reduction of H3K27me3 can be induced by the ectopic expression of catalytic domain of histone demethylase JMJD3 with doxycycline treatment (JMJD3c-hESCs). The overexpression of JMJD3c enhances MYOD1-mediated myogenic differentiation of hESCs. We compared the gene expression patterns of the generated myogenic cells with those of human skeletal myotubes. Overall design: Doxycycline-treated JMJD3c-hESCs were differentiated into myogenic cells by MYOD1 overexpression. Human myoblast HSMM cells were differentiated into myotubes with 2% horse serum.
Project description:MicroRNAs are well known to mediate translational repression and mRNA degradation in the cytoplasm. Various microRNAs have also been detected in membrane-compartmentalized organelles, but the functional significance has remained elusive. Here we report that miR-1, a microRNA specifically induced during myogenesis, efficiently enters the mitochondria where it unexpectedly stimulates, rather than represses, the translation of specific mitochondrial genome-encoded transcripts. We show that this positive effect requires specific miR:mRNA base-pairing and Ago2, but not its functional partner GW182, which is excluded from the mitochondria. We provide evidence for the direct action of Ago2 in mitochondrial translation by Ago2 CrossLinking ImmunoPrecipitation coupled with sequencing (CLIP-seq), functional rescue with mitochondria-targeted Ago2, and selective inhibition of the microRNA machinery in the cytoplasm. These findings unveil a positive function of microRNA in mitochondrial translation and suggest a highly coordinated myogenic program via miR-1 mediated translational stimulation in the mitochondria and repression in the cytoplasm. Examination of miRNA's regulation function in mitochondria in C2C12 myoblasts cells and myotubes cells with CLIP-seq (Ago2).
Project description:Cellular differentiation involves widespread epigenetic reprogramming, including modulation of DNA methylation patterns. We have investigated DNA genome-wide methylation dynamics in embryonic stem cells, primary myoblasts, terminal differentiated myotubes and mature myofibers. About 1.000 differentially methylated regions (DMRs) have been indentified during muscle-lineage determination and terminal differentiation. As a whole, muscle lineage commitment was characterized by a major gain of DNA methylation, while muscle differentiation was accompanied by loss of DNA methylation in CpG-poor regions. Notably, hypomethylated regions in muscle cells were neighboured by enhancer-type chromatin, suggesting the involvement of DNA methylation in the regulation of cell-type specific enhancers. Indeed, one of the hypomethylations detected in muscle cells affected the super-enhancer of the master transcription factor Myf5. Super-enhancers have been defined as large clusters of transcriptional enhancers driving cell-identity and gene expression, but how these lineage-specific super-enhancers are specifically activated or repressed in different tissues is not well understood. We demonstrated that the binding of the transcription factor USF1 to Myf5 locus occurs upon DNA demethylation of the super-enhancer region in myogenic committed cells. Taken all together, we have characterized the unique DNA methylation signatures of muscle-committed cells and highlighted the importance of DNA methylation mediated regulation of cell identity super-enhancers. We have investigated DNA genome-wide methylation dynamics in embryonic stem cells, primary myoblasts, terminal differentiated myotubes and mature myofibers by AIMS-seq techniques and coupled to microarray expression data by SurePrint G3 Mouse 8x60K from Agilent Technologies. Samples were in triplicates, except for ESCs (quadruplicates).
Project description:The methyl-cytosine binding protein 2 (MeCP2) is a reader of epigenetic DNA methylation marks and necessary and sufficient to reorganize 3D heterochromatin structure during cellular differentiation, e.g., myogenesis. In addition to global expression profile changes, myogenic differentiation is accompanied by 3D-heterochromatin reorganization that is dependent on MeCP2. MeCP2 is enriched at pericentric heterochromatin foci (chromocenters). During myogenesis, the total heterochromatin foci number per nucleus decreases while foci volumes and MeCP2 protein levels increase. Ectopic MeCP2 is able to mimic similar heterochromatin restructuring in the absence of differentiation. We compared expression profile changes during myogenic differentiation to changes related to MeCP2-induced heterochromatin reorganization in the absence of differentiation. We used the Affymetrix 430.2 microarray system to study the expression profile changes during myogenic differentiation (myotubes vs myoblast) and MeCP2 related expression changes in transiently transfected myoblasts (high vs. low MeCP2 protein levels) in five independent experiments for each condition. Overall design: To obtain expression profile changes during myogenic differentiation, five biological replicas of undifferentiated Pmi 28 myoblasts (MB) and in vitro differentiated Pmi 28 myotubes (MT) were cultured as described elsewhere. To obtain MeCP2 dependent and differentiation independent expression profile changes, five biological replica of undifferentiated Pmi 28 myoblasts were transiently transfected with MeCP2-YFP. Subsequently, transfected cells were FACSorted to generate MeCP2-high (R4) and -low (R5) level fractions. Total RNA was prepared for each sample out of cell pellets containing 6.5x10exp5 to 1.7x10exp6 cells and further processed according to the GeneChip Expression Analysis Technical Manual by Affymetrix and hybridized to Affymetrix 430.2 microarrays.