Ubiquitin-dependent turnover of MYC promotes loading of the PAF complex on RNA Polymerase II to drive transcriptional elongation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Susanne Walz
PROVIDER: E-GEOD-70009 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The MYC transcription factor is an unstable protein and its turnover is controlled by the ubiquitin system. Ubiquitination enhances MYC-dependent transactivation, but the underlying mechanism remains unresolved. Here we show that proteasomal turnover of MYC is dispensable for recruitment of RNA polymerase II (RNAPII), but is required to promote transcriptional elongation at MYC target genes. Degradation of MYC stimulates histone acetylation and recruitment of BRD4 and P-TEFb to target promoters, leading to phosphorylation of RNAPII CTD and the release of elongating RNAPII. In the absence of degradation, the RNA polymerase II-associated factor (PAF) complex associates with MYC via interaction of its CDC73 subunit with a conserved domain in the amino-terminus of MYC ("MYC box I"), suggesting that a MYC/PAF complex is an intermediate in transcriptional activation. Since histone acetylation depends on a second highly conserved domain in MYCs amino-terminus ("MYC box II"), we propose that both domains co-operate to transfer elongation factors onto paused RNAPII. RNA-Seq Experiments were performed in a primary breast epithelial cell line (IMEC).The cell line expressed doxycycline-inducible versions of MYC (WT;Kless,Swap=WTN-KC). Where indicated cells were transfected with siRNAs (siCtrl;siSKP2). Where indicated cells were treaed with the proteasome inhibitor MG132 or EtOH as solvent control. DGE was performed by comparing Dox-treated populations expressing either Dox-inducible MYC or a vector control or comparing Dox-induced cells with EtOH (solvent control) treated cells.
2016-01-04 | E-GEOD-70000 | biostudies-arrayexpress
Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. RNA-Seq Experiments in 2 different primary breast epithelial cell lines (HMLE, which were sorted according to CD44/CD24 surface markers & unsorted IMEC). Both cell lines expressed a doxycycline-inducible version of MYC. For the HMLE cell line DGE analysis was performed for the uninduced (EtOH) situation, comparing CD44high vs CD44 low and for the induced situation Dox vs. EtOH for the CD44high population. For the IMEC cell line DGE was performed by comparing Dox-treated populations expressing either Dox-inducible MYC or a vector control which allows to filter out potential effects due to doxycycline treatment.
2015-10-28 | E-GEOD-66250 | biostudies-arrayexpress
Project description:The MYC transcription factor is an unstable protein and its turnover is controlled by the ubiquitin system. Ubiquitination enhances MYC-dependent transactivation, but the underlying mechanism remains unresolved. Here we show that proteasomal turnover of MYC is dispensable for recruitment of RNA polymerase II (RNAPII), but is required to promote transcriptional elongation at MYC target genes. Degradation of MYC stimulates histone acetylation and recruitment of BRD4 and P-TEFb to target promoters, leading to phosphorylation of RNAPII CTD and the release of elongating RNAPII. In the absence of degradation, the RNA polymerase II-associated factor (PAF) complex associates with MYC via interaction of its CDC73 subunit with a conserved domain in the amino-terminus of MYC ("MYC box I"), suggesting that a MYC/PAF complex is an intermediate in transcriptional activation. Since histone acetylation depends on a second highly conserved domain in MYCs amino-terminus ("MYC box II"), we propose that both domains co-operate to transfer elongation factors onto paused RNAPII. ChIP-Seq experiments for MYC-HA (HA-IP) and RNAPII (total,Ser2p,Ser5p) performed in IMEC primary breast epithelial cells. Input-samples were sequenced as controls. The following antibodies were used: HA (Abcam; ab 9110)/ total RNAPII (Santa Cruz; sc-899x)/ Ser2p RNAPII (Abcam; ab 5095)/ Ser5p RNAPII (Covance; MMS-128P)
2016-01-04 | E-GEOD-70001 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2015-10-28 | E-GEOD-66263 | biostudies-arrayexpress
Project description:Deregulated expression of MYC is a driver of colorectal carcinogenesis, necessitating novel strategies to inhibit MYC function. The ubiquitin ligase HUWE1 (HECTH9, ARFBP1, MULE) associates with both MYC and the MYC-associated protein MIZ1. We show here that HUWE1 is required for growth of colorectal cancer cells in culture and in orthotopic xenograft models. Using high throughput screening, we identify small molecule inhibitors of HUWE1, which inhibit MYC-dependent transactivation in colorectal cancer cells, but not in stem and normal colon epithelial cells. Inhibition of HUWE1 stabilizes MIZ1. MIZ1 globally accumulates on MYC target genes and contributes to repression of MYC-activated target genes upon HUWE1 inhibition. Our data show that transcriptional activation by MYC in colon cancer cells requires the continuous degradation of MIZ1 and identify a novel principle that allows for inhibition of MYC function in tumor cells. MIZ1 and MYC ChIPseq experiments in HUWE1 inhibitor-treated Ls174T cells as well as RNAseq experiments in HUWE1- or MIZ1-depleted Ls174T cells after HUWE1 inhibitor treatment. Sequencing was performed on an Illumina Genome Analyzer IIx.
2014-10-21 | E-GEOD-59223 | biostudies-arrayexpress
Project description:In mammalian cells, the Myc oncoprotein binds to thousands of promoters. During mitogenic stimulation of primary lymphocytes, Myc promotes an increase in expression of virtually all genes. In contrast, Myc-driven tumour cells differ from normal cells in expression of specific sets of up- and downregulated genes that have significant prognostic value. To understand this discrepancy, we studied the consequences of inducible expression and depletion of Myc in human cells and murine tumour models. Changes in Myc levels activate and repress specific sets of direct target genes that are characteristic of Myc-transformed tumour cells. Three factors account for this specificity: First, the magnitude of response parallels the change in occupancy by Myc at each promoter. Functionally distinct classes of target genes differ in the E-box sequence bound by Myc, arguing that different cellular responses to physiological and oncogenic Myc levels are controlled by promoter affinity. Secondly, Myc both positively and negatively affects transcription initiation independent of its effect on transcriptional elongation. Third, complex formation with Miz1 mediates repression of multiple target genes by Myc and the ratio of Myc and Miz1 bound to each promoter correlates with the direction of response. Myc, Miz1 and RNA polymerase II ChIPseq as well as RNAseq experiments in two human cancer cell lines and murine carcinoma cells as well as fibroblasts from Miz1M-bM-^HM-^FPOZ mice. All sequencing experiment were performed on an Illumina Genome Analyzer IIx.
2014-07-10 | E-GEOD-44672 | biostudies-arrayexpress
Project description:The purpose of the study was to determine what genes in DN2 pro-T cells are immediately regulated by the transcription factor GATA-3, either as activation targets or as repression targets. To do this, two pairs of Gata3-floxed and control pro-T cells were generated and analyzed by RNA-seq within the first day of deletion of the Gata3 gene. Pro-T cells were generated by differentiation in vitro on OP9-DL1 monolayers of fetal liver-derive precursors from wildtype or Gata3-floxed mice, and the Gata3 gene was acutely deleted by transduction with Cre retroviral vector. Within 20 hr after transduction, samples of acutely Gata3-deleted and control DN2 cells were sorted and RNA prepared for RNA-seq analysis. High-throughput sequencing of the samples was carried out. Experimental Gata3 deleted samples in both cases were Gata3-floxed, ROSA26R-EYFP samples infected with Cre retrovirus and sorted for EYFP+ (Cre-activated) DN2 phenotype. Control for experiment 1: wildtype (C57BL/6) DN2 pro-T cells generated in parallel, also treated with Cre retrovirus but sorted only for DN2 phenotype. Control for experiment 2: same genotype as experimental, but infected with a GFP+ empty retroviral vector and sorted for GFP+ DN2 phenotype. Two pairs of RNA-seq samples of DN2 pro-T cells were generated for comparison, each pair consisting of a Gata3-deleted sample plus a stage-matched control.
2014-09-02 | E-GEOD-59215 | biostudies-arrayexpress
Project description:Inducible MYCN-knockdown, followed by RNA-seq analysis in the MYCN-amplified neuroblastoma cell line IMR5-75, reveals profound time-dependent transcriptome changes. For modulation of MYCN levels, stable neuroblastoma cell models were used where MYCN can be downregulated via vector-based hairpin RNA induction upon addition of 1µg/ml tetracycline (IMR5-75-shMYCN. From cells treated either with tetracycline or solvent (ethanol), RNA was isolated at time points 6 hours, 12 hours and 24 hours. Experiments were done in duplicates. RNA was sequenced.
2016-09-08 | E-GEOD-80397 | biostudies-arrayexpress
Project description:Fbw7, the substrate recognition subunit of SCF(Fbw7) ubiquitin ligase, mediates turnover of multiple proto-oncoproteins and promotes its own degradation. Fbw7-mediated substrate degradation is antagonized by the Usp28 deubiquitinase. We now show, using knockout mice, that Usp28 preferentially deubiquitinates and stabilizes Fbw7. Monoallelic deletion of Usp28 maintains stable Fbw7 but destabilizes Fbw7 substrates. In contrast, complete knockout of Usp28 promotes Pin1-dependent autocatalytic turnover of Fbw7, accumulation of Fbw7 substrates and oncogenic transformation. Overexpression of Usp28 stabilizes both Fbw7 and its substrates and similarly enhances transformation. We propose that dual regulation of Fbw7 activity by Usp28 maintains physiological levels of Fbw7 substrates, and that both loss and overexpression of Usp28 in human cancer promote Fbw7 substrate accumulation. RNAseq experiments of E13.5 murine embryonic fibroblasts (MEFs) derived from animals in which Usp28 was either deleted (-/-), wildtype (+/+) or heterozygous (+/-). In a first set of experiments immortalized MEFs of all three genotypes were analysed in biological triplicates. In a second set of experiments immortalized and Ras transformed MEFs of all three genotypes and MEFs which overexpress USP28 (+/+/+) where sequenced in duplicates.
2015-05-01 | E-GEOD-59354 | biostudies-arrayexpress
Project description:Background: Microorganisms are the major cause of food spoilage during storage, processing and distribution. Pseudomonas fluorescens is a typical spoilage bacterium that contributes to a large extent to the spoilage process of proteinaceous food. RpoS is considered an important global regulator involved in stress survival and virulence in many pathogens. Our previous work revealed that RpoS contributed to the spoilage activities of P. fluorescens by regulating resistance to different stress conditions, extracellular acylated homoserine lactone (AHL) levels, extracellular protease and total volatile basic nitrogen (TVB-N) production. However, RpoS-dependent genes in P. fluorescens remained undefined. Results: RNA-seq transcriptomics analysis combined with quantitative proteomics analysis basing on multiplexed isobaric tandem mass tag (TMT) labeling was performed for the P. fluorescens wild-type strain UK4 and its derivative carrying a rpoS mutation. A total of 375 differentially expressed genes (DEGs) and 212 differentially expressed proteins (DEPs) were identified in these two backgrounds. The DGEs were further verified by qRT-PCR tests, and the genes directly regulated by RpoS were confirmed by 5’-RACE-PCR sequencing. The combining transcriptome and proteome analysis revealed a role of this regulator in several cellular processes, including polysaccharide metabolism, intracellular secretion and extracellular structures, cell well biogenesis, stress responses, ammonia and biogenic amine production, which may contribute to biofilm formation, stress resistance and spoilage activities of P. fluorescens. Moreover, in this work we indeed observed that RpoS contributed to the production of the macrocolony biofilm’s matrix.
2019-11-12 | PXD010845 | Pride