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GSE19199
Homo sapiens
8 Downloadable Samples
Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
The Mediator complex allows communication between transcription factors and RNA polymerase II (RNAPII). CDK8, the kinase found in some variants of Mediator, has been characterized mostly as a transcriptional repressor. Recently, CDK8 was demonstrated to be a potent oncoprotein. Here we show that CDK8 is predominantly a positive regulator of gene expression within the serum response network, as it is required for expression of several members of the AP-1 and EGR family of oncogenic transcription factors (e.g. FOS, JUN, EGR1-3). Mechanistic studies demonstrate that CDK8 is not required for recruitment of RNAPII and promoter escape at these loci. Instead, CDK8 depletion leads to the appearance of slower elongation complexes carrying hypophosphorylated RNAPII. We show that CDK8-Mediator regulates precise steps in the assembly of a functional elongation complex, including the recruitment of P-TEFb and BRD4, but is dispensable for recruitment of SPT5 and FACT. Furthermore, CDK8-Mediator specifically interacts with P-TEFb. Thus, we uncovered a novel role for CDK8 in transcriptional regulation that may contribute to its oncogenic effects.
Publication Title
CDK8 is a positive regulator of transcriptional elongation within the serum response network.
Sample Metadata Fields
Cell line
View Samples- Homo sapiens
- 6 Downloadable Samples
IlluminaHiSeq2500
Description
Cortistatin A (CA) is a highly selective inhibitor of the Mediator kinases CDK8 and CDK19. Using CA, we report here the first large-scale identification of Mediator kinase substrates in human cells (HCT116). Among over 16,000 quantified phosphosites, we identified 78 high-confidence Mediator kinase targets within 64 proteins, including DNA-binding transcription factors and proteins associated with chromatin, DNA repair, and RNA polymerase II. Although RNA-Seq data correlated with Mediator kinase targets, CA effects on gene expression were limited and distinct from CDK8 or CDK19 knockdown. Quantitative proteome analyses, which tracked about 7,000 proteins across six time points (0 – 24h), revealed that CA selectively affected pathways implicated in inflammation, growth, and metabolic regulation; contrary to expectations, increased turnover of Mediator kinase targets was not generally observed. Collectively, these data support Mediator kinases as regulators of chromatin and RNA polymerase II activity and suggest cellular roles beyond transcription, including metabolism and DNA repair. Overall design: HCT116 cells were treated with either 100nM CA or DMSO in biological triplicate for each population (6 samples total). Treatment was for 24h for compound and vehicle.
Publication Title
Identification of Mediator Kinase Substrates in Human Cells using Cortistatin A and Quantitative Phosphoproteomics.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 24 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Super-enhancers (SEs), which are composed of large clusters of enhancers densely loaded with the Mediator complex, transcription factors and chromatin regulators, drive high expression of genes implicated in cell identity and disease, such as lineage-controlling transcription factors and oncogenes. BRD4 and CDK7 are positive regulators of SE-mediated transcription. By contrast, negative regulators of SE-associated genes have not been well described. Here we show that the Mediator-associated kinases cyclin-dependent kinase 8 (CDK8) and CDK19 restrain increased activation of key SE-associated genes in acute myeloid leukaemia (AML) cells. We report that the natural product cortistatin A (CA) selectively inhibits Mediator kinases, has anti-leukaemic activity in vitro and in vivo, and disproportionately induces upregulation of SE-associated genes in CA-sensitive AML cell lines but not in CA-insensitive cell lines. In AML cells, CA upregulated SE-associated genes with tumour suppressor and lineage-controlling functions, including the transcription factors CEBPA, IRF8, IRF1 and ETV6. The BRD4 inhibitor I-BET151 downregulated these SE-associated genes, yet also has anti-leukaemic activity. Individually increasing or decreasing the expression of these transcription factors suppressed AML cell growth, providing evidence that leukaemia cells are sensitive to the dosage of SE-associated genes. Our results demonstrate that Mediator kinases can negatively regulate SE-associated gene expression in specific cell types, and can be pharmacologically targeted as a therapeutic approach to AML.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
We characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
We characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
We characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
We characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Illumina HiSeq 2000
Description
We characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation. In this series, we examine the transcriptional effect on insensitive HCT116 cells of 3hrs exposure to CA. Overall design: HCT116 cells were treated in triplicate with either DMSO or CA for 3hrs after which RNA was harvested and prepared for RNA sequencing to assess transcriptional changes.
Publication Title
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 22 Downloadable Samples
- Affymetrix Mouse Gene 2.1 ST Array (mogene21st)
Description
Chronic cold exposure causes white adipose tissue (WAT) to adopt features of brown adipose tissue, a process known as browning. Previous studies have hinted at a possible role for the transcription factor Peroxisome Proliferator-Activated Receptor alpha (PPAR) in cold-induced browning. Here we aimed to investigate the importance of PPAR in driving transcriptional changes during cold-induced browning in mice. Male wildtype and PPAR/ mice were housed at thermoneutrality (28 C) or cold (5 C) for 10 days. Whole genome expression analysis was performed on inguinal WAT. In addition, other analyses were carried out. Whole genome expression data of livers of wildtype and PPAR/ mice fasted for 24 h served as positive control for PPAR-dependent gene regulation.Cold exposure increased food intake and decreased weight of BAT and WAT to a similar extent in wildtype and PPAR/ mice. Except for plasma non-esterified fatty acids, none of the cold-induced changes in plasma metabolites were dependent on PPAR genotype. Histological analysis of inguinal WAT showed clear browning upon cold exposure but did not reveal any morphological differences between wildtype and PPAR/ mice. Transcriptomics analysis of inguinal WAT showed a marked effect of cold on overall gene expression, as revealed by principle component analysis and hierarchical clustering. However, wildtype and PPAR/ mice clustered together, even after cold exposure, indicating a similar overall gene expression profile in the two genotypes. Pathway analysis revealed that cold upregulated pathways involved in energy usage, oxidative phosphorylation, and fatty acid -oxidation to a similar extent in wildtype and PPAR/ mice. Furthermore, cold-mediated induction of genes related to thermogenesis such as Ucp1, Elovl3, Cox7a1, Cox8, and Cidea, as well as many PPAR target genes, was similar in wildtype and PPAR/ mice. Finally, pharmacological PPAR activation had a minimal effect on expression of cold-induced genes in murine WAT.Cold-induced changes in gene expression in inguinal WAT are unaltered in mice lacking PPAR, indicating that PPAR is dispensable for cold-induced browning.
Publication Title
The Peroxisome Proliferator-Activated Receptor α is dispensable for cold-induced adipose tissue browning in mice.
Sample Metadata Fields
Sex
View Samples- Homo sapiens
- 50 Downloadable Samples
- Affymetrix Human Gene 1.1 ST Array (hugene11st)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Comparative transcriptome analysis of human skeletal muscle in response to cold acclimation and exercise training in human volunteers.
Sample Metadata Fields
Sex, Disease, Subject, Time
View Samples