Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The Cdk8 kinase module regulates Mediator-RNA polymerase II interaction

ABSTRACT: The Cdk8 kinase module (CKM) is a dissociable part of the coactivator complex Mediator that regulates RNA polymerase II (Pol II transcription. The CKM has negative and positive functions in gene transcription that remain poorly understood at the mechanistic level. Here, we prepare recombinant CKM from the yeast Saccharomyces cerevisiae and show that it binds core Mediator (cMed) to sterically inhibit cMed binding to the Pol II preinitiation complex (PIC) in vitro. We further show that the Cdk8 kinase activity of CKM counteracts CKM-cMed interaction,thereby releasing CKM and enabling Mediator to bind the PIC. Finally, we report that the kinase activity of Cdk8 is required for gene activation during heat shock in vivo, but not under steady state growth conditions. These results converge with previous literature on a model for CKM function. In this model, CKM negatively regulates Mediator function at upstream activating sequences by preventing Mediator binding to the PIC at the promoter. During gene activation, Cdk8 kinase activity may release Mediator and allow its binding to the PIC, thereby stimulating transcription initiation and accounting for the positive function of CKM.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE161140 | GEO | 2021/06/16

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

The Cdk8 kinase module regulates Mediator-RNA polymerase II interaction

Project description:We use biochemically reconstituted transcription initiation components including the Mediator core and Cdk8 kinase modules (CKM) to investigate the function of the CKM in regulating the Mediator-RNA polymerase II interaction in a highly purified system. We use cross-linking coupled to mass spectrometry to map the interaction of the CKM and core Mediator, and in vitro phosphorylation assays followed by phosphopeptide enrichment coupled to mass spectrometry to identify Cdk8 phosphorylation targets in this context and biochemically dissect their functions. Finally, we investigate the function of phosphorylation by Cdk8 on transcription in vivo. Based on that, we propose a model to integrate the phosphorylation-dependent and -independent functions of the CKM in transcription initiation.

2021-04-28 | PXD023361 | Pride

A study of Mediator subunit enhancer-promoter binding

Project description:Mediator is a transcriptional co-activator recruited to enhancers by DNA-binding activators, and it also interacts with RNA polymerase (Pol) II as part of the preinitiation complex (PIC). We demonstrate that a single Mediator complex associates with the enhancer and core promoter in vivo, indicating that it can physically bridge these transcriptional elements. However, the Mediator kinase module associates strongly with the enhancer, but not with the core promoter, and it dissociates from the enhancer upon depletion of the TFIIH kinase. Severing the kinase module from Mediator by removing the connecting subunit Med13 does not affect Mediator association at the core promoter, but increases occupancy at enhancers. Thus, Mediator undergoes a compositional change in which the kinase module, recruited via Mediator to the enhancer, dissociates from Mediator to permit association with Pol II and the PIC. As such, Mediator acts as a dynamic bridge between the enhancer and core promoter.

2016-10-31 | GSE82082 | GEO

The Mediator kinase module regulates transcriptional memory after heat stress by resolving blocked RNA polymerase complexes

Project description:In nature, plants are often exposed to recurring adverse environmental conditions. Acclimation to high temperature stress entails transcriptional responses that are mediated by heat-shock transcription factors (HSFs), and they are primed to better withstand subsequent stress events. This heat stress (HS)-induced transcriptional memory results in more efficient re-induction of transcription upon recurring HS. However, the mechanisms by which HSFs recruit and enact the transcriptional machinery remain unclear. Here, we identified two subunits of the kinase module of the Mediator transcriptional co-regulator complex, CDK8 and MED12, as regulators of HS memory in Arabidopsis thaliana. Enhanced re-induction of gene expression after recurrent HS and physiological HS memory, as well as H3K4 methylation are compromised in cdk8 and med12 mutants. HSFA2 interacts with CDK8 during and after HS and recruits it to memory gene loci, where CDK8 binds in the promoter but also the gene body, together with core Mediator and RNA polymerase II (Pol II). Our data suggest that CDK8 resolves stalled Pol II complexes or promotes efficient recycling for subsequent cycles of transcription. As HSFA2, CDK8 is largely dispensable for the initial induction of gene expression after HS and thus promotes transcriptional memory independently of HS-dependent primary gene induction. Our findings provide a model for the complex role of the Mediator kinase module during transcriptional memory in multicellular eukaryotes through interaction with transcription factors, chromatin modifications and promotion of Pol II productivity.

2023-12-12 | GSE232094 | GEO

Evidence that Mediator is essential for Pol II transcription but not a required component of the preinitiation complex in vivo

Project description:Mediator, a transcriptional co-activator complex, is recruited to enhancers by DNA-binding activators via its tail module, and it interacts with RNA polymerase (Pol) II as part of the preinitiation complex (PIC) via its head module. Although Mediator has been described as a general transcription factor, it is unclear if it is essential for Pol II transcription and/or is a required component of the PIC in vivo. We comprehensively analyze this issue by measuring Pol II transcription upon rapid depletion of individual or multiple Mediator subunits from the nucleus. Depletion of individual subunits, even those essential for cell growth, causes a general but only modest decrease in Pol II transcription. Transcriptional effects are stronger on SAGA-dependent genes as opposed to TFIID-dependent genes. Thus, Mediator modules that associate either with the enhancer or with the core promoter confer partial transcriptional activity. Furthermore, Pol II transcription can occur when Mediator is not detected at core promoters. In contrast, simultaneous depletion of all Mediator modules causes a drastic decrease in Pol II transcription that is roughly comparable to the effect observed upon anchor-away-mediated depletion of Pol II or TBP. These results provide strong evidence that Mediator is essential for Pol II transcription in vivo, but that it is not a required component of the PIC.

2017-07-13 | GSE93190 | GEO

The nuclear pore-associated TREX-2 complex employs the Mediator Med31 submodule as a docking site to regulate gene expression

Project description:Nuclear pore complexes (NPCs) influence gene expression besides their established function in nuclear transport. The TREX-2 complex localizes to the NPC basket and affects gene-NPC interactions, transcription and mRNA export. How TREX-2 regulates the gene expression machinery is unknown. Here, we show that TREX-2 interacts with the Mediator complex, an essential regulator of RNA Polymerase (Pol) II. Structural and biochemical studies identify a conserved region on TREX-2, which directly binds the Mediator Med31/Med7N submodule. TREX-2 regulates assembly of Mediator with its Cdk8 kinase and is required for recruitment and site-specific phosphorylation of Pol II. Transcriptome and phenotypic profiling confirm that TREX-2 and Med31 are functionally interdependent. TREX-2 additionally uses its Mediator-interacting surface to regulate mRNA export suggesting a mechanism for coupling transcription initiation and early steps of mRNA processing at the Mediator level. In sum, we provide insight into how NPC-associated adaptor complexes can access the core transcription machinery. RNAseq was performed from WT, sac3∆, cdk8∆ and Sac3 R288D mutant cells. For each strain triplicates were analyzed. WT strain was sac3∆ transformed with pRS315 SAC3 WT

2015-08-27 | E-GEOD-67431 | biostudies-arrayexpress

Tail and Kinase Modules Differently Regulate Core Mediator Recruitment and Function In Vivo

Project description:Mediator is a highly conserved transcriptional coactivator organized into four modules, namely Tail, Middle, Head and Kinase (CKM). Previous work suggests regulatory roles for Tail and CKM, but an integrated model for these activities is lacking. Here, we analyzed the genome-wide distribution of Mediator subunits in wild-type and mutant yeast cells in which RNA polymerase II promoter escape is blocked allowing detection of transient Mediator forms. We found that while all modules are recruited to upstream activated regions (UAS), assembly of Mediator within the pre-initiation complex is accompanied by the release of CKM. Interestingly, our data show that CKM regulates Mediator-UAS interaction rather than Mediator-promoter association. In addition, while Tail is required for Mediator recruitment to UAS, Tail-less Mediator nevertheless interacts with core promoters. Collectively, our data suggest that the essential function of Mediator is mediated by Head and Middle at core promoters, while Tail and CKM play regulatory roles.

2016-10-25 | GSE81107 | GEO

A Dynamic Model for the Function of Mediator Modules In Vivo

Project description:Mediator is a highly conserved transcriptional coactivator organized into four modules, namely Tail, Middle, Head and Kinase (CKM). Previous work suggests regulatory roles for Tail and CKM, but an integrated model for these activities is lacking. Here, we analyzed the genome-wide distribution of Mediator subunits in wild-type and mutant yeast cells in which RNA polymerase II promoter escape is blocked allowing detection of transient Mediator forms. We found that while all modules are recruited to upstream activated regions (UAS), assembly of Mediator within the pre-initiation complex is accompanied by the release of CKM. Surprisingly, our data show that CKM regulates Mediator-UAS interaction rather than Mediator-promoter association. In addition, while Tail is required for Mediator recruitment to UAS, Tail-less Mediator nevertheless interacts with core promoters. Collectively, our data suggest that the essential function of Mediator is mediated by Head and Middle at core promoters, while Tail and CKM play regulatory roles.

2016-10-20 | GSE81127 | GEO

Regulation of Mediator-dependent transcriptional activation of Pol II(G) through TFII

Project description:Pol II(G) is a novel form of RNA polymerase II that contains a tightly associated Gdown1 polypeptide. Whereas Pol II suffices for robust activator-dependent transcription in the absence of Mediator, Pol II(G) is highly dependent upon Mediator in a biochemically defined in vitro system. However, the mechanism(s) whereby Gdown1 alters the coactivator-dependence of Pol II is unknown. Here we show that Gdown1 competes with TFIIF for binding to the RPB1 and RPB5 subunits of Pol II in vitro, resulting in inhibition of a critical function of TFIIF in facilitating PIC assembly. The apparent inability of Pol II(G) to associate with TFIIF suggests that Gdown1 must be removed from Pol II for transcription initiation. However, Mediator can actually help Pol II(G) bind to the promoter prior to subsequent Mediator functions. Complementary cell-based analyses reveal that Pol II(G) is recruited to promoter regions of subsets of actively transcribed genes, where Pol II(G) appears to modulate transcription. Our findings indicate that differential regulation of subsets of genes by Pol II and Pol II(G) occurs through the regulation of TFIIF and consequent alterations in Mediator requirements. Genome-wide localization of PolII and Gdown1 in human IMR90 fibroblast cells using ChIP-seq

2012-01-13 | E-GEOD-33128 | biostudies-arrayexpress

Connection of core and and tail Mediator modules restrains transcription from TFIID-dependent promoters [ChEC-seq]

Project description:The Mediator coactivator complex is divided into four modules: head, middle, tail, and kinase. Deletion of the architectural subunit Med16 separates core Mediator (cMed), comprising the head, middle, and scaffold (Med14), from the tail. However, the direct global effects of tail/cMed disconnection are unclear. We find that rapid depletion of Med16 downregulates genes that require the SAGA complex for full expression, consistent with their reported tail dependence, but also moderately overactivates TFIID-dependent genes in a manner partly dependent on the separated tail, which remains associated with upstream activating sequences. Suppression of TBP dynamics via removal of the Mot1 ATPase partially restores normal transcriptional activity to Med16-depleted cells, suggesting that cMed/tail separation results in an imbalance in the levels PIC formation at SAGA-requiring and TFIID-dependent genes. We suggest that the preferential regulation of SAGA-requiring genes by tailed Mediator helps maintain a proper balance of transcription between these genes and those more dependent on TFIID.

2021-07-30 | GSE169746 | GEO

Connection of core and and tail Mediator modules restrains transcription from TFIID-dependent promoters [ChEC-seq Med16-AID]

2021-07-30 | GSE179765 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data