We show that Mediator, a protein originally isolated on the basis of its ability to respond to transcriptional activators, and thought to be regulated by an activator, can also be the master that controls the activator

A Gromöller

A Traven

A Varshavsky

A Wellhausen

A. Z Ansari

B. S Chew

C Jiang

C Reichel

C. A Keleher

C. A Sellick

C. Q Diep

C. T Archer

D Finley

D Kadosh

D Skowyra

D. J Taatjes

E Alani

E Rojo-Niersbach

Edwin Ang

Elvin Koh

F Gonzalez

F Jiang

F. C Holstege

G. A Collins

G. M Santangelo

G. O Bryant

Gary Ee

H Laser

H Takahashi

J. R Lipford

K Kitagawa

K Nalley

K. A Nasmyth

K. D Meyer

Keven Ang

M Carlson

M Floer

M Muratani

M Ptashne

M. A Treitel

M. H Kagey

M. J De Vit

M. K Lim

N Ding

N Lehming

Norbert Lehming

Oliver J. Rando

P. R Kumar

R. D Gietz

R. D Kornberg

R. G Hu

R. J Dohmen

R. S Sikorski

S Kuchin

S Malik

Sabrina Nur

T Maniatis

Wee Leng Siew

X Wang

Y Li

Yee Sun Tan

Yu Mun Chan

English

PubMed

Ang Keven

Ee Gary

Ang Edwin

Koh Elvin

Siew Wee Leng

Chan Yu Mun

Nur Sabrina

Tan Yee Sun

Lehming Norbert

Public Library of Science (PLOS)

Mediator Acts Upstream of the Transcriptional Activator Gal4

Crossref

PLoS Biology

<div><p>The proteasome inhibitor MG132 had been shown to prevent galactose induction of the <em>S. cerevisiae GAL1</em> gene, demonstrating that ubiquitin proteasome-dependent degradation of transcription factors plays an important role in the regulation of gene expression. The deletion of the gene encoding the F-box protein Mdm30 had been reported to stabilize the transcriptional activator Gal4 under inducing conditions and to lead to defects in galactose utilization, suggesting that recycling of Gal4 is required for its function. Subsequently, however, it was argued that Gal4 remains stably bound to the enhancer under inducing conditions, suggesting that proteolytic turnover of Gal4 might not be required for its function. We have performed an alanine-scanning mutagenesis of ubiquitin and isolated a galactose utilization-defective ubiquitin mutant. We have used it for an unbiased suppressor screen and identified the inhibitor Gal80 as a suppressor of the transcriptional defects of the ubiquitin mutant, indicating that the protein degradation of the inhibitor Gal80, and not of the activator Gal4, is required for galactose induction of the <em>GAL</em> genes. We also show that in the absence of Gal80, Mdm30 is not required for Gal4 function, strongly supporting this hypothesis. Furthermore, we have found that Mediator controls the galactose-induced protein degradation of Gal80, which places Mediator genetically upstream of the activator Gal4. Mediator had originally been isolated by its ability to respond to transcriptional activators, and here we have discovered a leading role for Mediator in the process of transcription. The protein kinase Snf1 senses the inducing conditions and transduces the signal to Mediator, which initiates the degradation of the inhibitor Gal80 with the help of the E3 ubiquitin ligase SCF<sup>Mdm30</sup>. The ability of Mediator to control the protein degradation of transcriptional inhibitors indicates that Mediator is actually able to direct its own recruitment to gene promoters.</p> </div

Keven Ang (176064)

Gary Ee (176071)

Edwin Ang (176076)

Elvin Koh (176081)

Wee Leng Siew (176086)

Yu Mun Chan (176091)

Sabrina Nur (176094)

Yee Sun Tan (176098)

Norbert Lehming (176101)

The Francis Crick Institute

The proteasome inhibitor MG132 had been shown to prevent galactose induction of the S. cerevisiae GAL1 gene, demonstrating that ubiquitin proteasome-dependent degradation of transcription factors plays an important role in the regulation of gene expression. The deletion of the gene encoding the F-box protein Mdm30 had been reported to stabilize the transcriptional activator Gal4 under inducing conditions and to lead to defects in galactose utilization, suggesting that recycling of Gal4 is required for its function. Subsequently, however, it was argued that Gal4 remains stably bound to the enhancer under inducing conditions, suggesting that proteolytic turnover of Gal4 might not be required for its function. We have performed an alanine-scanning mutagenesis of ubiquitin and isolated a galactose utilization-defective ubiquitin mutant. We have used it for an unbiased suppressor screen and identified the inhibitor Gal80 as a suppressor of the transcriptional defects of the ubiquitin mutant, indicating that the protein degradation of the inhibitor Gal80, and not of the activator Gal4, is required for galactose induction of the GAL genes. We also show that in the absence of Gal80, Mdm30 is not required for Gal4 function, strongly supporting this hypothesis. Furthermore, we have found that Mediator controls the galactose-induced protein degradation of Gal80, which places Mediator genetically upstream of the activator Gal4. Mediator had originally been isolated by its ability to respond to transcriptional activators, and here we have discovered a leading role for Mediator in the process of transcription. The protein kinase Snf1 senses the inducing conditions and transduces the signal to Mediator, which initiates the degradation of the inhibitor Gal80 with the help of the E3 ubiquitin ligase SCF(Mdm30). The ability of Mediator to control the protein degradation of transcriptional inhibitors indicates that Mediator is actually able to direct its own recruitment to gene promoters

Directory of Open Access Journals

Mediator acts upstream of the transcriptional activator Gal4.

A method for gene disruption that allows repeated use of URA3 selection in the construction of multiply disrupted yeast strains.

A new method for the selection of protein interactions in mammalian cells.

A new screen for protein interactions reveals that the Saccharomyces cerevisiae high mobility group proteins Nhp6A/B are involved in the regulation of the GAL1 promoter.

A putative stimulatory role for activator turnover in gene expression.

A regulatory shortcut between the Snf1 protein kinase and RNA polymerase II holoenzyme.

A RSC/ nucleosome complex determines chromatin architecture and facilitates activator binding.

A suppressor of SNF1 mutations causes constitutive high-level invertase synthesis in yeast.

A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae.

Activation domain-dependent monoubiquitylation of Gal4 protein is essential for promoter binding in vivo.

Activator control of nucleosome occupancy in activation and repression of transcription.

Alterations in the interaction between GAL4 and GAL80 affect regulation of the yeast GAL regulon mediated by the F box protein Dsg1.

An essential yeast gene encoding a homolog of ubiquitin-activating enzyme.

An extensive network of coupling among gene expression machines.

Analysis of protein-protein proximities using the splitubiquitin system.

Analysis of the in vivo interaction between a basic repressor and an acidic activator.

Dissecting the regulatory circuitry of a eukaryotic genome.

Eukaryotic transcription factors as direct nutrient sensors.

F-box proteins are receptors that recruit phosphorylated substrates to the SCF ubiquitin-ligase complex.

Gal11p dosage-compensates transcriptional activator deletions via Taf14p.

Gal4 turnover and transcription activation.

Gene activation by dissociation of an inhibitor from a transcriptional activation domain.

Genetic evidence for sites of interaction between the

Glucose signaling in Saccharomyces cerevisiae.

How the ubiquitin-proteasome system controls transcription.

Human mediator subunit MED26 functions as a docking site for transcription elongation factors.

Inhibition of proteolysis and cell cycle progression in a multiubiquitination-deficient yeast mutant.

Isolation of genes by complementation in yeast: molecular cloning of a cell-cycle gene.

Mediator and cohesin connect gene expression and chromatin architecture.

Mediator and the mechanism of transcriptional activation.

Mediator links epigenetic silencing of neuronal gene expression with x-linked mental retardation.

NADP regulates the yeast GAL induction system.

Nucleosome positioning and gene regulation: advances through genomics.

Proteolytic instability and the action of nonclassical transcriptional activators.

Proteolytic turnover of the Gal4 transcription factor is not required for function in vivo.

Recruitment of a 19S proteasome subcomplex to an activated promoter.

Regulated nuclear translocation of the Mig1 glucose repressor.

Regulation of transcription, from lambda to eukaryotes.

Repression by SSN6-TUP1 is directed by MIG1, a repressor/activator protein.

Repression by Ume6 involves recruitment of a complex containing Sin3 corepressor and Rpd3 histone deacetylase to target promoters.

SGT1 encodes an essential component of the yeast kinetochore assembly pathway and a novel subunit of the SCF ubiquitin ligase complex.

Snf1 protein kinase regulates phosphorylation of the Mig1 repressor in Saccharomyces cerevisiae.

Srb7p is a physical and physiological target of Tup1p.

Srb7p is essential for the activation of a subset of genes.

Ssn6-Tup1 is a general repressor of transcription in yeast.

Sugino A

Taatjes DJ (2010) p53 activates transcription by directing structural shifts in Mediator.

The F box protein Dsg1/ Mdm30 is a transcriptional coactivator that stimulates Gal4 turnover and cotranscriptional mRNA processing.

The human Mediator complex: a versatile, genome-wide regulator of transcription.

The hydrophobic patch of ubiquitin is required to protect transactivator-promoter complexes from destabilization by the proteasomal ATPases.

The metazoan Mediator co-activator complex as an integrative hub for transcriptional regulation.

The split-ubiquitin sensor: measuring interactions and conformational alterations of proteins in vivo.

The ubiquitin system.

Transcriptional activating regions target a cyclin-dependent kinase.

Varshavsky A

Yeast Gal4, a transcriptional paradigm revisited.

https://figshare.com/articles/Mediator_Acts_Upstream_of_the_Transcriptional_Activator_Gal4/127281

Mediator Acts Upstream of the Transcriptional Activator Gal4

Abstract

Similar works

Full text

Available Versions

Public Library of Science (PLOS)

Public Library of Science (PLOS)

Crossref

The Francis Crick Institute

Directory of Open Access Journals