scholarly journals Histone Deacetylase 7 and FoxA1 in Estrogen-Mediated Repression of RPRM

2009 ◽  
Vol 30 (2) ◽  
pp. 399-412 ◽  
Author(s):  
Simeen Malik ◽  
Shiming Jiang ◽  
Jason P. Garee ◽  
Eric Verdin ◽  
Adrian V. Lee ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Histone Deacetylase ◽  
Transcriptional Activity ◽  
Estrogen Receptor Α ◽  
Proximal Promoter ◽  
Pol Ii ◽  
Cell Cycle Inhibitor ◽  
Pioneer Factor ◽  
A Cell ◽  
Estrogen Induction

ABSTRACT Activation of estrogen receptor α (ERα) results in both induction and repression of gene transcription; while mechanistic details of estrogen induction are well described, details of repression remain largely unknown. We characterized several ERα-repressed targets and examined in detail the mechanism for estrogen repression of Reprimo (RPRM), a cell cycle inhibitor. Estrogen repression of RPRM is rapid and robust and requires a tripartite interaction between ERα, histone deacetylase 7 (HDAC7), and FoxA1. HDAC7 is the critical HDAC needed for repression of RPRM; it can bind to ERα and represses ERα's transcriptional activity—this repression does not require HDAC7's deacetylase activity. We further show that the chromatin pioneer factor FoxA1, well known for its role in estrogen induction of genes, is recruited to the RPRM promoter, is necessary for repression of RPRM, and interacts with HDAC7. Like other FoxA1 recruitment sites, the RPRM promoter is characterized by H3K4me1/me2. Estrogen treatment causes decreases in H3K4me1/me2 and release of RNA polymerase II (Pol II) from the RPRM proximal promoter. Overall, these data implicate a novel role for HDAC7 and FoxA1 in estrogen repression of RPRM, a mechanism which could potentially be generalized to many more estrogen-repressed genes and hence be important in both normal physiology and pathological processes.

scholarly journals Transcription-dependent redistribution of the large subunit of RNA polymerase II to discrete nuclear domains.

1995 ◽  
Vol 129 (2) ◽  
pp. 287-298 ◽  
Author(s):  
D B Bregman ◽  
L Du ◽  
S van der Zee ◽  
S L Warren
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcriptional Activity ◽  
Speckle Pattern ◽  
Large Subunit ◽  
Temperature Dependent ◽  
Pol Ii ◽  
Transcriptional Inhibition ◽  
Tight Association ◽  
Nuclear Domains

A subpopulation of the largest subunit of RNA polymerase II (Pol II LS) is located in 20-50 discrete subnuclear domains that are closely linked to speckle domains, which store splicing proteins. The speckle-associated fraction of Pol II LS is hyperphosphorylated on the COOH-terminal domain (CTD), and it is highly resistant to extraction by detergents. A diffuse nucleoplasmic fraction of Pol II LS is relatively hypophosphorylated on the CTD, and it is easily extracted by detergents. In transcriptionally active nuclei, speckle bound hyperphosphorylated Pol II LS molecules are distributed in irregularly shaped speckle domains, which appear to be interconnected via a reticular network. When transcription is inhibited, hyperphosphorylated Pol II LS and splicing protein SC35 accumulate in speckle domains, which are transformed into enlarged, dot-like structures lacking interconnections. When cells are released from transcriptional inhibition, Pol IIO and SC35 redistribute back to the interconnected speckle pattern of transcriptionally active cells. The redistribution of Pol II and SC35 is synchronous, reversible, and temperature dependent. It is concluded that: (a) hyperphosphorylation of Pol II LS's CTD is a better indicator of its tight association to discrete subnuclear domains than its transcriptional activity; (b) during states of transcriptional inhibition, hyperphosphorylated Pol II LS can be stored in enlarged speckle domains, which under the light microscope appear to coincide with the storage sites for splicing proteins; and (c) Pol II and splicing proteins redistribute simultaneously according to the overall transcriptional activity of the nucleus.

scholarly journals Release of promoter–proximal paused Pol II in response to histone deacetylase inhibition

2020 ◽  
Vol 48 (9) ◽  
pp. 4877-4890 ◽  
Author(s):  
Roshan Vaid ◽  
Jiayu Wen ◽  
Mattias Mannervik
Keyword(s):  
Histone Acetylation ◽  
Rna Polymerase Ii ◽  
Histone Deacetylase ◽  
Transcriptional Response ◽  
Feedback Regulation ◽  
Hdac Inhibition ◽  
Pol Ii ◽  
Histone Deacetylase Inhibition ◽  
Enhanced Expression ◽  
Long Time

Abstract A correlation between histone acetylation and transcription has been noted for a long time, but little is known about what step(s) in the transcription cycle is influenced by acetylation. We have examined the immediate transcriptional response to histone deacetylase (HDAC) inhibition, and find that release of promoter–proximal paused RNA polymerase II (Pol II) into elongation is stimulated, whereas initiation is not. Although histone acetylation is elevated globally by HDAC inhibition, less than 100 genes respond within 10 min. These genes are highly paused, are strongly associated with the chromatin regulators NURF and Trithorax, display a greater increase in acetylation of the first nucleosomes than other genes, and become transcriptionally activated by HDAC inhibition. Among these rapidly up-regulated genes are HDAC1 (Rpd3) and subunits of HDAC-containing co-repressor complexes, demonstrating feedback regulation upon HDAC inhibition. Our results suggest that histone acetylation stimulates transcription of paused genes by release of Pol II into elongation, and that increased acetylation is not a consequence of their enhanced expression. We propose that HDACs are major regulators of Pol II pausing and that this partly explains the presence of HDACs at active genes.

scholarly journals MED14 Tethers Mediator to the N-Terminal Domain of Peroxisome Proliferator-Activated Receptor γ and Is Required for Full Transcriptional Activity and Adipogenesis

2010 ◽  
Vol 30 (9) ◽  
pp. 2155-2169 ◽  
Author(s):  
Lars Grøntved ◽  
Maria S. Madsen ◽  
Michael Boergesen ◽  
Robert G. Roeder ◽  
Susanne Mandrup
Keyword(s):  
Rna Polymerase Ii ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Target Genes ◽  
Gene Activation ◽  
Proximal Promoter ◽  
Peroxisome Proliferator ◽  
Independent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Terminal Domain

ABSTRACT The Mediator subunit MED1/TRAP220/DRIP205/PBP interacts directly with many nuclear receptors and was long thought to be responsible for tethering Mediator to peroxisome proliferator-activated receptor (PPAR)-responsive promoters. However, it was demonstrated recently that PPARγ can recruit Mediator by MED1-independent mechanisms. Here, we show that target gene activation by ectopically expressed PPARγ and PPARα is independent of MED1. Consistent with this finding, recruitment of PPARγ, MED6, MED8, TATA box-binding protein (TBP), and RNA polymerase II (RNAPII) to the enhancer and proximal promoter of the PPARγ target gene Fabp4 is also independent of MED1. Using a small interfering RNA (siRNA)-based approach, we identify MED14 as a novel critical Mediator component for PPARγ-dependent transactivation, and we demonstrate that MED14 interacts directly with the N terminus of PPARγ in a ligand-independent manner. Interestingly, MED14 knockdown does not affect the recruitment of PPARγ, MED6, and MED8 to the Fabp4 enhancer but does reduce their occupancy of the Fabp4 proximal promoter. In agreement with the necessity of MED14 for PPARγ transcriptional activity, we show that knockdown of MED14 impairs adipogenesis of 3T3-L1 cells. Thus, MED14 constitutes a novel anchoring point between Mediator and the N-terminal domain of PPARγ that is necessary for functional PPARγ-mediated recruitment of Mediator and transactivation of PPARγ subtype-specific target genes.

scholarly journals KISS1 Is Down-Regulated by 17β-Estradiol in MDA-MB-231 Cells through a Nonclassical Mechanism and Loss of Ribonucleic Acid Polymerase II Binding at the Proximal Promoter

Endocrinology ◽  
2010 ◽  
Vol 151 (8) ◽  
pp. 3764-3772 ◽  
Author(s):  
Lukas Huijbregts ◽  
Nicolas de Roux
Keyword(s):  
Rna Polymerase Ii ◽  
Cell Line ◽  
Molecular Mechanisms ◽  
Active Form ◽  
Cancer Cell Line ◽  
Estrogen Receptor Α ◽  
Proximal Promoter ◽  
Gene Body ◽  
Down Regulation ◽  
17Β Estradiol

Kisspeptins are hypothalamic neuropeptides encoded by KISS1 and recently described as major regulators of GnRH release from hypothalamic neurons. Although 17β-estradiol (E2)-induced up-regulation of KISS1 expression has been documented in anteroventral periventricular nucleus neurons, E2 down-regulates KISS1 expression in arcuate nucleus neurons via the estrogen receptor α by unknown molecular mechanisms. Because KISS1 was initially described as a metastasis inhibitor, notably in breast tumors, we used the MDA-MB-231 breast cancer cell line, which expresses high levels of KISS1, to characterize the molecular mechanism underlying KISS1 regulation by E2. E2 rapidly down-regulated endogenous KISS1 in a stable ERα-expressing MDA-MB-231 cell line. Promoter analysis revealed that E2 down-regulation was determined by a short 93-bp sequence devoid of estrogen response element and Sp1 sites. E2 down-regulation persisted with an ERα that was unable to bind DNA and in the presence of histone deacetylase inhibitor. In the absence of E2, unliganded ERα and RNA polymerase II (RNAPII) were present on the proximal promoter. E2 stimulation induced recruitment of ERα and loss of RNAPII at the proximal promoter. Along the gene body, total RNAPII amounts were similar in E2-treated and untreated cells, whereas the active form was significantly less abundant in E2-treated cells. Thus, E2-induced down-regulation of KISS1 is mediated by a pathway combining RNAPII loss at the proximal promoter and modulation of active RNAPII along the gene body, which is a novel mechanism in the complex process of E2-induced repression of gene expression.

scholarly journals Pioneer factor GAF cooperates with PBAP and NURF to regulate transcription

2020 ◽  
Author(s):  
Julius Judd ◽  
Fabiana M. Duarte ◽  
John T. Lis
Keyword(s):  
Rna Polymerase Ii ◽  
Open Chromatin ◽  
Gaga Factor ◽  
Pol Ii ◽  
Chromatin Remodelers ◽  
Silent Genes ◽  
Pioneer Factor ◽  
Single Sequence ◽  
Chromatin Opening ◽  
Productive Elongation

SummaryTranscriptionally silent genes must be activated throughout development. This requires nucleosomes be removed from promoters and enhancers to allow transcription factor binding (TFs) and recruitment of coactivators and RNA Polymerase II (Pol II). Specialized pioneer TFs bind nucleosome-wrapped DNA to perform this chromatin opening by mechanisms that remain incompletely understood1–3. Here, we show that GAGA-factor (GAF), a Drosophila pioneer factor4, interacts with both SWI/SNF and ISWI family chromatin remodelers to allow recruitment of Pol II and entry to a promoter-proximal paused state, and also to promote Pol II’s transition to productive elongation. We found that GAF functions with PBAP (SWI/SNF) to open chromatin and allow Pol II to be recruited. Importantly this activity is not dependent on NURF as previously proposed5–7; however, GAF also functions with NURF downstream of this process to ensure efficient Pol II pause release and transition to productive elongation apparently through its role in precisely positioning the +1 nucleosome. These results demonstrate how a single sequence-specific pioneer TF can synergize with remodelers to activate sets of genes. Furthermore, this behavior of remodelers is consistent with findings in yeast8–10 and mice11–13, and likely represents general, conserved mechanisms found throughout Eukarya.

scholarly journals O-GlcNAc Transferase Activity is Essential for RNA Pol II Pausing in a Human Cell-Free Transcription System

2020 ◽  
Author(s):  
Brian A. Lewis ◽  
David Levens
Keyword(s):  
Rna Polymerase Ii ◽  
Transferase Activity ◽  
Rna Pol Ii ◽  
Free System ◽  
Pol Ii ◽  
Transcription System ◽  
A Cell ◽  
Pol Ii Pausing ◽  
Glcnac Transferase

AbstractRNA polymerase II pausing is the major regulatory point in transcription in higher eukaryotes. Despite considerable knowledge of the general transcriptional machinery that are required to recruit RNA pol II to a promoter, much less is known how a paused RNA pol II is established and its release regulated, and the entirety of the machinery is likely not known. In part, this is due to the absence of an appropriate biochemical system that functionally recapitulates RNA pol II pausing and elongation and with which the pausing machinery can be identified. We describe herein a cell-free system (CFS) derived from HeLa cells that recapitulates pausing and elongation events known to occur in vivo. We have used this system to show that O-GlcNAc transferase (OGT) activity is required to establish a paused pol II, without which RNA pol II does not pause and instead enters productive elongation. Coupled with previous observations we show that both O-GlcNAc addition and removal are functionally required for pausing and elongation, respectively. Furthermore, the CFS offers significant inroads into understanding RNA pol II pausing and its regulation.

scholarly journals A hyperactive transcriptional state marks genome reactivation at the mitosis-G1 transition

2016 ◽  
Author(s):  
Chris C.-S. Hsiung ◽  
Caroline Bartman ◽  
Peng Huang ◽  
Paul Ginart ◽  
Aaron J. Stonestrom ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Single Molecule ◽  
Mammalian Cells ◽  
Transcriptional Activity ◽  
De Novo ◽  
Pol Ii ◽  
Mature Mrna ◽  
Genome Wide ◽  
Transcriptional State ◽  
Active Genes

AbstractDuring mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis-G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis-G1 transition, ~50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer-promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry, but do not spike. Of the chromatin-associated features examined, histone H3 lysine 27 acetylation levels at individual loci in mitosis best predict the mitosis-G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis-G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis-G1 transition might predispose cells to diverge in gene expression states.

Downregulation of Dihydrotestosterone and Estradiol Levels by HEXIM1

Endocrinology ◽  
2021 ◽  
Vol 163 (1) ◽  
Author(s):  
Fitya Mozar ◽  
Vikas Sharma ◽  
Shashank Gorityala ◽  
Jeffrey M Albert ◽  
Yan Xu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Rna Polymerase Ii ◽  
Transcriptional Activity ◽  
Elongation Factor ◽  
Estrogen Receptor Α ◽  
Transcriptional Elongation ◽  
Key Enzyme ◽  
Functional Consequences ◽  
Inducible Protein

Abstract We have previously reported that hexamethylene bis-acetamide inducible protein 1 (HEXIM1) inhibits the activity of ligand-bound estrogen receptor α (ERα) and the androgen receptor (AR) by disrupting the interaction between these receptors and positive transcriptional elongation factor b (P-TEFb) and attenuating RNA polymerase II (RNAPII) phosphorylation at serine 2. Functional consequences of the inhibition of transcriptional activity of ERα and AR by HEXIM1 include the inhibition of ERα- and AR-dependent gene expression, respectively, and the resulting attenuation of breast cancer (BCa) and prostate cancer (PCa) cell proliferation and growth. In our present study, we determined that HEXIM1 inhibited AKR1C3 expression in BCa and PCa cells. AKR1C3, also known as 17β-hydroxysteroid dehydrogenase (17β-HSD) type 5, is a key enzyme involved in the synthesis of 17β-estradiol (E2) and 5-dihydrotestosterone (DHT). Downregulation of AKR1C3 by HEXIM1 influenced E2 and DHT production, estrogen- and androgen-dependent gene expression, and cell proliferation. Our studies indicate that HEXIM1 has the unique ability to inhibit both the transcriptional activity of the ER and AR and the synthesis of the endogenous ligands of these receptors.

scholarly journals Altered Mediator dynamics during heat shock in budding yeast

2020 ◽  
Author(s):  
Debasish Sarkar ◽  
Z. Iris Zhu ◽  
Emily Paul ◽  
David Landsman ◽  
Randall H. Morse
Keyword(s):  
Heat Shock ◽  
Rna Polymerase Ii ◽  
Growth Conditions ◽  
Proximal Promoter ◽  
Promoter Regions ◽  
Pol Ii ◽  
Genome Wide ◽  
A Genome ◽  
Similar Dependence ◽  
Wide Scale

AbstractThe Mediator complex is central to transcription by RNA polymerase II (Pol II) in eukaryotes. In yeast, Mediator is recruited by activators via its tail module and then facilitates assembly of the pre-initiation complex (PIC), including Pol II, setting the stage for productive transcription. Mediator occupies proximal promoter regions only transiently prior to Pol II escape; interruption of the transcription cycle by inactivation or depletion of Kin28 inhibits Pol II escape and stabilizes Mediator occupancy at promoters. However, whether Mediator occupancy and dynamics differ for gene cohorts induced by stress or alternative growth conditions has not been examined on a genome-wide scale. Here we investigate Mediator occupancy following heat shock or CdCl2 induction, with or without depletion of Kin28. We find that Pol II occupancy exhibits similar dependence on Mediator under normal and heat shock conditions; however, Mediator occupancy does not increase upon Kin28 depletion at most genes active during heat shock, indicating altered dynamics. Furthermore, Mediator occupancy persists at genes repressed by heat shock or CdCl2 induction and exhibits peaks upstream of the proximal promoter whether or not Kin28 is depleted, suggesting that Mediator is recruited by activators but is unable to engage PIC components at these repressed targets. Finally, we show a reduced dependence on PIC components for Mediator occupancy at promoters after heat shock, further supporting an altered dynamics or stronger engagement with activators under these conditions.

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