scholarly journals Dynamic Regulation of Histone Modifications in Xenopus Oocytes through Histone Exchange

2006 ◽  
Vol 26 (18) ◽  
pp. 6890-6901 ◽  
Author(s):  
M. David Stewart ◽  
John Sommerville ◽  
Jiemin Wong
Keyword(s):  
Transcriptional Repression ◽  
Xenopus Oocytes ◽  
Transcriptional Activity ◽  
Trichostatin A ◽  
Epigenetic Inheritance ◽  
Histone Methyltransferase ◽  
H3k9 Methylation ◽  
Dynamic Regulation ◽  
Dynamic Exchange ◽  
Histone Exchange

ABSTRACT Histone H3 lysine 9 (H3K9) methylation has broad roles in transcriptional repression, gene silencing, maintenance of heterochromatin, and epigenetic inheritance of heterochromatin. Using Xenopus laevis oocytes, we have previously shown that targeting G9a, an H3K9 histone methyltransferase, to chromatin increases H3K9 methylation and consequently represses transcription. Here we report that treatment with trichostatin A induces histone acetylation and is sufficient to activate transcription repressed by G9a, and this activation is accompanied by a reduction in dimethyl H3K9 (H3K9me2). We tested the possibility that the reduction in H3K9me2 was due to the replacement of methylated H3 with unmethylated H3.3. Surprisingly, we found that both free H3 and H3.3 are continually exchanged with chromatin-associated histones. This dynamic exchange of chromatin-associated H3 with free H3/H3.3 was not affected by alterations in transcriptional activity, elongation, acetylation, H3K9 methylation, or DNA replication. In support of this continual histone exchange model, we show that maintenance of H3K9 methylation at a specific site requires the continual presence of an H3K9 histone methyltransferase. Upon dissociation of the methyltransferase, H3K9 methylation decreases. Taken together, our data suggest that chromatin-associated and non-chromatin-associated histones are continually exchanged in the Xenopus oocyte, creating a highly dynamic chromatin environment.

scholarly journals Histone exchange is associated with activator function at transcribed promoters and with repression at histone loci

2020 ◽  
Vol 6 (36) ◽  
pp. eabb0333
Author(s):  
Sari Kassem ◽  
Paolo Ferrari ◽  
Amanda L. Hughes ◽  
Julien Soudet ◽  
Oliver J. Rando ◽  
...  
Keyword(s):  
Gene Expression ◽  
Causal Relationship ◽  
Mode Of Action ◽  
Transcriptional Repression ◽  
Transcriptional Activity ◽  
Gene Promoters ◽  
Regulate Gene Expression ◽  
Histone Exchange ◽  
Regulate Gene

Transcription in eukaryotes correlates with major chromatin changes, including the replacement of old nucleosomal histones by new histones at the promoters of genes. The role of these histone exchange events in transcription remains unclear. In particular, the causal relationship between histone exchange and activator binding, preinitiation complex (PIC) assembly, and/or subsequent transcription remains unclear. Here, we provide evidence that histone exchange at gene promoters is not simply a consequence of PIC assembly or transcription but instead is mediated by activators. We further show that not all activators up-regulate gene expression by inducing histone turnover. Thus, histone exchange does not simply correlate with transcriptional activity, but instead reflects the mode of action of the activator. Last, we show that histone turnover is not only associated with activator function but also plays a role in transcriptional repression at the histone loci.

scholarly journals Coordinated Recruitment of Histone Methyltransferase G9a and Other Chromatin-Modifying Enzymes in SHP-Mediated Regulation of Hepatic Bile Acid Metabolism

2006 ◽  
Vol 27 (4) ◽  
pp. 1407-1424 ◽  
Author(s):  
Sungsoon Fang ◽  
Ji Miao ◽  
Lingjin Xiang ◽  
Bhaskar Ponugoti ◽  
Eckardt Treuter ◽  
...  
Keyword(s):  
Bile Acid ◽  
Histone Deacetylases ◽  
Trichostatin A ◽  
Critical Role ◽  
Histone Methyltransferase ◽  
Bile Acid Metabolism ◽  
Dependent Manner ◽  
H3k9 Methylation ◽  
Hepatic Bile

ABSTRACT SHP has been implicated as a pleiotropic regulator of diverse biological functions by its ability to inhibit numerous nuclear receptors. Recently, we reported that SHP inhibits transcription of CYP7A1, a key gene in bile acid biosynthesis, by recruiting histone deacetylases (HDACs) and a Swi/Snf-Brm complex. To further delineate the mechanism of this inhibition, we have examined whether methylation of histones is also involved and whether a functional interplay between chromatin-modifying enzymes occurs. The histone methyltransferase G9a, but not SUV39, was colocalized with SHP in the nucleus and directly interacted with SHP in vitro. G9a, which was coimmunoprecipitated with hepatic SHP, methylated Lys-9 of histone 3 (H3K9) in vitro. Expression of G9a enhanced inhibition of CYP7A1 transcription by SHP, while a catalytically inactive G9a dominant negative (DN) mutant reversed the SHP inhibition. G9a was recruited to and H3K9 was methylated at the CYP7A1 promoter in a SHP-dependent manner in bile acid-treated HepG2 cells. Expression of the G9a-DN mutant inhibited H3K9 methylation, blocked the recruitment of the Brm complex, and partially reversed CYP7A1 inhibition by bile acids. Inhibition of HDAC activity with trichostatin A blocked deacetylation and methylation of H3K9 at the promoter, and, conversely, inhibition of H3K9 methylation by G9a-DN partially blocked deacetylation. Hepatic expression of G9a-DN in mice fed cholic acid disrupted bile acid homeostasis, resulting in increased bile acid pools and partial de-repression of Cyp7a1 and Cyp8b1. Our studies establish a critical role for G9a methyltransferase, histone deacetylases, and the Swi/Snf-Brm complex in the SHP-mediated inhibition of hepatic bile acid synthesis via coordinated chromatin modification at target genes.

scholarly journals An ERG (ets-related gene)-associated histone methyltransferase interacts with histone deacetylases 1/2 and transcription co-repressors mSin3A/B

2003 ◽  
Vol 369 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Liu YANG ◽  
Qi MEI ◽  
Anna ZIELINSKA-KWIATKOWSKA ◽  
Yoshito MATSUI ◽  
Michael L. BLACKBURN ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Trichostatin A ◽  
Histone Methyltransferase ◽  
Luciferase Reporter ◽  
Related Gene ◽  
Luciferase Reporter Gene ◽  
Histone Tails ◽  
Histone Deacetylase 1 ◽  
Covalent Modifications

Covalent modifications of histone tails play important roles in gene transcription and silencing. We recently identified an ERG (ets-related gene)-associated protein with a SET (suppressor of variegation, enhancer of zest and trithorax) domain (ESET) that was found to have the activity of a histone H3-specific methyltransferase. In the present study, we investigated the interaction of ESET with other chromatin remodelling factors. We show that ESET histone methyltransferase associates with histone deacetylase 1 (HDAC1) and HDAC2, and that ESET also interacts with the transcription co-repressors mSin3A and mSin3B. Deletion analysis of ESET reveals that an N-terminal region containing a tudor domain is responsible for interaction with mSin3A/B and association with HDAC1/2, and that truncation of ESET enhances its binding to mSin3. When bound to a promoter, ESET represses the transcription of a downstream luciferase reporter gene. This repression by ESET is independent of its histone methyltransferase activity, but correlates with its binding to the mSin3 co-repressors. In addition, the repression can be partially reversed by treatment with the HDAC inhibitor trichostatin A. Taken together, these data suggest that ESET histone methyltransferase can form a large, multi-protein complex(es) with mSin3A/B co-repressors and HDAC1/2 that participates in multiple pathways of transcriptional repression.

scholarly journals The Human Candidate Tumor Suppressor Gene HIC1 Recruits CtBP through a Degenerate GLDLSKK Motif

2002 ◽  
Vol 22 (13) ◽  
pp. 4890-4901 ◽  
Author(s):  
Sophie Deltour ◽  
Sébastien Pinte ◽  
Cateline Guerardel ◽  
Bohdan Wasylyk ◽  
Dominique Leprince
Keyword(s):  
Binding Site ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Trichostatin A ◽  
Suppressor Gene ◽  
Close Relative ◽  
Consensus Binding Site ◽  
Candidate Tumor Suppressor Gene

ABSTRACT HIC1 (hypermethylated in cancer) and its close relative HRG22 (HIC1-related gene on chromosome 22) encode transcriptional repressors with five C2H2 zinc fingers and an N-terminal BTB/POZ autonomous transcriptional repression domain that is unable to recruit histone deacetylases (HDACs). Alignment of the HIC1 and HRG22 proteins from various species highlighted a perfectly conserved GLDLSKK/R motif highly related to the consensus CtBP interaction motif (PXDLSXK/R), except for the replacement of the virtually invariant proline by a glycine. HIC1 strongly interacts with mCtBP1 both in vivo and in vitro through this conserved GLDLSKK motif, thus extending the CtBP consensus binding site. The BTB/POZ domain does not interact with mCtBP1, but the dimerization of HIC1 through this domain is required for the interaction with mCtBP1. When tethered to DNA by fusion with the Gal4 DNA-binding domain, the HIC1 central region represses transcription through interactions with CtBP in a trichostatin A-sensitive manner. In conclusion, our results demonstrate that HIC1 mediates transcriptional repression by both HDAC-independent and HDAC-dependent mechanisms and show that CtBP is a HIC1 corepressor that is recruited via a variant binding site.

scholarly journals MYC Interacts with the G9a Histone Methyltransferase to Drive Transcriptional Repression and Tumorigenesis

Cancer Cell ◽  
2018 ◽  
Vol 34 (4) ◽  
pp. 579-595.e8 ◽  
Author(s):  
William B. Tu ◽  
Yu-Jia Shiah ◽  
Corey Lourenco ◽  
Peter J. Mullen ◽  
Dharmendra Dingar ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Histone Methyltransferase

Abstract 3678: Protein Kinase C-zeta (PKCζ) Is A Novel Mediator Of Endothelial Dysfunction By Inhibiting The ERK5/ Kruppel-like Factor 2 (KLF2) Pathway

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Patrizia Nigro ◽  
Chang Hoon Woo ◽  
Maria Antonietta Belisario ◽  
Carolyn McClain ◽  
Jun-ichi Abe ◽  
...  
Keyword(s):  
Shear Stress ◽  
Endothelial Dysfunction ◽  
Transcriptional Repression ◽  
Transcriptional Activity ◽  
Catalytic Domain ◽  
Mutational Analysis ◽  
Critical Role ◽  
Enos Expression ◽  
Interaction Domain ◽  
Pb1 Domain

Background: Shear stress-induced activation of ERK5 and KLF2 leads to eNOS expression maintaining normal endothelial cell (EC) function. PKCζ has emerged as a pathologic mediator of EC dysfunction based on 1) a positive correlation between PKCζ activity and disturbed flow pattern; and 2) PKCζ activation is essential for TNFα stimulation of JNK, caspase-3 and EC apoptosis. Therefore we hypothesized that TNFα and its pathologic mediator ONOO − would inhibit ERK5 transcriptional activity and eNOS expression induced by flow. Results: TNFα and ONOO − significantly inhibited ERK5 transcriptional activity, KLF2 promoter activity, and eNOS expression induced by flow (shear stress = 12 dyn/cm2, 24 hrs). Both TNFαand ONOO − increased PKCζ activity. Transfection of wild type PKCζ (WT-PKCζ) and catalytic domain of PKCζ (CATζ) significantly inhibited ERK5 transcriptional activity (38±1.4% and 57±2.8% respectively; p<0.01, p<0.005). Also, transfection of PKCζ siRNA reversed TNFα-mediated inhibition of ERK5 transcriptional activity (control vs PKCz siRNA, 28±2.5% vs 9±0.3%, p<0.05), suggesting a critical role for PKCζ in ERK5 transcriptional repression. Surprisingly, TNFα and ONOO − did not significantly decrease ERK5 phosphorylation, suggesting that inhibition occurred downstream of ERK5 phosphorylation. Previously we reported that ERK5-SUMOylation inhibited flow-mediated eNOS expression, but we could not detect increased ERK5-SUMOylation in WT-PKCζ or CATζ transfected cells. Importantly, we found that ONOO − significantly increased PKCζ-ERK5 interaction. PKCζ is known to contain a PB1 domain, a well studied protein-protein interaction domain. However, mutational analysis demonstrated that the ERK5 binding site in PKCζ was within the catalytic domain of PKCζ, not the PB1 domain. These data suggest that the PKCζ-ERK5 interaction likely inhibits ERK5 transcriptional activity by direct phosphorylation of ERK5 by PKCζ kinase. Conclusion: PKCζ is a novel mediator of TNFα and ONOO − induced endothelial dysfunction by inhibiting ERK5 transcriptional activity independent of kinase activity and ERK5-SUMOylation.

scholarly journals The DEAD Box Protein DP103 Is a Regulator of Steroidogenic Factor-1

2001 ◽  
Vol 15 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Qinglin Ou ◽  
Jean-François Mouillet ◽  
Xiaomei Yan ◽  
Christoph Dorn ◽  
Peter A. Crawford ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Transcriptional Activity ◽  
Point Mutations ◽  
Hypothalamic Nucleus ◽  
Rna Helicases ◽  
Interacting Protein ◽  
Steroidogenic Factor 1 ◽  
Dead Box ◽  
The Dead ◽  
Repression Domain

Abstract The nuclear receptor steroidogenic factor-1 (SF-1) is essential for development of the gonads, adrenal gland, and the ventromedial hypothalamic nucleus. It also regulates the expression of pivotal steroidogenic enzymes and other important proteins in the reproductive system. We sought to elucidate the mechanisms that govern the transcriptional activity of SF-1. We demonstrate here that a previously uncharacterized domain, located C-terminal to the DNA binding domain of SF-1, exhibits transcriptional repression function. Point mutations in this domain markedly potentiate the transcriptional activity of native SF-1. Using an SF-1 region that spans this proximal repression domain as bait in a yeast two-hybrid system, we cloned an SF-1 interacting protein that is homologous to human DP103, a member of the DEAD box family of putative RNA helicases. DP103 directly interacts with the proximal repression domain of SF-1, and mutations in this domain abrogate its interaction with DP103. DP103 is expressed predominantly in the testis and is also expressed at a lower level in other steroidogenic and nonsteroidogenic tissues. Functionally, DP103 exhibits a native transcriptional repression function that localizes to the C-terminal region of the protein and represses the activity of wild-type, but not mutant, SF-1. Together, the physical and functional interaction of DP103 with a previously unrecognized repression domain within SF-1 represents a novel mechanism for regulation of SF-1 activity.

scholarly journals Involvement of the SMRT/NCoR–HDAC3 complex in transcriptional repression by the CNOT2 subunit of the human Ccr4–Not complex

2006 ◽  
Vol 398 (3) ◽  
pp. 461-467 ◽  
Author(s):  
Sandrine Jayne ◽  
Carin G. M. Zwartjes ◽  
Frederik M. A. Van Schaik ◽  
H. Th. Marc Timmers
Keyword(s):  
Rna Polymerase Ii ◽  
Hormone Receptor ◽  
Transcriptional Repression ◽  
Thyroid Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Trichostatin A ◽  
Chromatin Modification ◽  
Nuclear Hormone Receptor ◽  
C Terminus ◽  
Repressive Effect

In eukaryotic cells, the Ccr4–Not complex can regulate mRNA metabolism at various levels. Previously, we showed that promoter targeting of the CNOT2 subunit resulted in strong repression of RNA polymerase II transcription, which was sensitive to the HDAC (histone deacetylase) inhibitor, trichostatin A [Zwartjes, Jayne, van den Berg and Timmers (2004) J. Biol. Chem. 279, 10848–10854]. In the present study, the cofactor requirement for CNOT2-mediated repression was investigated. We found that coexpression of SMRT (silencing mediator for retinoic acid receptor and thyroid-hormone receptor) or NCoR (nuclear hormone receptor co-repressor) in combination with HDAC3 (or HDAC5 and HDAC6) augmented the repression by CNOT2. This repressive effect is mediated by the conserved Not-Box, which resides at the C-terminus of CNOT2 proteins. We observed physical interactions of CNOT2 with several subunits of the SMRT/NCoR–HDAC3 complex. Our results show that the SMRT/NCoR–HDAC3 complex is a cofactor of CNOT2-mediated repression and suggest that transcriptional regulation by the Ccr4–Not complex involves regulation of chromatin modification.

scholarly journals Dynamic regulation of the PR-Set7 histone methyltransferase is required for normal cell cycle progression

2010 ◽  
Vol 24 (22) ◽  
pp. 2531-2542 ◽  
Author(s):  
S. Wu ◽  
W. Wang ◽  
X. Kong ◽  
L. M. Congdon ◽  
K. Yokomori ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Normal Cell ◽  
Cell Cycle Progression ◽  
Histone Methyltransferase ◽  
Cycle Progression ◽  
Dynamic Regulation ◽  
Normal Cell Cycle

scholarly journals Global Replication-Independent Histone H4 Exchange in Budding Yeast

2006 ◽  
Vol 5 (10) ◽  
pp. 1780-1787 ◽  
Author(s):  
Jeffrey Linger ◽  
Jessica K. Tyler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Replication ◽  
Budding Yeast ◽  
Histone H3 ◽  
Eukaryotic Genome ◽  
Histone H4 ◽  
Histone Proteins ◽  
Dynamic Exchange ◽  
Histone Exchange

ABSTRACT The eukaryotic genome is packaged together with histone proteins into chromatin following DNA replication. Recent studies have shown that histones can also be assembled into chromatin independently of DNA replication and that this dynamic exchange of histones may be biased toward sites undergoing transcription. Here we show that epitope-tagged histone H4 can be incorporated into nucleosomes throughout the budding yeast (Saccharomyces cerevisiae) genome regardless of the phase of the cell cycle, the transcriptional status, or silencing of the region. Direct comparisons reveal that the amount of histone incorporation that occurs in G1-arrested cells is similar to that occurring in cells undergoing DNA replication. Additionally, we show that this histone incorporation is not dependent on the histone H3/H4 chaperones CAF-1, Asf1, and Hir1 individually. This study demonstrates that DNA replication and transcription are not necessary prerequisites for histone exchange in budding yeast, indicating that chromatin is more dynamic than previously thought.

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