scholarly journals Histone Acetylation and Chromatin Remodeling Are Required for UV-B–Dependent Transcriptional Activation of Regulated Genes in Maize

2008 ◽  
Vol 20 (4) ◽  
pp. 827-842 ◽  
Author(s):  
Paula Casati ◽  
Mabel Campi ◽  
Feixia Chu ◽  
Nagi Suzuki ◽  
David Maltby ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Transcriptional Activation

Co-dependent recruitment of Ino80p and Snf2p is required for yeast CUP1 activation

2014 ◽  
Vol 92 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Roshini N. Wimalarathna ◽  
Po Yun Pan ◽  
Chang-Hui Shen
Keyword(s):  
Rna Polymerase ◽  
Histone Acetylation ◽  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Copper Toxicity ◽  
Yeast Cells ◽  
Chromatin Remodelers ◽  
Insight Into ◽  
Cup1 Promoter

In yeast, Ace1p-dependent induction of CUP1 is responsible for protecting cells from copper toxicity. Although the mechanism of yeast CUP1 induction has been studied intensively, it is still uncertain which chromatin remodelers are involved in CUP1 transcriptional activation. Here, we show that yeast cells are inviable in the presence of copper when either chromatin remodeler, Ino80p or Snf2p, is not present. This inviability is due to the lack of CUP1 expression in ino80Δ and snf2Δ cells. Subsequently, we observe that both Ino80p and Snf2p are present at the promoter and they are responsible for recruiting chromatin remodeling activity to the CUP1 promoter under induced conditions. These results suggest that they directly participate in CUP1 transcriptional activation. Furthermore, the codependent recruitment of both INO80 and SWI/SNF depends on the presence of the transcriptional activator, Ace1p. We also demonstrate that both remodelers are required to recruit RNA polymerase II and targeted histone acetylation, indicating that remodelers are recruited to the CUP1 promoter before RNA polymerase II and histone acetylases. These observations provide evidence for the mechanism of CUP1 induction. As such, we propose a model that describes novel insight into the order of events in CUP1 activation.

scholarly journals Bypassing the Requirements for Epigenetic Modifications in Gene Transcription by Increasing Enhancer Strength

2007 ◽  
Vol 28 (3) ◽  
pp. 926-938 ◽  
Author(s):  
George Koutroubas ◽  
Menie Merika ◽  
Dimitris Thanos
Keyword(s):  
Transcription Factor ◽  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Gene Transcription ◽  
Transcriptional Activation ◽  
Epigenetic Modifications ◽  
Current Concept ◽  
Basal Transcription Factor ◽  
Activation Of Transcription ◽  
Transcription Complexes

ABSTRACT Our current concept postulates that histone acetylation is required for the recruitment of bromodomain-containing transcription complexes, such as the chromatin-remodeling machine SWI/SNF and the basal transcription factor TFIID. We generated simple NF-κB-dependent enhancers of increasing transcriptional strengths and found that the histone acetylation requirements for activation of transcription depended on the strengths of these enhancers. All enhancers function by recruiting SWI/SNF and TFIID to induce nucleosome sliding, a prerequisite for transcriptional activation. However, histone acetylation, although it occurs, is dispensable for TFIID and SWI/SNF recruitment by the strong enhancers, indicating that strong activators can overcome the chromatin barrier by directly recruiting the necessary transcriptional complexes. Weak enhancers depend on histone acetylation for recruitment, and this requirement is independent of a histone acetylation code. Thus, the need for nucleosome modifications is imposed on genes and translated according to the quality and strengths of the activators.

scholarly journals A Novel Human Ada2 Homologue Functions with Gcn5 or Brg1 To Coactivate Transcription

2003 ◽  
Vol 23 (19) ◽  
pp. 6944-6957 ◽  
Author(s):  
Nickolai A. Barlev ◽  
Alexander V. Emelyanov ◽  
Paola Castagnino ◽  
Philip Zegerman ◽  
Andrew J. Bannister ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Adaptor Protein ◽  
Saga Complex ◽  
Yeast Two Hybrid ◽  
Functional Assays ◽  
Two Hybrid ◽  
Histone Acetyltransferase Activity

ABSTRACT In yeast, the transcriptional adaptor yeast Ada2 (yAda2) is a part of the multicomponent SAGA complex, which possesses histone acetyltransferase activity through action of the yGcn5 catalytic enzyme. yAda2, among several SAGA proteins, serves to recruit SAGA to genes via interactions with promoter-bound transcription factors. Here we report identification of a new human Ada2 homologue, hAda2β. Ada2β differs both biochemically and functionally from the previously characterized hAda2α, which is a stable component of the human PCAF (human Gcn5 homologue) acetylase complex. Ada2β, relative to Ada2α, interacted selectively, although not stably, with the Gcn5-containing histone acetylation complex TFTC/STAGA. In addition, Ada2β interacted with Baf57 (a component of the human Swi/Snf complex) in a yeast two-hybrid screen and associated with human Swi/Snf in vitro. In functional assays, hAda2β (but not Ada2α), working in concert with Gcn5 (but not PCAF) or Brg1 (the catalytic component of hSwi/Snf complex), increased transcription via the B-cell-specific transcription factor Pax5/BSAP. These findings support the view that Gcn5 and PCAF have distinct roles in vivo and suggest a new mechanism of coactivator function, in which a single adaptor protein (Ada2β) can coordinate targeting of both histone acetylation and chromatin remodeling activities.

Abstract 15978: Acetyl-coa Catalysis by Atp-citrate Lyase is Essential for Myofibroblast Differentiation and Persistence

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Michael P Lazaropoulos ◽  
Andrew A Gibb ◽  
Anh Huynh ◽  
Kathryn Wellen ◽  
John W Elrod
Keyword(s):  
Histone Acetylation ◽  
Transcriptional Activation ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Metabolic Reprogramming ◽  
Myofibroblast Differentiation ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Matrix Deposition ◽  
Citrate Lyase

A feature of heart failure (HF) is excessive extracellular matrix deposition and cardiac remodeling by a differentiated fibroblast population known as myofibroblasts. Identifying mechanisms of myofibroblast differentiation in cardiac fibrosis could yield novel therapeutic targets to delay or reverse HF. Recent evidence suggests that myofibroblast differentiation requires metabolic reprogramming for transcriptional activation of the myofibroblast gene program by chromatin-dependent mechanisms. We previously reported that inhibition of histone demethylation blocks myofibroblast formation, however, whether histone acetylation (e.g., H3K27ac, a prominent mark associated with gene transcription) is involved in fibroblast reprogramming remains unclear. ATP-citrate lyase (ACLY) synthesizes acetyl-CoA and therein supplies acetyl-CoA to the nucleus, where it is used as a substrate by histone acetyltransferases (HATs). To define the role of acetyl-CoA metabolism in myofibroblast differentiation, we stimulated differentiation in mouse embryonic fibroblasts (MEFs) and adult mouse cardiac fibroblasts (ACFs) with the pro-fibrotic agonist transforming growth factor β (TGFβ) and treated cells with a pharmacological inhibitor of ACLY. ACLY inhibition decreased myofibroblast gene expression in ACF and MEFs in TGFβ-stimulated myofibroblast differentiation, in addition to decreasing the population of αSMA positive MEFs. Genetic deletion of ACLY in MEFs recapitulated the results observed with pharmacological inhibition. Encouragingly, the ACLY inhibitor was sufficient to revert fully differentiated myofibroblasts under continuous TGFβ stimulation to a quiescent, non-fibrotic phenotype. Altogether, our data indicate that ACLY activity is necessary for myofibroblast differentiation and persistence. We hypothesize that ACLY-dependent acetyl-CoA synthesis is necessary for histone acetylation and transcriptional activation of the myofibroblast gene program. Currently, we are examining mechanisms of ACLY-dependent chromatin remodeling in fibroblasts and the in vivo relevance of this mechanism in mutant mice. In summary, ACLY is a potential target to reverse cardiac fibrosis and lessen HF.

scholarly journals The Swi/Snf Chromatin Remodeling Complex Is Required for Ribosomal DNA and Telomeric Silencing in Saccharomyces cerevisiae

2004 ◽  
Vol 24 (18) ◽  
pp. 8227-8235 ◽  
Author(s):  
Vardit Dror ◽  
Fred Winston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Ribosomal Dna ◽  
Transcriptional Activation ◽  
Rdna Locus ◽  
Detectable Effect ◽  
Chromatin Remodeling Complex ◽  
Two Factors

ABSTRACT The Swi/Snf chromatin remodeling complex has been previously demonstrated to be required for transcriptional activation and repression of a subset of genes in Saccharomyces cerevisiae. In this work we demonstrate that Swi/Snf is also required for repression of RNA polymerase II-dependent transcription in the ribosomal DNA (rDNA) locus (rDNA silencing). This repression appears to be independent of both Sir2 and Set1, two factors known to be required for rDNA silencing. In contrast to many other rDNA silencing mutants that have elevated levels of rDNA recombination, snf2Δ mutants have a significantly decreased level of rDNA recombination. Additional studies have demonstrated that Swi/Snf is also required for silencing of genes near telomeres while having no detectable effect on silencing of HML or HMR.

scholarly journals A Specificity and Targeting Subunit of a Human SWI/SNF Family-Related Chromatin-Remodeling Complex

2000 ◽  
Vol 20 (23) ◽  
pp. 8879-8888 ◽  
Author(s):  
Zuqin Nie ◽  
Yutong Xue ◽  
Dafeng Yang ◽  
Sharleen Zhou ◽  
Bonnie J. Deroo ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Chromatin Remodeling ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Gene Activation ◽  
Dna Interaction ◽  
Protein Protein Interactions ◽  
Baf Complex ◽  
Chromatin Remodeling Complexes

ABSTRACT The SWI/SNF family of chromatin-remodeling complexes facilitates gene activation by assisting transcription machinery to gain access to targets in chromatin. This family includes BAF (also called hSWI/SNF-A) and PBAF (hSWI/SNF-B) from humans and SWI/SNF and Rsc fromSaccharomyces cerevisiae. However, the relationship between the human and yeast complexes is unclear because all human subunits published to date are similar to those of both yeast SWI/SNF and Rsc. Also, the two human complexes have many identical subunits, making it difficult to distinguish their structures or functions. Here we describe the cloning and characterization of BAF250, a subunit present in human BAF but not PBAF. BAF250 contains structural motifs conserved in yeast SWI1 but not in any Rsc components, suggesting that BAF is related to SWI/SNF. BAF250 is also a homolog of the Drosophila melanogaster Osa protein, which has been shown to interact with a SWI/SNF-like complex in flies. BAF250 possesses at least two conserved domains that could be important for its function. First, it has an AT-rich DNA interaction-type DNA-binding domain, which can specifically bind a DNA sequence known to be recognized by a SWI/SNF family-related complex at the β-globin locus. Second, BAF250 stimulates glucocorticoid receptor-dependent transcriptional activation, and the stimulation is sharply reduced when the C-terminal region of BAF250 is deleted. This region of BAF250 is capable of interacting directly with the glucocorticoid receptor in vitro. Our data suggest that BAF250 confers specificity to the human BAF complex and may recruit the complex to its targets through either protein-DNA or protein-protein interactions.

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