scholarly journals Effects of the SANT Domain of Tension-Induced/Inhibited Proteins (TIPs), Novel Partners of the Histone Acetyltransferase p300, on p300 Activity and TIP-6-Induced Adipogenesis

2008 ◽  
Vol 28 (20) ◽  
pp. 6358-6372 ◽  
Author(s):  
Kameswara Rao Badri ◽  
Yuanxiang Zhou ◽  
Urmil Dhru ◽  
Sreelatha Aramgam ◽  
Lucia Schuger
Keyword(s):  
Histone Acetyltransferase ◽  
De Novo ◽  
Adipogenic Differentiation ◽  
Histone H4 ◽  
Preadipocyte Differentiation ◽  
Transcription Regulators ◽  
Sant Domain ◽  
Adipogenic Gene ◽  
Nih 3T3

ABSTRACT We previously identified a set of transcription regulators, referred to as TIPs (tension-induced/inhibited proteins), with a role in myogenic versus adipogenic differentiation. Here we report that the TIP family comprises eight isoforms, all bearing a SANT (switching-defective protein 3, adaptor 2, nuclear receptor corepressor, and transcription factor IIIB) domain and some of them presenting S-adenosyl-l-methionine (SAM) and nuclear receptor box (NRB) motifs, all characteristic of histone-modifying enzymatic complexes. TIPs have SANT-dependent, p300-mediated histone acetyltransferase (HAT) activity. Ectopic TIP-6 (SANT+ SAM− NRB−) but not TIP-6ΔSANT induced de novo PPARγ2-mediated adipogenic gene expression in NIH 3T3 cells and promoted preadipocyte differentiation into fat cells. TIP-6 was also involved in mediating hormonally/biochemically induced adipogenic differentiation of 3T3-L1 cells. Furthermore, TIP-6 was identified in adipose tissue in vivo. TIP-6 bound directly and indirectly to p300 and histone H4 (H4). Deletion of the SANT domain did not abolish TIP-6 interaction with p300 and H4 but eliminated direct TIP-6 binding to p300. Chromatin immunoprecipitation assays showed the recruitment of TIP-6, TIP-6ΔSANT, and p300 to the PPARγ2 promoter, but H3/H4 acetylation occurred only when p300 was directly associated with TIP-6. These studies demonstrated the importance of TIPs in the recruitment of p300 to specific promoters and in the regulation of p300 HAT activity through the involvement of the SANT domain. Furthermore, we identified TIP-6 as a new member of the adipogenic cascade.

scholarly journals In vivo cycling of the Escherichia coli transcription factor FNR between active and inactive states

Microbiology ◽  
2005 ◽  
Vol 151 (12) ◽  
pp. 4063-4070 ◽  
Author(s):  
David P. Dibden ◽  
Jeffrey Green
Keyword(s):  
Escherichia Coli ◽  
De Novo ◽  
Oxygen Availability ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Fnr Protein ◽  
Transcription Regulators ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

FNR proteins are transcription regulators that sense changes in oxygen availability via assembly–disassembly of [4Fe–4S] clusters. The Escherichia coli FNR protein is present in bacteria grown under aerobic and anaerobic conditions. Under aerobic conditions, FNR is isolated as an inactive monomeric apoprotein, whereas under anaerobic conditions, FNR is present as an active dimeric holoprotein containing one [4Fe–4S] cluster per subunit. It has been suggested that the active and inactive forms of FNR are interconverted in vivo, or that iron–sulphur clusters are mostly incorporated into newly synthesized FNR. Here, experiments using a thermo-inducible fnr expression plasmid showed that a model FNR-dependent promoter is activated under anaerobic conditions by FNR that was synthesized under aerobic conditions. Immunoblots suggested that FNR was more prone to degradation under aerobic compared with anaerobic conditions, and that the ClpXP protease contributes to this degradation. Nevertheless, FNR was sufficiently long lived (half-life under aerobic conditions, ∼45 min) to allow cycling between active and inactive forms. Measuring the abundance of the FNR-activated dms transcript when chloramphenicol-treated cultures were switched between aerobic and anaerobic conditions showed that it increased when cultures were switched to anaerobic conditions, and decreased when aerobic conditions were restored. In contrast, measurement of the abundance of the FNR-repressed ndh transcript under the same conditions showed that it decreased upon switching to anaerobic conditions, and then increased when aerobic conditions were restored. The abundance of the FNR- and oxygen-independent tatE transcript was unaffected by changes in oxygen availability. Thus, the simplest explanation for the observations reported here is that the FNR protein can be switched between inactive and active forms in vivo in the absence of de novo protein synthesis.

scholarly journals Role of an ING1 Growth Regulator in Transcriptional Activation and Targeted Histone Acetylation by the NuA4 Complex

2001 ◽  
Vol 21 (22) ◽  
pp. 7629-7640 ◽  
Author(s):  
Amine Nourani ◽  
Yannick Doyon ◽  
Rhea T. Utley ◽  
Stéphane Allard ◽  
William S. Lane ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transcription Regulation ◽  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Yeast Cells ◽  
Growth Defect ◽  
Histone H4 ◽  
Phd Finger

ABSTRACT The yeast NuA4 complex is a histone H4 and H2A acetyltransferase involved in transcription regulation and essential for cell cycle progression. We identify here a novel subunit of the complex, Yng2p, a plant homeodomain (PHD)-finger protein homologous to human p33/ING1, which has tumor suppressor activity and is essential for p53 function. Mass spectrometry, immunoblotting, and immunoprecipitation experiments confirm the stable stoichiometric association of this protein with purified NuA4. Yeast cells harboring a deletion of theYNG2 gene show severe growth phenotype and have gene-specific transcription defects. NuA4 complex purified from the mutant strain is low in abundance and shows weak histone acetyltransferase activity. We demonstrate conservation of function by the requirement of Yng2p for p53 to function as a transcriptional activator in yeast. Accordingly, p53 interacts with NuA4 in vitro and in vivo, an interaction reminiscent of the p53-ING1 physical link in human cells. The growth defect of Δyng2 cells can be rescued by the N-terminal part of the protein, lacking the PHD-finger. While Yng2 PHD-finger is not required for p53 interaction, it is necessary for full expression of the p53-responsive gene and other NuA4 target genes. Transcriptional activation by p53 in vivo is associated with targeted NuA4-dependent histone H4 hyperacetylation, while histone H3 acetylation levels remain unchanged. These results emphasize the essential role of the NuA4 complex in the control of cell proliferation through gene-specific transcription regulation. They also suggest that regulation of mammalian cell proliferation by p53-dependent transcriptional activation functions through recruitment of an ING1-containing histone acetyltransferase complex.

scholarly journals The Drosophila Histone Acetyltransferase Gcn5 and Transcriptional Adaptor Ada2a Are Involved in Nucleosomal Histone H4 Acetylation

2006 ◽  
Vol 26 (24) ◽  
pp. 9413-9423 ◽  
Author(s):  
Anita Ciurciu ◽  
Orbán Komonyi ◽  
Tibor Pankotai ◽  
Imre M. Boros
Keyword(s):  
Histone Acetyltransferase ◽  
Gene Expression Regulation ◽  
Genetic Interaction ◽  
Histone H4 ◽  
Functional Link ◽  
Developmental Defects ◽  
Histone H4 Acetylation ◽  
Histone Acetyltransferase Gcn5 ◽  
Lysine Residues

ABSTRACT The histone acetyltransferase (HAT) Gcn5 plays a role in chromatin structure and gene expression regulation as a catalytic component of multiprotein complexes, some of which also contain Ada2-type transcriptional coactivators. Data obtained mostly from studies on yeast (Saccharomyces cerevisiae) suggest that Ada2 potentiates Gcn5 activity and substrate recognition. dAda2b, one of two related Ada2 proteins of Drosophila melanogaster, was recently found to play a role in complexes acetylating histone 3 (H3). Evidence of an in vivo functional link between the related coactivator dAda2a and dGcn5, however, is lacking. Here we present data on the genetic interaction of dGcn5 and dAda2a. The loss of either dGcn5 or dAda2a function results in similar chromosome structural and developmental defects. In dAda2a mutants, the nucleosomal H4 acetylation at lysines 12 and 5 is significantly reduced, while the acetylation established by dAda2b-containing Gcn5 complexes at H3 lysines 9 and 14 is unaffected. The data presented here, together with our earlier data on the function of dAda2b, provide evidence that related Ada2 proteins of Drosophila, together with Gcn5 HAT, are involved in the acetylation of specific lysine residues in the N-terminal tails of nucleosomal H3 and H4. Our data suggest dAda2a involvement in both uniformly distributed H4 acetylation and gene-specific transcription regulation.

scholarly journals Methylation-Mediated Proviral Silencing Is Associated with MeCP2 Recruitment and Localized Histone H3 Deacetylation

2001 ◽  
Vol 21 (23) ◽  
pp. 7913-7922 ◽  
Author(s):  
Matthew C. Lorincz ◽  
Dirk Schübeler ◽  
Mark Groudine
Keyword(s):  
Chromatin Immunoprecipitation ◽  
De Novo ◽  
Histone H3 ◽  
Transcriptional Silencing ◽  
Dependent Manner ◽  
Histone H4 ◽  
Acetylation Status ◽  
Murine Leukemia

ABSTRACT The majority of 5-methylcytosine in mammalian DNA resides in endogenous transposable elements and is associated with the transcriptional silencing of these parasitic elements. Methylation also plays an important role in the silencing of exogenous retroviruses. One of the difficulties inherent in the study of proviral silencing is that the sites in which proviruses randomly integrate influence the probability of de novo methylation and expression. In order to compare methylated and unmethylated proviruses at the same genomic site, we used a recombinase-based targeting approach to introduce an in vitro methylated or unmethylated Moloney murine leukemia-based provirus in MEL cells. The methylated and unmethylated states are maintained in vivo, with the exception of the initially methylated proviral enhancer, which becomes demethylated in vivo. Although the enhancer is unmethylated and remodeled, the methylated provirus is transcriptionally silent. To further analyze the repressed state, histone acetylation status was determined by chromatin immunoprecipitation (ChIP) analyses, which revealed that localized histone H3 but not histone H4 hyperacetylation is inversely correlated with proviral methylation density. Since members of the methyl-CpG binding domain (MBD) family of proteins recruit histone deacetylase activity, these proteins may play a role in proviral repression. Interestingly, only MBD3 and MeCP2 are expressed in MEL cells. ChIPs with antibodies specific for these proteins revealed that only MeCP2 associates with the provirus in a methylation-dependent manner. Taken together, our results suggest that MeCP2 recruitment to a methylated provirus is sufficient for transcriptional silencing, despite the presence of a remodeled enhancer.

scholarly journals Mutual Balance of Histone Deacetylases 1 and 2 and the Acetyl Reader ATAD2 Regulates the Level of Acetylation of Histone H4 on Nascent Chromatin of Human Cells

2020 ◽  
Vol 40 (9) ◽  
Author(s):  
Pavlo Lazarchuk ◽  
John Hernandez-Villanueva ◽  
Maria N. Pavlova ◽  
Alexander Federation ◽  
Michael MacCoss ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
De Novo ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Histone H4 ◽  
Wild Type ◽  
Histone Deacetylase 1 ◽  
Replication Fork Progression ◽  
Model Cell

ABSTRACT Newly synthesized histone H4 that is incorporated into chromatin during DNA replication is acetylated on lysines 5 and 12. Histone deacetylase 1 (HDAC1) and HDAC2 are responsible for reducing H4 acetylation as chromatin matures. Using CRISPR-Cas9-generated hdac1- or hdac2-null fibroblasts, we determined that HDAC1 and HDAC2 do not fully compensate for each other in removing de novo acetyls on H4 in vivo. Proteomics of nascent chromatin and proximity ligation assays with newly replicated DNA revealed the binding of ATAD2, a bromodomain-containing posttranslational modification (PTM) reader that recognizes acetylated H4. ATAD2 is a transcription facilitator overexpressed in several cancers and in the simian virus 40 (SV40)-transformed human fibroblast model cell line used in this study. The recruitment of ATAD2 to nascent chromatin was increased in hdac2 cells over the wild type, and ATAD2 depletion reduced the levels of nascent chromatin-associated, acetylated H4 in wild-type and hdac2 cells. We propose that overexpressed ATAD2 shifts the balance of H4 acetylation by protecting this mark from removal and that HDAC2 but not HDAC1 can effectively compete with ATAD2 for the target acetyls. ATAD2 depletion also reduced global RNA synthesis and nascent DNA-associated RNA. A moderate dependence on ATAD2 for replication fork progression was noted only for hdac2 cells overexpressing the protein.

scholarly journals Inhibition of Histone Deacetylation Induces Constitutive Derepression of the Beta Interferon Promoter and Confers Antiviral Activity

2001 ◽  
Vol 75 (7) ◽  
pp. 3444-3452 ◽  
Author(s):  
Elena Shestakova ◽  
Marie-Thérèse Bandu ◽  
Janine Doly ◽  
Eliette Bonnefoy
Keyword(s):  
Virus Infection ◽  
De Novo ◽  
Trichostatin A ◽  
Specific Inhibitor ◽  
Histone Deacetylation ◽  
Histone H4 ◽  
Antiviral State ◽  
Beta Interferon ◽  
Silent State

ABSTRACT The induction of alpha/beta interferon (IFN-α/β) genes constitutes one of the first responses of the cell to virus infection. The IFN-β gene is constitutively repressed in uninfected cells and is transiently activated after virus infection. In this work we demonstrate that histone deacetylation regulates the silent state of the murine IFN-β gene. Using chromatin immunoprecipitation (ChIP) assays, we show a direct in vivo correlation between the transcriptionally silent state and a state of hypoacetylation of histone H4 on the IFN-β promoter region. Trichostatin A (TSA), a specific inhibitor of histone deacetylases, induced strong, constitutive derepression of the murine IFN-β promoter stably integrated into a chromatin context, as well as the hyperacetylation of histone H4, without requiring de novo protein synthesis. We also show in this work that TSA treatment strongly enhances the endogenous IFN level and confers an antiviral state to murine fibroblastic L929 cells. Inhibition of histone deacetylation with TSA protected the cells against the lost of viability induced by vesicular stomatitis virus (VSV) and inhibited VSV multiplication. Using antibodies neutralizing IFN-α/β, we show that the antiviral state induced by TSA is due to TSA-induced IFN production. The demonstration of the predominant role of histone deacetylation during the regulation of the constitutive repressed state of the IFN-β promoter constitutes an interesting advance on the understanding of the negative regulation of this gene and opens up the possibility of new therapeutic perspectives.

scholarly journals A single histone acetyltransferase from Tetrahymena macronuclei catalyzes deposition-related acetylation of free histones and transcription-related acetylation of nucleosomal histones.

1987 ◽  
Vol 105 (1) ◽  
pp. 127-135 ◽  
Author(s):  
L G Chicoine ◽  
R Richman ◽  
R G Cook ◽  
M A Gorovsky ◽  
C D Allis
Keyword(s):  
Enzyme Activity ◽  
Histone Acetylation ◽  
Histone Acetyltransferase ◽  
Histone H3 ◽  
Heat Inactivation ◽  
Histone H4 ◽  
Isolated Nuclei ◽  
Core Histones ◽  
Histone Acetyltransferase Activity

A salt-extracted histone acetyltransferase activity from Tetrahymena macronuclei acetylates mostly histone H3 and H4 when free histones are used as substrate. Free histone H4 is acetylated first at position 11 (monoacetylated) or positions 11 and 4 (diacetylated). This activity strongly resembles in vivo, deposition-related acetylation of newly synthesized histones. When acetylase-free mononucleosomes are used as substrate, all four core histones are acetylated by the same extract, and H4 is acetylated first at position 7 (monoacetylated) or positions 7 and 4 (diacetylated). In this respect, the activity of the extract is indistinguishable from postsynthetic, transcription-related histone acetylation that occurs in vivo or in isolated nuclei. Heat inactivation curves with both substrates are indistinguishable, and free histones compete with chromatin for limiting amounts of enzyme activity. These results argue strongly that two distinct, biologically important histone acetylations, one deposition related and one transcription related, are carried out by a single acetyltransferase.

scholarly journals The SAGA Subunit Ada2 Functions in Transcriptional Silencing

2009 ◽  
Vol 29 (22) ◽  
pp. 6033-6045 ◽  
Author(s):  
Sandra Jacobson ◽  
Lorraine Pillus
Keyword(s):  
Transcriptional Repression ◽  
Histone Acetyltransferase ◽  
Environmental Changes ◽  
Transcriptional Silencing ◽  
Histone H4 ◽  
Nutrient Signaling ◽  
Subtelomeric Regions ◽  
Inducible Gene

ABSTRACT The cellular role of the Ada2 coactivator is currently understood in the context of the SAGA histone acetyltransferase (HAT) complex, where Ada2 increases the HAT activity of Gcn5 and interacts with transcriptional activators. Here we report a new function for Ada2 in promoting transcriptional silencing at telomeres and ribosomal DNA. This silencing function is the first characterized role for Ada2 distinct from its involvement with Gcn5. Ada2 binds telomeric chromatin and the silencing protein Sir2 in vivo. Loss of ADA2 causes the spreading of Sir2 and Sir3 into subtelomeric regions and decreased histone H4 K16 acetylation. This previously uncharacterized boundary activity of Ada2 is functionally similar to, but mechanistically distinct from, that of the MYST family HAT Sas2. Mounting evidence in the literature indicates that boundary activities create chromosomal domains important for regulating gene expression in response to environmental changes. Consistent with this, we show that upon nutritional changes, Ada2 occupancy increases at a subtelomeric region proximal to a SAGA-inducible gene and causes derepression of a silenced telomeric reporter gene. Thus, Ada2, likely in the context of SAGA, is positioned at chromosomal termini to participate in both transcriptional repression and activation in response to nutrient signaling.

Sign in / Sign up

Export Citation Format

Share Document