scholarly journals Plasmodium falciparum Histone Acetyltransferase, a Yeast GCN5 Homologue Involved in Chromatin Remodeling

2004 ◽  
Vol 3 (2) ◽  
pp. 264-276 ◽  
Author(s):  
Qi Fan ◽  
Lijia An ◽  
Liwang Cui
Keyword(s):  
Plasmodium Falciparum ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Northern Analysis ◽  
Binding Assays ◽  
Core Histones ◽  
Chromatin Remodeling Complexes

ABSTRACT The yeast transcriptional coactivator GCN5 (yGCN5), a histone acetyltransferase (HAT), is part of large multimeric complexes that are required for chromatin remodeling and transcriptional activation. Like other eukaryotes, the malaria parasite DNA is organized into nucleosomes and the genome encodes components of chromatin-remodeling complexes. Here we show that GCN5 is conserved in Plasmodium species and that the most homologous regions are within the HAT domain and the bromodomain. The Plasmodium falciparum GCN5 homologue (PfGCN5) is spliced with three introns, encoding a protein of 1,464 residues. Mapping of the ends of the PfGCN5 transcript suggests that the mRNA is 5.2 to 5.4 kb, consistent with the result from Northern analysis. Using free core histones, we determined that recombinant PfGCN5 proteins have conserved HAT activity with a substrate preference for histone H3. Using substrate-specific antibodies, we determined that both Lys-8 and -14 of H3 were acetylated by the recombinant PfGCN5. In eukaryotes, GCN5 homologues interact with yeast ADA2 homologues and form large multiprotein HAT complexes. We have identified an ADA2 homologue in P. falciparum, PfADA2. Yeast two-hybrid and in vitro binding assays verified the interactions between PfGCN5 and PfADA2, suggesting that they may be associated with each other in vivo. The conserved function of the HAT domain in PfGCN5 was further illustrated with yeast complementation experiments, which showed that the PfGCN5 region corresponding to the full-length yGCN5 could partially complement the yGCN5 deletion mutation. Furthermore, a chimera comprising the PfGCN5 HAT domain fused to the remainder of yeast GCN5 (yGCN5) fully rescued the yGCN5 deletion mutant. These data demonstrate that PfGCN5 is an authentic GCN5 family member and may exist in chromatin-remodeling complexes to regulate gene expression in P. falciparum.

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.

scholarly journals Differential Cofactor Requirements for Histone Eviction from Two Nucleosomes at the Yeast PHO84 Promoter Are Determined by Intrinsic Nucleosome Stability

2009 ◽  
Vol 29 (11) ◽  
pp. 2960-2981 ◽  
Author(s):  
Christian J. Wippo ◽  
Bojana Silic Krstulovic ◽  
Franziska Ertel ◽  
Sanja Musladin ◽  
Dorothea Blaschke ◽  
...  
Keyword(s):  
Causal Relationship ◽  
Chromatin Remodeling ◽  
In Silico ◽  
Histone Acetyltransferase ◽  
Promoter Strength ◽  
Histone Acetyltransferase Gcn5 ◽  
Nucleosome Stability

ABSTRACT We showed previously that the strong PHO5 promoter is less dependent on chromatin cofactors than the weaker coregulated PHO8 promoter. In this study we asked if chromatin remodeling at the even stronger PHO84 promoter was correspondingly less cofactor dependent. The repressed PHO84 promoter showed a short hypersensitive region that was flanked upstream and downstream by a positioned nucleosome and contained two transactivator Pho4 sites. Promoter induction generated an extensive hypersensitive and histone-depleted region, yielding two more Pho4 sites accessible. This remodeling was strictly Pho4 dependent, strongly dependent on the remodelers Snf2 and Ino80 and on the histone acetyltransferase Gcn5, and more weakly on the acetyltransferase Rtt109. Importantly, remodeling of each of the two positioned nucleosomes required Snf2 and Ino80 to different degrees. Only remodeling of the upstream nucleosome was strictly dependent on Snf2. Further, remodeling of the upstream nucleosome was more dependent on Ino80 than remodeling of the downstream nucleosome. Both nucleosomes differed in their intrinsic stabilities as predicted in silico and measured in vitro. The causal relationship between the different nucleosome stabilities and the different cofactor requirements was shown by introducing destabilizing mutations in vivo. Therefore, chromatin cofactor requirements were determined by intrinsic nucleosome stabilities rather than correlated to promoter strength.

scholarly journals PCAF Interacts with Tax and Stimulates Tax Transactivation in a Histone Acetyltransferase-Independent Manner

1999 ◽  
Vol 19 (12) ◽  
pp. 8136-8145 ◽  
Author(s):  
Hua Jiang ◽  
Hanxin Lu ◽  
R. Louis Schiltz ◽  
Cynthia A. Pise-Masison ◽  
Vasily V. Ogryzko ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Point Mutations ◽  
Creb Binding Protein ◽  
Independent Manner ◽  
Cell Leukemia Virus Type ◽  
Knock Out ◽  
Human T Cell

ABSTRACT Recent studies have shown that the p300/CREB binding protein (CBP)-associated factor (PCAF) is involved in transcriptional activation. PCAF activity has been shown strongly associated with histone acetyltransferase (HAT) activity. In this report, we present evidence for a HAT-independent transcription function that is activated in the presence of the human T-cell leukemia virus type 1 (HTLV-1) Tax protein. In vitro and in vivo GST-Tax pull-down and coimmunoprecipitation experiments demonstrate that there is a direct interaction between Tax and PCAF, independent of p300/CBP. PCAF can be recruited to the HTLV-1 Tax responsive element in the presence of Tax, and PCAF cooperates with Tax in vivo to activate transcription from the HTLV-1 LTR over 10-fold. Point mutations at Tax amino acid 318 (TaxS318A) or 319 to 320 (Tax M47), which have decreased or no activity on the HTLV-1 promoter, are defective for PCAF binding. Strikingly, the ability of PCAF to stimulate Tax transactivation is not solely dependent on the PCAF HAT domain. Two independent PCAF HAT mutants, which knock out acetyltransferase enzyme activity, activate Tax transactivation to approximately the same level as wild-type PCAF. In contrast, p300 stimulation of Tax transactivation is HAT dependent. These studies provide experimental evidence that PCAF contains a coactivator transcription function independent of the HAT activity on the viral long terminal repeat.

scholarly journals Structure of theArabidopsisTOPLESS corepressor provides insight into the evolution of transcriptional repression

2017 ◽  
Vol 114 (30) ◽  
pp. 8107-8112 ◽  
Author(s):  
Raquel Martin-Arevalillo ◽  
Max H. Nanao ◽  
Antoine Larrieu ◽  
Thomas Vinos-Poyo ◽  
David Mast ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Transcriptional Repression ◽  
Site Directed Mutagenesis ◽  
Crystallographic Structure ◽  
Hormone Signaling ◽  
Chromatin Remodeling Complexes ◽  
Insight Into ◽  
Similar Domain

Transcriptional repression involves a class of proteins called corepressors that link transcription factors to chromatin remodeling complexes. In plants such asArabidopsis thaliana, the most prominent corepressor is TOPLESS (TPL), which plays a key role in hormone signaling and development. Here we present the crystallographic structure of theArabidopsisTPL N-terminal region comprising the LisH and CTLH (C-terminal to LisH) domains and a newly identified third region, which corresponds to a CRA domain. Comparing the structure of TPL with the mammalian TBL1, which shares a similar domain structure and performs a parallel corepressor function, revealed that the plant TPLs have evolved a new tetramerization interface and unique and highly conserved surface for interaction with repressors. Using site-directed mutagenesis, we validated those surfaces in vitro and in vivo and showed that TPL tetramerization and repressor binding are interdependent. Our results illustrate how evolution used a common set of protein domains to create a diversity of corepressors, achieving similar properties with different molecular solutions.

scholarly journals Gal4p-Mediated Chromatin Remodeling Depends on Binding Site Position in Nucleosomes but Does Not Require DNA Replication

1998 ◽  
Vol 18 (3) ◽  
pp. 1201-1212 ◽  
Author(s):  
Mai Xu ◽  
Robert T. Simpson ◽  
Michael P. Kladde
Keyword(s):  
Dna Replication ◽  
Binding Site ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Chromatin Modification ◽  
Factor Binding ◽  
Affect Factor ◽  
Nucleosome Binding

ABSTRACT Biochemical studies have demonstrated decreased binding of various proteins to DNA in nucleosome cores as their cognate sites are moved from the edge of the nucleosome to the pseudodyad (center). However, to date no study has addressed whether this structural characteristic of nucleosomes modulates the function of a transcription factor in living cells, where processes of DNA replication and chromatin modification or remodeling could significantly affect factor binding. Using a sensitive, high-resolution methyltransferase assay, we have monitored the ability of Gal4p in vivo to interact with a nucleosome at positions that are known to be inaccessible in nucleosome cores in vitro. Gal4p efficiently bound a single cognate site (UASG) centered at 41 bp from the edge of a positioned nucleosome, perturbing chromatin structure and inducing transcription. DNA binding and chromatin perturbation accompanying this interaction also occurred in the presence of hydroxyurea, indicating that DNA replication is not necessary for Gal4p-mediated nucleosome disruption. These data extend previous studies, which demonstrated DNA replication-independent chromatin remodeling, by showing that a single dimer of Gal4p, without the benefit of cooperative interactions that occur at complex wild-type promoters, is competent for invasion of a preestablished nucleosome. When the UASG was localized at the nucleosomal pseudodyad, relative occupancy by Gal4p, nucleosome disruption, and transcriptional activation were substantially compromised. Therefore, despite the increased nucleosome binding capability of Gal4p in cells, the precise translational position of a factor binding site in one nucleosome in an array can affect the ability of a transcriptional regulator to overcome the repressive influence of chromatin.

The molecular basis of chromatin dynamics during nucleotide excision repairThis paper is one of a selection of papers published in this Special Issue, entitled 29th Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 87 (1) ◽  
pp. 265-272 ◽  
Author(s):  
Ling Zhang ◽  
Kristi Jones ◽  
Feng Gong
Keyword(s):  
Chromatin Remodeling ◽  
Molecular Basis ◽  
Excision Repair ◽  
Peer Review Process ◽  
Critical Role ◽  
Chromatin Dynamics ◽  
Nucleotide Excision ◽  
Chromatin Remodeling Complexes

The assembly of DNA into chromatin in eukaryotic cells affects all DNA-related cellular activities, such as replication, transcription, recombination, and repair. Rearrangement of chromatin structure during nucleotide excision repair (NER) was discovered more than 2 decades ago. However, the molecular basis of chromatin dynamics during NER remains undefined. Pioneering studies in the field of gene transcription have shown that ATP-dependent chromatin-remodeling complexes and histone-modifying enzymes play a critical role in chromatin dynamics during transcription. Similarly, recent studies have demonstrated that the SWI/SNF chromatin-remodeling complex facilitates NER both in vitro and in vivo. Additionally, histone acetylation has also been linked to the NER of ultraviolet light damage. In this article, we will discuss the role of these identified chromatin-modifying activities in NER.

scholarly journals BZLF1 interacts with chromatin remodelers promoting escape from latent infections with EBV

2019 ◽  
Vol 2 (2) ◽  
pp. e201800108 ◽  
Author(s):  
Marisa Schaeffner ◽  
Paulina Mrozek-Gorska ◽  
Alexander Buschle ◽  
Anne Woellmer ◽  
Takanobu Tagawa ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Nucleosome Occupancy ◽  
Dna Methyltransferases ◽  
Viral Transcription ◽  
Sequence Motifs ◽  
Viral Dna ◽  
Accessible Chromatin

A hallmark of EBV infections is its latent phase, when all viral lytic genes are repressed. Repression results from a high nucleosome occupancy and epigenetic silencing by cellular factors such as the Polycomb repressive complex 2 (PRC2) and DNA methyltransferases that, respectively, introduce repressive histone marks and DNA methylation. The viral transcription factor BZLF1 acts as a molecular switch to induce transition from the latent to the lytic or productive phase of EBV’s life cycle. It is unknown how BZLF1 can bind to the epigenetically silenced viral DNA and whether it directly reactivates the viral genome through chromatin remodeling. We addressed these fundamental questions and found that BZLF1 binds to nucleosomal DNA motifs both in vivo and in vitro. BZLF1 co-precipitates with cellular chromatin remodeler ATPases, and the knock-down of one of them, INO80, impaired lytic reactivation and virus synthesis. In Assay for Transposase-Accessible Chromatin-seq experiments, non-accessible chromatin opens up locally when BZLF1 binds to its cognate sequence motifs in viral DNA. We conclude that BZLF1 reactivates the EBV genome by directly binding to silenced chromatin and recruiting cellular chromatin-remodeling enzymes, which implement a permissive state for lytic viral transcription. BZLF1 shares this mode of action with a limited number of cellular pioneer factors, which are instrumental in transcriptional activation, differentiation, and reprogramming in all eukaryotic cells.

scholarly journals Distinct Domains of Erythroid Krüppel-Like Factor Modulate Chromatin Remodeling and Transactivation at the Endogenous β-Globin Gene Promoter

2002 ◽  
Vol 22 (1) ◽  
pp. 161-170 ◽  
Author(s):  
R. Clark Brown ◽  
Scott Pattison ◽  
Janine van Ree ◽  
Elise Coghill ◽  
Andrew Perkins ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Gene Transcription ◽  
Transcriptional Activation ◽  
Globin Gene ◽  
Regulatory Elements ◽  
Binding Studies ◽  
Amino Terminal ◽  
Cellular Models

ABSTRACT Characterization of the mechanism(s) of action of trans-acting factors in higher eukaryotes requires the establishment of cellular models that test their function at endogenous target gene regulatory elements. Erythroid Krüppel-like factor (EKLF) is essential for β-globin gene transcription. To elucidate the in vivo determinants leading to transcription of the adult β-globin gene, functional domains of EKLF were examined in the context of chromatin remodeling and transcriptional activation at the endogenous locus. Human EKLF (hEKLF) sequences, linked to an estrogen-responsive domain, were studied with an erythroblast cell line lacking endogenous EKLF expression (J2eΔeklf). J2eΔeklf cells transduced with hEKLF demonstrated a dose-dependent rescue of β-globin transcription in the presence of inducing ligand. Further analysis using a series of amino-terminal truncation mutants of hEKLF identified a distinct internal domain, which is sufficient for transactivation. Interestingly, studies of the chromatin structure of the β-promoter revealed that a smaller carboxy-terminal domain generated an open promoter configuration. In vitro and in vivo binding studies demonstrated that this region interacted with BRG1, a component of the SWI/SNF chromatin remodeling complex. However, further study revealed that BRG1 interacted with an even smaller domain of EKLF, suggesting that additional protein interactions are required for chromatin remodeling at the endogenous β-promoter. Taken together, our findings support a stepwise process of chromatin remodeling and coactivator recruitment to the β-globin promoter in vivo. The J2eΔeklf inducible hEKLF system will be a valuable tool for further characterizing the temporal series of events required for endogenous β-globin gene transcription.

scholarly journals Histone acetyltransferase activity is conserved between yeast and human GCN5 and is required for complementation of growth and transcriptional activation.

1997 ◽  
Vol 17 (1) ◽  
pp. 519-527 ◽  
Author(s):  
L Wang ◽  
C Mizzen ◽  
C Ying ◽  
R Candau ◽  
N Barlev ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Evolutionary Conservation ◽  
Enzymatic Modification ◽  
Basal Transcriptional Machinery ◽  
Physical Interactions ◽  
Substitution Mutation ◽  
Histone Acetyltransferase Activity

Yeast and human ADA2 and GCN5 (y- and hADA2 and y- and hGCN5, respectively) have been shown to potentiate transcription in vivo and may function as adaptors to bridge physical interactions between DNA-bound activators and the basal transcriptional machinery. Recently it was shown that yGCN5 is a histone acetyltransferase (HAT), suggesting a link between enzymatic modification of nucleosomes and transcriptional activation. In this report, we demonstrate that hGCN5 is also an HAT and has the same substrate specificity as yGCN5. Since hGCN5 does not complement functional defects caused by deletion of yGCN5, we constructed a series of hGCN5-yGCN5 chimeras to identify human regions capable of activity in yeast. Interestingly, only the putative HAT domain of hGCN5, when fused to the remainder of yGCN5, complemented gcn5- cells for growth and transcriptional activation. Moreover, an amino acid substitution mutation within the HAT domain reduced both HAT activity in vitro and transcription in vivo. These findings directly link enzymatic histone acetylation and transcriptional activation and show evolutionary conservation of this potentially crucial pathway in gene regulation.

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