1
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Struhl K. Non-canonical functions of enhancers: regulation of RNA polymerase III transcription, DNA replication, and V(D)J recombination. Trends Genet 2024:S0168-9525(24)00075-1. [PMID: 38643034 DOI: 10.1016/j.tig.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/02/2024] [Indexed: 04/22/2024]
Abstract
Enhancers are the key regulators of other DNA-based processes by virtue of their unique ability to generate nucleosome-depleted regions in a highly regulated manner. Enhancers regulate cell-type-specific transcription of tRNA genes by RNA polymerase III (Pol III). They are also responsible for the binding of the origin replication complex (ORC) to DNA replication origins, thereby regulating origin utilization, replication timing, and replication-dependent chromosome breaks. Additionally, enhancers regulate V(D)J recombination by increasing access of the recombination-activating gene (RAG) recombinase to target sites and by generating non-coding enhancer RNAs and localized regions of trimethylated histone H3-K4 recognized by the RAG2 PHD domain. Thus, enhancers represent the first step in decoding the genome, and hence they regulate biological processes that, unlike RNA polymerase II (Pol II) transcription, do not have dedicated regulatory proteins.
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Affiliation(s)
- Kevin Struhl
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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2
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Dickson BM, Kupai A, Vaughan RM, Rothbart SB. Streamlined quantitative analysis of histone modification abundance at nucleosome-scale resolution with siQ-ChIP version 2.0. Sci Rep 2023; 13:7508. [PMID: 37160995 PMCID: PMC10169836 DOI: 10.1038/s41598-023-34430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/29/2023] [Indexed: 05/11/2023] Open
Abstract
We recently introduced an absolute and physical quantitative scale for chromatin immunoprecipitation followed by sequencing (ChIP-seq). The scale itself was determined directly from measurements routinely made on sequencing samples without additional reagents or spike-ins. We called this approach sans spike-in quantitative ChIP, or siQ-ChIP. Herein, we extend those results in several ways. First, we simplified the calculations defining the quantitative scale, reducing practitioner burden. Second, we reveal a normalization constraint implied by the quantitative scale and introduce a new scheme for generating 'tracks'. The constraint requires that tracks are probability distributions so that quantified ChIP-seq is analogous to a mass distribution. Third, we introduce some whole-genome analyses that allow us, for example, to project the IP mass (immunoprecipitated mass) onto the genome to evaluate how much of any genomic interval was captured in the IP. We applied siQ-ChIP to p300/CBP inhibition and compare our results to those of others. We detail how the same data-level observations are misinterpreted in the literature when tracks are not understood as probability densities and are compared without correct quantitative scaling, and we offer new interpretations of p300/CBP inhibition outcomes.
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Affiliation(s)
- Bradley M Dickson
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503, USA.
| | - Ariana Kupai
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503, USA
| | - Robert M Vaughan
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503, USA
- Department of Pediatrics and Human Development, Michigan State University, Grand Rapids, MI, USA
| | - Scott B Rothbart
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503, USA.
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3
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González L, Kolbin D, Trahan C, Jeronimo C, Robert F, Oeffinger M, Bloom K, Michnick SW. Adaptive partitioning of a gene locus to the nuclear envelope in Saccharomyces cerevisiae is driven by polymer-polymer phase separation. Nat Commun 2023; 14:1135. [PMID: 36854718 PMCID: PMC9975218 DOI: 10.1038/s41467-023-36391-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/30/2023] [Indexed: 03/03/2023] Open
Abstract
Partitioning of active gene loci to the nuclear envelope (NE) is a mechanism by which organisms increase the speed of adaptation and metabolic robustness to fluctuating resources in the environment. In the yeast Saccharomyces cerevisiae, adaptation to nutrient depletion or other stresses, manifests as relocalization of active gene loci from nucleoplasm to the NE, resulting in more efficient transport and translation of mRNA. The mechanism by which this partitioning occurs remains a mystery. Here, we demonstrate that the yeast inositol depletion-responsive gene locus INO1 partitions to the nuclear envelope, driven by local histone acetylation-induced polymer-polymer phase separation from the nucleoplasmic phase. This demixing is consistent with recent evidence for chromatin phase separation by acetylation-mediated dissolution of multivalent histone association and fits a physical model where increased bending stiffness of acetylated chromatin polymer causes its phase separation from de-acetylated chromatin. Increased chromatin spring stiffness could explain nucleation of transcriptional machinery at active gene loci.
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Affiliation(s)
- Lidice González
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, QC, H3C 3J7, Canada
| | - Daniel Kolbin
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Christian Trahan
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Célia Jeronimo
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC, H3A 1A3, Canada
- Département de Médecine, Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, QC, H3T 1J4, Canada
| | - Marlene Oeffinger
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, QC, H3C 3J7, Canada
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Stephen W Michnick
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, QC, H3C 3J7, Canada.
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4
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Hu Y, Liu Z, Xu S, Zhao Q, Liu G, Song X, Qu Y, Qin Y. The interaction between the histone acetyltransferase complex Hat1-Hat2 and transcription factor AmyR provides a molecular brake to regulate amylase gene expression. Mol Microbiol 2023; 119:471-491. [PMID: 36760021 DOI: 10.1111/mmi.15036] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 01/15/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023]
Abstract
The chromatin structure is generally regulated by chromatin remodelers and histone modifiers, which affect DNA replication, repair, and levels of transcription. The first identified histone acetyltransferase was Hat1/KAT1, which belongs to lysine (K) acetyltransferases. The catalytic subunit Hat1 and the regulatory subunit Hat2 make up the core HAT1 complex. In this study, the results of tandem affinity purification and mass spectrometry and bimolecular fluorescence complementation proved that the Penicillium oxalicum PoHat1-Hat2 is the transcriptional cofactor of the sequence-specific transcription factor PoAmyR, a transcription activator essential for the transcription of amylase gene. ChIP-qPCR results demonstrated that the complex PoHat1-Hat2 is recruited by PoAmyR to the promoters of prominent amylase genes Poamy13A and Poamy15A and performs histone H4 lysine12 acetylation. The result of the yeast two-hybrid test indicated that PoHat2 is the subunit that directly interacts with PoAmyR. PoHat1-Hat2 acts as the molecular brake of the PoAmyR-regulating transcription of amylase genes. A putative model for amylase gene regulation by PoAmyR-Hat2-Hat1 was constructed. Our paper is the first report that the Hat1-Hat2 complex acts as a cofactor for sequence-specific TF to regulate gene expression and explains the mechanism of TF AmyR regulating amylase genes expression.
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Affiliation(s)
- Yueyan Hu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China.,Shandong Lishan Biotechnology Co., Ltd, Jinan, China
| | - Zhongjiao Liu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Shaohua Xu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Qinqin Zhao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guodong Liu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
| | - Xin Song
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
| | - Yinbo Qu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
| | - Yuqi Qin
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.,Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China.,NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
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5
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Zaheri B, Morse D. An overview of transcription in dinoflagellates. Gene 2022; 829:146505. [PMID: 35447242 DOI: 10.1016/j.gene.2022.146505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 02/18/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022]
Abstract
Dinoflagellates are a vital diverse family of unicellular algae widespread in various aquatic environments. Typically large genomes and permanently condensed chromosomes without histones make these organisms unique among eukaryotes in terms of chromatin structure and gene expression. Genomic and transcriptomic sequencing projects have provided new insight into the genetic foundation of dinoflagellate behaviors. Genes in tandem arrays, trans-splicing of mRNAs and lower levels of transcriptional regulation compared to other eukaryotes all contribute to the differences seen. Here we present a general overview of transcription in dinoflagellates based on previously described work.
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Affiliation(s)
- Bahareh Zaheri
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, 4101 Sherbrooke est, Université de Montréal, Montréal H1X 2B2, Canada
| | - David Morse
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, 4101 Sherbrooke est, Université de Montréal, Montréal H1X 2B2, Canada.
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6
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Gu Q, Wang Y, Zhao X, Yuan B, Zhang M, Tan Z, Zhang X, Chen Y, Wu H, Luo Y, Keller NP, Gao X, Ma Z. Inhibition of histone acetyltransferase GCN5 by a transcription factor FgPacC controls fungal adaption to host-derived iron stress. Nucleic Acids Res 2022; 50:6190-6210. [PMID: 35687128 PMCID: PMC9226496 DOI: 10.1093/nar/gkac498] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 05/19/2022] [Accepted: 05/27/2022] [Indexed: 02/07/2023] Open
Abstract
Poaceae plants can locally accumulate iron to suppress pathogen infection. It remains unknown how pathogens overcome host-derived iron stress during their successful infections. Here, we report that Fusarium graminearum (Fg), a destructive fungal pathogen of cereal crops, is challenged by host-derived high-iron stress. Fg infection induces host alkalinization, and the pH-dependent transcription factor FgPacC undergoes a proteolytic cleavage into the functional isoform named FgPacC30 under alkaline host environment. Subsequently FgPacC30 binds to a GCCAR(R = A/G)G element at the promoters of the genes involved in iron uptake and inhibits their expression, leading to adaption of Fg to high-iron stress. Mechanistically, FgPacC30 binds to FgGcn5 protein, a catalytic subunit of Spt-Ada-Gcn5 Acetyltransferase (SAGA) complex, leading to deregulation of histone acetylation at H3K18 and H2BK11, and repression of iron uptake genes. Moreover, we identified a protein kinase FgHal4, which is highly induced by extracellular high-iron stress and protects FgPacC30 against 26S proteasome-dependent degradation by promoting FgPacC30 phosphorylation at Ser2. Collectively, this study uncovers a novel inhibitory mechanism of the SAGA complex by a transcription factor that enables a fungal pathogen to adapt to dynamic microenvironments during infection.
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Affiliation(s)
- Qin Gu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Yujie Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Xiaozhen Zhao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Bingqin Yuan
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Mengxuan Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Zheng Tan
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Xinyue Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Huijun Wu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Yuming Luo
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, Huaiyin Normal University, Huai'an, China
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Xuewen Gao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing, China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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7
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Deshpande N, Jordan R, Henderson Pozzi M, Bryk M. Histone 3 lysine 4 monomethylation supports activation of transcription in S. cerevisiae during nutrient stress. Curr Genet 2022; 68:181-194. [PMID: 35041077 PMCID: PMC8976815 DOI: 10.1007/s00294-022-01226-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 12/17/2021] [Accepted: 12/31/2021] [Indexed: 12/11/2022]
Abstract
Mono-methylation of the fourth lysine on the N-terminal tail of histone H3 was found to support the induction of RNA polymerase II transcription in S. cerevisiae during nutrient stress. In S. cerevisiae, the mono-, di- and tri-methylation of lysine 4 on histone H3 (H3K4) is catalyzed by the protein methyltransferase, Set1. The three distinct methyl marks on H3K4 act in discrete ways to regulate transcription. Nucleosomes enriched with tri-methylated H3K4 are usually associated with active transcription whereas di-methylated H3K4 is associated with gene repression. Mono-methylated H3K4 has been shown to repress gene expression in S. cerevisiae and is detected at enhancers and promoters in eukaryotes. S. cerevisiae set1Δ mutants unable to methylate H3K4 exhibit growth defects during histidine starvation. The growth defects are rescued by either a wild-type allele of SET1 or partial-function alleles of set1, including a mutant that predominantly generates H3K4me1 and not H3K4me3. Rescue of the growth defect is associated with induction of the HIS3 gene. Growth defects observed when set1Δ cultures were starved for isoleucine and valine were also rescued by wild-type SET1 or partial-function set1 alleles. The results show that H3K4me1, in the absence of H3K4me3, supports transcription of the HIS3 gene and expression of one or more of the genes required for biosynthesis of isoleucine and valine during nutrient stress. Set1-like methyltransferases are evolutionarily conserved, and research has linked their functions to developmental gene regulation and several cancers in higher eukaryotes. Identification of mechanisms of H3K4me1-mediated activation of transcription in budding yeast will provide insight into gene regulation in all eukaryotes.
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Affiliation(s)
- Neha Deshpande
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Rachel Jordan
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
- iBio, 8800 HSC Blvd, Bryan, TX, 77807, USA
| | - Michelle Henderson Pozzi
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Mary Bryk
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA.
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8
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Li J, Guo C, Rood C, Zhang J. A C terminus-dependent conformational change is required for HDAC3 activation by nuclear receptor corepressors. J Biol Chem 2021; 297:101192. [PMID: 34520758 PMCID: PMC8502911 DOI: 10.1016/j.jbc.2021.101192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/30/2021] [Accepted: 09/10/2021] [Indexed: 11/21/2022] Open
Abstract
Histone deacetylase 3 (HDAC3) plays an important role in signal-dependent transcription and is dysregulated in diseases such as cancer. Previous studies have shown that the function of HDAC3 requires an activation step, which is mediated by the interactions of HDAC3 with the deacetylase-activation domain (DAD) of nuclear receptor corepressors and inositol tetraphosphate (IP4). However, the role of the unique HDAC3 C-terminal region in HDAC3 activation is elusive. Here multiple biochemical, structural, and functional studies show that HDAC3 activation requires a priming step mediated by the C terminus to remodel HDAC3 conformation. We show that multiple C-terminal mutations prevent HDAC3 activation by preventing this C terminus–dependent conformational change. Mechanistically, we demonstrate that the C terminus–mediated function in altering HDAC3 conformation is required for proper complex formation of HDAC3 with DAD and IP4 by allowing HDAC3 to undergo IP4-dependent interaction with DAD. Remarkably, we found that this C terminus function is conformation dependent, being necessary for HDAC3 activation prior to but not after the conformational change. Together, our study defines two functional states of free HDAC3, reveals the complete HDAC3 activation pathway, and links the C terminus function to the specific interaction between HDAC3 and DAD. These results also have implications in how signaling pathways may converge on the C terminus to regulate HDAC3 and suggest that the C terminus–mediated conformational change could represent a new target for inhibiting HDAC3 in diseases such as cancer.
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Affiliation(s)
- Jian Li
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Chun Guo
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Christopher Rood
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA
| | - Jinsong Zhang
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St Louis, Missouri, USA.
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9
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Pinto D, Pagé V, Fisher RP, Tanny JC. New connections between ubiquitylation and methylation in the co-transcriptional histone modification network. Curr Genet 2021; 67:695-705. [PMID: 34089069 DOI: 10.1007/s00294-021-01196-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 01/01/2023]
Abstract
Co-transcriptional histone modifications are a ubiquitous feature of RNA polymerase II (RNAPII) transcription, with profound but incompletely understood effects on gene expression. Unlike the covalent marks found at promoters, which are thought to be instructive for transcriptional activation, these modifications occur in gene bodies as a result of transcription, which has made elucidation of their functions challenging. Here we review recent insights into the regulation and roles of two such modifications: monoubiquitylation of histone H2B at lysine 120 (H2Bub1) and methylation of histone H3 at lysine 36 (H3K36me). Both H2Bub1 and H3K36me are enriched in the coding regions of transcribed genes, with highly overlapping distributions, but they were thought to work largely independently. We highlight our recent demonstration that, as was previously shown for H3K36me, H2Bub1 signals to the histone deacetylase (HDAC) complex Rpd3S/Clr6-CII, and that Rpd3S/Clr6-CII and H2Bub1 function in the same pathway to repress aberrant antisense transcription initiating within gene coding regions. Moreover, both of these histone modification pathways are influenced by protein phosphorylation catalyzed by the cyclin-dependent kinases (CDKs) that regulate RNAPII elongation, chiefly Cdk9. Therefore, H2Bub1 and H3K36me are more tightly linked than previously thought, sharing both upstream regulatory inputs and downstream effectors. Moreover, these newfound connections suggest extensive, bidirectional signaling between RNAPII elongation complexes and chromatin-modifying enzymes, which helps to determine transcriptional outputs and should be a focus for future investigation.
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Affiliation(s)
- Daniel Pinto
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Vivane Pagé
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Robert P Fisher
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Jason C Tanny
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
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10
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Culbertson SJ, Shogren-Knaak MA. Mechanisms of stimulation of SAGA-mediated nucleosome acetylation by a transcriptional activator. Biochem Biophys Rep 2021; 25:100884. [PMID: 33437882 PMCID: PMC7786029 DOI: 10.1016/j.bbrep.2020.100884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 11/06/2020] [Accepted: 12/18/2020] [Indexed: 12/02/2022] Open
Abstract
Eukaryotic gene expression requires the coordination of multiple factors to overcome the repressive nature of chromatin. However, the mechanistic details of this coordination are not well understood. The SAGA family of transcriptional coactivators interacts with DNA-binding activators to establish regions of hyperacetylation. We have previously shown that, contrary to the prevailing model in which activator protein increases SAGA affinity for nucleosome substrate, the Gal4-VP16 activator model system augments the rate of acetylation turnover for the SAGA complex from budding yeast. To better understand how this stimulation occurs, we have identified necessary components using both kinetics assays and binding interactions studies. We find that Gal4-VP16-mediated stimulation requires activator binding to DNA flanking the nucleosome, as it cannot be reproduced in trans by activator protein alone or by exogenous DNA containing the activator binding site in combination with the activator protein. Further, activator-mediated stimulation requires subunits outside of the histone acetylation (HAT) module, with the Tra1 subunit being responsible for the majority of the stimulation. Interestingly, for the HAT module alone, nucleosome acetylation is inhibited by activator proteins due to non-specific binding of the activator to the nucleosomes. This inhibition is not observed for the yeast ADA complex, a small complex comprised mostly of the HAT module, suggesting that subunits outside of the HAT module in both it and SAGA can overcome non-specific activator binding to nucleosomes. However, this activity appears distinct from activator-mediated stimulation, as ADA complex acetylation is not stimulated by Gal4-VP16. Stimulation of nucleosome acetylation by SAGA requires activator in cis Tra1 mediates the majority of activator stimulation The core HAT complex of SAGA is inhibited by activator due to non-specific binding The related ADA complex is neither stimulated nor inhibited by activator
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Affiliation(s)
- Sannie J Culbertson
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, United States
| | - Michael A Shogren-Knaak
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, United States
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11
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Rawat M, Kanyal A, Sahasrabudhe A, Vembar SS, Lopez-Rubio JJ, Karmodiya K. Histone acetyltransferase PfGCN5 regulates stress responsive and artemisinin resistance related genes in Plasmodium falciparum. Sci Rep 2021; 11:852. [PMID: 33441725 PMCID: PMC7806804 DOI: 10.1038/s41598-020-79539-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
Plasmodium falciparum has evolved resistance to almost all front-line drugs including artemisinin, which threatens malaria control and elimination strategies. Oxidative stress and protein damage responses have emerged as key players in the generation of artemisinin resistance. In this study, we show that PfGCN5, a histone acetyltransferase, binds to the stress-responsive genes in a poised state and regulates their expression under stress conditions. Furthermore, we show that upon artemisinin exposure, genome-wide binding sites for PfGCN5 are increased and it is directly associated with the genes implicated in artemisinin resistance generation like BiP and TRiC chaperone. Interestingly, expression of genes bound by PfGCN5 was found to be upregulated during stress conditions. Moreover, inhibition of PfGCN5 in artemisinin-resistant parasites increases the sensitivity of the parasites to artemisinin treatment indicating its role in drug resistance generation. Together, these findings elucidate the role of PfGCN5 as a global chromatin regulator of stress-responses with a potential role in modulating artemisinin drug resistance and identify PfGCN5 as an important target against artemisinin-resistant parasites.
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Affiliation(s)
- Mukul Rawat
- Department of Biology, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411 008, India
| | - Abhishek Kanyal
- Department of Biology, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411 008, India
| | - Aishwarya Sahasrabudhe
- Department of Biology, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411 008, India
| | | | - Jose-Juan Lopez-Rubio
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, INSERM, Montpellier University, Montpellier, France
| | - Krishanpal Karmodiya
- Department of Biology, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411 008, India.
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12
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Mittal C, Culbertson SJ, Shogren-Knaak MA. Distinct requirements of linker DNA and transcriptional activators in promoting SAGA-mediated nucleosome acetylation. J Biol Chem 2018; 293:13736-13749. [PMID: 30054274 DOI: 10.1074/jbc.ra118.004487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/20/2018] [Indexed: 01/08/2023] Open
Abstract
The Spt-Ada-Gcn5 acetyltransferase (SAGA) family of transcriptional coactivators are prototypical nucleosome acetyltransferase complexes that regulate multiple steps in gene transcription. The size and complexity of both the SAGA enzyme and the chromatin substrate provide numerous opportunities for regulating the acetylation process. To better probe this regulation, here we developed a bead-based nucleosome acetylation assay to characterize the binding interactions and kinetics of acetylation with different nucleosomal substrates and the full SAGA complex purified from budding yeast (Saccharomyces cerevisiae). We found that SAGA-mediated nucleosome acetylation is stimulated up to 9-fold by DNA flanking the nucleosome, both by facilitating the binding of SAGA and by accelerating acetylation turnover. This stimulation required that flanking DNA is present on both sides of the nucleosome and that one side is >15 bp long. The Gal4-VP16 transcriptional activator fusion protein could also augment nucleosome acetylation up to 5-fold. However, contrary to our expectations, this stimulation did not appear to occur by stabilizing the binding of SAGA toward nucleosomes containing an activator-binding site. Instead, increased acetylation turnover by SAGA stimulated nucleosome acetylation. These results suggest that the Gal4-VP16 transcriptional activator directly stimulates acetylation via a dual interaction with both flanking DNA and SAGA. Altogether, these findings uncover several critical mechanisms of SAGA regulation by chromatin substrates.
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Affiliation(s)
- Chitvan Mittal
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - Sannie J Culbertson
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - Michael A Shogren-Knaak
- From the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
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13
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Simpson K, Fuentes P, Quiroz-Iturra LF, Flores-Ortiz C, Contreras R, Handford M, Stange C. Unraveling the induction of phytoene synthase 2 expression by salt stress and abscisic acid in Daucus carota. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4113-4126. [PMID: 29860511 PMCID: PMC6054239 DOI: 10.1093/jxb/ery207] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/21/2018] [Indexed: 05/09/2023]
Abstract
Phytoene synthase (PSY) is the first committed enzyme of the carotenoid biosynthesis pathway and the most important point of regulation. Carotenoids are precursors of abscisic acid (ABA), which mediates abiotic stress tolerance responses in plants. ABA activates the synthesis of its own precursors through induction of PSY expression. Carrot, a species that accumulates very high amounts of carotenoids in its reserve root, has two PSY paralog genes that are expressed differentially in the root. Here, we determined that DcPSY2 expression is induced by salt stress and ABA. A DcPSY2 promoter fragment was obtained and characterized. Bioinformatic analysis showed the presence of three ABA responsive elements (ABREs). Through overexpressing pPSY2:GFP in Nicotiana tabacum we determined that all three ABREs are necessary for the ABA response. In the carrot transcriptome, we identified three ABRE binding protein (DcAREB) transcription factor candidates that localized in the nucleus, but only one, DcAREB3, was induced under ABA treatment in carrot roots. We found that AREB transcription factors bind to the carrot DcPSY2 promoter and transactivate the expression of reporter genes. We conclude that DcPSY2 is involved in ABA-mediated salt stress tolerance in carrot through the binding of AREB transcription factors to its promoter.
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Affiliation(s)
- Kevin Simpson
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
| | - Paulina Fuentes
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
| | - Luis Felipe Quiroz-Iturra
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
| | - Carlos Flores-Ortiz
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
| | - Rodrigo Contreras
- Laboratorio de Fisiología y Biotecnología Vegetal, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Michael Handford
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
| | - Claudia Stange
- Laboratorio de Biología Molecular Vegetal, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Ñuñoa, Santiago, Chile
- Correspondence:
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14
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Qi S, He L, Zhang Q, Dong Q, Wang Y, Yang Q, Tian C, He Q, Wang Y. Cross-pathway control gene CPC1/GCN4 coordinates with histone acetyltransferase GCN5 to regulate catalase-3 expression under oxidative stress in Neurospora crassa. Free Radic Biol Med 2018; 117:218-227. [PMID: 29421311 DOI: 10.1016/j.freeradbiomed.2018.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/04/2018] [Accepted: 02/02/2018] [Indexed: 12/16/2022]
Abstract
Catalase is an important enzyme found in nearly all aerobic organisms and plays an essential role in protecting cells from oxidative damage by catalyzing the degradation of hydrogen peroxide into water and oxygen. In filamentous fungus Neurospora crassa, the expression levels of catalases are rigorously regulated by morphogenetic transition during growth and development in cells. Our study revealed that catalase-3 transcription is positively regulated by histone acetyltransferase GCN5 and the cross-pathway control gene cpc-1, as the cat-3 expression level is significantly decreased in gcn5KO and cpc-1 (j-5) mutants. Moreover, gcn5KO and cpc-1 (j-5) mutants could not respond to H2O2 treatment due to the inadequate cat-3 transcription, while wild-type strains showed high expression levels of catalase upon H2O2 treatment. The global H3 acetylation and the acetylation of H3 at cat-3 locus dramatically decreased in gcn5KO under normal or oxidative stress conditions. Meanwhile, the expression of CAT-3 is reduced in gcn5E146Q, the catalytically dead mutant, suggesting that the catalytic activity of GCN5 functions in regulation of cat-3 transcription. In addition, GCN5 cannot acetylate histone H3 efficiently at cat-3 locus in cpc-1 (j-5) mutant strains under normal or oxidative stress conditions. Furthermore, ChIP assays data revealed that the CPC1/GCN4 can directly target the cat-3 promoter region, which may recruit GCN5 to modify the histone acetylation of this region. These results disclosed a distinctive function of CPC1/GCN4 in the regulatory pathway of cat-3 transcription, which is mediated by GCN5-dependent acetylation.
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Affiliation(s)
- Shaohua Qi
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Lingaonan He
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qin Zhang
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qing Dong
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yajun Wang
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qiuying Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chaoguang Tian
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Qun He
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ying Wang
- State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
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15
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Martel A, Brar H, Mayer BF, Charron JB. Diversification of the Histone Acetyltransferase GCN5 through Alternative Splicing in Brachypodium distachyon. FRONTIERS IN PLANT SCIENCE 2017; 8:2176. [PMID: 29312415 PMCID: PMC5743026 DOI: 10.3389/fpls.2017.02176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
The epigenetic modulatory SAGA complex is involved in various developmental and stress responsive pathways in plants. Alternative transcripts of the SAGA complex's enzymatic subunit GCN5 have been identified in Brachypodium distachyon. These splice variants differ based on the presence and integrity of their conserved domain sequences: the histone acetyltransferase domain, responsible for catalytic activity, and the bromodomain, involved in acetyl-lysine binding and genomic loci targeting. GCN5 is the wild-type transcript, while alternative splice sites result in the following transcriptional variants: L-GCN5, which is missing the bromodomain and S-GCN5, which lacks the bromodomain as well as certain motifs of the histone acetyltransferase domain. Absolute mRNA quantification revealed that, across eight B. distachyon accessions, GCN5 was the dominant transcript isoform, accounting for up to 90% of the entire transcript pool, followed by L-GCN5 and S-GCN5. A cycloheximide treatment further revealed that the S-GCN5 splice variant was degraded through the nonsense-mediated decay pathway. All alternative BdGCN5 transcripts displayed similar transcript profiles, being induced during early exposure to heat and displaying higher levels of accumulation in the crown, compared to aerial tissues. All predicted protein isoforms localize to the nucleus, which lends weight to their purported epigenetic functions. S-GCN5 was incapable of forming an in vivo protein interaction with ADA2, the transcriptional adaptor that links the histone acetyltransferase subunit to the SAGA complex, while both GCN5 and L-GCN5 interacted with ADA2, which suggests that a complete histone acetyltransferase domain is required for BdGCN5-BdADA2 interaction in vivo. Thus, there has been a diversification in BdGCN5 through alternative splicing that has resulted in differences in conserved domain composition, transcript fate and in vivo protein interaction partners. Furthermore, our results suggest that B. distachyon may harbor compositionally distinct SAGA-like complexes that differ based on their histone acetyltransferase subunit.
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16
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Translation Initiation from Conserved Non-AUG Codons Provides Additional Layers of Regulation and Coding Capacity. mBio 2017; 8:mBio.00844-17. [PMID: 28655822 PMCID: PMC5487733 DOI: 10.1128/mbio.00844-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neurospora crassa cpc-1 and Saccharomyces cerevisiae GCN4 are homologs specifying transcription activators that drive the transcriptional response to amino acid limitation. The cpc-1 mRNA contains two upstream open reading frames (uORFs) in its >700-nucleotide (nt) 5′ leader, and its expression is controlled at the level of translation in response to amino acid starvation. We used N. crassa cell extracts and obtained data indicating that cpc-1 uORF1 and uORF2 are functionally analogous to GCN4 uORF1 and uORF4, respectively, in controlling translation. We also found that the 5′ region upstream of the main coding sequence of the cpc-1 mRNA extends for more than 700 nucleotides without any in-frame stop codon. For 100 cpc-1 homologs from Pezizomycotina and from selected Basidiomycota, 5′ conserved extensions of the CPC1 reading frame are also observed. Multiple non-AUG near-cognate codons (NCCs) in the CPC1 reading frame upstream of uORF2, some deeply conserved, could potentially initiate translation. At least four NCCs initiated translation in vitro. In vivo data were consistent with initiation at NCCs to produce N-terminally extended N. crassa CPC1 isoforms. The pivotal role played by CPC1, combined with its translational regulation by uORFs and NCC utilization, underscores the emerging significance of noncanonical initiation events in controlling gene expression. There is a deepening and widening appreciation of the diverse roles of translation in controlling gene expression. A central fungal transcription factor, the best-studied example of which is Saccharomyces cerevisiae GCN4, is crucial for the response to amino acid limitation. Two upstream open reading frames (uORFs) in the GCN4 mRNA are critical for controlling GCN4 synthesis. We observed that two uORFs in the corresponding Neurospora crassa cpc-1 mRNA appear functionally analogous to the GCN4 uORFs. We also discovered that, surprisingly, unlike GCN4, the CPC1 coding sequence extends far upstream from the presumed AUG start codon with no other in-frame AUG codons. Similar extensions were seen in homologs from many filamentous fungi. We observed that multiple non-AUG near-cognate codons (NCCs) in this extended reading frame, some conserved, initiated translation to produce longer forms of CPC1, underscoring the significance of noncanonical initiation in controlling gene expression.
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17
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Cui Y, Ling Y, Zhou J, Li X. Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast. PLoS One 2015; 10:e0145661. [PMID: 26710276 PMCID: PMC4692408 DOI: 10.1371/journal.pone.0145661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/07/2015] [Indexed: 12/17/2022] Open
Abstract
Histone deacetylase (HDAC) is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA) and sodium butyrate (NaB) to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components.
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Affiliation(s)
- Yaning Cui
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yu Ling
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Junhui Zhou
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiaojuan Li
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
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18
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Qiu H, Chereji RV, Hu C, Cole HA, Rawal Y, Clark DJ, Hinnebusch AG. Genome-wide cooperation by HAT Gcn5, remodeler SWI/SNF, and chaperone Ydj1 in promoter nucleosome eviction and transcriptional activation. Genome Res 2015; 26:211-25. [PMID: 26602697 PMCID: PMC4728374 DOI: 10.1101/gr.196337.115] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/18/2015] [Indexed: 12/27/2022]
Abstract
Chaperones, nucleosome remodeling complexes, and histone acetyltransferases have been implicated in nucleosome disassembly at promoters of particular yeast genes, but whether these cofactors function ubiquitously, as well as the impact of nucleosome eviction on transcription genome-wide, is poorly understood. We used chromatin immunoprecipitation of histone H3 and RNA polymerase II (Pol II) in mutants lacking single or multiple cofactors to address these issues for about 200 genes belonging to the Gcn4 transcriptome, of which about 70 exhibit marked reductions in H3 promoter occupancy on induction by amino acid starvation. Examining four target genes in a panel of mutants indicated that SWI/SNF, Gcn5, the Hsp70 cochaperone Ydj1, and chromatin-associated factor Yta7 are required downstream from Gcn4 binding, whereas Asf1/Rtt109, Nap1, RSC, and H2AZ are dispensable for robust H3 eviction in otherwise wild-type cells. Using ChIP-seq to interrogate all 70 exemplar genes in single, double, and triple mutants implicated Gcn5, Snf2, and Ydj1 in H3 eviction at most, but not all, Gcn4 target promoters, with Gcn5 generally playing the greatest role and Ydj1 the least. Remarkably, these three cofactors cooperate similarly in H3 eviction at virtually all yeast promoters. Defective H3 eviction in cofactor mutants was coupled with reduced Pol II occupancies for the Gcn4 transcriptome and the most highly expressed uninduced genes, but the relative Pol II levels at most genes were unaffected or even elevated. These findings indicate that nucleosome eviction is crucial for robust transcription of highly expressed genes but that other steps in gene activation are more rate-limiting for most other yeast genes.
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Affiliation(s)
- Hongfang Qiu
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Răzvan V Chereji
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Cuihua Hu
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Hope A Cole
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yashpal Rawal
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - David J Clark
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Alan G Hinnebusch
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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19
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The Histone Acetyltransferase Gcn5 Regulates ncRNA-ICR1 and FLO11 Expression during Pseudohyphal Development in Saccharomyces cerevisiae. BIOMED RESEARCH INTERNATIONAL 2015; 2015:284692. [PMID: 25922832 PMCID: PMC4398931 DOI: 10.1155/2015/284692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 03/09/2015] [Indexed: 11/18/2022]
Abstract
Filamentous growth is one of the key features of pathogenic fungi during the early infectious phase. The pseudohyphal development of yeast Saccharomyces cerevisiae shares similar characteristics with hyphae elongation in pathogenic fungi. The expression of FLO11 is essential for adhesive growth and filament formation in yeast and is governed by a multilayered transcriptional network. Here we discovered a role for the histone acetyltransferase general control nonderepressible 5 (Gcn5) in regulating FLO11-mediated pseudohyphal growth. The expression patterns of FLO11 were distinct in haploid and diploid yeast under amino acid starvation induced by 3-amino-1,2,4-triazole (3AT). In diploids, FLO11 expression was substantially induced at a very early stage of pseudohyphal development and decreased quickly, but in haploids, it was gradually induced. Furthermore, the transcription factor Gcn4 was recruited to the Sfl1-Flo8 toggle sites at the FLO11 promoter under 3AT treatment. Moreover, the histone acetylase activity of Gcn5 was required for FLO11 induction. Finally, Gcn5 functioned as a negative regulator of the noncoding RNA ICR1, which is known to suppress FLO11 expression. Gcn5 plays an important role in the regulatory network of FLO11 expression via Gcn4 by downregulating ICR1 expression, which derepresses FLO11 for promoting pseudohyphal development.
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Yang P, Zhang F, Luo X, Zhou Y, Xie J. Histone deacetylation modification participates in the repression of peanut (Arachis hypogaea L.) seed storage protein gene Ara h 2.02 during germination. PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:522-7. [PMID: 25262939 DOI: 10.1111/plb.12268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/16/2014] [Indexed: 05/02/2023]
Abstract
Genes encoding seed storage proteins (SSPs) are specifically and highly expressed during seed maturation. In Arabidopsis, chromatin-based mechanisms involved in the repression of SSPs during germination have been proposed. However, epigenetic regulation involved in repressing SSPs in vegetative tissues of peanut is not well understood. Histone deacetylase (HDAC) is a chromatin-remodelling factor that contributes to transcriptional repression in eukaryotes. To address whether histone deacetylation modification is involved in the repression of SSP genes during germination in peanut, we generated an Ara h 2.02pro : β-glucuronidase (GUS) construct by fusing the 1972 bp Ara h 2.02 promoter of peanut (from -1972 to -1) to the GUS reporter gene and transformed it into wild-type Arabidopsis plants and HDAC mutants. GUS staining revealed that the mutation in HISTONE DEACETYLASE19 (HDA19) resulted in the ectopic expression of peanut SSP gene Ara h 2.02 in seedlings. In addition, Chromatin immunoprecipitation (ChIP) assays showed that the ectopic expression of Ara h 2.02 was accompanied by histone hyperacetylation during germination. These results suggest that histone deacetylation modification may play a vital role in repressing embryonic properties during the peanut vegetative growth.
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Affiliation(s)
- P Yang
- College of Life Sciences, Jiangxi Normal University, Nanchang, China
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21
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Wang J, Dixon SE, Ting LM, Liu TK, Jeffers V, Croken MM, Calloway M, Cannella D, Ali Hakimi M, Kim K, Sullivan WJ. Lysine acetyltransferase GCN5b interacts with AP2 factors and is required for Toxoplasma gondii proliferation. PLoS Pathog 2014; 10:e1003830. [PMID: 24391497 PMCID: PMC3879359 DOI: 10.1371/journal.ppat.1003830] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/26/2013] [Indexed: 12/26/2022] Open
Abstract
Histone acetylation has been linked to developmental changes in gene expression and is a validated drug target of apicomplexan parasites, but little is known about the roles of individual histone modifying enzymes and how they are recruited to target genes. The protozoan parasite Toxoplasma gondii (phylum Apicomplexa) is unusual among invertebrates in possessing two GCN5-family lysine acetyltransferases (KATs). While GCN5a is required for gene expression in response to alkaline stress, this KAT is dispensable for parasite proliferation in normal culture conditions. In contrast, GCN5b cannot be disrupted, suggesting it is essential for Toxoplasma viability. To further explore the function of GCN5b, we generated clonal parasites expressing an inducible HA-tagged dominant-negative form of GCN5b containing a point mutation that ablates enzymatic activity (E703G). Stabilization of this dominant-negative GCN5b was mediated through ligand-binding to a destabilization domain (dd) fused to the protein. Induced accumulation of the ddHAGCN5b(E703G) protein led to a rapid arrest in parasite replication. Growth arrest was accompanied by a decrease in histone H3 acetylation at specific lysine residues as well as reduced expression of GCN5b target genes in GCN5b(E703G) parasites, which were identified using chromatin immunoprecipitation coupled with microarray hybridization (ChIP-chip). Proteomics studies revealed that GCN5b interacts with AP2-domain proteins, apicomplexan plant-like transcription factors, as well as a “core complex” that includes the co-activator ADA2-A, TFIID subunits, LEO1 polymerase-associated factor (Paf1) subunit, and RRM proteins. The dominant-negative phenotype of ddHAGCN5b(E703G) parasites, considered with the proteomics and ChIP-chip data, indicate that GCN5b plays a central role in transcriptional and chromatin remodeling complexes. We conclude that GCN5b has a non-redundant and indispensable role in regulating gene expression required during the Toxoplasma lytic cycle. Toxoplasma gondii is a protozoan parasite that causes significant opportunistic infection in AIDS and other immunocompromised patients. Acute episodes of toxoplasmosis stem from tissue destruction caused by the rapidly growing form of the parasite, the tachyzoite. In this study, we identify a lysine acetyltransferase (KAT) enzyme called GCN5b that is an essential driver of tachyzoite proliferation. Our studies show that GCN5b is present at a wide variety of parasite genes and that expression of defective GCN5b compromises gene expression through its diminished ability to acetylate histone proteins. We also identified the likely mechanism by which GCN5b is recruited to target genes by co-purifying this KAT with plant-like AP2-domain proteins, a subset of which function as DNA-binding transcription factors in Apicomplexa. Our findings demonstrate that KATs play a critical role in parasite replication, which leads to tissue destruction and acute disease in the host. Parasite KAT enzyme complexes may therefore serve as attractive targets for future drug development.
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Affiliation(s)
- Jiachen Wang
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Stacy E. Dixon
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Li-Min Ting
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Ting-Kai Liu
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Victoria Jeffers
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Matthew M. Croken
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Myrasol Calloway
- Laboratory for Macromolecular Analysis, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | | | | | - Kami Kim
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - William J. Sullivan
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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22
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Llorca CM, Potschin M, Zentgraf U. bZIPs and WRKYs: two large transcription factor families executing two different functional strategies. FRONTIERS IN PLANT SCIENCE 2014; 5:169. [PMID: 24817872 PMCID: PMC4012195 DOI: 10.3389/fpls.2014.00169] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 04/08/2014] [Indexed: 05/20/2023]
Abstract
bZIPs and WRKYs are two important plant transcription factor (TF) families regulating diverse developmental and stress-related processes. Since a partial overlap in these biological processes is obvious, it can be speculated that they fulfill non-redundant functions in a complex regulatory network. Here, we focus on the regulatory mechanisms that are so far described for bZIPs and WRKYs. bZIP factors need to heterodimerize for DNA-binding and regulation of transcription, and based on a bioinformatics approach, bZIPs can build up more than the double of protein interactions than WRKYs. In contrast, an enrichment of the WRKY DNA-binding motifs can be found in WRKY promoters, a phenomenon which is not observed for the bZIP family. Thus, the two TF families follow two different functional strategies in which WRKYs regulate each other's transcription in a transcriptional network whereas bZIP action relies on intensive heterodimerization.
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Affiliation(s)
| | | | - Ulrike Zentgraf
- *Correspondence: Ulrike Zentgraf, Department of General Genetics, Center of Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany e-mail:
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Kamata K, Goswami G, Kashio S, Urano T, Nakagawa R, Uchida H, Oki M. The N-terminus and Tudor domains of Sgf29 are important for its heterochromatin boundary formation function. ACTA ACUST UNITED AC 2013; 155:159-71. [DOI: 10.1093/jb/mvt108] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Kuo YM, Andrews AJ. Quantitating the specificity and selectivity of Gcn5-mediated acetylation of histone H3. PLoS One 2013; 8:e54896. [PMID: 23437046 PMCID: PMC3578832 DOI: 10.1371/journal.pone.0054896] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/17/2012] [Indexed: 12/28/2022] Open
Abstract
Lysine acetyltransferases (KATs) play a unique role in regulating gene transcription as well as maintaining the epigenetic state of the cell. KATs such as Gcn5 and p300/CBP can modify multiple residues on a single histone; however, order and specificity of acetylation can be altered by factors such as histone chaperones, subunit proteins or external stimulus. While the importance of acetylation is well documented, it has been difficult to quantitatively measure the specificity and selectivity of acetylation at different residues within a histone. In this paper, we demonstrate a label-free quantitative high throughput mass spectrometry-based assay capable of quantitatively monitoring all known acetylation sites of H3 simultaneously. Using this assay, we are able to analyze the steady-state enzyme kinetics of Gcn5, an evolutionarily conserved KAT. In doing so, we measured Gcn5-mediated acetylation at six residues (K14>K9 ≈ K23> K18> K27 ≈ K36) and the catalytic efficiency (k(cat)/K(m)) for K9, K14, K18, and K23 as well as the nonenzymatic acetylation rate. We observed selectivity differences of up to -4 kcal/mol between K14 and K18, the highest and lowest measurable k(cat)/K(m). These data provide a first look at quantitating the specificity and selectivity of multiple lysines on a single substrate (H3) by Gcn5.
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Affiliation(s)
- Yin-Ming Kuo
- Department of Cancer Biology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
| | - Andrew J. Andrews
- Department of Cancer Biology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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25
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Verta JP, Landry CR, MacKay JJ. Are long-lived trees poised for evolutionary change? Single locus effects in the evolution of gene expression networks in spruce. Mol Ecol 2013; 22:2369-79. [DOI: 10.1111/mec.12189] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 11/26/2012] [Indexed: 02/04/2023]
Affiliation(s)
- Jukka-Pekka Verta
- Département des Sciences du Bois et de la Forêt & Centre d’Étude de la Forêt; Université Laval; Québec QC Canada G1V 0A6
- Institut de Biologie Intégrative et des Systèmes; Université Laval; Québec QC Canada G1V 0A6
| | - Christian R. Landry
- Institut de Biologie Intégrative et des Systèmes; Université Laval; Québec QC Canada G1V 0A6
- Département de Biologie & PROTEO; Université Laval; Québec QC Canada G1V 0A6
| | - John J. MacKay
- Département des Sciences du Bois et de la Forêt & Centre d’Étude de la Forêt; Université Laval; Québec QC Canada G1V 0A6
- Institut de Biologie Intégrative et des Systèmes; Université Laval; Québec QC Canada G1V 0A6
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Raveh-Sadka T, Levo M, Shabi U, Shany B, Keren L, Lotan-Pompan M, Zeevi D, Sharon E, Weinberger A, Segal E. Manipulating nucleosome disfavoring sequences allows fine-tune regulation of gene expression in yeast. Nat Genet 2012; 44:743-50. [PMID: 22634752 DOI: 10.1038/ng.2305] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/03/2012] [Indexed: 11/09/2022]
Abstract
Understanding how precise control of gene expression is specified within regulatory DNA sequences is a key challenge with far-reaching implications. Many studies have focused on the regulatory role of transcription factor-binding sites. Here, we explore the transcriptional effects of different elements, nucleosome-disfavoring sequences and, specifically, poly(dA:dT) tracts that are highly prevalent in eukaryotic promoters. By measuring promoter activity for a large-scale promoter library, designed with systematic manipulations to the properties and spatial arrangement of poly(dA:dT) tracts, we show that these tracts significantly and causally affect transcription. We show that manipulating these elements offers a general genetic mechanism, applicable to promoters regulated by different transcription factors, for tuning expression in a predictable manner, with resolution that can be even finer than that attained by altering transcription factor sites. Overall, our results advance the understanding of the regulatory code and suggest a potential mechanism by which promoters yielding prespecified expression patterns can be designed.
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Affiliation(s)
- Tali Raveh-Sadka
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
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27
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Pelzel HR, Nickells RW. A role for epigenetic changes in the development of retinal neurodegenerative conditions. J Ocul Biol Dis Infor 2012; 4:104-10. [PMID: 23515137 DOI: 10.1007/s12177-012-9079-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 03/05/2012] [Indexed: 11/25/2022] Open
Affiliation(s)
- Heather R Pelzel
- Department of Biology, University of Wisconsin-Whitewater, 800 W Main St, Whitewater, WI 53190 USA
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Paf1 restricts Gcn4 occupancy and antisense transcription at the ARG1 promoter. Mol Cell Biol 2012; 32:1150-63. [PMID: 22252319 DOI: 10.1128/mcb.06262-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conserved Paf1 complex negatively regulates the expression of numerous genes, yet the mechanisms by which it represses gene expression are not well understood. In this study, we use the ARG1 gene as a model to investigate the repressive functions of the Paf1 complex in Saccharomyces cerevisiae. Our results indicate that Paf1 mediates repression of the ARG1 gene independently of the gene-specific repressor, ArgR/Mcm1. Rather, by promoting histone H2B lysine 123 ubiquitylation, Paf1 represses the ARG1 gene by negatively affecting Gcn4 occupancy at the promoter. Consistent with this observation, Gcn5 and its acetylation sites on histone H3 are required for full ARG1 derepression in paf1Δ cells, and the repressive effect of Paf1 is largely maintained when the ARG1 promoter directs transcription of a heterologous coding region. Derepression of the ARG1 gene in paf1Δ cells is accompanied by small changes in nucleosome occupancy, although these changes are subtle in comparison to those that accompany gene activation through amino acid starvation. Additionally, conditions that stimulate ARG1 transcription, including PAF1 deletion, lead to increased antisense transcription across the ARG1 promoter. This promoter-associated antisense transcription positively correlates with ARG1 sense transcription. Finally, our results indicate that Paf1 represses other genes through mechanisms similar to those used at the ARG1 gene.
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Shukla A, Lahudkar S, Durairaj G, Bhaumik SR. Sgf29p facilitates the recruitment of TATA box binding protein but does not alter SAGA's global structural integrity in vivo. Biochemistry 2012; 51:706-14. [PMID: 22224423 DOI: 10.1021/bi201708z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although Sgf29p has been biochemically implicated as a component of SAGA (Spt-Ada-Gcn5 acetyltransferase), its precise mechanism of action in transcription is not clearly understood in vivo. Here, using a formaldehyde-based in vivo cross-linking and chromatin immunoprecipitation (ChIP) assay in conjunction with transcriptional and mutational analyses, we show that Sgf29p along with other SAGA components is recruited to the upstream activating sequence (UAS) of a SAGA-regulated gene, GAL1, in an activation domain-dependent manner. However, Sgf29p does not alter the recruitment of Spt20p that maintains the overall structural and functional integrity of SAGA. The recruitment of other SAGA components such as TAF10p, TAF12p, and Ubp8p to the GAL1 UAS is also not altered in the absence of Sgf29p. Interestingly, we find that the recruitment of TBP (TATA box binding protein that nucleates the assembly of general transcription factors to form the preinitiation complex for transcriptional initiation) to the core promoter of GAL1 is weakened in Δsgf29. Likewise, Sgf29p also enhances the recruitment of TBP to other SAGA-regulated promoters. Such weakening of recruitment of TBP to these promoters subsequently decreases the level of transcription. Taken together, these results support the idea that SAGA-associated Sgf29p facilitates the recruitment of TBP (and hence transcription) without altering the global structural integrity of SAGA in vivo.
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Affiliation(s)
- Abhijit Shukla
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
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Bacteria-induced natural product formation in the fungus Aspergillus nidulans requires Saga/Ada-mediated histone acetylation. Proc Natl Acad Sci U S A 2011; 108:14282-7. [PMID: 21825172 DOI: 10.1073/pnas.1103523108] [Citation(s) in RCA: 257] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sequence analyses of fungal genomes have revealed that the potential of fungi to produce secondary metabolites is greatly underestimated. In fact, most gene clusters coding for the biosynthesis of antibiotics, toxins, or pigments are silent under standard laboratory conditions. Hence, it is one of the major challenges in microbiology to uncover the mechanisms required for pathway activation. Recently, we discovered that intimate physical interaction of the important model fungus Aspergillus nidulans with the soil-dwelling bacterium Streptomyces rapamycinicus specifically activated silent fungal secondary metabolism genes, resulting in the production of the archetypal polyketide orsellinic acid and its derivatives. Here, we report that the streptomycete triggers modification of fungal histones. Deletion analysis of 36 of 40 acetyltransferases, including histone acetyltransferases (HATs) of A. nidulans, demonstrated that the Saga/Ada complex containing the HAT GcnE and the AdaB protein is required for induction of the orsellinic acid gene cluster by the bacterium. We also showed that Saga/Ada plays a major role for specific induction of other biosynthesis gene clusters, such as sterigmatocystin, terrequinone, and penicillin. Chromatin immunoprecipitation showed that the Saga/Ada-dependent increase of histone 3 acetylation at lysine 9 and 14 occurs during interaction of fungus and bacterium. Furthermore, the production of secondary metabolites in A. nidulans is accompanied by a global increase in H3K14 acetylation. Increased H3K9 acetylation, however, was only found within gene clusters. This report provides previously undescribed evidence of Saga/Ada dependent histone acetylation triggered by prokaryotes.
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Trichostatin A selectively suppresses the cold-induced transcription of the ZmDREB1 gene in maize. PLoS One 2011; 6:e22132. [PMID: 21811564 PMCID: PMC3141014 DOI: 10.1371/journal.pone.0022132] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Accepted: 06/16/2011] [Indexed: 02/06/2023] Open
Abstract
Post-translational modifications of histone proteins play a crucial role in responding to environmental stresses. Histone deacetylases (HDACs) catalyze the removal of an acetyl group from histones and are generally believed to be a transcriptional repressor. In this paper, we report that cold treatment highly induces the up-regulation of HDACs, leading to global deacetylation of histones H3 and H4. Treatment of maize with the HDAC inhibitor trichostatin A (TSA) under cold stress conditions strongly inhibits induction of the maize cold-responsive genes ZmDREB1 and ZmCOR413. However, up-regulation of the ZmICE1 gene in response to cold stress is less affected. The expression of drought and salt induced genes, ZmDBF1 and rab17, is almost unaffected by TSA treatment. Thus, these observations show that HDACs may selectively activate transcription. The time course of TSA effects on the expression of ZmDREB1 and ZmCOR413 genes indicates that HDACs appear to directly activate the ZmDREB1 gene, which in turn modulates ZmCOR413 expression. After cold treatment, histone hyperacetylation and DNA demethylation occurs in the ICE1 binding region, accompanied by an increase in accessibility to micrococcal nuclease (MNase). The two regions adjacent to the ICE1 binding site remain hypoacetylated and methylated. However, during cold acclimation, TSA treatment increases the acetylation status and accessibility of MNase and decreases DNA methylation at these two regions. However, TSA treatment does not affect histone hyperacetylation and DNA methylation levels at the ICE1 binding regions of the ZmDREB1 gene. Altogether, our findings indicate that HDACs positively regulate the expression of the cold-induced ZmDREB1 gene through histone modification and chromatin conformational changes and that this activation is both gene and site selective.
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Dot1 binding induces chromatin rearrangements by histone methylation-dependent and -independent mechanisms. Epigenetics Chromatin 2011; 4:2. [PMID: 21291527 PMCID: PMC3038881 DOI: 10.1186/1756-8935-4-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/03/2011] [Indexed: 11/27/2022] Open
Abstract
Background Methylation of histone H3 lysine 79 (H3K79) by Dot1 is highly conserved among species and has been associated with both gene repression and activation. To eliminate indirect effects and examine the direct consequences of Dot1 binding and H3K79 methylation, we investigated the effects of targeting Dot1 to different positions in the yeast genome. Results Targeting Dot1 did not activate transcription at a euchromatic locus. However, chromatin-bound Dot1 derepressed heterochromatin-mediated gene silencing over a considerable distance. Unexpectedly, Dot1-mediated derepression was established by both a H3K79 methylation-dependent and a methylation-independent mechanism; the latter required the histone acetyltransferase Gcn5. By monitoring the localization of a fluorescently tagged telomere in living cells, we found that the targeting of Dot1, but not its methylation activity, led to the release of a telomere from the repressive environment at the nuclear periphery. This probably contributes to the activity-independent derepression effect of Dot1. Conclusions Targeting of Dot1 promoted gene expression by antagonizing gene repression through both histone methylation and chromatin relocalization. Our findings show that binding of Dot1 to chromatin can positively affect local gene expression by chromatin rearrangements over a considerable distance.
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Subrahmanyam R, Sen R. RAGs' eye view of the immunoglobulin heavy chain gene locus. Semin Immunol 2010; 22:337-45. [PMID: 20864355 DOI: 10.1016/j.smim.2010.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
The immunoglobulin heavy chain (IgH) gene locus is activated at a precise stage of B lymphocyte development to undergo gene rearrangements that assemble the functional gene. In this review we summarize our current understanding of the chromatin state of the IgH as it appears just prior to the initiation of V(D)J recombination, and the implications of this structure for regulation of recombination. We also examine the role of the intron enhancer, Eμ, in establishing the pre-rearrangement chromatin structure. The emerging picture shows that the IgH locus consists of independently regulated domains, each of which requires multiple levels of epigenetic changes to reach the fully activated state.
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Affiliation(s)
- Ramesh Subrahmanyam
- Gene Regulation Section, Laboratory of Cellular and Molecular Biology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Room 06C214, Baltimore, MD 21224, United States
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Bhaumik SR. Distinct regulatory mechanisms of eukaryotic transcriptional activation by SAGA and TFIID. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:97-108. [PMID: 20800707 DOI: 10.1016/j.bbagrm.2010.08.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 08/18/2010] [Accepted: 08/19/2010] [Indexed: 01/08/2023]
Abstract
A growing number of human diseases are linked to abnormal gene expression which is largely controlled at the level of transcriptional initiation. The gene-specific activator promotes the initiation of transcription through its interaction with one or more components of the transcriptional initiation machinery, hence leading to stimulated transcriptional initiation or activation. However, all activator proteins do not target the same component(s) of the transcriptional initiation machinery. Rather, they can have different target specificities, and thus, can lead to distinct mechanisms of transcriptional activation. Two such distinct mechanisms of transcriptional activation in yeast are mediated by the SAGA (Spt-Ada-Gcn5-Acetyltransferase) and TFIID (Transcription factor IID) complexes, and are termed as "SAGA-dependent" and "TFIID-dependent" transcriptional activation, respectively. SAGA is the target of the activator in case of SAGA-dependent transcriptional activation, while the targeting of TFIID by the activator leads to TFIID-dependent transcriptional activation. Both the SAGA and TFIID complexes are highly conserved from yeast to human, and play crucial roles in gene activation among eukaryotes. The regulatory mechanisms of eukaryotic transcriptional activation by SAGA and TFIID are discussed here. This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!
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Affiliation(s)
- Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illnois University School of Medicine, Carbondale, IL 62901, USA.
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Hansen JC, Nyborg JK, Luger K, Stargell LA. Histone chaperones, histone acetylation, and the fluidity of the chromogenome. J Cell Physiol 2010; 224:289-99. [PMID: 20432449 DOI: 10.1002/jcp.22150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The "chromogenome" is defined as the structural and functional status of the genome at any given moment within a eukaryotic cell. This article focuses on recently uncovered relationships between histone chaperones, post-translational acetylation of histones, and modulation of the chromogenome. We emphasize those chaperones that function in a replication-independent manner, and for which three-dimensional structural information has been obtained. The emerging links between histone acetylation and chaperone function in both yeast and higher metazoans are discussed, including the importance of nucleosome-free regions. We close by posing many questions pertaining to how the coupled action of histone chaperones and acetylation influences chromogenome structure and function.
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Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA.
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Spedale G, Mischerikow N, Heck AJR, Timmers HTM, Pijnappel WWMP. Identification of Pep4p as the protease responsible for formation of the SAGA-related SLIK protein complex. J Biol Chem 2010; 285:22793-9. [PMID: 20498363 DOI: 10.1074/jbc.m110.108787] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae Spt-Ada-Gcn5 acetyltransferase (SAGA) protein complex is a coactivator for transcription by RNA polymerase II and has various activities, including acetylation and deubuiqitination of histones and recruitment of TATA-binding protein to promoters. The Spt7p subunit is subject to proteolytic cleavage at its C terminus resulting in removal of the Spt8p-binding domain and generation of the SAGA-related SALSA/SAGA-like (SLIK) protein complex. Here, we report identification of the protease responsible for this cleavage. Screening of a protease knock-out collection revealed PEP4 to be required for cleavage of Spt7p within SAGA in vitro. Endogenous formation of truncated Spt7p was abolished in cells lacking PEP4. Purified Pep4p but not catalytic dead mutant Pep4p or unrelated Prc1p protease specifically cleaved Spt7p within SAGA into SLIK-related Spt7p. Interestingly, SAGA lacking Spt8p was more sensitive to Pep4p-mediated truncation of Spt7p, suggesting that Spt8p counteracted its own release from SAGA. Strains mimicking constitutive SLIK formation showed increased resistance to rapamycin treatment, suggesting a role for SLIK in regulating cellular responses to nutrient stress.
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Affiliation(s)
- Gianpiero Spedale
- Department of Physiological Chemistry, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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Abstract
The budding yeast Gcn5p is a prototypic histone acetyltransferase controlling transcription of diverse genes. Here we show that Gcn5p is itself regulated by Snf1p and Spt3p. Snf1p likely controls Gcn5p via direct interaction. Mutating four residues in the Gcn5p catalytic domain, T203, S204, T211, and Y212 (TSTY), phenocopies snf1 null cells, including Gcn5p hypophosphorylation, hypoacetylation at the HIS3 promoter, and transcriptional defects of the HIS3 gene. However, overexpressing Snf1p suppresses the above phenotypes associated with the phosphodeficient TSTY mutant, suggesting that it is the interaction with Snf1p important for Gcn5p to activate HIS3. A likely mechanism by which Snf1p potentiates Gcn5p function is to antagonize Spt3p, because the HIS3 expression defects caused by snf1 knockout, or by the TSTY gcn5 mutations, can be suppressed by deleting SPT3. In vitro, Spt3p binds Gcn5p, but the interaction is drastically enhanced by the TSTY mutations, indicating that a stabilized Spt3p-Gcn5p interaction may be an underlying cause for the aforementioned HIS3 transcriptional defects. These results suggest that Gcn5p is a target regulated by the competing actions of Snf1p and Spt3p.
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Friis RMN, Schultz MC. Untargeted tail acetylation of histones in chromatin: lessons from yeast. Biochem Cell Biol 2009; 87:107-16. [PMID: 19234527 DOI: 10.1139/o08-097] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Dynamic acetylation of lysine residues in the amino-terminal tails of the core histones is functionally important for the regulation of diverse DNA-dependent processes in the nucleus, including replication, transcription, and DNA repair. The targeted and untargeted activities of histone lysine acetylases (KATs) and deacetylases (HDACs) both contribute to the dynamics of chromatin acetylation. While the mechanisms and functional consequences of targeted on histone acetylation are well understood, relatively little is known about untargeted histone acetylation. Here, we review the current understanding of the mechanisms by which untargeted KAT and HDAC activities modulate the acetylation state of nucleosomal histones, focusing on results obtained for H3 and H4 in budding yeast. We also highlight unresolved problems in this area, including the question of how a particular steady-state level of untargeted acetylation is set in the absence of cis-dependent mechanisms that instruct the activity of KATs and HDACs.
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Affiliation(s)
- R Magnus N Friis
- Department of Biochemistry, University of Alberta, Edmonton, ABT6G2H7, Canada
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Friis RMN, Wu BP, Reinke SN, Hockman DJ, Sykes BD, Schultz MC. A glycolytic burst drives glucose induction of global histone acetylation by picNuA4 and SAGA. Nucleic Acids Res 2009; 37:3969-80. [PMID: 19406923 PMCID: PMC2709565 DOI: 10.1093/nar/gkp270] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Little is known about what enzyme complexes or mechanisms control global lysine acetylation in the amino-terminal tails of the histones. Here, we show that glucose induces overall acetylation of H3 K9, 18, 27 and H4 K5, 8, 12 in quiescent yeast cells mainly by stimulating two KATs, Gcn5 and Esa1. Genetic and pharmacological perturbation of carbon metabolism, combined with 1H-NMR metabolic profiling, revealed that glucose induction of KAT activity directly depends on increased glucose catabolism. Glucose-inducible Esa1 and Gcn5 activities predominantly reside in the picNuA4 and SAGA complexes, respectively, and act on chromatin by an untargeted mechanism. We conclude that direct metabolic regulation of globally acting KATs can be a potent driving force for reconfiguration of overall histone acetylation in response to a physiological cue.
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Affiliation(s)
- R Magnus N Friis
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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40
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Kuo MH, Xu XJ, Bolck HA, Guo D. Functional connection between histone acetyltransferase Gcn5p and methyltransferase Hmt1p. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:395-402. [PMID: 19358899 DOI: 10.1016/j.bbagrm.2009.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 03/10/2009] [Accepted: 03/24/2009] [Indexed: 10/20/2022]
Abstract
Histone acetylation and methylation are linked to a variety of nuclear activities, most notably transcriptional regulation. Both synergistic and antagonistic relationships between these two modifications have been reported in different systems. Here we show that the budding yeast histone H4 arginine 3 (R3) methyltransferase Hmt1p binds acetylated histones H3 and H4, and importantly, that acetylated H4 is a significantly better methylation substrate for Hmt1p. Kinetic studies show that acetylation at any of the four acetylatable lysine residues of histone H4 results in more efficient methylation. Among the four, K8 acetylation imposes the strongest effect on reducing K(M), consistent with the observed acetylation-stimulated interaction. In vivo, hmt1Delta cells rescue the transcriptional defect caused by GCN5 deletion, indicating that one of the functions of Gcn5p is to neutralize the negative effect of Hmt1p. Mutating either K8 or R3 to alanine causes similar growth defects in selective histone and gcn5 mutant background, suggesting that these two residues function in the same pathway for optimal vegetative growth. Together, these results reveal a functional connection between histone acetylation, methylation, and two of the responsible enzymes, Gcn5p and Hmt1p.
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Affiliation(s)
- Min-Hao Kuo
- Department of Biochemistry and Molecular Biology, Programs in Cell and Molecular Biology and in Genetics, Michigan State University, East Lansing, MI 48824, USA.
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Abstract
Histone acetylation levels are regulated through the opposing activities of histone acetyltransferases (HATs) and deacetylases (HDACs). While much is known about gene-specific control of histone acetylation, little is understood about how total or cellular levels of histone acetylation are regulated. To identify regulators of cellular levels of histone acetylation, we developed an immunofluorescence-based approach to screen the single-gene deletion library of Saccharomyces cerevisiae for strains with significant reductions in cellular histone acetylation levels. Of the 4848 mutants screened, we identified 63 strains with considerable cellular hypoacetylation of N-terminal lysines in histones H3 and H4. The cellular hypoacetylation was validated for subsets of the identified strains through secondary screens including mass spectrometric analysis of individual lysines and chromatin immunoprecipitation of specific genomic loci. Among the identified mutants were several members of the Ccr4-Not complex, V-type ATPases, and vacuolar protein-sorting complexes as well as genes with unknown functions. We show that Gcn5, a major HAT in yeast, has diminished histone acetyltransferase activity in particular mutants, providing a plausible explanation for reduction of cellular acetylation levels in vivo. Our findings have revealed unexpected and novel links between histone acetylation, Gcn5 HAT activity, and diverse processes such as transcription, cellular ion homeostasis, and protein transport.
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Komaki-Yasuda K, Okuwaki M, Kano S, Nagata K, Kawazu SI. 5' sequence- and chromatin modification-dependent gene expression in Plasmodium falciparum erythrocytic stage. Mol Biochem Parasitol 2008; 162:40-51. [PMID: 18692528 DOI: 10.1016/j.molbiopara.2008.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 07/09/2008] [Accepted: 07/10/2008] [Indexed: 11/18/2022]
Abstract
Plasmodium falciparum, the human malaria parasite, is evolutionarily distant from other eukaryotes. Genome-wide analyses of transcription-associated proteins have revealed a relative paucity of putative regulatory transcription factors and an abundance of putative chromatin remodeling machinery, suggesting that this parasite has a transcription regulatory system that is distinct from those of other eukaryotes. Here, we have analyzed transcriptional regulation of the peroxiredoxin genes, pf1-cys-prx and pftpx-1, which show different expression patterns in P. falciparum. The reporter assays revealed the presence of putative enhancers in the 5' regions of these genes. Although pf1-cys-prx shows trophozoite/schizont stage-specific transcription, a putative cis-acting enhancer sequence in pf1-cys-prx was constitutively active when inserted into the 5' region of pftpx-1. Electrophoretic mobility shift and DNase I footprinting assays showed that this enhancer region is the target of trophozoite/schizont stage-specific DNA binding proteins. In addition, chromatin immunoprecipitation assays showed that the increased levels of histone acetylation in the 5' region of pf1-cys-prx and pftpx-1 correlate with the transcriptional activity of these genes. Recruitment of PfGCN5 histone acetyltransferase to the pf1-cys-prx enhancer in trophozoite/schizont stage was observed. These results suggest that P. falciparum possesses a sophisticated system of transcriptional regulation during intraerythrocytic stages that is managed by coordinated interactions of unique cis-elements and trans-acting factors and chromatin modifications.
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Gamper AM, Roeder RG. Multivalent binding of p53 to the STAGA complex mediates coactivator recruitment after UV damage. Mol Cell Biol 2008; 28:2517-27. [PMID: 18250150 PMCID: PMC2293101 DOI: 10.1128/mcb.01461-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 10/22/2007] [Accepted: 01/28/2008] [Indexed: 12/29/2022] Open
Abstract
The recruitment of transcriptional coactivators, including histone modifying enzymes, is an important step in transcription regulation. A typical activator is thought to interact with several cofactors, presumably in a sequential manner. The common use of several cofactors raises the question of how activators achieve both cofactor selectivity and diversity. Human STAGA is a multiprotein complex with the acetyltransferase GCN5L as the catalytic subunit. Here, we first show, through RNA interference-mediated knock-down and chromatin immunoprecipitation assays, that GCN5 plays a role in p53-dependent gene activation. We then employ p53 mutagenesis, in vitro binding, protein-protein cross-linking, and chromatin immunoprecipitation assays to establish a novel role for the second p53 activation subdomain (AD2) in STAGA recruitment and, further, to demonstrate that optimal binding of STAGA to p53 involves interactions of STAGA subunits TAF9, GCN5, and ADA2b, respectively, with AD1, AD2, and carboxy-terminal domains of p53. These results provide concrete evidence for mediation of transcription factor binding to coactivator complexes through multiple interactions. Based on our data, we propose a cooperative and modular binding mode for the recruitment of coactivator complexes to promoters.
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Affiliation(s)
- Armin M Gamper
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10021, USA
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44
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Tanaka M, Kikuchi A, Kamada H. The Arabidopsis histone deacetylases HDA6 and HDA19 contribute to the repression of embryonic properties after germination. PLANT PHYSIOLOGY 2008; 146:149-61. [PMID: 18024558 PMCID: PMC2230551 DOI: 10.1104/pp.107.111674] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 11/11/2007] [Indexed: 05/19/2023]
Abstract
Histone deacetylase (HDAC) is a chromatin-remodeling factor that contributes to transcriptional repression in eukaryotes. In Arabidopsis (Arabidopsis thaliana), the transcription factors LEAFY COTYLEDON1 (LEC1), FUSCA3 (FUS3), and ABSCISIC ACID INSENSITIVE3 (ABI3) play key roles in embryogenesis. Although the repression of embryogenesis-related genes during germination has been proposed to occur, the role of HDAC in this process has not been elucidated. To address this question, the effects of an HDAC inhibitor and suppression of the Arabidopsis HDAC genes on this process were investigated. Here, we show that treatment of an HDA6 repression line with the HDAC inhibitor trichostatin A resulted in growth arrest and elevated transcription of LEC1, FUS3, and ABI3 during germination. The growth-arrest phenotype of the repression line was suppressed by lec1, fus3, and abi3. An HDA6/HDA19 double-repression line displayed arrested growth after germination and the formation of embryo-like structures on the true leaves of 6-week-old plants even without trichostatin A. The growth-arrest phenotype of this line was rescued by lec1. These results suggest that during germination in Arabidopsis, HDA6 and HDA19 redundantly regulate the repression of embryonic properties directly or indirectly via repression of embryo-specific gene function.
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Affiliation(s)
- Motoki Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Japan
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45
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Gcn5p plays an important role in centromere kinetochore function in budding yeast. Mol Cell Biol 2007; 28:988-96. [PMID: 18039853 DOI: 10.1128/mcb.01366-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We report that the histone acetyltransferase Gcn5p is involved in cell cycle progression, whereas its absence induces several mitotic defects, including inefficient nuclear division, chromosome loss, delayed G(2) progression, and spindle elongation. The fidelity of chromosome segregation is finely regulated by the close interplay between the centromere and the kinetochore, a protein complex hierarchically assembled in the centromeric DNA region, while disruption of GCN5 in mutants of inner components results in sick phenotype. These synthetic interactions involving the ADA complex lay the genetic basis for the critical role of Gcn5p in kinetochore assembly and function. We found that Gcn5p is, in fact, physically linked to the centromere, where it affects the structure of the variant centromeric nucleosome. Our findings offer a key insight into a Gcn5p-dependent epigenetic regulation at centromere/kinetochore in mitosis.
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46
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Abstract
Histone acetylation regulates many cellular processes, and specific acetylation marks, either singly or in combination, produce distinct outcomes. For example, the acetylation pattern on newly synthesized histones is important for their assembly into nucleosomes by histone chaperones. Additionally, the degree of chromatin compaction and folding may be regulated by acetylation of histone H4 at lysine 16. Histone acetylation also regulates the formation of heterochromatin; deacetylation of H4 lysine 16 is important for spreading of heterochromatin components, whereas acetylation of this site serves as a barrier to this spreading. Finally, histone acetylation is critical for gene transcription, but recent results suggest that deacetylation of certain sites also plays an important role. There are many histone acetyltransferases (HATs) and deacetylases, with differing preferences for the various histone proteins and for specific sites on individual histones. Determining how these enzymes create distinct acetylation patterns and regulate the functional outcome is an important challenge.
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Affiliation(s)
- Mona D Shahbazian
- Department of Biological Chemistry, Geffen School of Medicine and the Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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47
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Mandava V, Fernandez JP, Deng H, Janzen CJ, Hake SB, Cross GAM. Histone modifications in Trypanosoma brucei. Mol Biochem Parasitol 2007; 156:41-50. [PMID: 17714803 PMCID: PMC2012948 DOI: 10.1016/j.molbiopara.2007.07.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 07/11/2007] [Accepted: 07/11/2007] [Indexed: 10/23/2022]
Abstract
Several biological processes in Trypanosoma brucei are affected by chromatin structure, including gene expression, cell cycle regulation, and life-cycle stage differentiation. In Saccharomyces cerevisiae and other organisms, chromatin structure is dependent upon posttranslational modifications of histones, which have been mapped in detail. The tails of the four core histones of T. brucei are highly diverged from those of mammals and yeasts, so sites of potential modification cannot be reliably inferred, and no cross-species antibodies are available to map the modifications. We therefore undertook an extensive survey to identify posttranslational modifications by Edman degradation and mass spectrometry. Edman analysis showed that the N-terminal alanine of H2A, H2B, and H4 could be monomethylated. We found that the histone H4 N-terminus is heavily modified, while, in contrast to other organisms, the histone H2A and H2B N-termini have relatively few modifications. Histone H3 appears to have a number of modifications at the N-terminus, but we were unable to assign many of these to a specific amino acid. Therefore, we focused our efforts on uncovering modification states of H4. We discuss the potential relevance of these modifications.
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Affiliation(s)
- Veena Mandava
- Laboratory of Molecular Parasitology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Joseph P. Fernandez
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Haiteng Deng
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Christian J. Janzen
- Laboratory of Molecular Parasitology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Sandra B. Hake
- Laboratory of Chromatin Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - George A. M. Cross
- Laboratory of Molecular Parasitology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
- * Corresponding author. Tel.: +1 212-327-7577; Fax.: +1 212-327-7845, E-mail address:
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48
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Koehler RN, Rachfall N, Rolfes RJ. Activation of the ADE genes requires the chromatin remodeling complexes SAGA and SWI/SNF. EUKARYOTIC CELL 2007; 6:1474-85. [PMID: 17573544 PMCID: PMC1951130 DOI: 10.1128/ec.00068-07] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The activation of the ADE regulon genes requires the pair of transcription factors Bas1 and Pho2. In a genome-wide screen for additional regulators of the pathway, strains with mutations in multiple subunits of the chromatin remodeling complexes SAGA and SWI/SNF were uncovered. These mutants exhibited decreased expression of an ADE5,7-lacZ reporter and native ADE compared to the wild-type strains, but the expression of the BAS1 and PHO2 genes was not substantially decreased. An unregulated Bas1-Pho2 fusion protein depended upon SAGA and SWI/SNF activity to promote transcription of a reporter. A significant but low-level association of Gcn5-myc and Snf2-myc with the ADE5,7 promoter was independent of adenine growth conditions and independent of the presence of the activator proteins Bas1 and Pho2. However, the increase in occupancy of Bas1 and Pho2 at ADE5,7 depended on both SAGA and SWI/SNF. The loss of catalytic activity of both SAGA and SWI/SNF complexes in the gcn5Delta snf2Delta double mutant was severely detrimental to ADE-lacZ reporter expression and native ADE gene expression, indicating complementary roles for these complexes. We conclude that Bas1 and Pho2 do not recruit the SAGA and SWI/SNF complexes to the ADE5,7 promoter but that the remodeling complexes are necessary to increase the binding of Bas1 and Pho2 in response to the adenine regulatory signal. Our data support the model that the SAGA and SWI/SNF complexes engage in global surveillance that is necessary for the specific response by Bas1 and Pho2.
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Affiliation(s)
- Rebecca N Koehler
- Department of Biology, Georgetown University, Washington, DC 20057-1229, USA
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Durant M, Pugh BF. NuA4-directed chromatin transactions throughout the Saccharomyces cerevisiae genome. Mol Cell Biol 2007; 27:5327-35. [PMID: 17526728 PMCID: PMC1952100 DOI: 10.1128/mcb.00468-07] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two of the major histone acetyltransferases in Saccharomyces cerevisiae are NuA4 and SAGA, which acetylate histones H4 and H3, respectively. Acetylated H3 and H4 tails have been implicated in binding bromodomain proteins, including Bdf1. Bdf1 interacts with the general transcription factor TFIID, which might promote preinitiation complex (PIC) assembly. Bdf1 also interacts with the SWR complex (SWR-C). SWR-C is responsible for the deposition of the histone H2A variant H2A.Z. The placement of these interactions into a connected pathway of PIC assembly has not been fully established. Moreover, it is not known how widespread and how variable such a pathway might be on a genomic scale. Here we provide genomic evidence for S. cerevisiae that PIC assembly (TFIID occupancy) and chromatin remodeling (SWR-C and H2A.Z occupancy) are linked in large part to NuA4-directed H4 acetylation and subsequent Bdf1 binding, rather than through SAGA-directed H3 acetylation. Bdf1 and its homolog Bdf2 tend to have distinct locations in the genome. However, the deletion of BDF1 leads to the accumulation of Bdf2 at Bdf1-vacated sites. Thus, while Bdf1 and Bdf2 are at least partially redundant in function, their functions in the genome are geographically distinct.
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Affiliation(s)
- Melissa Durant
- Center for Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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50
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Teng Y, Yu Y, Ferreiro JA, Waters R. Histone acetylation, chromatin remodelling, transcription and nucleotide excision repair in S. cerevisiae: studies with two model genes. DNA Repair (Amst) 2007; 4:870-83. [PMID: 15950549 DOI: 10.1016/j.dnarep.2005.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2005] [Indexed: 11/23/2022]
Abstract
We describe the technology and two model systems in yeast designed to study nucleotide excision repair (NER) in relation to transcription and chromatin modifications. We employed the MFA2 and MET16 genes as models. How transcription-coupled (TCR) and global genome repair (GGR) operate at the transcriptionally active and/or repressed S. cerevisiae MFA2 locus, and how this relates to nucleosome positioning are considered. We discuss the role of the Gcn5p histone acetyltransferase, also associated with MFA2's transcriptional activation, in facilitating efficient NER at the transcriptionally active and inactive genes. The effect of Gcn5p's absence in reducing NER was local and UV stimulates Gcn5p-mediated histone acetylation at the repressed MFA2 promoter. After UV irradiation Swi2p is partly responsible for facilitating access to restriction of DNA in the cores of the nucleosomes at the MFA2 promoter. The data suggest similarities between chromatin remodelling for NER and transcription, yet differences must exist to ensure this gene remains repressed in alpha cells during NER. For MET16, we consider experiments examining chromatin structure, transcription and repair in wild type and cbf1Delta cells under repressing or derepressing conditions. Cbf1p is a sequence specific DNA binding protein required for MET16 chromatin remodelling and transcription.
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Affiliation(s)
- Yumin Teng
- Department of Pathology, University Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK
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