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Ferdoush J, Kadir RA, Ogle M, Saha A. Regulation of eukaryotic transcription initiation in response to cellular stress. Gene 2024; 924:148616. [PMID: 38795856 DOI: 10.1016/j.gene.2024.148616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Transcription initiation is a vital step in the regulation of eukaryotic gene expression. It can be dysregulated in response to various cellular stressors which is associated with numerous human diseases including cancer. Transcription initiation is facilitated via many gene-specific trans-regulatory elements such as transcription factors, activators, and coactivators through their interactions with transcription pre-initiation complex (PIC). These trans-regulatory elements can uniquely facilitate PIC formation (hence, transcription initiation) in response to cellular nutrient stress. Cellular nutrient stress also regulates the activity of other pathways such as target of rapamycin (TOR) pathway. TOR pathway exhibits distinct regulatory mechanisms of transcriptional activation in response to stress. Like TOR pathway, the cell cycle regulatory pathway is also found to be linked to transcriptional regulation in response to cellular stress. Several transcription factors such as p53, C/EBP Homologous Protein (CHOP), activating transcription factor 6 (ATF6α), E2F, transforming growth factor (TGF)-β, Adenomatous polyposis coli (APC), SMAD, and MYC have been implicated in regulation of transcription of target genes involved in cell cycle progression, apoptosis, and DNA damage repair pathways. Additionally, cellular metabolic and oxidative stressors have been found to regulate the activity of long non-coding RNAs (lncRNA). LncRNA regulates transcription by upregulating or downregulating the transcription regulatory proteins involved in metabolic and cell signaling pathways. Numerous human diseases, triggered by chronic cellular stressors, are associated with abnormal regulation of transcription. Hence, understanding these mechanisms would help unravel the molecular regulatory insights with potential therapeutic interventions. Therefore, here we emphasize the recent advances of regulation of eukaryotic transcription initiation in response to cellular stress.
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Affiliation(s)
- Jannatul Ferdoush
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, 615 McCallie Ave, Chattanooga, TN 37403, USA.
| | - Rizwaan Abdul Kadir
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, 615 McCallie Ave, Chattanooga, TN 37403, USA
| | - Matthew Ogle
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, 615 McCallie Ave, Chattanooga, TN 37403, USA
| | - Ayan Saha
- Department of Bioinformatics and Biotechnology, Asian University for Women, Chattogram, Bangladesh
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2
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Barman P, Chakraborty P, Bhaumik R, Bhaumik SR. UPS writes a new saga of SAGA. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194981. [PMID: 37657588 PMCID: PMC10843445 DOI: 10.1016/j.bbagrm.2023.194981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023]
Abstract
SAGA (Spt-Ada-Gcn5-Acetyltransferase), an evolutionarily conserved transcriptional co-activator among eukaryotes, is a large multi-subunit protein complex with two distinct enzymatic activities, namely HAT (Histone acetyltransferase) and DUB (De-ubiquitinase), and is targeted to the promoter by the gene-specific activator proteins for histone covalent modifications and PIC (Pre-initiation complex) formation in enhancing transcription (or gene activation). Targeting of SAGA to the gene promoter is further facilitated by the 19S RP (Regulatory particle) of the 26S proteasome (that is involved in targeted degradation of protein via ubiquitylation) in a proteolysis-independent manner. Moreover, SAGA is also recently found to be regulated by the 26S proteasome in a proteolysis-dependent manner via the ubiquitylation of its Sgf73/ataxin-7 component that is required for SAGA's integrity and DUB activity (and hence transcription), and is linked to various diseases including neurodegenerative disorders and cancer. Thus, SAGA itself and its targeting to the active gene are regulated by the UPS (Ubiquitin-proteasome system) with implications in diseases.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale IL-62901, USA
| | - Pritam Chakraborty
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale IL-62901, USA
| | - Rhea Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale IL-62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale IL-62901, USA.
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3
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Lee H, Kim S, Lee D. The versatility of the proteasome in gene expression and silencing: Unraveling proteolytic and non-proteolytic functions. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194978. [PMID: 37633648 DOI: 10.1016/j.bbagrm.2023.194978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/02/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023]
Abstract
The 26S proteasome consists of a 20S core particle and a 19S regulatory particle and critically regulates gene expression and silencing through both proteolytic and non-proteolytic functions. The 20S core particle mediates proteolysis, while the 19S regulatory particle performs non-proteolytic functions. The proteasome plays a role in regulating gene expression in euchromatin by modifying histones, activating transcription, initiating and terminating transcription, mRNA export, and maintaining transcriptome integrity. In gene silencing, the proteasome modulates the heterochromatin formation, spreading, and subtelomere silencing by degrading specific proteins and interacting with anti-silencing factors such as Epe1, Mst2, and Leo1. This review discusses the proteolytic and non-proteolytic functions of the proteasome in regulating gene expression and gene silencing-related heterochromatin formation. This article is part of a special issue on the regulation of gene expression and genome integrity by the ubiquitin-proteasome system.
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Affiliation(s)
- Hyesu Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Sungwook Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea.
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4
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Kumari P, Sarovar Bhavesh N. Birth and death view of DNA, RNA, and proteins. Gene 2023; 883:147672. [PMID: 37506987 DOI: 10.1016/j.gene.2023.147672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/26/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
The potential of cells to guide their genome and configure genes to express at a given time and in response to specific stimuli is pivotal to regulate cellular processes such as tissue differentiation, organogenesis, organismal development, homeostasis, and disease. In this review, we focus on the diverse mechanisms involved in DNA replication and its degradation, mRNA synthesis, and associated regulation such as RNA capping, splicing, tailing, and export. mRNA turnover including Decapping, deadenylation, RNA interference, and Nonsense mediated mRNA decay followed by protein translation, post-translational modification, and protein turnover. We highlight recent advances in understanding the complex series of molecular mechanisms responsible for the remarkable cellular regulatory mechanisms.
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Affiliation(s)
- Pooja Kumari
- Amity Institute of Biotechnology, Amity University Jharkhand, Ranchi, Jharkhand 834001, India.
| | - Neel Sarovar Bhavesh
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India.
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5
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Barman P, Kaja A, Chakraborty P, Guha S, Roy A, Ferdoush J, Bhaumik SR. A novel ubiquitin-proteasome system regulation of Sgf73/ataxin-7 that maintains the integrity of the coactivator SAGA in orchestrating transcription. Genetics 2023; 224:iyad071. [PMID: 37075097 PMCID: PMC10324951 DOI: 10.1093/genetics/iyad071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 01/31/2023] [Accepted: 03/15/2023] [Indexed: 04/20/2023] Open
Abstract
Ataxin-7 maintains the integrity of Spt-Ada-Gcn5-Acetyltransferase (SAGA), an evolutionarily conserved coactivator in stimulating preinitiation complex (PIC) formation for transcription initiation, and thus, its upregulation or downregulation is associated with various diseases. However, it remains unknown how ataxin-7 is regulated that could provide new insights into disease pathogenesis and therapeutic interventions. Here, we show that ataxin-7's yeast homologue, Sgf73, undergoes ubiquitylation and proteasomal degradation. Impairment of such regulation increases Sgf73's abundance, which enhances recruitment of TATA box-binding protein (TBP) (that nucleates PIC formation) to the promoter but impairs transcription elongation. Further, decreased Sgf73 level reduces PIC formation and transcription. Thus, Sgf73 is fine-tuned by ubiquitin-proteasome system (UPS) in orchestrating transcription. Likewise, ataxin-7 undergoes ubiquitylation and proteasomal degradation, alteration of which changes ataxin-7's abundance that is associated with altered transcription and cellular pathologies/diseases. Collectively, our results unveil a novel UPS regulation of Sgf73/ataxin-7 for normal cellular health and implicate alteration of such regulation in diseases.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Amala Kaja
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX-77030, USA
| | - Pritam Chakraborty
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Arpan Roy
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Jannatul Ferdoush
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
- Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, 615 McCallie Ave, Chattanooga, TN 37403, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
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6
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Geng Q, Li H, Wang D, Sheng RC, Zhu H, Klosterman SJ, Subbarao KV, Chen JY, Chen FM, Zhang DD. The Verticillium dahliae Spt-Ada-Gcn5 Acetyltransferase Complex Subunit Ada1 Is Essential for Conidia and Microsclerotia Production and Contributes to Virulence. Front Microbiol 2022; 13:852571. [PMID: 35283850 PMCID: PMC8905346 DOI: 10.3389/fmicb.2022.852571] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 01/31/2022] [Indexed: 12/16/2022] Open
Abstract
Verticillium dahliae is a destructive soil-borne pathogen of many economically important dicots. The genetics of pathogenesis in V. dahliae has been extensively studied. Spt-Ada-Gcn5 acetyltransferase complex (SAGA) is an ATP-independent multifunctional chromatin remodeling complex that contributes to diverse transcriptional regulatory functions. As members of the core module in the SAGA complex in Saccharomyces cerevisiae, Ada1, together with Spt7 and Spt20, play an important role in maintaining the integrity of the complex. In this study, we identified homologs of the SAGA complex in V. dahliae and found that deletion of the Ada1 subunit (VdAda1) causes severe defects in the formation of conidia and microsclerotia, and in melanin biosynthesis and virulence. The effect of VdAda1 on histone acetylation in V. dahliae was confirmed by western blot analysis. The deletion of VdAda1 resulted in genome-wide alteration of the V. dahliae transcriptome, including genes encoding transcription factors and secreted proteins, suggesting its prominent role in the regulation of transcription and virulence. Overall, we demonstrated that VdAda1, a member of the SAGA complex, modulates multiple physiological processes by regulating global gene expression that impinge on virulence and survival in V. dahliae.
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Affiliation(s)
- Qi Geng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Huan Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Dan Wang
- Team of Crop Verticillium Wilt, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ruo-Cheng Sheng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - He Zhu
- National Cotton Industry Technology System Liaohe Comprehensive Experimental Station, The Cotton Research Center of Liaoning Academy of Agricultural Sciences, Liaoning Provincial Institute of Economic Crops, Liaoyang, China
| | - Steven J Klosterman
- United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, Salinas, CA, United States
| | - Krishna V Subbarao
- Department of Plant Pathology, c/o U.S. Agricultural Research Station, University of California, Davis, Salinas, CA, United States
| | - Jie-Yin Chen
- Team of Crop Verticillium Wilt, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Feng-Mao Chen
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Dan-Dan Zhang
- Team of Crop Verticillium Wilt, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Barman P, Sen R, Kaja A, Ferdoush J, Guha S, Govind CK, Bhaumik SR. Genome-Wide Regulations of the Preinitiation Complex Formation and Elongating RNA Polymerase II by an E3 Ubiquitin Ligase, San1. Mol Cell Biol 2022; 42:e0036821. [PMID: 34661445 PMCID: PMC8773080 DOI: 10.1128/mcb.00368-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/18/2021] [Accepted: 10/12/2021] [Indexed: 11/20/2022] Open
Abstract
San1 ubiquitin ligase is involved in nuclear protein quality control via its interaction with intrinsically disordered proteins for ubiquitylation and proteasomal degradation. Since several transcription/chromatin regulatory factors contain intrinsically disordered domains and can be inhibitory to transcription when in excess, San1 might be involved in transcription regulation. To address this, we analyzed the role of San1 in the genome-wide association of TATA box binding protein (TBP; which nucleates preinitiation complex [PIC] formation for transcription initiation) and RNA polymerase II (Pol II). Our results reveal the roles of San1 in regulating TBP recruitment to the promoters and Pol II association with the coding sequences and, hence, PIC formation and coordination of elongating Pol II, respectively. Consistently, transcription is altered in the absence of San1. Such transcriptional alteration is associated with impaired ubiquitylation and proteasomal degradation of Spt16 and gene association of Paf1 but not the incorporation of centromeric histone, Cse4, into the active genes in the Δsan1 strain. Collectively, our results demonstrate distinct functions of a nuclear protein quality control factor in regulating the genome-wide PIC formation and elongating Pol II (and hence transcription), thus unraveling new gene regulatory mechanisms.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Rwik Sen
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Amala Kaja
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Jannatul Ferdoush
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Chhabi K. Govind
- Department of Biological Sciences, Oakland University, Rochester, Minnesota, USA
| | - Sukesh R. Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
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8
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Stimulus-specific responses in innate immunity: Multilayered regulatory circuits. Immunity 2021; 54:1915-1932. [PMID: 34525335 DOI: 10.1016/j.immuni.2021.08.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 03/07/2021] [Accepted: 08/16/2021] [Indexed: 12/24/2022]
Abstract
Immune sentinel cells initiate immune responses to pathogens and tissue injury and are capable of producing highly stimulus-specific responses. Insight into the mechanisms underlying such specificity has come from the identification of regulatory factors and biochemical pathways, as well as the definition of signaling circuits that enable combinatorial and temporal coding of information. Here, we review the multi-layered molecular mechanisms that underlie stimulus-specific gene expression in macrophages. We categorize components of inflammatory and anti-pathogenic signaling pathways into five layers of regulatory control and discuss unifying mechanisms determining signaling characteristics at each layer. In this context, we review mechanisms that enable combinatorial and temporal encoding of information, identify recurring regulatory motifs and principles, and present strategies for integrating experimental and computational approaches toward the understanding of signaling specificity in innate immunity.
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9
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Guha S, Bhaumik SR. Transcription-coupled DNA double-strand break repair. DNA Repair (Amst) 2021; 109:103211. [PMID: 34883263 DOI: 10.1016/j.dnarep.2021.103211] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 12/20/2022]
Abstract
The genomic DNA is constantly under attack by cellular and/or environmental factors. Fortunately, the cell is armed to safeguard its genome by various mechanisms such as nucleotide excision, base excision, mismatch and DNA double-strand break repairs. While these processes maintain the integrity of the genome throughout, DNA repair occurs preferentially faster at the transcriptionally active genes. Such transcription-coupled repair phenomenon plays important roles to maintain active genome integrity, failure of which would interfere with transcription, leading to an altered gene expression (and hence cellular pathologies/diseases). Among the various DNA damages, DNA double-strand breaks are quite toxic to the cells. If DNA double-strand break occurs at the active gene, it would interfere with transcription/gene expression, thus threatening cellular viability. Such DNA double-strand breaks are found to be repaired faster at the active gene in comparison to its inactive state or the inactive gene, thus supporting the existence of a new phenomenon of transcription-coupled DNA double-strand break repair. Here, we describe the advances of this repair process.
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Affiliation(s)
- Shalini Guha
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL, 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL, 62901, USA.
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10
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Fluorescence resonance energy transfer in revealing protein-protein interactions in living cells. Emerg Top Life Sci 2021; 5:49-59. [PMID: 33856021 DOI: 10.1042/etls20200337] [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: 11/29/2020] [Revised: 02/22/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022]
Abstract
Genes are expressed to proteins for a wide variety of fundamental biological processes at the cellular and organismal levels. However, a protein rarely functions alone, but rather acts through interactions with other proteins to maintain normal cellular and organismal functions. Therefore, it is important to analyze the protein-protein interactions to determine functional mechanisms of proteins, which can also guide to develop therapeutic targets for treatment of diseases caused by altered protein-protein interactions leading to cellular/organismal dysfunctions. There is a large number of methodologies to study protein interactions in vitro, in vivo and in silico, which led to the development of many protein interaction databases, and thus, have enriched our knowledge about protein-protein interactions and functions. However, many of these interactions were identified in vitro, but need to be verified/validated in living cells. Furthermore, it is unclear whether these interactions are direct or mediated via other proteins. Moreover, these interactions are representative of cell- and time-average, but not a single cell in real time. Therefore, it is crucial to detect direct protein-protein interactions in a single cell during biological processes in vivo, towards understanding the functional mechanisms of proteins in living cells. Importantly, a fluorescence resonance energy transfer (FRET)-based methodology has emerged as a powerful technique to decipher direct protein-protein interactions at a single cell resolution in living cells, which is briefly described in a limited available space in this mini-review.
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11
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Sen S, Cheng Z, Sheu KM, Chen YH, Hoffmann A. Gene Regulatory Strategies that Decode the Duration of NFκB Dynamics Contribute to LPS- versus TNF-Specific Gene Expression. Cell Syst 2020; 10:169-182.e5. [PMID: 31972132 DOI: 10.1016/j.cels.2019.12.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/20/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022]
Abstract
Pathogen-derived lipopolysaccharide (LPS) and cytokine tumor necrosis factor (TNF) activate NFκB with distinct duration dynamics, but how immune response genes decode NFκB duration to produce stimulus-specific expression remains unclear. Here, detailed transcriptomic profiling of combinatorial and temporal control mutants identified 81 genes that depend on stimulus-specific NFκB duration for their stimulus-specificity. Combining quantitative experimentation with mathematical modeling, we found that for some genes a long mRNA half-life allowed effective decoding, but for many genes this was insufficient to account for the data; instead, we found that chromatin mechanisms, such as a slow transition rate between inactive and RelA-bound enhancer states, could also decode NFκB dynamics. Chromatin-mediated decoding is favored by genes acting as immune effectors (e.g., tissue remodelers and T cell recruiters) rather than immune regulators (e.g., signaling proteins and monocyte recruiters). Overall, our results delineate two gene regulatory strategies that decode stimulus-specific NFκB dynamics and determine distinct biological functions.
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Affiliation(s)
- Supriya Sen
- Department of Microbiology, Immunology, and Molecular Genetics (MIMG), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Zhang Cheng
- Department of Microbiology, Immunology, and Molecular Genetics (MIMG), University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences (QCB), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Katherine M Sheu
- Department of Microbiology, Immunology, and Molecular Genetics (MIMG), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yu Hsin Chen
- Department of Microbiology, Immunology, and Molecular Genetics (MIMG), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander Hoffmann
- Department of Microbiology, Immunology, and Molecular Genetics (MIMG), University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences (QCB), University of California, Los Angeles, Los Angeles, CA 90095, USA.
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12
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Hsu CH, Chen YJ, Yang CN. Loss of function in SAGA deubiquitinating module caused by Sgf73 H93A mutation: A molecular dynamics study. J Mol Graph Model 2019; 91:112-118. [DOI: 10.1016/j.jmgm.2019.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/31/2019] [Accepted: 06/02/2019] [Indexed: 01/23/2023]
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13
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Barman P, Reddy D, Bhaumik SR. Mechanisms of Antisense Transcription Initiation with Implications in Gene Expression, Genomic Integrity and Disease Pathogenesis. Noncoding RNA 2019; 5:ncrna5010011. [PMID: 30669611 PMCID: PMC6468509 DOI: 10.3390/ncrna5010011] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/01/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Non-coding antisense transcripts arise from the strand opposite the sense strand. Over 70% of the human genome generates non-coding antisense transcripts while less than 2% of the genome codes for proteins. Antisense transcripts and/or the act of antisense transcription regulate gene expression and genome integrity by interfering with sense transcription and modulating histone modifications or DNA methylation. Hence, they have significant pathological and physiological relevance. Indeed, antisense transcripts were found to be associated with various diseases including cancer, diabetes, cardiac and neurodegenerative disorders, and, thus, have promising potentials for prognostic and diagnostic markers and therapeutic development. However, it is not clearly understood how antisense transcription is initiated and epigenetically regulated. Such knowledge would provide new insights into the regulation of antisense transcription, and hence disease pathogenesis with therapeutic development. The recent studies on antisense transcription initiation and its epigenetic regulation, which are limited, are discussed here. Furthermore, we concisely describe how antisense transcription/transcripts regulate gene expression and genome integrity with implications in disease pathogenesis and therapeutic development.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
| | - Divya Reddy
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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14
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Knoll ER, Zhu ZI, Sarkar D, Landsman D, Morse RH. Role of the pre-initiation complex in Mediator recruitment and dynamics. eLife 2018; 7:39633. [PMID: 30540252 PMCID: PMC6322861 DOI: 10.7554/elife.39633] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/12/2018] [Indexed: 12/19/2022] Open
Abstract
The Mediator complex stimulates the cooperative assembly of a pre-initiation complex (PIC) and recruitment of RNA Polymerase II (Pol II) for gene activation. The core Mediator complex is organized into head, middle, and tail modules, and in budding yeast (Saccharomyces cerevisiae), Mediator recruitment has generally been ascribed to sequence-specific activators engaging the tail module triad of Med2-Med3-Med15 at upstream activating sequences (UASs). We show that yeast lacking Med2-Med3-Med15 are viable and that Mediator and PolII are recruited to promoters genome-wide in these cells, albeit at reduced levels. To test whether Mediator might alternatively be recruited via interactions with the PIC, we examined Mediator association genome-wide after depleting PIC components. We found that depletion of Taf1, Rpb3, and TBP profoundly affected Mediator association at active gene promoters, with TBP being critical for transit of Mediator from UAS to promoter, while Pol II and Taf1 stabilize Mediator association at proximal promoters.
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Affiliation(s)
- Elisabeth R Knoll
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, United States
| | - Z Iris Zhu
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, Bethesda, United States
| | - Debasish Sarkar
- Wadsworth Center, New York State Department of Health, Albany, United States
| | - David Landsman
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, Bethesda, United States
| | - Randall H Morse
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, United States.,Wadsworth Center, New York State Department of Health, Albany, United States
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15
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Bruzzone MJ, Grünberg S, Kubik S, Zentner GE, Shore D. Distinct patterns of histone acetyltransferase and Mediator deployment at yeast protein-coding genes. Genes Dev 2018; 32:1252-1265. [PMID: 30108132 PMCID: PMC6120713 DOI: 10.1101/gad.312173.118] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 06/19/2018] [Indexed: 02/07/2023]
Abstract
Here, Bruzzone et al. explore the relative contributions of the transcriptional coactivators Mediator and two histone acetyltransferase (HAT) complexes, NuA4 and SAGA, to RNA polymerase II association at specific genes and gene classes by rapid nuclear depletion of key complex subunits. They show that the NuA4 HAT Esa1 differentially affects certain groups of genes, whereas the SAGA HAT Gcn5 has a weaker but more uniform effect, and their findings suggest that at least three distinct combinations of coactivator deployment are used to generate moderate or high transcription levels. The transcriptional coactivators Mediator and two histone acetyltransferase (HAT) complexes, NuA4 and SAGA, play global roles in transcriptional activation. Here we explore the relative contributions of these factors to RNA polymerase II association at specific genes and gene classes by rapid nuclear depletion of key complex subunits. We show that the NuA4 HAT Esa1 differentially affects certain groups of genes, whereas the SAGA HAT Gcn5 has a weaker but more uniform effect. Relative dependence on Esa1 and Tra1, a shared component of NuA4 and SAGA, distinguishes two large groups of coregulated growth-promoting genes. In contrast, we show that the activity of Mediator is particularly important at a separate, small set of highly transcribed TATA-box-containing genes. Our analysis indicates that at least three distinct combinations of coactivator deployment are used to generate moderate or high transcription levels and suggests that each may be associated with distinct forms of regulation.
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Affiliation(s)
- Maria Jessica Bruzzone
- Department of Molecular Biology, Institute of Genetics and Genomics in Geneva, 1211 Geneva 4, Switzerland
| | - Sebastian Grünberg
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Slawomir Kubik
- Department of Molecular Biology, Institute of Genetics and Genomics in Geneva, 1211 Geneva 4, Switzerland
| | - Gabriel E Zentner
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - David Shore
- Department of Molecular Biology, Institute of Genetics and Genomics in Geneva, 1211 Geneva 4, Switzerland
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TOR Facilitates the Targeting of the 19S Proteasome Subcomplex To Enhance Transcription Complex Assembly at the Promoters of the Ribosomal Protein Genes. Mol Cell Biol 2018; 38:MCB.00469-17. [PMID: 29712756 DOI: 10.1128/mcb.00469-17] [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: 09/02/2017] [Accepted: 04/23/2018] [Indexed: 12/12/2022] Open
Abstract
TOR (target of rapamycin) has been previously implicated in transcriptional stimulation of the ribosomal protein (RP) genes via enhanced recruitment of NuA4 (nucleosome acetyltransferase of H4) to the promoters. However, it is not clearly understood how TOR enhances NuA4 recruitment to the promoters of the RP genes. Here we show that TOR facilitates the recruitment of the 19S proteasome subcomplex to the activator to enhance the targeting of NuA4 to the promoters of the RP genes. NuA4, in turn, promotes the recruitment of TFIID (transcription factor IID, composed of TATA box-binding protein [TBP] and a set of TBP-associated factors [TAFs]) and RNA polymerase II to the promoters of the RP genes to enhance transcriptional initiation. Therefore, our results demonstrate that TOR facilitates the recruitment of the 19S proteasome subcomplex to the promoters of the RP genes to promote the targeting of NuA4 for enhanced preinitiation complex (PIC) formation and consequently transcriptional initiation, hence illuminating TOR regulation of RP gene activation. Further, our results reveal that TOR differentially regulates PIC formation (and hence transcription) at the non-RP genes, thus demonstrating a complex regulation of gene activation by TOR.
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17
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Watanabe K, Kokubo T. SAGA mediates transcription from the TATA-like element independently of Taf1p/TFIID but dependent on core promoter structures in Saccharomyces cerevisiae. PLoS One 2017; 12:e0188435. [PMID: 29176831 PMCID: PMC5703507 DOI: 10.1371/journal.pone.0188435] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/07/2017] [Indexed: 11/21/2022] Open
Abstract
In Saccharomyces cerevisiae, core promoters of class II genes contain a TATA element, either a TATA box (TATA[A/T]A[A/T][A/G]) or TATA-like element (1 or 2 bp mismatched version of the TATA box). The TATA element directs the assembly of the preinitiation complex (PIC) to ensure accurate transcriptional initiation. It has been proposed the PIC is assembled by two distinct pathways in which TBP is delivered by TFIID or SAGA, leading to the widely accepted model that these complexes mediate transcription mainly from TATA-like element- or TATA box-containing promoters, respectively. Although both complexes are involved in transcription of nearly all class II genes, it remains unclear how efficiently SAGA mediates transcription from TATA-like element-containing promoters independently of TFIID. We found that transcription from the TATA box-containing AGP1 promoter was greatly stimulated in a Spt3p-dependent manner after inactivation of Taf1p/TFIID. Thus, this promoter provides a novel experimental system in which to evaluate SAGA-mediated transcription from TATA-like element(s). We quantitatively measured transcription from various TATA-like elements in the Taf1p-dependent CYC1 promoter and Taf1p-independent AGP1 promoter. The results revealed that SAGA could mediate transcription from at least some TATA-like elements independently of Taf1p/TFIID, and that Taf1p-dependence or -independence is highly robust with respect to variation of the TATA sequence. Furthermore, chimeric promoter mapping revealed that Taf1p-dependence or independence was conferred by the upstream activating sequence (UAS), whereas Spt3p-dependent transcriptional stimulation after inactivation of Taf1p/TFIID was specific to the AGP1 promoter and dependent on core promoter regions other than the TATA box. These results suggest that TFIID and/or SAGA are regulated in two steps: the UAS first specifies TFIID or SAGA as the predominant factor on a given promoter, and then the core promoter structure guides the pertinent factor to conduct transcription in an appropriate manner.
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Affiliation(s)
- Kiyoshi Watanabe
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Tetsuro Kokubo
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
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18
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Two Distinct Regulatory Mechanisms of Transcriptional Initiation in Response to Nutrient Signaling. Genetics 2017; 208:191-205. [PMID: 29141908 DOI: 10.1534/genetics.117.300518] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/26/2017] [Indexed: 12/19/2022] Open
Abstract
SAGA (Spt-Ada-Gcn5-Acetyltransferase) and TFIID (transcription factor IID) have been previously shown to facilitate the formation of the PIC (pre-initiation complex) at the promoters of two distinct sets of genes. Here, we demonstrate that TFIID and SAGA differentially participate in the stimulation of PIC formation (and hence transcriptional initiation) at the promoter of PHO84, a gene for the high-affinity inorganic phosphate (Pi) transporter for crucial cellular functions, in response to nutrient signaling. We show that transcriptional initiation of PHO84 occurs predominantly in a TFIID-dependent manner in the absence of Pi in the growth medium. Such TFIID dependency is mediated via the NuA4 (nucleosome acetyltransferase of H4) histone acetyltransferase (HAT). Intriguingly, transcriptional initiation of PHO84 also occurs in the presence of Pi in the growth medium, predominantly via the SAGA complex, but independently of NuA4 HAT. Thus, Pi in the growth medium switches transcriptional initiation of PHO84 from NuA4-TFIID to SAGA dependency. Further, we find that both NuA4-TFIID- and SAGA-dependent transcriptional initiations of PHO84 are facilitated by the 19S proteasome subcomplex or regulatory particle (RP) via enhanced recruitment of the coactivators SAGA and NuA4 HAT, which promote TFIID-independent and -dependent PIC formation for transcriptional initiation, respectively. NuA4 HAT does not regulate activator binding to PHO84, but rather facilitates PIC formation for transcriptional initiation in the absence of Pi in the growth medium. On the other hand, SAGA promotes activator recruitment to PHO84 for transcriptional initiation in the growth medium containing Pi. Collectively, our results demonstrate two distinct stimulatory pathways for PIC formation (and hence transcriptional initiation) at PHO84 by TFIID, SAGA, NuA4, and 19S RP in the presence and absence of an essential nutrient, Pi, in the growth media, thus providing new regulatory mechanisms of transcriptional initiation in response to nutrient signaling.
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19
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Ferdoush J, Karmakar S, Barman P, Kaja A, Uprety B, Batra SK, Bhaumik SR. Ubiquitin–Proteasome System Regulation of an Evolutionarily Conserved RNA Polymerase II-Associated Factor 1 Involved in Pancreatic Oncogenesis. Biochemistry 2017; 56:6083-6086. [PMID: 29023102 DOI: 10.1021/acs.biochem.7b00865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The evolutionarily conserved RNA polymerase II-associated factor 1 (Paf1) from yeast to humans regulates transcription and associated processes, and thus, malfunctions and/or misregulations of Paf1 are associated with cellular pathologies. Indeed, Paf1 (also known as PD2 or pancreatic differentiation 2) is found to be upregulated in poorly differentiated cancer cells, and such upregulation is involved in cellular transformation or oncogenesis. However, the basis for Paf1 upregulation in these cells remains largely unknown. In light of this, we have tested here the idea that the ubiquitin-proteasome system (UPS) regulates the cellular abundance of Paf1. In this direction, we analyzed the role of UPS in regulation of Paf1's abundance in yeast. We find that Paf1 undergoes ubiquitylation and is degraded by the 26S proteasome in yeast, thus deciphering UPS regulation of an evolutionarily conserved factor, Paf1, involved in various cellular processes at the crossroads of the cancer networks. Likewise, Paf1 undergoes proteasomal degradation in well-differentiated, but not poorly differentiated, pancreatic cancer cells, hence pointing to the UPS in upregulation of Paf1 in poorly differentiated cancers. Collectively, our results reveal UPS regulation of Paf1 and suggest downregulation of UPS in elevating Paf1's abundance in poorly differentiated cancers.
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Affiliation(s)
- Jannatul Ferdoush
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Saswati Karmakar
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Priyanka Barman
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Amala Kaja
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Bhawana Uprety
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Surinder K. Batra
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Sukesh R. Bhaumik
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
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20
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Hintze S, Engelhardt M, van Diepen L, Witt E, Schüller HJ. Multiple Taf subunits of TFIID interact with Ino2 activation domains and contribute to expression of genes required for yeast phospholipid biosynthesis. Mol Microbiol 2017; 106:876-890. [PMID: 28994223 DOI: 10.1111/mmi.13850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2017] [Indexed: 12/15/2022]
Abstract
Expression of phospholipid biosynthetic genes in yeast requires activator protein Ino2 which can bind to the UAS element inositol/choline-responsive element (ICRE) and trigger activation of target genes, using two separate transcriptional activation domains, TAD1 and TAD2. However, it is still unknown which cofactors mediate activation by TADs of Ino2. Here, we show that multiple subunits of basal transcription factor TFIID (TBP-associated factors Taf1, Taf4, Taf6, Taf10 and Taf12) are able to interact in vitro with activation domains of Ino2. Interaction was no longer observed with activation-defective variants of TAD1. We were able to identify two nonoverlapping regions in the N-terminus of Taf1 (aa 1-100 and aa 182-250) each of which could interact with TAD1 of Ino2 as well as with TAD4 of activator Adr1. Specific missense mutations within Taf1 domain aa 182-250 affecting basic and hydrophobic residues prevented interaction with wild-type TAD1 and caused reduced expression of INO1. Using chromatin immunoprecipitation we demonstrated Ino2-dependent recruitment of Taf1 and Taf6 to ICRE-containing promoters INO1 and CHO2. Transcriptional derepression of INO1 was no longer possible with temperature-sensitive taf1 and taf6 mutants cultivated under nonpermissive conditions. This result supports the hypothesis of Taf-dependent expression of structural genes activated by Ino2.
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Affiliation(s)
- Stefan Hintze
- Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Jahnstrasse 15a, D-17487 Greifswald, Germany
| | - Maike Engelhardt
- Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Jahnstrasse 15a, D-17487 Greifswald, Germany
| | - Laura van Diepen
- Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Jahnstrasse 15a, D-17487 Greifswald, Germany
| | - Eric Witt
- Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Jahnstrasse 15a, D-17487 Greifswald, Germany
| | - Hans-Joachim Schüller
- Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Jahnstrasse 15a, D-17487 Greifswald, Germany
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21
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An mRNA Capping Enzyme Targets FACT to the Active Gene To Enhance the Engagement of RNA Polymerase II into Transcriptional Elongation. Mol Cell Biol 2017; 37:MCB.00029-17. [PMID: 28396559 DOI: 10.1128/mcb.00029-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/30/2017] [Indexed: 12/22/2022] Open
Abstract
We have recently demonstrated that an mRNA capping enzyme, Cet1, impairs promoter-proximal accumulation/pausing of RNA polymerase II (Pol II) independently of its capping activity in Saccharomyces cerevisiae to control transcription. However, it is still unknown how Pol II pausing is regulated by Cet1. Here, we show that Cet1's N-terminal domain (NTD) promotes the recruitment of FACT (facilitates chromatin transcription that enhances the engagement of Pol II into transcriptional elongation) to the coding sequence of an active gene, ADH1, independently of mRNA-capping activity. Absence of Cet1's NTD decreases FACT targeting to ADH1 and consequently reduces the engagement of Pol II in transcriptional elongation, leading to promoter-proximal accumulation of Pol II. Similar results were also observed at other genes. Consistently, Cet1 interacts with FACT. Collectively, our results support the notion that Cet1's NTD promotes FACT targeting to the active gene independently of mRNA-capping activity in facilitating Pol II's engagement in transcriptional elongation, thus deciphering a novel regulatory pathway of gene expression.
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22
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Liu Z, Moran GP, Sullivan DJ, MacCallum DM, Myers LC. Amplification of TLO Mediator Subunit Genes Facilitate Filamentous Growth in Candida Spp. PLoS Genet 2016; 12:e1006373. [PMID: 27741243 PMCID: PMC5065183 DOI: 10.1371/journal.pgen.1006373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/19/2016] [Indexed: 01/06/2023] Open
Abstract
Filamentous growth is a hallmark of C. albicans pathogenicity compared to less-virulent ascomycetes. A multitude of transcription factors regulate filamentous growth in response to specific environmental cues. Our work, however, suggests the evolutionary history of C. albicans that resulted in its filamentous growth plasticity may be tied to a change in the general transcription machinery rather than transcription factors and their specific targets. A key genomic difference between C. albicans and its less-virulent relatives, including its closest relative C. dubliniensis, is the unique expansion of the TLO (TeLOmere-associated) gene family in C. albicans. Individual Tlo proteins are fungal-specific subunits of Mediator, a large multi-subunit eukaryotic transcriptional co-activator complex. This amplification results in a large pool of ‘free,’ non-Mediator associated, Tlo protein present in C. albicans, but not in C. dubliniensis or other ascomycetes with attenuated virulence. We show that engineering a large ‘free’ pool of the C. dubliniensis Tlo2 (CdTlo2) protein in C. dubliniensis, through overexpression, results in a number of filamentation phenotypes typically associated only with C. albicans. The amplitude of these phenotypes is proportional to the amount of overexpressed CdTlo2 protein. Overexpression of other C. dubliniensis and C. albicans Tlo proteins do result in these phenotypes. Tlo proteins and their orthologs contain a Mediator interaction domain, and a potent transcriptional activation domain. Nuclear localization of the CdTlo2 activation domain, facilitated naturally by the Tlo Mediator binding domain or artificially through an appended nuclear localization signal, is sufficient for the CdTlo2 overexpression phenotypes. A C. albicans med3 null mutant causes multiple defects including the inability to localize Tlo proteins to the nucleus and reduced virulence in a murine systemic infection model. Our data supports a model in which the activation domain of ‘free’ Tlo protein competes with DNA bound transcription factors for targets that regulate key aspects of C. albicans cell physiology. The ascomycete fungus Candida albicans is a leading cause of hospital-acquired bloodstream infections in the United States. Due to limited anti-fungal drug options, there is an approximately 40% mortality rate and over 10,000 deaths per year associated with systemic C. albicans infections. It is unknown why C. albicans is the primary cause of systemic Candidiasis, versus related ascomycetes such as Candida dubliniensis. The genomes of C. albicans and C. dubliniensis are remarkably similar, yet C. dubliniensis has reduced virulence and exhibits less phenotypic plasticity. A striking genomic difference between the fungi is the amplification of the TLO (TeLOmere-associated) genes in C. albicans, which encode a fungal-specific subunit of the Mediator co-activator complex. Amplification results in a large pool of ‘free’ (non-Mediator associated) Tlo protein in C. albicans that is absent in C. dubliniensis. Engineering a large ‘free’ pool of Tlo protein in C. dubliniensis, through overexpression, results in phenotypes common in C. albicans, yet typically absent in C. dubliniensis. Tlo proteins contain a potent transcriptional activation domain. Nuclear localization of the Tlo activation domain is necessary and sufficient for the TLO overexpression phenotypes. This study provides a mechanistic explanation for how TLO amplification in C. albicans may enhance its virulence.
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Affiliation(s)
- Zhongle Liu
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Gary P. Moran
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Dublin, Ireland
| | - Derek J. Sullivan
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Dublin, Ireland
| | - Donna M. MacCallum
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Lawrence C. Myers
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Medical Education, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
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23
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Fine-Tuning of FACT by the Ubiquitin Proteasome System in Regulation of Transcriptional Elongation. Mol Cell Biol 2016; 36:1691-703. [PMID: 27044865 DOI: 10.1128/mcb.01112-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/27/2016] [Indexed: 11/20/2022] Open
Abstract
FACT (facilitates chromatin transcription), an evolutionarily conserved histone chaperone involved in transcription and other DNA transactions, is upregulated in cancers, and its downregulation is associated with cellular death. However, it is not clearly understood how FACT is fine-tuned for normal cellular functions. Here, we show that the FACT subunit Spt16 is ubiquitylated by San1 (an E3 ubiquitin ligase) and degraded by the 26S proteasome. Enhanced abundance of Spt16 in the absence of San1 impairs transcriptional elongation. Likewise, decreased abundance of Spt16 also reduces transcription. Thus, an optimal level of Spt16 is required for efficient transcriptional elongation, which is maintained by San1 via ubiquitylation and proteasomal degradation. Consistently, San1 associates with the coding sequences of active genes to regulate Spt16's abundance. Further, we found that enhanced abundance of Spt16 in the absence of San1 impairs chromatin reassembly at the coding sequence, similarly to the results seen following inactivation of Spt16. Efficient chromatin reassembly enhances the fidelity of transcriptional elongation. Taken together, our results demonstrate for the first time a fine-tuning of FACT by a ubiquitin proteasome system in promoting chromatin reassembly in the wake of elongating RNA polymerase II and transcriptional elongation, thus revealing novel regulatory mechanisms of gene expression.
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24
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Ravarani CNJ, Chalancon G, Breker M, de Groot NS, Babu MM. Affinity and competition for TBP are molecular determinants of gene expression noise. Nat Commun 2016; 7:10417. [PMID: 26832815 PMCID: PMC4740812 DOI: 10.1038/ncomms10417] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 12/09/2015] [Indexed: 12/14/2022] Open
Abstract
Cell-to-cell variation in gene expression levels (noise) generates phenotypic diversity and is an important phenomenon in evolution, development and disease. TATA-box binding protein (TBP) is an essential factor that is required at virtually every eukaryotic promoter to initiate transcription. While the presence of a TATA-box motif in the promoter has been strongly linked with noise, the molecular mechanism driving this relationship is less well understood. Through an integrated analysis of multiple large-scale data sets, computer simulation and experimental validation in yeast, we provide molecular insights into how noise arises as an emergent property of variable binding affinity of TBP for different promoter sequences, competition between interaction partners to bind the same surface on TBP (to either promote or disrupt transcription initiation) and variable residence times of TBP complexes at a promoter. These determinants may be fine-tuned under different conditions and during evolution to modulate eukaryotic gene expression noise.
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Affiliation(s)
- Charles N J Ravarani
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Guilhem Chalancon
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Michal Breker
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | | | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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25
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Spt-Ada-Gcn5-Acetyltransferase (SAGA) Complex in Plants: Genome Wide Identification, Evolutionary Conservation and Functional Determination. PLoS One 2015; 10:e0134709. [PMID: 26263547 PMCID: PMC4532415 DOI: 10.1371/journal.pone.0134709] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/13/2015] [Indexed: 01/17/2023] Open
Abstract
The recruitment of RNA polymerase II on a promoter is assisted by the assembly of basal transcriptional machinery in eukaryotes. The Spt-Ada-Gcn5-Acetyltransferase (SAGA) complex plays an important role in transcription regulation in eukaryotes. However, even in the advent of genome sequencing of various plants, SAGA complex has been poorly defined for their components and roles in plant development and physiological functions. Computational analysis of Arabidopsis thaliana and Oryza sativa genomes for SAGA complex resulted in the identification of 17 to 18 potential candidates for SAGA subunits. We have further classified the SAGA complex based on the conserved domains. Phylogenetic analysis revealed that the SAGA complex proteins are evolutionary conserved between plants, yeast and mammals. Functional annotation showed that they participate not only in chromatin remodeling and gene regulation, but also in different biological processes, which could be indirect and possibly mediated via the regulation of gene expression. The in silico expression analysis of the SAGA components in Arabidopsis and O. sativa clearly indicates that its components have a distinct expression profile at different developmental stages. The co-expression analysis of the SAGA components suggests that many of these subunits co-express at different developmental stages, during hormonal interaction and in response to stress conditions. Quantitative real-time PCR analysis of SAGA component genes further confirmed their expression in different plant tissues and stresses. The expression of representative salt, heat and light inducible genes were affected in mutant lines of SAGA subunits in Arabidopsis. Altogether, the present study reveals expedient evidences of involvement of the SAGA complex in plant gene regulation and stress responses.
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26
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Eaf1p Is Required for Recruitment of NuA4 in Targeting TFIID to the Promoters of the Ribosomal Protein Genes for Transcriptional Initiation In Vivo. Mol Cell Biol 2015; 35:2947-64. [PMID: 26100014 DOI: 10.1128/mcb.01524-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/24/2015] [Indexed: 01/13/2023] Open
Abstract
NuA4 (nucleosome acetyltransferase of H4) promotes transcriptional initiation of TFIID (a complex of TBP and TBP-associated factors [TAFs])-dependent ribosomal protein genes involved in ribosome biogenesis. However, it is not clearly understood how NuA4 regulates the transcription of ribosomal protein genes. Here, we show that NuA4 is recruited to the promoters of ribosomal protein genes, such as RPS5, RPL2B, and RPS11B, for TFIID recruitment to initiate transcription, and the recruitment of NuA4 to these promoters is impaired in the absence of its Eaf1p component. Intriguingly, impaired NuA4 recruitment in a Δeaf1 strain depletes recruitment of TFIID (a TAF-dependent form of TBP) but not the TAF-independent form of TBP to the promoters of ribosomal protein genes. However, in the absence of NuA4, SAGA (Spt-Ada-Gcn5-acetyltransferase) is involved in targeting the TAF-independent form of TBP to the promoters of ribosomal protein genes for transcriptional initiation. Thus, NuA4 plays an important role in targeting TFIID to the promoters of ribosomal protein genes for transcriptional initiation in vivo. Such a function is mediated via its targeted histone acetyltransferase activity. In the absence of NuA4, ribosomal protein genes lose TFIID dependency and become SAGA dependent for transcriptional initiation. Collectively, these results provide significant insights into the regulation of ribosomal protein gene expression and, hence, ribosome biogenesis and functions.
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27
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Izhar L, Adamson B, Ciccia A, Lewis J, Pontano-Vaites L, Leng Y, Liang AC, Westbrook TF, Harper JW, Elledge SJ. A Systematic Analysis of Factors Localized to Damaged Chromatin Reveals PARP-Dependent Recruitment of Transcription Factors. Cell Rep 2015; 11:1486-500. [PMID: 26004182 DOI: 10.1016/j.celrep.2015.04.053] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/16/2015] [Accepted: 04/25/2015] [Indexed: 01/09/2023] Open
Abstract
Localization to sites of DNA damage is a hallmark of DNA damage response (DDR) proteins. To identify DDR factors, we screened epitope-tagged proteins for localization to sites of chromatin damaged by UV laser microirradiation and found >120 proteins that localize to damaged chromatin. These include the BAF tumor suppressor complex and the amyotrophic lateral sclerosis (ALS) candidate protein TAF15. TAF15 contains multiple domains that bind damaged chromatin in a poly-(ADP-ribose) polymerase (PARP)-dependent manner, suggesting a possible role as glue that tethers multiple PAR chains together. Many positives were transcription factors; > 70% of randomly tested transcription factors localized to sites of DNA damage, and of these, ∼90% were PARP dependent for localization. Mutational analyses showed that localization to damaged chromatin is DNA-binding-domain dependent. By examining Hoechst staining patterns at damage sites, we see evidence of chromatin decompaction that is PARP dependent. We propose that PARP-regulated chromatin remodeling at sites of damage allows transient accessibility of DNA-binding proteins.
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Affiliation(s)
- Lior Izhar
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Britt Adamson
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alberto Ciccia
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Jedd Lewis
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Laura Pontano-Vaites
- Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Yumei Leng
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Anthony C Liang
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Thomas F Westbrook
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Human Genetics, and Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Stephen J Elledge
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Han Y, Luo J, Ranish J, Hahn S. Architecture of the Saccharomyces cerevisiae SAGA transcription coactivator complex. EMBO J 2014; 33:2534-46. [PMID: 25216679 DOI: 10.15252/embj.201488638] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The conserved transcription coactivator SAGA is comprised of several modules that are involved in activator binding, TBP binding, histone acetylation (HAT) and deubiquitination (DUB). Crosslinking and mass spectrometry, together with genetic and biochemical analyses, were used to determine the molecular architecture of the SAGA-TBP complex. We find that the SAGA Taf and Taf-like subunits form a TFIID-like core complex at the center of SAGA that makes extensive interactions with all other SAGA modules. SAGA-TBP binding involves a network of interactions between subunits Spt3, Spt8, Spt20, and Spt7. The HAT and DUB modules are in close proximity, and the DUB module modestly stimulates HAT function. The large activator-binding subunit Tra1 primarily connects to the TFIID-like core via its FAT domain. These combined results were used to derive a model for the arrangement of the SAGA subunits and its interactions with TBP. Our results provide new insight into SAGA function in gene regulation, its structural similarity with TFIID, and functional interactions between the SAGA modules.
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Affiliation(s)
- Yan Han
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Biological Physics, Structure and Design Program, University of Washington, Seattle, WA, USA
| | - Jie Luo
- Institute for Systems Biology, Seattle, WA, USA
| | | | - Steven Hahn
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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29
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The 26S proteasome and initiation of gene transcription. Biomolecules 2014; 4:827-47. [PMID: 25211636 PMCID: PMC4192674 DOI: 10.3390/biom4030827] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 08/20/2014] [Accepted: 09/01/2014] [Indexed: 11/17/2022] Open
Abstract
Transcription activation is the foremost step of gene expression and is modulated by various factors that act in synergy. Misregulation of this process and its associated factors has severe effects and hence requires strong regulatory control. In recent years, growing evidence has highlighted the 26S proteasome as an important contributor to the regulation of transcription initiation. Well known for its role in protein destruction, its contribution to protein synthesis was initially viewed with skepticism. However, studies over the past several years have established the proteasome as an important component of transcription initiation through proteolytic and non-proteolytic activities. In this review, we discuss findings made so far in understanding the connections between transcription initiation and the 26S proteasome complex.
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30
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Gaupel AC, Begley T, Tenniswood M. High throughput screening identifies modulators of histone deacetylase inhibitors. BMC Genomics 2014; 15:528. [PMID: 24968945 PMCID: PMC4089024 DOI: 10.1186/1471-2164-15-528] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 06/18/2014] [Indexed: 12/26/2022] Open
Abstract
Background Previous studies from our laboratory and others have demonstrated that in addition to altering chromatin acetylation and conformation, histone deacetylase inhibitors (HDACi) disrupt the acetylation status of numerous transcription factors and other proteins. A whole genome yeast deletion library screen was used to identify components of the transcriptional apparatus that modulate the sensitivity to the hydroxamic acid-based HDACi, CG-1521. Results Screening 4852 haploid Saccharomyces cerevisiae deletion strains for sensitivity to CG-1521 identifies 407 sensitive and 80 resistant strains. Gene ontology (GO) enrichment analysis shows that strains sensitive to CG-1521 are highly enriched in processes regulating chromatin remodeling and transcription as well as other ontologies, including vacuolar acidification and vesicle-mediated transport. CG-1521-resistant strains include those deficient in the regulation of transcription and tRNA modification. Components of the SAGA histone acetyltransferase (HAT) complex are overrepresented in the sensitive strains, including the catalytic subunit, Gcn5. Cell cycle analysis indicates that both the wild-type and gcn5Δ strains show a G1 delay after CG-1521 treatment, however the gcn5Δ strain displays increased sensitivity to CG-1521-induced cell death compared to the wild-type strain. To test whether the enzymatic activity of Gcn5 is necessary in the response to CG-1521, growth assays with a yeast strain expressing a catalytically inactive variant of the Gcn5 protein were performed and the results show that this strain is less sensitive to CG-1521 than the gcn5Δ strain. Conclusion Genome-wide deletion mutant screening identifies biological processes that affect the sensitivity to the HDAC inhibitor CG-1521, including transcription and chromatin remodeling. This study illuminates the pathways involved in the response to CG-1521 in yeast and provides incentives to understand the mechanisms of HDAC inhibitors in cancer cells. The data presented here demonstrate that components of the SAGA complex are involved in mediating the response to CG-1521. Additional experiments suggest that functions other than the acetyltransferase activity of Gcn5 may be sufficient to attenuate the effects of CG-1521 on cell growth. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-528) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Martin Tenniswood
- Department of Biomedical Sciences, School of Public Health, University at Albany, New York 12222, USA.
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31
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Durairaj G, Sen R, Uprety B, Shukla A, Bhaumik SR. Sus1p facilitates pre-initiation complex formation at the SAGA-regulated genes independently of histone H2B de-ubiquitylation. J Mol Biol 2014; 426:2928-2941. [PMID: 24911582 DOI: 10.1016/j.jmb.2014.05.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/29/2014] [Accepted: 05/31/2014] [Indexed: 12/23/2022]
Abstract
Sus1p is a common component of transcriptional co-activator, SAGA (Spt-Ada-Gcn5-Acetyltransferase), and mRNA export complex, TREX-2 (Transcription-export 2), and is involved in promoting transcription and mRNA export. However, it is not clearly understood how Sus1p promotes transcription. Here, we show that Sus1p is predominantly recruited to the upstream activating sequence of a SAGA-dependent gene, GAL1, under transcriptionally active conditions as a component of SAGA to promote the formation of pre-initiation complex (PIC) at the core promoter and, consequently, transcriptional initiation. Likewise, Sus1p promotes the PIC formation at other SAGA-dependent genes and hence transcriptional initiation. Such function of Sus1p in promoting PIC formation and transcriptional initiation is not mediated via its role in regulation of SAGA's histone H2B de-ubiquitylation activity. However, Sus1p's function in regulation of histone H2B ubiquitylation is associated with transcriptional elongation, DNA repair and replication. Collectively, our results support that Sus1p promotes PIC formation (and hence transcriptional initiation) at the SAGA-regulated genes independently of histone H2B de-ubiquitylation and further controls transcriptional elongation, DNA repair and replication via orchestration of histone H2B ubiquitylation, thus providing distinct functional insights of Sus1p in regulation of DNA transacting processes.
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Affiliation(s)
- Geetha Durairaj
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Rwik Sen
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Bhawana Uprety
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Abhijit Shukla
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology Southern Illinois University School of Medicine Carbondale, IL-62901 USA
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32
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Gurskiy DY, Nabirochkina EN, Kopytova DV. Role of multifunctional coactivator complex SAGA in regulation of eukaryotic gene expression. Mol Biol 2013. [DOI: 10.1134/s002689331306006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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33
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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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34
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Grimaldi Y, Ferrari P, Strubin M. Independent RNA polymerase II preinitiation complex dynamics and nucleosome turnover at promoter sites in vivo. Genome Res 2013; 24:117-24. [PMID: 24298073 PMCID: PMC3875852 DOI: 10.1101/gr.157792.113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Transcription by all three eukaryotic RNA polymerases involves the assembly of a large preinitiation complex (PIC) at gene promoters. The PIC comprises several general transcription factors (GTFs), including TBP, and the respective RNA polymerase. It has been suggested that some GTFs remain stably bound at active promoters to facilitate multiple transcription events. Here we used two complementary approaches to show that, in G1-arrested yeast cells, TBP exchanges very rapidly even at the most highly active RNA Pol II promoters. A similar situation is observed at RNA Pol III promoters. In contrast, TBP remains stably bound at RNA Pol I promoters. We also provide evidence that, unexpectedly, PIC dynamics are neither the cause nor the consequence of nucleosome exchange at most of the RNA Pol II promoters we analyzed. These results point to a stable reinitiation complex at RNA Pol I promoters and suggest independent PIC and nucleosome turnover at many RNA Pol II promoters.
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Affiliation(s)
- Yoselin Grimaldi
- Department of Microbiology and Molecular Medicine, University Medical Centre (C.M.U.), 1211 Geneva 4, Switzerland
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35
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Johnson A, Wu R, Peetz M, Gygi SP, Moazed D. Heterochromatic gene silencing by activator interference and a transcription elongation barrier. J Biol Chem 2013; 288:28771-82. [PMID: 23940036 PMCID: PMC3789973 DOI: 10.1074/jbc.m113.460071] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Heterochromatin silences transcription, contributing to development, differentiation, and genome stability in eukaryotic organisms. Budding yeast heterochromatic silencing is strictly dependent on the silent information regulator (SIR) complex composed of the Sir2 histone deacetylase and the chromatin-interacting proteins Sir3 and Sir4. We use reconstituted SIR heterochromatin to characterize the steps in transcription that are disrupted to achieve silencing. Transcriptional activator binding is permitted before and after heterochromatin assembly. A comprehensive proteomic approach identified heterochromatin-mediated disruption of activator interactions with coactivator complexes. We also find that if RNA polymerase II (Pol II) is allowed to initiate transcription, the SIR complex blocks elongation on chromatin while maintaining Pol II in a halted conformation. This Pol II elongation barrier functions for even one nucleosome, is more effective when assembled with multiple nucleosomes, and is sensitive to a histone mutation that is known to disrupt silencing. This dual mechanism of silencing suggests a conserved principle of heterochromatin in assembling a specific structure that targets multiple steps to achieve repression.
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36
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Mechanisms of antisense transcription initiation from the 3' end of the GAL10 coding sequence in vivo. Mol Cell Biol 2013; 33:3549-67. [PMID: 23836882 DOI: 10.1128/mcb.01715-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In spite of the important regulatory functions of antisense transcripts in gene expression, it remains unknown how antisense transcription is initiated. Recent studies implicated RNA polymerase II in initiation of antisense transcription. However, how RNA polymerase II is targeted to initiate antisense transcription has not been elucidated. Here, we have analyzed the association of RNA polymerase II with the antisense initiation site at the 3' end of the GAL10 coding sequence in dextrose-containing growth medium that induces antisense transcription. We find that RNA polymerase II is targeted to the antisense initiation site at GAL10 by Reb1p activator as well as general transcription factors (e.g., TFIID, TFIIB, and Mediator) for antisense transcription initiation. Intriguingly, while GAL10 antisense transcription is dependent on TFIID, its sense transcription does not require TFIID. Further, the Gal4p activator that promotes GAL10 sense transcription is dispensable for antisense transcription. Moreover, the proteasome that facilitates GAL10 sense transcription does not control its antisense transcription. Taken together, our results reveal that GAL10 sense and antisense transcriptions are regulated differently and shed much light on the mechanisms of antisense transcription initiation.
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37
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Chaurasia P, Sen R, Bhaumik SR. Functional analysis of Rad14p, a DNA damage recognition factor in nucleotide excision repair, in regulation of transcription in vivo. J Biol Chem 2012. [PMID: 23188830 DOI: 10.1074/jbc.m112.413716] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rad14p is a DNA damage recognition factor in nucleotide excision repair. Intriguingly, we show here that Rad14p associates with the promoter of a galactose-inducible GAL1 gene after transcriptional induction in the absence of DNA lesion. Such an association of Rad14p facilitates the recruitment of TBP, TFIIH, and RNA polymerase II to the GAL1 promoter. Furthermore, the association of RNA polymerase II with the GAL1 promoter is significantly decreased in the absence of Rad14p, when the coding sequence was deleted. These results support the role of Rad14p in transcriptional initiation. Consistently, the level of GAL1 mRNA is significantly decreased in the absence of Rad14p. Similar results are also obtained at other galactose-inducible GAL genes such as GAL7 and GAL10. Likewise, Rad14p promotes transcription of other non-GAL genes such as CUP1, CTT1, and STL1 after transcriptional induction. However, the effect of Rad14p on the steady-state levels of transcription of GAL genes or constitutively active genes such as ADH1, PGK1, PYK1, and RPS5 is not observed. Thus, Rad14p promotes initial transcription but does not appear to regulate the steady-state level. Collectively, our results unveil a new role of Rad14p in stimulating transcription in addition to its well-known function in nucleotide excision repair.
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Affiliation(s)
- Priyasri Chaurasia
- Department of Biochemistry and Molecular Biology, Southern Illinois University, School of Medicine, Carbondale, Illinois 62901, USA
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38
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Frey AG, Eide DJ. Zinc-responsive coactivator recruitment by the yeast Zap1 transcription factor. Microbiologyopen 2012; 1:105-14. [PMID: 22950018 PMCID: PMC3426420 DOI: 10.1002/mbo3.8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 12/19/2011] [Indexed: 11/11/2022] Open
Abstract
The zinc-responsive Zap1 transcription factor of Saccharomyces cerevisiae controls many genes involved in zinc homeostasis. Zap1 has two activation domains, AD1 and AD2, which are independently regulated by zinc. While AD1 can fully activate most Zap1 target genes, AD2 is active only on a subset of those genes. One hypothesis explaining this promoter specificity was that AD1 and AD2 recruit different coactivators. To address this question, we carried out a genetic screen to identify coactivator complexes that are required for Zap1-mediated activation. SWI/SNF, SAGA, and Mediator complexes were implicated as playing major roles in Zap1 activation. Consistent with this conclusion, we found that these three complexes are recruited to Zap1 target promoters in a zinc-responsive and Zap1-dependent manner. Coactivator recruitment was highly interdependent such that mutations disrupting SAGA impaired recruitment of SWI/SNF and vice versa. Optimal Mediator recruitment was dependent on both SAGA and SWI/SNF. A comparison of the coactivators recruited by AD1 and AD2 found no obvious differences suggesting that recruitment of different coactivators is not likely the mechanism of AD specificity. Rather, our results suggest that AD2 recruits coactivators less effectively than AD1 and is therefore only functional on some promoters.
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Affiliation(s)
- Avery G Frey
- Department of Nutritional Sciences, University of Wisconsin-Madison Madison, Wisconsin
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39
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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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40
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Frankland-Searby S, Bhaumik SR. The 26S proteasome complex: an attractive target for cancer therapy. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1825:64-76. [PMID: 22037302 PMCID: PMC3242858 DOI: 10.1016/j.bbcan.2011.10.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/08/2011] [Accepted: 10/10/2011] [Indexed: 01/26/2023]
Abstract
The 26S proteasome complex engages in an ATP-dependent proteolytic degradation of a variety of oncoproteins, transcription factors, cell cycle specific cyclins, cyclin-dependent kinase inhibitors, ornithine decarboxylase, and other key regulatory cellular proteins. Thus, the proteasome regulates either directly or indirectly many important cellular processes. Altered regulation of these cellular events is linked to the development of cancer. Therefore, the proteasome has become an attractive target for the treatment of numerous cancers. Several proteasome inhibitors that target the proteolytic active sites of the 26S proteasome complex have been developed and tested for anti-tumor activities. These proteasome inhibitors have displayed impressive anti-tumor functions by inducing apoptosis in different tumor types. Further, the proteasome inhibitors have been shown to induce cell cycle arrest, and inhibit angiogenesis, cell-cell adhesion, cell migration, immune and inflammatory responses, and DNA repair response. A number of proteasome inhibitors are now in clinical trials to treat multiple myeloma and solid tumors. Many other proteasome inhibitors with different efficiencies are being developed and tested for anti-tumor activities. Several proteasome inhibitors currently in clinical trials have shown significantly improved anti-tumor activities when combined with other drugs such as histone deacetylase (HDAC) inhibitors, Akt (protein kinase B) inhibitors, DNA damaging agents, Hsp90 (heat shock protein 90) inhibitors, and lenalidomide. The proteasome inhibitor bortezomib is now in the clinic to treat multiple myeloma and mantle cell lymphoma. Here, we discuss the 26S proteasome complex in carcinogenesis and different proteasome inhibitors with their potential therapeutic applications in treatment of numerous cancers.
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Affiliation(s)
- Sarah Frankland-Searby
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R. Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
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41
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García-Oliver E, García-Molinero V, Rodríguez-Navarro S. mRNA export and gene expression: the SAGA-TREX-2 connection. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:555-65. [PMID: 22178374 DOI: 10.1016/j.bbagrm.2011.11.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 01/07/2023]
Abstract
In the gene expression field, different steps have been traditionally viewed as discrete and unconnected events. Nowadays, genetic and functional studies support the model of a coupled network of physical and functional connections to carry out mRNA biogenesis. Gene expression is a coordinated process that comprises different linked steps like transcription, RNA processing, export to the cytoplasm, translation and degradation of mRNAs. Its regulation is essential for cellular survival and can occur at many different levels. Transcription is the central function that occurs in the nucleus, and RNAPII plays an essential role in mRNA biogenesis. During transcription, nascent mRNA is associated with the mRNA-binding proteins involved in processing and export of the mRNA particle. Cells have developed a network of multi-protein complexes whose functions regulate the different factors involved both temporally and spatially. This coupling mechanism acts as a quality control to solve some of the organization problems of gene expression in vivo, where all the factors implicated ensure that mRNAs are ready to be exported and translated. In this review, we focus on the functional coupling of gene transcription and mRNA export, and place particular emphasis on the relationship between the NPC-associated complex, TREX2, and the transcription co-activator, SAGA. We have pinpointed the experimental evidence for Sus1's roles in transcription initiation, transcription elongation and mRNA export. In addition, we have reviewed other NPC-related processes such as gene gating to the nuclear envelope, the chromatin structure and the cellular context in which these processes take place. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Encar García-Oliver
- Centro de Investigación Príncipe Felipe (CIPF), Gene Expression coupled with RNA Transport Laboratory, Valencia, Spain
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42
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Uprety B, Lahudkar S, Malik S, Bhaumik SR. The 19S proteasome subcomplex promotes the targeting of NuA4 HAT to the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional initiation in vivo. Nucleic Acids Res 2011; 40:1969-83. [PMID: 22086954 PMCID: PMC3300024 DOI: 10.1093/nar/gkr977] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Previous studies have implicated SAGA (Spt-Ada-Gcn5-acetyltransferase) and TFIID (Transcription factor-IID)-dependent mechanisms of transcriptional activation in yeast. SAGA-dependent transcriptional activation is further regulated by the 19S proteasome subcomplex. However, the role of the 19S proteasome subcomplex in transcriptional activation of the TFIID-dependent genes has not been elucidated. Therefore, we have performed a series of chromatin immunoprecipitation, mutational and transcriptional analyses at the TFIID-dependent ribosomal protein genes such as RPS5, RPL2B and RPS11B. We find that the 19S proteasome subcomplex is recruited to the promoters of these ribosomal protein genes, and promotes the association of NuA4 (Nucleosome acetyltransferase of histone H4) co-activator, but not activator Rap1p (repressor-activator protein 1). These observations support that the 19S proteasome subcomplex enhances the targeting of co-activator at the TFIID-dependent promoter. Such an enhanced targeting of NuA4 HAT (histone acetyltransferase) promotes the recruitment of the TFIID complex for transcriptional initiation. Collectively, our data demonstrate that the 19S proteasome subcomplex enhances the targeting of NuA4 HAT to activator Rap1p at the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional stimulation, hence providing a new role of the 19S proteasome subcomplex in establishing a specific regulatory network at the TFIID-dependent promoter for productive transcriptional initiation in vivo.
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Affiliation(s)
- Bhawana Uprety
- Department of Biochemistry and Molecular Biology, Southern Illinois University-School of Medicine, Carbondale, IL 62901, USA
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