1
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Mittal C, Lang O, Lai WKM, Pugh BF. An integrated SAGA and TFIID PIC assembly pathway selective for poised and induced promoters. Genes Dev 2022; 36:985-1001. [PMID: 36302553 PMCID: PMC9732905 DOI: 10.1101/gad.350026.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/11/2022] [Indexed: 02/05/2023]
Abstract
Genome-wide, little is understood about how proteins organize at inducible promoters before and after induction and to what extent inducible and constitutive architectures depend on cofactors. We report that sequence-specific transcription factors and their tethered cofactors (e.g., SAGA [Spt-Ada-Gcn5-acetyltransferase], Mediator, TUP, NuA4, SWI/SNF, and RPD3-L) are generally bound to promoters prior to induction ("poised"), rather than recruited upon induction, whereas induction recruits the preinitiation complex (PIC) to DNA. Through depletion and/or deletion experiments, we show that SAGA does not function at constitutive promoters, although a SAGA-independent Gcn5 acetylates +1 nucleosomes there. When inducible promoters are poised, SAGA catalyzes +1 nucleosome acetylation but not PIC assembly. When induced, SAGA catalyzes acetylation, deubiquitylation, and PIC assembly. Surprisingly, SAGA mediates induction by creating a PIC that allows TFIID (transcription factor II-D) to stably associate, rather than creating a completely TFIID-independent PIC, as generally thought. These findings suggest that inducible systems, where present, are integrated with constitutive systems.
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Affiliation(s)
- Chitvan Mittal
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Olivia Lang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - William K M Lai
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - B Franklin Pugh
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
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2
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Iwami R, Takai N, Kokubo T. The function of Spt3, a subunit of the SAGA complex, in <i>PGK1</i> transcription is restored only partially when reintroduced by plasmid into <i>taf1 spt3</i> double mutant yeast strains. Genes Genet Syst 2020; 95:151-163. [DOI: 10.1266/ggs.20-00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Ryo Iwami
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University
| | - Naoki Takai
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University
| | - Tetsuro Kokubo
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University
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3
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Molecular determinants underlying functional innovations of TBP and their impact on transcription initiation. Nat Commun 2020; 11:2384. [PMID: 32404905 PMCID: PMC7221094 DOI: 10.1038/s41467-020-16182-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
TATA-box binding protein (TBP) is required for every single transcription event in archaea and eukaryotes. It binds DNA and harbors two repeats with an internal structural symmetry that show sequence asymmetry. At various times in evolution, TBP has acquired multiple interaction partners and different organisms have evolved TBP paralogs with additional protein regions. Together, these observations raise questions of what molecular determinants (i.e. key residues) led to the ability of TBP to acquire new interactions, resulting in an increasingly complex transcriptional system in eukaryotes. We present a comprehensive study of the evolutionary history of TBP and its interaction partners across all domains of life, including viruses. Our analysis reveals the molecular determinants and suggests a unified and multi-stage evolutionary model for the functional innovations of TBP. These findings highlight how concerted chemical changes on a conserved structural scaffold allow for the emergence of complexity in a fundamental biological process. The TATA-box binding protein (TBP) is required for transcription initiation in archaea and eukaryotes. Here the authors delineate how TBP’s function has evolved new functional features through context-dependent interactions with various protein partners.
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4
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Heiss G, Ploetz E, Voith von Voithenberg L, Viswanathan R, Glaser S, Schluesche P, Madhira S, Meisterernst M, Auble DT, Lamb DC. Conformational changes and catalytic inefficiency associated with Mot1-mediated TBP-DNA dissociation. Nucleic Acids Res 2019; 47:2793-2806. [PMID: 30649478 PMCID: PMC6451094 DOI: 10.1093/nar/gky1322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 12/21/2018] [Accepted: 01/07/2019] [Indexed: 11/12/2022] Open
Abstract
The TATA-box Binding Protein (TBP) plays a central role in regulating gene expression and is the first step in the process of pre-initiation complex (PIC) formation on promoter DNA. The lifetime of TBP at the promoter site is controlled by several cofactors including the Modifier of transcription 1 (Mot1), an essential TBP-associated ATPase. Based on ensemble measurements, Mot1 can use adenosine triphosphate (ATP) hydrolysis to displace TBP from DNA and various models for how this activity is coupled to transcriptional regulation have been proposed. However, the underlying molecular mechanism of Mot1 action is not well understood. In this work, the interaction of Mot1 with the DNA/TBP complex was investigated by single-pair Förster resonance energy transfer (spFRET). Upon Mot1 binding to the DNA/TBP complex, a transition in the DNA/TBP conformation was observed. Hydrolysis of ATP by Mot1 led to a conformational change but was not sufficient to efficiently disrupt the complex. SpFRET measurements of dual-labeled DNA suggest that Mot1's ATPase activity primes incorrectly oriented TBP for dissociation from DNA and additional Mot1 in solution is necessary for TBP unbinding. These findings provide a framework for understanding how the efficiency of Mot1's catalytic activity is tuned to establish a dynamic pool of TBP without interfering with stable and functional TBP-containing complexes.
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Affiliation(s)
- Gregor Heiss
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Evelyn Ploetz
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Lena Voith von Voithenberg
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Ramya Viswanathan
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Samson Glaser
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Peter Schluesche
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Sushi Madhira
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Michael Meisterernst
- Institut für Molekulare Tumorbiologie, Westfälische Wilhelms-Universität, Münster 48149, Germany
| | - David T Auble
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Don C Lamb
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
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5
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Bunch H, Choe H, Kim J, Jo DS, Jeon S, Lee S, Cho DH, Kang K. P-TEFb Regulates Transcriptional Activation in Non-coding RNA Genes. Front Genet 2019; 10:342. [PMID: 31068966 PMCID: PMC6491683 DOI: 10.3389/fgene.2019.00342] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/16/2023] Open
Abstract
Many non-coding RNAs (ncRNAs) serve as regulatory molecules in various physiological pathways, including gene expression in mammalian cells. Distinct from protein-coding RNA expression, ncRNA expression is regulated solely by transcription and RNA processing/stability. It is thus important to understand transcriptional regulation in ncRNA genes but is yet to be known completely. Previously, we identified that a subset of mammalian ncRNA genes is transcriptionally regulated by RNA polymerase II (Pol II) promoter-proximal pausing and in a tissue-specific manner. In this study, human ncRNA genes that are expressed in the early G1 phase, termed immediate early ncRNA genes, were monitored to assess the function of positive transcription elongation factor b (P-TEFb), a master Pol II pausing regulator for protein-coding genes, in ncRNA transcription. Our findings indicate that the expression of many ncRNA genes is induced in the G0–G1 transition and regulated by P-TEFb. Interestingly, a biphasic characteristic of P-TEFb-dependent transcription of serum responsive ncRNA genes was observed: Pol II carboxyl-terminal domain phosphorylated at serine 2 (S2) was largely increased in the transcription start site (TSS, -300 to +300) whereas overall, it was decreased in the gene body (GB, > +350) upon chemical inhibition of P-TEFb. In addition, the three representative, immediate early ncRNAs, whose expression is dependent on P-TEFb, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), nuclear enriched abundant transcript 1 (NEAT1), and X-inactive specific transcript (XIST), were further analyzed for determining P-TEFb association. Taken together, our data suggest that transcriptional activation of many human ncRNAs utilizes the pausing and releasing of Pol II, and that the regulatory mechanism of transcriptional elongation in these genes requires the function of P-TEFb. Furthermore, we propose that ncRNA and mRNA transcription are regulated by similar mechanisms while P-TEFb inhibition unexpectedly increases S2 Pol II phosphorylation in the TSSs in many ncRNA genes. One Sentence Summary: P-TEFb regulates Pol II phosphorylation for transcriptional activation in many stimulus-inducible ncRNA genes.
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Affiliation(s)
- Heeyoun Bunch
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Hyeseung Choe
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Jongbum Kim
- Department of Transcriptome & Epigenome, Macrogen Incorporated, Seoul, South Korea
| | - Doo Sin Jo
- Institute of Life Science and Biotechnology, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Soyeon Jeon
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Sanghwa Lee
- Department of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Dong-Hyung Cho
- Department of Life Science, College of Natural Science, Kyungpook National University, Daegu, South Korea
| | - Keunsoo Kang
- Department of Microbiology, College of Natural Sciences, Dankook University, Cheonan, South Korea
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6
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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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7
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An J, Kwon H, Kim E, Lee YM, Ko HJ, Park H, Choi IG, Kim S, Kim KH, Kim W, Choi W. Tolerance to acetic acid is improved by mutations of the TATA-binding protein gene. Environ Microbiol 2014; 17:656-69. [DOI: 10.1111/1462-2920.12489] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 04/16/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Jieun An
- Division of Life and Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Korea
| | - Hyeji Kwon
- Division of Life and Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Korea
| | - Eunjung Kim
- Department of Pharmacology, School of Medicine; Ajou University; Suwon 442-749 Korea
| | - Young Mi Lee
- Microbial Resources Research Center; Ewha Womans University; Seoul 120-750 Korea
| | - Hyeok Jin Ko
- School of Life Sciences and Biotechnology; Korea University; Seoul 136-713 Korea
| | - Hongjae Park
- School of Life Sciences and Biotechnology; Korea University; Seoul 136-713 Korea
| | - In-Geol Choi
- School of Life Sciences and Biotechnology; Korea University; Seoul 136-713 Korea
| | - Sooah Kim
- School of Life Sciences and Biotechnology; Korea University; Seoul 136-713 Korea
| | - Kyoung Heon Kim
- School of Life Sciences and Biotechnology; Korea University; Seoul 136-713 Korea
| | - Wankee Kim
- Department of Pharmacology, School of Medicine; Ajou University; Suwon 442-749 Korea
| | - Wonja Choi
- Division of Life and Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Korea
- Microbial Resources Research Center; Ewha Womans University; Seoul 120-750 Korea
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8
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Hieb AR, Gansen A, Böhm V, Langowski J. The conformational state of the nucleosome entry-exit site modulates TATA box-specific TBP binding. Nucleic Acids Res 2014; 42:7561-76. [PMID: 24829456 PMCID: PMC4081063 DOI: 10.1093/nar/gku423] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The TATA binding protein (TBP) is a critical transcription factor used for nucleating assembly of the RNA polymerase II machinery. TBP binds TATA box elements with high affinity and kinetic stability and in vivo is correlated with high levels of transcription activation. However, since most promoters use less stable TATA-less or TATA-like elements, while also competing with nucleosome occupancy, further mechanistic insight into TBP's DNA binding properties and ability to access chromatin is needed. Using bulk and single-molecule FRET, we find that TBP binds a minimal consensus TATA box as a two-state equilibrium process, showing no evidence for intermediate states. However, upon addition of flanking DNA sequence, we observe non-specific cooperative binding to multiple DNA sites that compete for TATA-box specificity. Thus, we conclude that TBP binding is defined by a branched pathway, wherein TBP initially binds with little sequence specificity and is thermodynamically positioned by its kinetic stability to the TATA box. Furthermore, we observed the real-time access of TBP binding to TATA box DNA located within the DNA entry–exit site of the nucleosome. From these data, we determined salt-dependent changes in the nucleosome conformation regulate TBP's access to the TATA box, where access is highly constrained under physiological conditions, but is alleviated by histone acetylation and TFIIA.
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Affiliation(s)
- Aaron R Hieb
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
| | - Alexander Gansen
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
| | - Vera Böhm
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
| | - Jörg Langowski
- Division Biophysics of Macromolecules, German Cancer Research Center, D-69120 Heidelberg, Germany
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9
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Abstract
The Swi2/Snf2 family ATPase Mot1 displaces TATA-binding protein (TBP) from DNA in vitro, but the global relationship between Mot1 and TBP in vivo is unclear. In particular, how Mot1 activates transcription is poorly understood. To address these issues, we mapped the distribution of Mot1 and TBP on native chromatin at base pair resolution. Mot1 and TBP binding sites coincide throughout the genome, and depletion of TBP results in a global decrease in Mot1 binding. We find evidence that Mot1 approaches TBP from the upstream direction, consistent with its in vitro mode of action. Strikingly, inactivation of Mot1 leads to both increases and decreases in TBP-genome association. Sites of TBP gain tend to contain robust TATA boxes, while sites of TBP loss contain poly(dA-dT) tracts that may contribute to nucleosome exclusion. Sites of TBP gain are associated with increased gene expression, while decreased TBP binding is associated with reduced gene expression. We propose that the action of Mot1 is required to clear TBP from intrinsically preferred (TATA-containing) binding sites, ensuring sufficient soluble TBP to bind intrinsically disfavored (TATA-less) sites.
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10
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Viswanathan R, Auble DT. One small step for Mot1; one giant leap for other Swi2/Snf2 enzymes? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:488-96. [PMID: 21658482 DOI: 10.1016/j.bbagrm.2011.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/14/2011] [Accepted: 05/20/2011] [Indexed: 12/13/2022]
Abstract
The TATA-binding protein (TBP) is a major target for transcriptional regulation. Mot1, a Swi2/Snf2-related ATPase, dissociates TBP from DNA in an ATP dependent process. The experimental advantages of this relatively simple reaction have been exploited to learn more about how Swi2/Snf2 ATPases function biochemically. However, many unanswered questions remain and fundamental aspects of the Mot1 mechanism are still under debate. Here, we review the available data and integrate the results with structural and biochemical studies of related enzymes to derive a model for Mot1's catalytic action consistent with the broad literature on enzymes in this family. We propose that the Mot1 ATPase domain is tethered to TBP by a flexible, spring-like linker of alpha helical hairpins. The linker juxtaposes the ATPase domain such that it can engage duplex DNA on one side of the TBP-DNA complex. This allows the ATPase to employ short-range, nonprocessive ATP-driven DNA tracking to pull or push TBP off its DNA site. DNA translocation is a conserved property of ATPases in the broader enzyme family. As such, the model explains how a structurally and functionally conserved ATPase domain has been put to use in a very different context than other enzymes in the Swi2/Snf2 family. This article is part of a Special Issue entitled:Snf2/Swi2 ATPase structure and function.
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Affiliation(s)
- Ramya Viswanathan
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
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11
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Abstract
TATA binding protein (TBP) plays a central role in transcription complex assembly and is regulated by a variety of transcription factors, including Mot1. Mot1 is an essential protein in Saccharomyces cerevisiae that exerts both negative and positive effects on transcription via interactions with TBP. It contains two conserved regions important for TBP interactions, another conserved region that hydrolyzes ATP to remove TBP from DNA, and a fourth conserved region with unknown function. Whether these regions contribute equally to transcriptional regulation genome-wide is unknown. Here, we employ a transient-replacement assay using deletion derivatives in the conserved regions of Mot1 to investigate their contributions to gene regulation throughout the S. cerevisiae genome. These four regions of Mot1 are essential for growth and are generally required for all Mot1-regulated genes. Loss of the ATPase region, but not other conserved regions, caused TBP to redistribute away from a subset of Mot1-inhibited genes, leading to decreased expression of those genes. A corresponding increase in TBP occupancy and expression occurred at another set of genes that are normally Mot1 independent. The data suggest that Mot1 uses ATP hydrolysis to redistribute accessible TBP away from intrinsically preferred sites to other sites of intrinsically low preference.
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12
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Pang K, Cheng C, Xuan Z, Sheng H, Ma X. Understanding protein evolutionary rate by integrating gene co-expression with protein interactions. BMC SYSTEMS BIOLOGY 2010; 4:179. [PMID: 21190591 PMCID: PMC3022652 DOI: 10.1186/1752-0509-4-179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 12/30/2010] [Indexed: 12/23/2022]
Abstract
Background Among the many factors determining protein evolutionary rate, protein-protein interaction degree (PPID) has been intensively investigated in recent years, but its precise effect on protein evolutionary rate is still heavily debated. Results We first confirmed that the correlation between protein evolutionary rate and PPID varies considerably across different protein interaction datasets. Specifically, because of the maximal inconsistency between yeast two-hybrid and other datasets, we reasoned that the difference in experimental methods contributes to our inability to clearly define how PPID affects protein evolutionary rate. To address this, we integrated protein interaction and gene co-expression data to derive a co-expressed protein-protein interaction degree (ePPID) measure, which reflects the number of partners with which a protein can permanently interact. Thus, irrespective of the experimental method employed, we found that (1) ePPID is a better predictor of protein evolutionary rate than PPID, (2) ePPID is a more robust predictor of protein evolutionary rate than PPID, and (3) the contribution of ePPID to protein evolutionary rate is statistically independent of expression level. Analysis of hub proteins in the Structural Interaction Network further supported ePPID as a better predictor of protein evolutionary rate than the number of distinct binding interfaces and clarified the slower evolution of co-expressed multi-interface hub proteins over that of other hub proteins. Conclusions Our study firmly established ePPID as a robust predictor of protein evolutionary rate, irrespective of experimental method, and underscored the importance of permanent interactions in shaping the evolutionary outcome.
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Affiliation(s)
- Kaifang Pang
- Department of Computer Science and Engineering, Shanghai Jiao Tong University, China
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13
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Lahudkar S, Shukla A, Bajwa P, Durairaj G, Stanojevic N, Bhaumik SR. The mRNA cap-binding complex stimulates the formation of pre-initiation complex at the promoter via its interaction with Mot1p in vivo. Nucleic Acids Res 2010; 39:2188-209. [PMID: 21075799 PMCID: PMC3064766 DOI: 10.1093/nar/gkq1029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The cap-binding complex (CBC) binds to the cap structure of mRNA to protect it from exonucleases as well as to regulate downstream post-transcriptional events, translational initiation and nonsense-mediated mRNA decay. However, its role in regulation of the upstream transcriptional events such as initiation or elongation remains unknown. Here, using a formaldehyde-based in vivo cross-linking and chromatin immunoprecipitation assay in conjunction with transcriptional, mutational and co-immunoprecipitational analyses, we show that CBC is recruited to the body of yeast gene, and then stimulates the formation of pre-initiation complex (PIC) at several yeast promoters through its interaction with Mot1p (modifier of transcription). Mot1p is recruited to these promoters, and enhances the PIC formation. We find that CBC promotes the recruitment of Mot1p which subsequently stimulates PIC formation at these promoters. Furthermore, the formation of PIC is essential for recruitment of CBC. Thus, our study presents an interesting observation that an mRNA binding factor exhibits a reciprocal synergistic effect on formation of PIC (and hence transcriptional initiation) at the promoter, revealing a new pathway of eukaryotic gene regulation in vivo.
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Affiliation(s)
| | | | | | | | | | - Sukesh R. Bhaumik
- *To whom correspondence should be addressed. Tel: +1 618 453 6479; Fax: +1 618 453 6440;
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14
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Pang K, Sheng H, Ma X. Understanding gene essentiality by finely characterizing hubs in the yeast protein interaction network. Biochem Biophys Res Commun 2010; 401:112-6. [PMID: 20833129 DOI: 10.1016/j.bbrc.2010.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 09/05/2010] [Indexed: 10/19/2022]
Abstract
The centrality-lethality rule, i.e., high-degree proteins or hubs tend to be more essential than low-degree proteins in the yeast protein interaction network, reveals that a protein's central position indicates its important function, but whether and why hubs tend to be more essential have been heavily debated. Here, we integrated gene expression and functional module data to classify hubs into four types: non-co-expressed non-co-cluster hubs, non-co-expressed co-cluster hubs, co-expressed non-co-cluster hubs and co-expressed co-cluster hubs. We found that all the four hub types are more essential than non-hubs, but they also show different enrichments in essential proteins. Non-co-expressed non-co-cluster hubs play key role in organizing different modules formed by the other three hub types, but they are less important to the survival of the yeast cell. Among the four hub types, co-expressed co-cluster hubs, which likely correspond to the core components of stable protein complexes, are the most essential. These results demonstrated that our classification of hubs into four types could better improve the understanding of gene essentiality.
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Affiliation(s)
- Kaifang Pang
- Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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15
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Chandrasekharan MB, Huang F, Sun ZW. Histone H2B ubiquitination and beyond: Regulation of nucleosome stability, chromatin dynamics and the trans-histone H3 methylation. Epigenetics 2010; 5:460-8. [PMID: 20523115 DOI: 10.4161/epi.5.6.12314] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Regulation of Set1-COMPASS-mediated H3K4 methylation and Dot1-mediated H3K79 methylation by H2BK123 ubiquitination (H2Bub1) is an evolutionarily conserved trans-histone crosstalk mechanism. How H2Bub1 impacts chromatin structure and affects Set1-COMPASS/Dot1 functions has not been fully defined. Ubiquitin was proposed to bind proteins to physically bridge H2Bub1 with Set1-COMPASS/Dot1. Alternatively, the bulky ubiquitin was thought to be a "wedge" that loosens the nucleosome for factor access. Contrary to the latter possibility, recent discoveries provide evidence for nucleosome stabilization by H2Bub1 via preventing the constant H2A-H2B eviction. Recent data has also uncovered a "docking-site" on H2B for Set1-COMPASS. Collectively, these findings invoke a model, where ubiquitin acts as a "glue" to bind the nucleosome together for supporting Set1-COMPASS/Dot1 functions. This review provides an overview of these novel findings. Additionally, how H2Bub1 and its deubiquitination might alter the chromatin dynamics during transcription is discussed. Possible models for nucleosome stabilization by ubiquitin are also provided.
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Affiliation(s)
- Mahesh B Chandrasekharan
- Department of Biochemistry and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA
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16
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Albert TK, Grote K, Boeing S, Meisterernst M. Basal core promoters control the equilibrium between negative cofactor 2 and preinitiation complexes in human cells. Genome Biol 2010; 11:R33. [PMID: 20230619 PMCID: PMC2864573 DOI: 10.1186/gb-2010-11-3-r33] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Revised: 02/22/2010] [Accepted: 03/15/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The general transcription factor TFIIB and its antagonist negative cofactor 2 (NC2) are hallmarks of RNA polymerase II (RNAPII) transcription. Both factors bind TATA box-binding protein (TBP) at promoters in a mutually exclusive manner. Dissociation of NC2 is thought to be followed by TFIIB association and subsequent preinitiation complex formation. TFIIB dissociates upon RNAPII promoter clearance, thereby providing a specific measure for steady-state preinitiation complex levels. As yet, genome-scale promoter mapping of human TFIIB has not been reported. It thus remains elusive how human core promoters contribute to preinitiation complex formation in vivo. RESULTS We compare target genes of TFIIB and NC2 in human B cells and analyze associated core promoter architectures. TFIIB occupancy is positively correlated with gene expression, with the vast majority of promoters being GC-rich and lacking defined core promoter elements. TATA elements, but not the previously in vitro defined TFIIB recognition elements, are enriched in some 4 to 5% of the genes. NC2 binds to a highly related target gene set. Nonetheless, subpopulations show strong variations in factor ratios: whereas high TFIIB/NC2 ratios select for promoters with focused start sites and conserved core elements, high NC2/TFIIB ratios correlate to multiple start-site promoters lacking defined core elements. CONCLUSIONS TFIIB and NC2 are global players that occupy active genes. Preinitiation complex formation is independent of core elements at the majority of genes. TATA and TATA-like elements dictate TFIIB occupancy at a subset of genes. Biochemical data support a model in which preinitiation complex but not TBP-NC2 complex formation is regulated.
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Affiliation(s)
- Thomas K Albert
- Institute of Molecular Tumor Biology (IMTB), University of Muenster, Robert-Koch-Str. 43, 48149 Muenster, Germany
| | - Korbinian Grote
- Genomatix Software GmbH, Bayerstr. 85a, 80335 Munich, Germany
| | - Stefan Boeing
- Institute of Molecular Tumor Biology (IMTB), University of Muenster, Robert-Koch-Str. 43, 48149 Muenster, Germany
| | - Michael Meisterernst
- Institute of Molecular Tumor Biology (IMTB), University of Muenster, Robert-Koch-Str. 43, 48149 Muenster, Germany
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17
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Layer JH, Miller SG, Weil PA. Direct transactivator-transcription factor IID (TFIID) contacts drive yeast ribosomal protein gene transcription. J Biol Chem 2010; 285:15489-15499. [PMID: 20189987 DOI: 10.1074/jbc.m110.104810] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transcription factor IID (TFIID) plays a key role in regulating eukaryotic gene expression by directly binding promoters and enhancer-bound transactivator proteins. However, the precise mechanisms and outcomes of transactivator-TFIID interaction remain unclear. Transcription of yeast ribosomal protein genes requires TFIID and the DNA-binding transactivator Rap1. We have previously shown that Rap1 directly binds to the TFIID complex through interaction with its TATA-binding protein-associated factor (Taf) subunits Taf4, -5, and -12. Here, we identify and characterize the Rap1 binding domains (RBDs) of Taf4 and Taf5. These RBDs are essential for viability but dispensable for Taf-Taf interactions and TFIID stability. Cells expressing altered Rap1 binding domains exhibit conditional growth, synthetic phenotypes when expressed in combination or with altered Rap1, and are selectively defective in ribosomal protein gene transcription. Taf4 and Taf5 proteins with altered RBDs bind Rap1 with reduced affinity. We propose that collectively the Taf4, Taf5, and Taf12 subunits of TFIID represent the physical and functional targets for Rap1 interaction and, furthermore, that these interactions drive ribosomal protein gene transcription.
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Affiliation(s)
- Justin H Layer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615
| | - Scott G Miller
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615
| | - P Anthony Weil
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615.
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18
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GCN5 is a positive regulator of origins of DNA replication in Saccharomyces cerevisiae. PLoS One 2010; 5:e8964. [PMID: 20126453 PMCID: PMC2813283 DOI: 10.1371/journal.pone.0008964] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 01/05/2010] [Indexed: 12/31/2022] Open
Abstract
GCN5 encodes one of the non-essential Histone Acetyl Transferases in Saccharomyces cerevisiae. Extensive evidence has indicated that GCN5 is a key regulator of gene expression and could also be involved in transcriptional elongation, DNA repair and centromere maintenance. Here we show that the deletion of GCN5 decreases the stability of mini-chromosomes; that the tethering of Gcn5p to a crippled origin of replication stimulates its activity; that high dosage of GCN5 suppresses conditional phenotypes caused by mutant alleles of bona fide replication factors, orc2-1, orc5-1 and mcm5-461. Furthermore, Gcn5p physically associates with origins of DNA replication, while its deletion leads to localized condensation of chromatin at origins. Finally, Deltagcn5 cells display a deficiency in the assembly of pre-replicative complexes. We propose that GCN5 acts as a positive regulator of DNA replication by counteracting the inhibitory effect of Histone Deacetylases.
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19
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Ohtsuki K, Kasahara K, Shirahige K, Kokubo T. Genome-wide localization analysis of a complete set of Tafs reveals a specific effect of the taf1 mutation on Taf2 occupancy and provides indirect evidence for different TFIID conformations at different promoters. Nucleic Acids Res 2009; 38:1805-20. [PMID: 20026583 PMCID: PMC2847235 DOI: 10.1093/nar/gkp1172] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In Saccharomyces cerevisiae, TFIID and SAGA principally mediate transcription of constitutive housekeeping genes and stress-inducible genes, respectively, by delivering TBP to the core promoter. Both are multi-protein complexes composed of 15 and 20 subunits, respectively, five of which are common and which may constitute a core sub-module in each complex. Although genome-wide gene expression studies have been conducted extensively in several TFIID and/or SAGA mutants, there are only a limited number of studies investigating genome-wide localization of the components of these two complexes. Specifically, there are no previous reports on localization of a complete set of Tafs and the effects of taf mutations on localization. Here, we examine the localization profiles of a complete set of Tafs, Gcn5, Bur6/Ncb2, Sua7, Tfa2, Tfg1, Tfb3 and Rpb1, on chromosomes III, IV and V by chromatin immunoprecipitation (ChIP)-chip analysis in wild-type and taf1-T657K mutant strains. In addition, we conducted conventional and sequential ChIP analysis of several ribosomal protein genes (RPGs) and non-RPGs. Intriguingly, the results revealed a novel relationship between TFIIB and NC2, simultaneous co-localization of SAGA and TFIID on RPG promoters, specific effects of taf1 mutation on Taf2 occupancy, and an indirect evidence for the existence of different TFIID conformations.
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Affiliation(s)
- Kazushige Ohtsuki
- Division of Molecular and Cellular Biology, Graduate School of Nanobioscience, Yokohama City University, Yokohama 230-0045, Japan
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20
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van Werven FJ, van Teeffelen HAAM, Holstege FCP, Timmers HTM. Distinct promoter dynamics of the basal transcription factor TBP across the yeast genome. Nat Struct Mol Biol 2009; 16:1043-8. [PMID: 19767748 DOI: 10.1038/nsmb.1674] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 08/19/2009] [Indexed: 12/13/2022]
Abstract
Transcription regulation in eukaryotes involves rapid recruitment and proper assembly of transcription factors at gene promoters. To determine the dynamics of the transcription machinery on DNA, we used a differential chromatin immunoprecipitation procedure coupled to whole-genome microarray detection in Saccharomyces cerevisiae. We find that TATA-binding protein (TBP) turnover is low at RNA polymerase I (Pol I) promoters. Whereas RNA polymerase III (Pol III) promoters represent an intermediate case, TBP turnover is high at RNA polymerase II (Pol II) promoters. Within these promoters, the highest turnover correlates with binding of the Spt-Ada-Gcn5 acetyltransferase complex (SAGA) coactivator, Mot1p dependence and presence of a canonical TATA box. In contrast, slow turnover Pol II promoters depend on TFIID and on the gene-specific factor, Rap1p. Together this shows that TBP turnover is regulated by protein factors rather than DNA sequence and argues that TBP turnover is an important determinant in regulating gene expression.
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Affiliation(s)
- Folkert J van Werven
- Department of Physiological Chemistry, University Medical Center Utrecht, Utrecht, The Netherlands
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21
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Pelechano V, Jimeno-González S, Rodríguez-Gil A, García-Martínez J, Pérez-Ortín JE, Chávez S. Regulon-specific control of transcription elongation across the yeast genome. PLoS Genet 2009; 5:e1000614. [PMID: 19696888 PMCID: PMC2721418 DOI: 10.1371/journal.pgen.1000614] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 07/24/2009] [Indexed: 11/19/2022] Open
Abstract
Transcription elongation by RNA polymerase II was often considered an invariant non-regulated process. However, genome-wide studies have shown that transcriptional pausing during elongation is a frequent phenomenon in tightly-regulated metazoan genes. Using a combination of ChIP-on-chip and genomic run-on approaches, we found that the proportion of transcriptionally active RNA polymerase II (active versus total) present throughout the yeast genome is characteristic of some functional gene classes, like those related to ribosomes and mitochondria. This proportion also responds to regulatory stimuli mediated by protein kinase A and, in relation to cytosolic ribosomal-protein genes, it is mediated by the silencing domain of Rap1. We found that this inactive form of RNA polymerase II, which accumulates along the full length of ribosomal protein genes, is phosphorylated in the Ser5 residue of the CTD, but is hypophosphorylated in Ser2. Using the same experimental approach, we show that the in vivo–depletion of FACT, a chromatin-related elongation factor, also produces a regulon-specific effect on the expression of the yeast genome. This work demonstrates that the regulation of transcription elongation is a widespread, gene class–dependent phenomenon that also affects housekeeping genes. Transcription of DNA–encoded information into RNA is the first step in gene regulation. RNA polymerases initiate transcription at the promoter region and elongate the transcripts traveling throughout the gene until reaching the termination sequences. Classical models of transcriptional regulation were focused on the initiation step, but there is increasing evidence for gene regulation after initiation. We have investigated the importance of elongation in gene regulation using the yeast Saccharomyces cerevisiae, one of the main experimental systems in modern biology. By comparing the genomic distribution of RNA polymerase molecules with the actual transcriptional signal across the genome, we have detected that many genes are regulated at the elongation level. We show that yeast cells use this step to modulate the expression of several groups of genes, which have to be simultaneously regulated in a very coordinated manner. Genes encoding essential functions, like those related to protein synthesis and respiration, change their transcriptional activities in response to environmental stimuli, without changing in the same extension the amount of RNA polymerase that is physically associated to them. We also show that this kind of regulation, in spite of taking place during the elongation step, can be mediated by promoter-binding transcription factors.
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Affiliation(s)
- Vicent Pelechano
- Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Spain
| | | | | | - José García-Martínez
- Sección de Chips de DNA, Servei Central de Suport a la Investigació, Universitat de València, Burjassot, Spain
| | - José E. Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular, Universitat de València, Burjassot, Spain
- * E-mail: (JEPO); (SC)
| | - Sebastián Chávez
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
- * E-mail: (JEPO); (SC)
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22
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Sikorski TW, Buratowski S. The basal initiation machinery: beyond the general transcription factors. Curr Opin Cell Biol 2009; 21:344-51. [PMID: 19411170 DOI: 10.1016/j.ceb.2009.03.006] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/26/2009] [Accepted: 03/29/2009] [Indexed: 01/19/2023]
Abstract
In vitro experiments led to a simple model in which basal transcription factors sequentially assembled with RNA Polymerase II to generate a preinitiation complex (PIC). Emerging evidence indicates that PIC composition is not universal, but promoter-dependent. Active promoters are occupied by a mixed population of complexes, including regulatory factors such as NC2, Mot1, Mediator, and TFIIS. Recent studies are expanding our understanding of the roles of these factors, demonstrating that their functions are both broader and more context dependent than previously realized.
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Affiliation(s)
- Timothy W Sikorski
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, United States
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23
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Luo F, Li B, Wan XF, Scheuermann RH. Core and periphery structures in protein interaction networks. BMC Bioinformatics 2009; 10 Suppl 4:S8. [PMID: 19426456 PMCID: PMC2681073 DOI: 10.1186/1471-2105-10-s4-s8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Characterizing the structural properties of protein interaction networks will help illuminate the organizational and functional relationships among elements in biological systems. RESULTS In this paper, we present a systematic exploration of the core/periphery structures in protein interaction networks (PINs). First, the concepts of cores and peripheries in PINs are defined. Then, computational methods are proposed to identify two types of cores, k-plex cores and star cores, from PINs. Application of these methods to a yeast protein interaction network has identified 110 k-plex cores and 109 star cores. We find that the k-plex cores consist of either "party" proteins, "date" proteins, or both. We also reveal that there are two classes of 1-peripheral proteins: "party" peripheries, which are more likely to be part of protein complex, and "connector" peripheries, which are more likely connected to different proteins or protein complexes. Our results also show that, besides connectivity, other variations in structural properties are related to the variation in biological properties. Furthermore, the negative correlation between evolutionary rate and connectivity are shown toysis. Moreover, the core/periphery structures help to reveal the existence of multiple levels of protein expression dynamics. CONCLUSION Our results show that both the structure and connectivity can be used to characterize topological properties in protein interaction networks, illuminating the functional organization of cellular systems.
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Affiliation(s)
- Feng Luo
- School of Computing, Clemson University, Clemson, SC, USA.
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24
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Sprouse RO, Wells MN, Auble DT. TATA-binding protein variants that bypass the requirement for Mot1 in vivo. J Biol Chem 2009; 284:4525-35. [PMID: 19098311 PMCID: PMC2640957 DOI: 10.1074/jbc.m808951200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 12/18/2008] [Indexed: 12/27/2022] Open
Abstract
Mot1 is an essential TATA-binding protein (TBP)-associated factor and Snf2/Swi2 ATPase that both represses and activates transcription. Biochemical and structural results support a model in which ATP binding and hydrolysis induce a conformational change in Mot1 that drives local translocation along DNA, thus removing TBP. Although this activity explains transcriptional repression, it does not as easily explain Mot1-mediated transcriptional activation, and several different models have been proposed to explain how Mot1 activates transcription. To better understand the function of Mot1 in yeast cells in vivo, particularly with regard to gene activation, TBP mutants were identified that bypass the requirement for Mot1 in vivo. Although TBP has been extensively mutated and analyzed previously, this screen uncovered two novel TBP variants that are unique in their ability to bypass the requirement for Mot1. Surprisingly, in vitro analyses reveal that rather than having acquired an improved biochemical activity, one of the TBPs was defective for interaction with polymerase II preinitiation complex (PIC) components and other regulators of TBP function. The other mutant was defective for DNA binding in vitro yet was still recruited to chromatin in vivo. These results suggest that Mot1-mediated dissociation of TBP (or TBP-containing complexes) from chromatin can explain the Mot1 activation mechanism at some promoters. The results also suggest that PICs can be dynamically unstable and that appropriate PIC instability is critical for the regulation of transcription in vivo.
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Affiliation(s)
- Rebekka O Sprouse
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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25
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TFIIB recognition elements control the TFIIA-NC2 axis in transcriptional regulation. Mol Cell Biol 2008; 29:1389-400. [PMID: 19114554 DOI: 10.1128/mcb.01346-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
TFIIB recognizes DNA sequence-specific motifs that can flank the TATA elements of the promoters of protein-encoding genes. The TFIIB recognition elements (BRE(u) and BRE(d)) can have positive or negative effects on transcription in a promoter context-dependent manner. Here we show that the BREs direct the selective recruitment of TFIIA and NC2 to the promoter. We find that TFIIA preferentially associates with BRE-containing promoters while NC2 is recruited to promoters that lack consensus BREs. The functional relevance of the BRE-dependent recruitment of TFIIA and NC2 was determined by small interfering RNA-mediated knockdown of TFIIA and NC2, both of which elicited BRE-dependent effects on transcription. Our results confirm the established functional reciprocity of TFIIA and NC2. However, our findings show that TFIIA assembly at BRE-containing promoters results in reduced transcriptional activity, while NC2 acts as a positive factor at promoters that lack functional BREs. Taken together, our results provide a basis for the selective recruitment of TFIIA and NC2 to the promoter and give new insights into the functional relationship between core promoter elements and general transcription factor activity.
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26
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Auble DT. The dynamic personality of TATA-binding protein. Trends Biochem Sci 2008; 34:49-52. [PMID: 19038550 DOI: 10.1016/j.tibs.2008.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 10/23/2008] [Accepted: 10/27/2008] [Indexed: 11/26/2022]
Abstract
TATA-binding protein (TBP) is a central component of the transcription apparatus and its association with promoters is dynamically regulated genome-wide. Recent work has shed new light on the functional specificity of Mot1 and NC2, two factors that control TBP distribution and activity. These studies underscore how regulation of TBP globally influences fundamental aspects of gene expression, including the balance of transcriptional output from different types of promoters, and the amplitude and timing of gene activation.
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Affiliation(s)
- David T Auble
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA.
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27
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Azmy YY, Gupta A, Pugh BF. Computational modelling of genome-wide [corrected] transcription assembly networks using a fluidics analogy. PLoS One 2008; 3:e3095. [PMID: 18769485 PMCID: PMC2518210 DOI: 10.1371/journal.pone.0003095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 08/04/2008] [Indexed: 11/29/2022] Open
Abstract
Understanding how a myriad of transcription regulators work to modulate mRNA output at thousands of genes remains a fundamental challenge in molecular biology. Here we develop a computational tool to aid in assessing the plausibility of gene regulatory models derived from genome-wide expression profiling of cells mutant for transcription regulators. mRNA output is modelled as fluid flow in a pipe lattice, with assembly of the transcription machinery represented by the effect of valves. Transcriptional regulators are represented as external pressure heads that determine flow rate. Modelling mutations in regulatory proteins is achieved by adjusting valves' on/off settings. The topology of the lattice is designed by the experimentalist to resemble the expected interconnection between the modelled agents and their influence on mRNA expression. Users can compare multiple lattice configurations so as to find the one that minimizes the error with experimental data. This computational model provides a means to test the plausibility of transcription regulation models derived from large genomic data sets.
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Affiliation(s)
- Yousry Y. Azmy
- Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Anshuman Gupta
- Department of Academic Services & Emerging Technologies, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - B. Franklin Pugh
- Center for Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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28
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Bendjennat M, Weil PA. The transcriptional repressor activator protein Rap1p is a direct regulator of TATA-binding protein. J Biol Chem 2008; 283:8699-710. [PMID: 18195009 DOI: 10.1074/jbc.m709436200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Essentially all nuclear eukaryotic gene transcription depends upon the function of the transcription factor TATA-binding protein (TBP). Here we show that the abundant, multifunctional DNA binding transcription factor repressor activator protein Rap1p interacts directly with TBP. TBP-Rap1p binding occurs efficiently in vivo at physiological expression levels, and in vitro analyses confirm that this is a direct interaction. The DNA binding domains of the two proteins mediate interaction between TBP and Rap1p. TBP-Rap1p complex formation inhibits TBP binding to TATA promoter DNA. Alterations in either Rap1p or TBP levels modulate mRNA gene transcription in vivo. We propose that Rap1p represents a heretofore unrecognized regulator of TBP.
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Affiliation(s)
- Mourad Bendjennat
- Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, Nashville, TN 37232-0615, USA
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29
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Masson P, Leimgruber E, Creton S, Collart MA. The dual control of TFIIB recruitment by NC2 is gene specific. Nucleic Acids Res 2007; 36:539-49. [PMID: 18048413 PMCID: PMC2241854 DOI: 10.1093/nar/gkm1078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Negative co-factor 2 (NC2) is a conserved eukaryotic complex composed of two subunits, NC2alpha (Drap1) and NC2beta (Dr1) that associate through a histone-fold motif. In this work, we generated mutants of NC2, characterized target genes for these mutants and studied the assembly of NC2 and general transcription factors on target promoters. We determined that the two NC2 subunits mostly function together to be recruited to DNA and regulate gene expression. We found that NC2 strongly controls promoter association of TFIIB, both negatively and positively. We could attribute the gene-specific repressor effect of NC2 on TFIIB to the C-terminal domain of NC2beta, and define that it requires ORF sequences of the target gene. In contrast, the positive function of NC2 on TFIIB targets is more general and requires adequate levels of the NC2 histone-fold heterodimer on promoters. Finally, we determined that NC2 becomes limiting for TATA-binding protein (TBP) association with a heat inducible promoter under heat stress. This study demonstrates an important positive role of NC2 for formation of the pre-initiation complex on promoters, under normal conditions through control of TFIIB, or upon activation by stress via control of TBP.
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Affiliation(s)
- Patrick Masson
- Department of Microbiology and Molecular Medicine, CMU, 1 rue Michel Servet 1211, Geneva 4, Switzerland
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30
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Peters TW, Huang M. Protein aggregation and polyasparagine-mediated cellular toxicity in Saccharomyces cerevisiae. Prion 2007; 1:144-53. [PMID: 19164913 DOI: 10.4161/pri.1.2.4630] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
It is well established that protein aggregation is associated with many neurodegenerative disorders including polyglutamine diseases, but a mechanistic understanding of the role of protein aggregates in the disease pathogenesis remains elusive. Previously thought to be the cause of cellular toxicity such as cellular dysfunction and cell death, protein aggregation is now proposed to serve a protective role by sequestering toxic oligomers from interfering with essential physiological processes. To investigate the relationship between protein aggregation and cellular toxicity, we have characterized and compared the effects of two GFP-fusion proteins that form aggregates in Saccharomyces cerevisiae, one with a polyasparagine repeat (GFP(N104)) and one without (GFP(C)). Although both proteins can form microscopically visible GFP-positive aggregates, only the GFP(N104)-containing aggregates exhibit morphological and biochemical characteristics that resemble the aggregates formed by mutant huntingtin in yeast cells. Formation of both the GFP(C) and GFP(N104) aggregates depends on microtubules, while only the GFP(N104) aggregate requires the chaperone Hsp104 and the prion Rnq1 and is resistant to SDS. Although no microscopically visible GFP(N104) aggregates were observed in the hsp104Delta and rnq1Delta mutant cells, SDS-insoluble aggregates can still be detected by the filter trap assay. These observations argue that the GFP(N104)-containing aggregates can exist in at least two distinct states in vivo. We also show that a nucleus-targeted GFP(N104) interferes with transcription from two SAGA-dependant promoters and results in a decrease in cell viability. Overall, the results imply that the GFP(N104) protein behaves similarly to the mutant huntingtin in yeast cells and provides a new model for investigating the interplay between protein aggregates and the associated phenotypes.
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Affiliation(s)
- Theodore W Peters
- Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA
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