1
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Weiß E, Hennig T, Graßl P, Djakovic L, Whisnant AW, Jürges CS, Koller F, Kluge M, Erhard F, Dölken L, Friedel CC. HSV-1 Infection Induces a Downstream Shift of Promoter-Proximal Pausing for Host Genes. J Virol 2023; 97:e0038123. [PMID: 37093003 PMCID: PMC10231138 DOI: 10.1128/jvi.00381-23] [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: 03/10/2023] [Accepted: 04/03/2023] [Indexed: 04/25/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) infection exerts a profound shutoff of host gene expression at multiple levels. Recently, HSV-1 infection was reported to also impact promoter-proximal RNA polymerase II (Pol II) pausing, a key step in the eukaryotic transcription cycle, with decreased and increased Pol II pausing observed for activated and repressed genes, respectively. Here, we demonstrate that HSV-1 infection induces more complex alterations in promoter-proximal pausing than previously suspected for the vast majority of cellular genes. While pausing is generally retained, it is shifted to more downstream and less well-positioned sites for most host genes. The downstream shift of Pol II pausing was established between 1.5 and 3 h of infection, remained stable until at least 6 hours postinfection, and was observed in the absence of ICP22. The shift in Pol II pausing does not result from alternative de novo transcription initiation at downstream sites or read-in transcription originating from disruption of transcription termination of upstream genes. The use of downstream secondary pause sites associated with +1 nucleosomes was previously observed upon negative elongation factor (NELF) depletion. However, downstream shifts of Pol II pausing in HSV-1 infection were much more pronounced than observed upon NELF depletion. Thus, our study reveals a novel aspect in which HSV-1 infection fundamentally reshapes host transcriptional processes, providing new insights into the regulation of promoter-proximal Pol II pausing in eukaryotic cells. IMPORTANCE This study provides a genome-wide analysis of changes in promoter-proximal polymerase II (Pol II) pausing on host genes induced by HSV-1 infection. It shows that standard measures of pausing, i.e., pausing indices, do not properly capture the complex and unsuspected alterations in Pol II pausing occurring in HSV-1 infection. Instead of a reduction of pausing with increased elongation, as suggested by pausing index analysis, HSV-1 infection leads to a shift of pausing to downstream and less well-positioned sites than in uninfected cells for the majority of host genes. Thus, HSV-1 infection fundamentally reshapes a key regulatory step at the beginning of the host transcriptional cycle on a genome-wide scale.
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Affiliation(s)
- Elena Weiß
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Thomas Hennig
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Pilar Graßl
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Lara Djakovic
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Adam W. Whisnant
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Christopher S. Jürges
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Franziska Koller
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Kluge
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Florian Erhard
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Lars Dölken
- Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz-Center for Infection Research (HZI), Würzburg, Germany
| | - Caroline C. Friedel
- Institute of Informatics, Ludwig-Maximilians-Universität München, Munich, Germany
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2
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ERK-mediated NELF-A phosphorylation promotes transcription elongation of immediate-early genes by releasing promoter-proximal pausing of RNA polymerase II. Nat Commun 2022; 13:7476. [PMID: 36463234 PMCID: PMC9719515 DOI: 10.1038/s41467-022-35230-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/22/2022] [Indexed: 12/05/2022] Open
Abstract
Growth factor-induced, ERK-mediated induction of immediate-early genes (IEGs) is crucial for cell growth and tumorigenesis. Although IEG expression is mainly regulated at the level of transcription elongation by RNA polymerase-II (Pol-II) promoter-proximal pausing and its release, the role of ERK in this process remains unknown. Here, we identified negative elongation factor (NELF)-A as an ERK substrate. Upon growth factor stimulation, ERK phosphorylates NELF-A, which dissociates NELF from paused Pol-II at the promoter-proximal regions of IEGs, allowing Pol-II to resume elongation and produce full-length transcripts. Furthermore, we found that in cancer cells, PP2A efficiently dephosphorylates NELF-A, thereby preventing aberrant IEG expression induced by ERK-activating oncogenes. However, when PP2A inhibitor proteins are overexpressed, as is frequently observed in cancers, decreased PP2A activity combined with oncogene-mediated ERK activation conspire to induce NELF-A phosphorylation and IEG upregulation, resulting in tumor progression. Our data delineate previously unexplored roles of ERK and PP2A inhibitor proteins in carcinogenesis.
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3
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Abstract
Melanoma is the deadliest form of skin cancer. While clinical developments have significantly improved patient prognosis, effective treatment is often obstructed by limited response rates, intrinsic or acquired resistance to therapy, and adverse events. Melanoma initiation and progression are associated with transcriptional reprogramming of melanocytes to a cell state that resembles the lineage from which the cells are specified during development, that is the neural crest. Convergence to a neural crest cell (NCC)-like state revealed the therapeutic potential of targeting developmental pathways for the treatment of melanoma. Neural crest cells have a unique sensitivity to metabolic dysregulation, especially nucleotide depletion. Mutations in the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH) particularly affect neural crest-derived tissues and cause Miller syndrome, a genetic disorder characterized by craniofacial malformations in patients. The developmental susceptibility of the neural crest to nucleotide deficiency is conserved in melanoma and provides a metabolic vulnerability that can be exploited for therapeutic purposes. We review the current knowledge on nucleotide stress responses in neural crest and melanoma and discuss how the recent scientific advances that have improved our understanding of transcriptional regulation during nucleotide depletion can impact melanoma treatment.
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Affiliation(s)
- Audrey Sporrij
- Harvard Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Leonard I Zon
- Harvard Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Harvard Stem Cell Institute, Harvard Medical School and Howard Hughes Medical Institute, Boston, MA, USA
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4
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Aoi Y, Smith ER, Shah AP, Rendleman EJ, Marshall SA, Woodfin AR, Chen FX, Shiekhattar R, Shilatifard A. NELF Regulates a Promoter-Proximal Step Distinct from RNA Pol II Pause-Release. Mol Cell 2020; 78:261-274.e5. [PMID: 32155413 PMCID: PMC7402197 DOI: 10.1016/j.molcel.2020.02.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 12/17/2019] [Accepted: 02/18/2020] [Indexed: 02/08/2023]
Abstract
RNA polymerase II (RNA Pol II) is generally paused at promoter-proximal regions in most metazoans, and based on in vitro studies, this function has been attributed to the negative elongation factor (NELF). Here, we show that upon rapid depletion of NELF, RNA Pol II fails to be released into gene bodies, stopping instead around the +1 nucleosomal dyad-associated region. The transition to the 2nd pause region is independent of positive transcription elongation factor P-TEFb. During the heat shock response, RNA Pol II is rapidly released from pausing at heat shock-induced genes, while most genes are paused and transcriptionally downregulated. Both of these aspects of the heat shock response remain intact upon NELF loss. We find that NELF depletion results in global loss of cap-binding complex from chromatin without global reduction of nascent transcript 5' cap stability. Thus, our studies implicate NELF functioning in early elongation complexes distinct from RNA Pol II pause-release.
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Affiliation(s)
- Yuki Aoi
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Edwin R Smith
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Avani P Shah
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Emily J Rendleman
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Stacy A Marshall
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ashley R Woodfin
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Fei X Chen
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ramin Shiekhattar
- Department of Human Genetics, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ali Shilatifard
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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5
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Bahat A, Lahav O, Plotnikov A, Leshkowitz D, Dikstein R. Targeting Spt5-Pol II by Small-Molecule Inhibitors Uncouples Distinct Activities and Reveals Additional Regulatory Roles. Mol Cell 2019; 76:617-631.e4. [PMID: 31564557 DOI: 10.1016/j.molcel.2019.08.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 06/12/2019] [Accepted: 08/26/2019] [Indexed: 12/27/2022]
Abstract
Spt5 is a conserved and essential transcription elongation factor that promotes promoter-proximal pausing, promoter escape, elongation, and mRNA processing. Spt5 plays specific roles in the transcription of inflammation and stress-induced genes and tri-nucleotide expanded-repeat genes involved in inherited neurological pathologies. Here, we report the identification of Spt5-Pol II small-molecule inhibitors (SPIs). SPIs faithfully reproduced Spt5 knockdown effects on promoter-proximal pausing, NF-κB activation, and expanded-repeat huntingtin gene transcription. Using SPIs, we identified Spt5 target genes that responded with profoundly diverse kinetics. SPIs uncovered the regulatory role of Spt5 in metabolism via GDF15, a food intake- and body weight-inhibitory hormone. SPIs further unveiled a role for Spt5 in promoting the 3' end processing of histone genes. While several SPIs affect all Spt5 functions, a few inhibit a single one, implying uncoupling and selective targeting of Spt5 activities. SPIs expand the understanding of Spt5-Pol II functions and are potential drugs against metabolic and neurodegenerative diseases.
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Affiliation(s)
- Anat Bahat
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Or Lahav
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Plotnikov
- The Nancy and Stephen Grand Israel National Center for Personalized Medicine, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dena Leshkowitz
- Bioinformatics Unit, Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
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6
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Sacta MA, Tharmalingam B, Coppo M, Rollins DA, Deochand DK, Benjamin B, Yu L, Zhang B, Hu X, Li R, Chinenov Y, Rogatsky I. Gene-specific mechanisms direct glucocorticoid-receptor-driven repression of inflammatory response genes in macrophages. eLife 2018; 7:34864. [PMID: 29424686 PMCID: PMC5821458 DOI: 10.7554/elife.34864] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 01/28/2018] [Indexed: 01/13/2023] Open
Abstract
The glucocorticoid receptor (GR) potently represses macrophage-elicited inflammation, however, the underlying mechanisms remain obscure. Our genome-wide analysis in mouse macrophages reveals that pro-inflammatory paused genes, activated via global negative elongation factor (NELF) dissociation and RNA Polymerase (Pol)2 release from early elongation arrest, and non-paused genes, induced by de novo Pol2 recruitment, are equally susceptible to acute glucocorticoid repression. Moreover, in both cases the dominant mechanism involves rapid GR tethering to p65 at NF-kB-binding sites. Yet, specifically at paused genes, GR activation triggers widespread promoter accumulation of NELF, with myeloid cell-specific NELF deletion conferring glucocorticoid resistance. Conversely, at non-paused genes, GR attenuates the recruitment of p300 and histone acetylation, leading to a failure to assemble BRD4 and Mediator at promoters and enhancers, ultimately blocking Pol2 initiation. Thus, GR displays no preference for a specific pro-inflammatory gene class; however, it effects repression by targeting distinct temporal events and components of transcriptional machinery.
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Affiliation(s)
- Maria A Sacta
- Weill Cornell/ Rockefeller/ Sloan Kettering Tri-Institutional MD-PhD Program, New York, United States.,Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States.,Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, United States
| | - Bowranigan Tharmalingam
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States
| | - Maddalena Coppo
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States
| | - David A Rollins
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States.,Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, United States
| | - Dinesh K Deochand
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States
| | - Bradley Benjamin
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States
| | - Li Yu
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Bin Zhang
- Institute for Immunology and School of Medicine, Tsinghua University, Beijing, China
| | - Xiaoyu Hu
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States.,Institute for Immunology and School of Medicine, Tsinghua University, Beijing, China
| | - Rong Li
- Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, United States
| | - Yurii Chinenov
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States
| | - Inez Rogatsky
- Hospital for Special Surgery Research Institute, The David Rosensweig Genomics Center, New York, United States.,Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, United States
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7
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Mazina MY, Kovalenko EV, Derevyanko PK, Nikolenko JV, Krasnov AN, Vorobyeva NE. One signal stimulates different transcriptional activation mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:178-189. [PMID: 29410380 DOI: 10.1016/j.bbagrm.2018.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/10/2017] [Accepted: 01/15/2018] [Indexed: 12/30/2022]
Abstract
Transcriptional activation is often represented as a "one-step process" that involves the simultaneous recruitment of co-activator proteins, leading to a change in gene status. Using Drosophila developmental ecdysone-dependent genes as a model, we demonstrated that activation of transcription is instead a continuous process that consists of a number of steps at which different phases of transcription (initiation or elongation) are stimulated. Thorough evaluation of the behaviour of multiple transcriptional complexes during the early activation process has shown that the pathways by which activation proceeds for different genes may vary considerably, even in response to the same induction signal. RNA polymerase II recruitment is an important step that is involved in one of the pathways. RNA polymerase II recruitment is accompanied by the recruitment of a significant number of transcriptional coactivators as well as slight changes in the chromatin structure. The second pathway involves the stimulation of transcriptional elongation as its key step. The level of coactivator binding to the promoter shows almost no increase, whereas chromatin modification levels change significantly.
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Affiliation(s)
- Marina Yu Mazina
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Elena V Kovalenko
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Polina K Derevyanko
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Julia V Nikolenko
- Group of Studying an Association of Transcription and mRNA Transport, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Aleksey N Krasnov
- Group of Studying an Association of Transcription and mRNA Transport, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Nadezhda E Vorobyeva
- Group of Transcriptional Complexes Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia.
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8
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Tastemel M, Gogate AA, Malladi VS, Nguyen K, Mitchell C, Banaszynski LA, Bai X. Transcription pausing regulates mouse embryonic stem cell differentiation. Stem Cell Res 2017; 25:250-255. [PMID: 29174978 DOI: 10.1016/j.scr.2017.11.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/25/2017] [Accepted: 11/14/2017] [Indexed: 01/08/2023] Open
Abstract
The pluripotency of embryonic stem cells (ESCs) relies on appropriate responsiveness to developmental cues. Promoter-proximal pausing of RNA polymerase II (Pol II) has been suggested to play a role in keeping genes poised for future activation. To identify the role of Pol II pausing in regulating ESC pluripotency, we have generated mouse ESCs carrying a mutation in the pause-inducing factor SPT5. Genomic studies reveal genome-wide reduction of paused Pol II caused by mutant SPT5 and further identify a tight correlation between pausing-mediated transcription effect and local chromatin environment. Functionally, this pausing-deficient SPT5 disrupts ESC differentiation upon removal of self-renewal signals. Thus, our study uncovers an important role of Pol II pausing in regulating ESC differentiation and suggests a model that Pol II pausing coordinates with epigenetic modification to influence transcription during mESC differentiation.
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Affiliation(s)
- Melodi Tastemel
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Genetics, Development and Diseases Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Aishwarya A Gogate
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Venkat S Malladi
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kim Nguyen
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Courtney Mitchell
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Laura A Banaszynski
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaoying Bai
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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9
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Vihervaara A, Mahat DB, Guertin MJ, Chu T, Danko CG, Lis JT, Sistonen L. Transcriptional response to stress is pre-wired by promoter and enhancer architecture. Nat Commun 2017; 8:255. [PMID: 28811569 PMCID: PMC5557961 DOI: 10.1038/s41467-017-00151-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 06/05/2017] [Indexed: 12/29/2022] Open
Abstract
Programs of gene expression are executed by a battery of transcription factors that coordinate divergent transcription from a pair of tightly linked core initiation regions of promoters and enhancers. Here, to investigate how divergent transcription is reprogrammed upon stress, we measured nascent RNA synthesis at nucleotide-resolution, and profiled histone H4 acetylation in human cells. Our results globally show that the release of promoter-proximal paused RNA polymerase into elongation functions as a critical switch at which a gene’s response to stress is determined. Highly transcribed and highly inducible genes display strong transcriptional directionality and selective assembly of general transcription factors on the core sense promoter. Heat-induced transcription at enhancers, instead, correlates with prior binding of cell-type, sequence-specific transcription factors. Activated Heat Shock Factor 1 (HSF1) binds to transcription-primed promoters and enhancers, and CTCF-occupied, non-transcribed chromatin. These results reveal chromatin architectural features that orient transcription at divergent regulatory elements and prime transcriptional responses genome-wide. Heat Shock Factor 1 (HSF1) is a regulator of stress-induced transcription. Here, the authors investigate changes to transcription and chromatin organization upon stress and find that activated HSF1 binds to transcription-primed promoters and enhancers, and to CTCF occupied, untranscribed chromatin.
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Affiliation(s)
- Anniina Vihervaara
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, 20520, Finland.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, 14853, USA
| | - Dig Bijay Mahat
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, 14853, USA
| | - Michael J Guertin
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 22908, USA
| | - Tinyi Chu
- Department of Biomedical Sciences, The Baker Institute for Animal Health, Cornell University, Ithaca, New York, 14853, USA.,Graduate Field of Computational Biology, Cornell University, Ithaca, New York, 14853, USA
| | - Charles G Danko
- Department of Biomedical Sciences, The Baker Institute for Animal Health, Cornell University, Ithaca, New York, 14853, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, 14853, USA.
| | - Lea Sistonen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, 20520, Finland.
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10
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Dynamic Change of Transcription Pausing through Modulating NELF Protein Stability Regulates Granulocytic Differentiation. Blood Adv 2017; 1:1358-1367. [PMID: 28868519 DOI: 10.1182/bloodadvances.2017008383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The NELF complex is a metazoan-specific factor essential for establishing transcription pausing. Although NELF has been implicated in cell fate regulation, the cellular regulation of NELF and its intrinsic role in specific lineage differentiation remains largely unknown. Using mammalian hematopoietic differentiation as a model system, here we identified a dynamic change of NELF-mediated transcription pausing as a novel mechanism regulating hematopoietic differentiation. We found a sharp decrease of NELF protein abundance upon granulocytic differentiation and a subsequent genome-wide reduction of transcription pausing. This loss of pausing coincides with activation of granulocyte-affiliated genes and diminished expression of progenitor markers. Functional studies revealed that sustained expression of NELF inhibits granulocytic differentiation, whereas NELF depletion in progenitor cells leads to premature differentiation towards the granulocytic lineage. Our results thus uncover a previously unrecognized regulation of transcription pausing by modulating NELF protein abundance to control cellular differentiation.
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11
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Pause & go: from the discovery of RNA polymerase pausing to its functional implications. Curr Opin Cell Biol 2017; 46:72-80. [PMID: 28363125 DOI: 10.1016/j.ceb.2017.03.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/06/2017] [Accepted: 03/07/2017] [Indexed: 12/25/2022]
Abstract
The synthesis of nascent RNA is a discontinuous process in which phases of productive elongation by RNA polymerase are interrupted by frequent pauses. Transcriptional pausing was first observed decades ago, but was long considered to be a special feature of transcription at certain genes. This view was challenged when studies using genome-wide approaches revealed that RNA polymerase II pauses at promoter-proximal regions in large sets of genes in Drosophila and mammalian cells. High-resolution genomic methods uncovered that pausing is not restricted to promoters, but occurs globally throughout gene-body regions, implying the existence of key-rate limiting steps in nascent RNA synthesis downstream of transcription initiation. Here, we outline the experimental breakthroughs that led to the discovery of pervasive transcriptional pausing, discuss its emerging roles and regulation, and highlight the importance of pausing in human development and disease.
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12
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Yang Q, Liu X, Zhou T, Cook J, Nguyen K, Bai X. RNA polymerase II pausing modulates hematopoietic stem cell emergence in zebrafish. Blood 2016; 128:1701-10. [PMID: 27520065 PMCID: PMC5043126 DOI: 10.1182/blood-2016-02-697847] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022] Open
Abstract
The promoter-proximal pausing of RNA polymerase II (Pol II) plays a critical role in regulating metazoan gene transcription. Despite the prevalence of Pol II pausing across the metazoan genomes, little is known about the in vivo effect of Pol II pausing on vertebrate development. We use the emergence of hematopoietic stem cells (HSCs) in zebrafish embryos as a model to investigate the role of Pol II pausing in vertebrate organogenesis. Disrupting Pol II pausing machinery causes a severe reduction of HSC specification, a defect that can be effectively rescued by inhibiting Pol II elongation. In pausing-deficient embryos, the transforming growth factor β (TGFβ) signaling is elevated due to enhanced transcription elongation of key pathway genes, leading to HSC inhibition; in contrast, the interferon-γ (IFN-γ) signaling and its downstream effector Jak2/Stat3, which are required for HSC formation, are markedly attenuated owing to reduced chromatin accessibility on IFN-γ receptor genes. These findings reveal a novel transcription mechanism instructing HSC fate by pausing-mediated differential regulation of key signaling pathways.
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Affiliation(s)
- Qiwen Yang
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Xiuli Liu
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Ting Zhou
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jennifer Cook
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Kim Nguyen
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Xiaoying Bai
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
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13
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Bahrami S, Drabløs F. Gene regulation in the immediate-early response process. Adv Biol Regul 2016; 62:37-49. [PMID: 27220739 DOI: 10.1016/j.jbior.2016.05.001] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/03/2016] [Indexed: 05/13/2023]
Abstract
Immediate-early genes (IEGs) can be activated and transcribed within minutes after stimulation, without the need for de novo protein synthesis, and they are stimulated in response to both cell-extrinsic and cell-intrinsic signals. Extracellular signals are transduced from the cell surface, through receptors activating a chain of proteins in the cell, in particular extracellular-signal-regulated kinases (ERKs), mitogen-activated protein kinases (MAPKs) and members of the RhoA-actin pathway. These communicate through a signaling cascade by adding phosphate groups to neighboring proteins, and this will eventually activate and translocate TFs to the nucleus and thereby induce gene expression. The gene activation also involves proximal and distal enhancers that interact with promoters to simulate gene expression. The immediate-early genes have essential biological roles, in particular in stress response, like the immune system, and in differentiation. Therefore they also have important roles in various diseases, including cancer development. In this paper we summarize some recent advances on key aspects of the activation and regulation of immediate-early genes.
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Affiliation(s)
- Shahram Bahrami
- Department of Cancer Research and Molecular Medicine, NTNU - Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.
| | - Finn Drabløs
- Department of Cancer Research and Molecular Medicine, NTNU - Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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14
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Lu X, Zhu X, Li Y, Liu M, Yu B, Wang Y, Rao M, Yang H, Zhou K, Wang Y, Chen Y, Chen M, Zhuang S, Chen LF, Liu R, Chen R. Multiple P-TEFbs cooperatively regulate the release of promoter-proximally paused RNA polymerase II. Nucleic Acids Res 2016; 44:6853-67. [PMID: 27353326 PMCID: PMC5001612 DOI: 10.1093/nar/gkw571] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/06/2016] [Indexed: 01/09/2023] Open
Abstract
The association of DSIF and NELF with initiated RNA Polymerase II (Pol II) is the general mechanism for inducing promoter-proximal pausing of Pol II. However, it remains largely unclear how the paused Pol II is released in response to stimulation. Here, we show that the release of the paused Pol II is cooperatively regulated by multiple P-TEFbs which are recruited by bromodomain-containing protein Brd4 and super elongation complex (SEC) via different recruitment mechanisms. Upon stimulation, Brd4 recruits P-TEFb to Spt5/DSIF via a recruitment pathway consisting of Med1, Med23 and Tat-SF1, whereas SEC recruits P-TEFb to NELF-A and NELF-E via Paf1c and Med26, respectively. P-TEFb-mediated phosphorylation of Spt5, NELF-A and NELF-E results in the dissociation of NELF from Pol II, thereby transiting transcription from pausing to elongation. Additionally, we demonstrate that P-TEFb-mediated Ser2 phosphorylation of Pol II is dispensable for pause release. Therefore, our studies reveal a co-regulatory mechanism of Brd4 and SEC in modulating the transcriptional pause release by recruiting multiple P-TEFbs via a Mediator- and Paf1c-coordinated recruitment network.
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Affiliation(s)
- Xiaodong Lu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Xinxing Zhu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - You Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Min Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Bin Yu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Yu Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Muhua Rao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Haiyang Yang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Kai Zhou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Yao Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Yanheng Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Meihua Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Songkuan Zhuang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Lin-Feng Chen
- Department of Biochemistry, College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Runzhong Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
| | - Ruichuan Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian, China
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15
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Vos SM, Pöllmann D, Caizzi L, Hofmann KB, Rombaut P, Zimniak T, Herzog F, Cramer P. Architecture and RNA binding of the human negative elongation factor. eLife 2016; 5. [PMID: 27282391 PMCID: PMC4940160 DOI: 10.7554/elife.14981] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/09/2016] [Indexed: 11/30/2022] Open
Abstract
Transcription regulation in metazoans often involves promoter-proximal pausing of RNA polymerase (Pol) II, which requires the 4-subunit negative elongation factor (NELF). Here we discern the functional architecture of human NELF through X-ray crystallography, protein crosslinking, biochemical assays, and RNA crosslinking in cells. We identify a NELF core subcomplex formed by conserved regions in subunits NELF-A and NELF-C, and resolve its crystal structure. The NELF-AC subcomplex binds single-stranded nucleic acids in vitro, and NELF-C associates with RNA in vivo. A positively charged face of NELF-AC is involved in RNA binding, whereas the opposite face of the NELF-AC subcomplex binds NELF-B. NELF-B is predicted to form a HEAT repeat fold, also binds RNA in vivo, and anchors the subunit NELF-E, which is confirmed to bind RNA in vivo. These results reveal the three-dimensional architecture and three RNA-binding faces of NELF. DOI:http://dx.doi.org/10.7554/eLife.14981.001
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Affiliation(s)
- Seychelle M Vos
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - David Pöllmann
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Livia Caizzi
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Katharina B Hofmann
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Pascaline Rombaut
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Tomasz Zimniak
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Franz Herzog
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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16
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Dao P, Wojtowicz D, Nelson S, Levens D, Przytycka TM. Ups and Downs of Poised RNA Polymerase II in B-Cells. PLoS Comput Biol 2016; 12:e1004821. [PMID: 27078128 PMCID: PMC4831825 DOI: 10.1371/journal.pcbi.1004821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 02/19/2016] [Indexed: 11/18/2022] Open
Abstract
Recent genome-wide analyses have uncovered a high accumulation of RNA polymerase II (Pol II) at the 5' end of genes. This elevated Pol II presence at promoters, referred to here as Poll II poising, is mainly (but not exclusively) attributed to temporal pausing of transcription during early elongation which, in turn, has been proposed to be a regulatory step for processes that need to be activated "on demand". Yet, the full genome-wide regulatory role of Pol II poising is yet to be delineated. To elucidate the role of Pol II poising in B cell activation, we compared Pol II profiles in resting and activated B cells. We found that while Pol II poised genes generally overlap functionally among different B cell states and correspond to the functional groups previously identified for other cell types, non-poised genes are B cell state specific. Focusing on the changes in transcription activity upon B cell activation, we found that the majority of such changes were from poised to non-poised state. The genes showing this type of transition were functionally enriched in translation, RNA processing and mRNA metabolic process. Interestingly, we also observed a transition from non-poised to poised state. Within this set of genes we identified several Immediate Early Genes (IEG), which were highly expressed in resting B cell and shifted from non-poised to poised state after B cell activation. Thus Pol II poising does not only mark genes for rapid expression in the future, but it is also associated with genes that are silenced after a burst of their expression. Finally, we performed comparative analysis of the presence of G4 motifs in the context of poised versus non-poised but active genes. Interestingly we observed a differential enrichment of these motifs upstream versus downstream of TSS depending on poising status. The enrichment of G4 sequence motifs upstream of TSS of non-poised active genes suggests a potential role of quadruplexes in expression regulation.
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Affiliation(s)
- Phuong Dao
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Damian Wojtowicz
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Steevenson Nelson
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David Levens
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Teresa M. Przytycka
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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17
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Bastide MF, Bido S, Duteil N, Bézard E. Striatal NELF-mediated RNA polymerase II stalling controls l -dopa induced dyskinesia. Neurobiol Dis 2016; 85:93-98. [DOI: 10.1016/j.nbd.2015.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/07/2015] [Accepted: 10/14/2015] [Indexed: 02/02/2023] Open
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18
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de Cubas AA, Korpershoek E, Inglada-Pérez L, Letouzé E, Currás-Freixes M, Fernández AF, Comino-Méndez I, Schiavi F, Mancikova V, Eisenhofer G, Mannelli M, Opocher G, Timmers H, Beuschlein F, de Krijger R, Cascon A, Rodríguez-Antona C, Fraga MF, Favier J, Gimenez-Roqueplo AP, Robledo M. DNA Methylation Profiling in Pheochromocytoma and Paraganglioma Reveals Diagnostic and Prognostic Markers. Clin Cancer Res 2015; 21:3020-30. [DOI: 10.1158/1078-0432.ccr-14-2804] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/14/2015] [Indexed: 11/16/2022]
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19
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Retroviral cyclin controls cyclin-dependent kinase 8-mediated transcription elongation and reinitiation. J Virol 2015; 89:5450-61. [PMID: 25741012 DOI: 10.1128/jvi.00464-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 02/24/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Walleye dermal sarcoma virus (WDSV) infection is associated with the seasonal development and regression of walleye dermal sarcoma. Previous work showed that the retroviral cyclin (RV-cyclin), encoded by WDSV, has separable cyclin box and transcription activation domains. It binds to cyclin-dependent kinase 8 (CDK8) and enhances its kinase activity. CDK8 is evolutionarily conserved and is frequently overexpressed in human cancers. It is normally activated by cyclin C and is required for transcription elongation of the serum response genes (immediate early genes [IEGs]) FOS, EGR1, and cJUN. The IEGs drive cell proliferation, and their expression is brief and highly regulated. Here we show that constitutive expression of RV-cyclin in the HCT116 colon cancer cell line significantly increases the level of IEG expression in response to serum stimulation. Quantitative reverse transcription-PCR (RT-PCR) and nuclear run-on assays provide evidence that RV-cyclin does not alter the initiation of IEG transcription but does enhance the overall rate of transcription elongation and maintains transcription reinitiation. RV-cyclin does not increase activating phosphorylation events in the mitogen-activated protein kinase pathway and does not inhibit decay of IEG mRNAs. At the EGR1 gene locus, RV-cyclin increases and maintains RNA polymerase II (Pol II) occupancy after serum stimulation, in conjunction with increased and extended EGR1 gene expression. The RV-cyclin increases CDK8 occupancy at the EGR1 gene locus before and after serum stimulation. Both of RV-cyclin's functional domains, i.e., the cyclin box and the activation domain, are necessary for the overall enhancement of IEG expression. RV-cyclin presents a novel and ancient mechanism of retrovirus-induced oncogenesis. IMPORTANCE The data reported here are important to both virology and cancer biology. The novel mechanism pinpoints CDK8 in the development of walleye dermal sarcoma and sheds light on CDK8's role in many human cancers. CDK8 controls expression from highly regulated genes, including the interferon-stimulated genes. Its function is likely the target of many viral interferon-resistance mechanisms. CDK8 also controls cellular responses to metabolic stimuli, stress, and hypoxia, in addition to the serum response. The retroviral cyclin (RV-cyclin) represents a highly selected probe of CDK8 function. RV-cyclin does not control CDK8 specificity but instead enhances CDK8's effects on regulated genes, an important distinction for its use to delineate natural CDK8 targets. The outcomes of this research are applicable to investigations of normal and abnormal CDK8 functions. The mechanisms defined here will contribute directly to the dermal sarcoma model in fish and clarify an important path for oncogenesis and innate resistance to viruses.
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20
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Skaar JR, Ferris AL, Wu X, Saraf A, Khanna KK, Florens L, Washburn MP, Hughes SH, Pagano M. The Integrator complex controls the termination of transcription at diverse classes of gene targets. Cell Res 2015; 25:288-305. [PMID: 25675981 PMCID: PMC4349240 DOI: 10.1038/cr.2015.19] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/22/2014] [Accepted: 12/25/2014] [Indexed: 02/08/2023] Open
Abstract
Complexes containing INTS3 and either NABP1 or NABP2 were initially characterized in DNA damage responses, but their biochemical function remained unknown. Using affinity purifications and HIV Integration targeting-sequencing (HIT-Seq), we find that these complexes are part of the Integrator complex, which binds RNA Polymerase II and regulates specific target genes. Integrator cleaves snRNAs as part of their processing to their mature form in a mechanism that is intimately coupled with transcription termination. However, HIT-Seq reveals that Integrator also binds to the 3' end of replication-dependent histones and promoter proximal regions of genes with polyadenylated transcripts. Depletion of Integrator subunits results in transcription termination failure, disruption of histone mRNA processing, and polyadenylation of snRNAs and histone mRNAs. Furthermore, promoter proximal binding of Integrator negatively regulates expression of genes whose transcripts are normally polyadenylated. Integrator recruitment to all three gene classes is DSIF-dependent, suggesting that Integrator functions as a termination complex at DSIF-dependent RNA Polymerase II pause sites.
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Affiliation(s)
- Jeffrey R Skaar
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, 522 First Avenue, New York, NY 10016, USA
| | - Andrea L Ferris
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Anita Saraf
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
| | - Kum Kum Khanna
- QIMR Berghofer Medical Research Institute, Herston, Brisbane, Queensland 4006, Australia
| | - Laurence Florens
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
| | - Michael P Washburn
- The Stowers Institute for Medical Research, Kansas City, MO 6411, USA
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Stephen H Hughes
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Michele Pagano
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, 522 First Avenue, New York, NY 10016, USA
- Howard Hughes Medical Institute, 522 First Avenue New York, NY 10016, USA
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21
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Hicks MJ, Hu Q, Macrae E, DeWille J. Mitogen-activated protein kinase signaling controls basal and oncostatin M-mediated JUNB gene expression. Mol Cell Biochem 2015; 403:115-24. [PMID: 25662951 DOI: 10.1007/s11010-015-2342-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/30/2015] [Indexed: 12/22/2022]
Abstract
The mitogen-activated protein kinase (MAPK) pathway is aberrantly activated in many human cancers, including breast cancer. Activation of MAPK signaling is associated with the increased expression of a wide range of genes that promote cell survival, proliferation, and migration. This report investigated the influence of MAPK signaling on the regulation and expression of JUNB in human breast cancer cell lines. JUNB has been associated with tumor suppressor and oncogenic functions, with most reports describing JUNB as an oncogene in breast cancer. Our results indicated that JUNB expression is elevated in MCF10A(met), SKBR3, and MDA-MB-231 human breast cancer cell lines compared to nontransformed MCF10A mammary epithelial cells. Increased RAS/MAPK signaling in MCF10A(met) cells correlates with the increased association of RNA polymerase II (Pol II) phosphorylated on serine 5 (Pol IIser5p) with the JUNB proximal promoter. Pol IIser5p is the "transcription initiating" form of Pol II. Treatment with U0126, a MAPK pathway inhibitor, reduces Pol IIser5p association with the JUNB proximal promoter and reduces JUNB expression. Oncostatin M (OSM) enhances MAPK and STAT3 signaling and significantly induces JUNB expression. U0126 treatment reduces OSM-induced Pol IIser5p binding to the JUNB proximal promoter and JUNB expression, but does not reduce pSTAT3 levels or the association of pSTAT3 with the JUNB proximal promoter. These results demonstrate that the MAPK pathway plays a primary role in the control of JUNB gene expression by promoting the association of Pol IIser5p with the JUNB proximal promoter.
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Affiliation(s)
- Mellissa J Hicks
- Department of Veterinary Biosciences, College of Veterinary Medicine, Ohio State University, Columbus, OH, 43210, USA
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22
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Rao MK, Matsumoto Y, Richardson ME, Panneerdoss S, Bhardwaj A, Ward JM, Shanker S, Bettegowda A, Wilkinson MF. Hormone-induced and DNA demethylation-induced relief of a tissue-specific and developmentally regulated block in transcriptional elongation. J Biol Chem 2014; 289:35087-101. [PMID: 25331959 DOI: 10.1074/jbc.m114.615435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Genome-wide studies have revealed that genes commonly have a high density of RNA polymerase II just downstream of the transcription start site. This has raised the possibility that genes are commonly regulated by transcriptional elongation, but this remains largely untested in vivo, particularly in vertebrates. Here, we show that the proximal promoter from the Rhox5 homeobox gene recruits polymerase II and begins elongating in all tissues and cell lines that we tested, but it only completes elongation in a tissue-specific and developmentally regulated manner. Relief of the elongation block is associated with recruitment of the elongation factor P-TEFb, the co-activator GRIP1, the chromatin remodeling factor BRG1, and specific histone modifications. We provide evidence that two mechanisms relieve the elongation block at the proximal promoter: demethylation and recruitment of androgen receptor. Together, our findings support a model in which promoter proximal pausing helps confer tissue-specific and developmental gene expression through a mechanism regulated by DNA demethylation-dependent nuclear hormone receptor recruitment.
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Affiliation(s)
- Manjeet K Rao
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Greehey Children's Cancer Research Institute, Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Yuiko Matsumoto
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Marcy E Richardson
- the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Subbarayalu Panneerdoss
- the Greehey Children's Cancer Research Institute, Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Anjana Bhardwaj
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Jacqueline M Ward
- the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Sreenath Shanker
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Anilkumar Bettegowda
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Miles F Wilkinson
- From the Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, the Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92037, the Institute of Genomic Medicine, University of California at San Diego, La Jolla, California 92093, and
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23
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JUNB promotes the survival of Flavopiridol treated human breast cancer cells. Biochem Biophys Res Commun 2014; 450:19-24. [PMID: 24858691 DOI: 10.1016/j.bbrc.2014.05.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 05/14/2014] [Indexed: 11/23/2022]
Abstract
Chemotherapy resistance is a major obstacle to achieving durable progression-free-survival in breast cancer patients. Identifying resistance mechanisms is crucial to the development of effective breast cancer therapies. Immediate early genes (IEGs) function in the initial cellular reprogramming response to alterations in the extracellular environment and IEGs have been implicated in cancer cell development and progression. The purpose of this study was to investigate the influence of kinase inhibitors on IEG expression in breast cancer cells. The results demonstrated that Flavopiridol (FP), a CDK9 inhibitor, effectively reduced gene expression. FP treatment, however, consistently produced a delayed induction of JUNB gene expression in multiple breast cancer cell lines. Similar results were obtained with Sorafenib, a multi-kinase inhibitor and U0126, a MEK1 inhibitor. Functional studies revealed that JUNB plays a pro-survival role in kinase inhibitor treated breast cancer cells. These results demonstrate a unique induction of JUNB in response to kinase inhibitor therapies that may be among the earliest events in the progression to treatment resistance.
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24
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Zhu R, Lu X, Pradhan M, Armstrong S, Storchan GB, Chow C, Simons SS. A kinase-independent activity of Cdk9 modulates glucocorticoid receptor-mediated gene induction. Biochemistry 2014; 53:1753-67. [PMID: 24559102 PMCID: PMC3985961 DOI: 10.1021/bi5000178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/20/2014] [Indexed: 12/18/2022]
Abstract
A gene induction competition assay has recently uncovered new inhibitory activities of two transcriptional cofactors, NELF-A and NELF-B, in glucocorticoid-regulated transactivation. NELF-A and -B are also components of the NELF complex, which participates in RNA polymerase II pausing shortly after the initiation of gene transcription. We therefore asked if cofactors (Cdk9 and ELL) best known to affect paused polymerase could reverse the effects of NELF-A and -B. Unexpectedly, Cdk9 and ELL augmented, rather than prevented, the effects of NELF-A and -B. Furthermore, Cdk9 actions are not blocked either by Ckd9 inhibitors (DRB or flavopiridol) or by two Cdk9 mutants defective in kinase activity. The mode and site of action of NELF-A and -B mutants with an altered NELF domain are similarly affected by wild-type and kinase-dead Cdk9. We conclude that Cdk9 is a new modulator of GR action, that Ckd9 and ELL have novel activities in GR-regulated gene expression, that NELF-A and -B can act separately from the NELF complex, and that Cdk9 possesses activities that are independent of Cdk9 kinase activity. Finally, the competition assay has succeeded in ordering the site of action of several cofactors of GR transactivation. Extension of this methodology should be helpful in determining the site and mode of action of numerous additional cofactors and in reducing unwanted side effects.
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Affiliation(s)
- Rong Zhu
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Xinping Lu
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Madhumita Pradhan
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Stephen
P. Armstrong
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Geoffrey B. Storchan
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - Carson
C. Chow
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
| | - S. Stoney Simons
- Steroid Hormones Section, National Institute
of Diabetes and Digestive
and Kidney Diseases/Laboratory of Endocrinology and Receptor Biology, and Laboratory of
Biological Modeling, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United
States
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25
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Luo M, Lu X, Zhu R, Zhang Z, Chow CC, Li R, Simons SS. A conserved protein motif is required for full modulatory activity of negative elongation factor subunits NELF-A and NELF-B in modifying glucocorticoid receptor-regulated gene induction properties. J Biol Chem 2013; 288:34055-34072. [PMID: 24097989 DOI: 10.1074/jbc.m113.512426] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
NELF-B is a BRCA1-interacting protein and subunit (with NELF-A, -C/D, and -E) of the human negative elongation factor (NELF) complex, which participates in RNA polymerase II pausing shortly after transcription initiation, especially for synchronized gene expression. We now report new activities of NELF-B and other NELF complex subunits, which are to attenuate glucocorticoid receptor (GR)-mediated gene induction, reduce the partial agonist activity of an antagonist, and increase the EC50 of an agonist during nonsynchronized expression of exogenous and endogenous reporters. Stable knockdown of endogenous NELF-B has the opposite effects on an exogenous gene. The GR ligand-binding domain suffices for these biological responses. ChIP assays reveal that NELF-B diminishes GR recruitment to promoter regions of two endogenous genes. Using a new competition assay, NELF-A and NELF-B are each shown to act independently as competitive decelerators at two steps after the site of GR action and before or at the site of reporter gene activity. A common motif in each NELF was identified that is required for full activity of both NELF-A and NELF-B. These studies allow us to position the actions of two new modulators of GR-regulated transactivation, NELF-A and NELF-B, relative to other factors in the overall gene induction sequence.
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Affiliation(s)
- Min Luo
- Steroid Hormones Section, NIDDK/Laboratory of Endocrinology and Receptor Biology (LERB), National Institutes of Health, Bethesda, Maryland 20892
| | - Xinping Lu
- Steroid Hormones Section, NIDDK/Laboratory of Endocrinology and Receptor Biology (LERB), National Institutes of Health, Bethesda, Maryland 20892
| | - Rong Zhu
- Steroid Hormones Section, NIDDK/Laboratory of Endocrinology and Receptor Biology (LERB), National Institutes of Health, Bethesda, Maryland 20892
| | - Zhenhuan Zhang
- Steroid Hormones Section, NIDDK/Laboratory of Endocrinology and Receptor Biology (LERB), National Institutes of Health, Bethesda, Maryland 20892
| | - Carson C Chow
- Laboratory of Biological Modeling, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Rong Li
- Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas 78229
| | - S Stoney Simons
- Steroid Hormones Section, NIDDK/Laboratory of Endocrinology and Receptor Biology (LERB), National Institutes of Health, Bethesda, Maryland 20892.
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26
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Salem T, Gomard T, Court F, Moquet-Torcy G, Brockly F, Forné T, Piechaczyk M. Chromatin loop organization of the junb locus in mouse dendritic cells. Nucleic Acids Res 2013; 41:8908-25. [PMID: 23921639 PMCID: PMC3799436 DOI: 10.1093/nar/gkt669] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The junb gene behaves as an immediate early gene in bacterial lipopolysaccharide (LPS)-stimulated dendritic cells (DCs), where its transient transcriptional activation is necessary for the induction of inflammatory cytokines. junb is a short gene and its transcriptional activation by LPS depends on the binding of NF-κB to an enhancer located just downstream of its 3′ UTR. Here, we have addressed the mechanisms underlying the transcriptional hyper-reactivity of junb. Using transfection and pharmacological assays to complement chromatin immunoprecipitation analyses addressing the localization of histones, polymerase II, negative elongation factor (NELF)-, DRB sensitivity-inducing factor (DSIF)- and Positive Transcription Factor b complexes, we demonstrate that junb is a RNA Pol II-paused gene where Pol II is loaded in the transcription start site domain but poorly active. Moreover, High salt-Recovered Sequence, chromosome conformation capture (3C)- and gene transfer experiments show that (i) junb is organized in a nuclear chromatin loop bringing into close spatial proximity the upstream promoter region and the downstream enhancer and (ii) this configuration permits immediate Pol II release on the junb body on binding of LPS-activated NF-κB to the enhancer. Thus, our work unveils a novel topological framework underlying fast junb transcriptional response in DCs. Moreover, it also points to a novel layer of complexity in the modes of action of NF-κB.
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Affiliation(s)
- Tamara Salem
- Equipe labellisée par la Ligue Nationale contre le Cancer, Institut de Génétique Moléculaire de Montpellier UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France, Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier cedex 5, France and Université Montpellier 1, 5 Bd Henry IV, 34967 Montpellier cedex 2, France
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27
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Kawauchi J, Inoue M, Fukuda M, Uchida Y, Yasukawa T, Conaway RC, Conaway JW, Aso T, Kitajima S. Transcriptional properties of mammalian elongin A and its role in stress response. J Biol Chem 2013; 288:24302-15. [PMID: 23828199 DOI: 10.1074/jbc.m113.496703] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Elongin A was shown previously to be capable of potently activating the rate of RNA polymerase II (RNAPII) transcription elongation in vitro by suppressing transient pausing by the enzyme at many sites along DNA templates. The role of Elongin A in RNAPII transcription in mammalian cells, however, has not been clearly established. In this report, we investigate the function of Elongin A in RNAPII transcription. We present evidence that Elongin A associates with the IIO form of RNAPII at sites of newly transcribed RNA and is relocated to dotlike domains distinct from those containing RNAPII when cells are treated with the kinase inhibitor 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole. Significantly, Elongin A is required for maximal induction of transcription of the stress response genes ATF3 and p21 in response to several stimuli. Evidence from structure-function studies argues that Elongin A transcription elongation activity, but not its ubiquitination activity, is most important for its function in induction of transcription of ATF3 and p21. Taken together, our data provide new insights into the function of Elongin A in RNAPII transcription and bring to light a previously unrecognized role for Elongin A in the regulation of stress response genes.
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Affiliation(s)
- Junya Kawauchi
- Department of Biochemical Genetics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
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28
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Valin A, Gill G. Enforcing the pause: transcription factor Sp3 limits productive elongation by RNA polymerase II. Cell Cycle 2013; 12:1828-34. [PMID: 23676218 DOI: 10.4161/cc.24992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transition of paused RNA polymerase II into productive elongation is a highly dynamic process that serves to fine-tune gene expression in response to changing cellular environments. We have recently reported that the transcription factor Sp3 inhibits the transition of paused RNA Pol II to productive elongation at the promoter of the cyclin-dependent kinase inhibitor p21(CIP1) and other Sp3-repressed genes. Our studies support the view that Sp3 has three modes of action: activation, SUMO-Sp3-mediated heterochromatin silencing and SUMO-independent inhibition of elongation. At the p21(CIP1) promoter, binding of the positive elongation factor P-TEFb kinase was not affected by Sp3. In contrast, Sp3 promoted binding of the protein phosphatase PP1 to the p21(CIP1) promoter, suggesting that Sp3-dependent regulation of the local balance between kinase and phosphatase activities may contribute to gene expression. Our findings show that the transition of paused RNA Pol II to productive elongation is an important step regulated by both promoter-specific activators and repressors to finely modulate mRNA expression levels.
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Affiliation(s)
- Alvaro Valin
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA, USA
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29
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BRD4 coordinates recruitment of pause release factor P-TEFb and the pausing complex NELF/DSIF to regulate transcription elongation of interferon-stimulated genes. Mol Cell Biol 2013; 33:2497-507. [PMID: 23589332 DOI: 10.1128/mcb.01180-12] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
RNA polymerase II (Pol II) and the pausing complex, NELF and DSIF, are detected near the transcription start site (TSS) of many active and silent genes. Active transcription starts when the pause release factor P-TEFb is recruited to initiate productive elongation. However, the mechanism of P-TEFb recruitment and regulation of NELF/DSIF during transcription is not fully understood. We investigated this question in interferon (IFN)-stimulated transcription, focusing on BRD4, a BET family protein that interacts with P-TEFb. Besides P-TEFb, BRD4 binds to acetylated histones through the bromodomain. We found that BRD4 and P-TEFb, although not present prior to IFN treatment, were robustly recruited to IFN-stimulated genes (ISGs) after stimulation. Likewise, NELF and DSIF prior to stimulation were hardly detectable on ISGs, which were strongly recruited after IFN treatment. A shRNA-based knockdown assay of NELF revealed that it negatively regulates the passage of Pol II and DSIF across the ISGs during elongation, reducing total ISG transcript output. Analyses with a BRD4 small-molecule inhibitor showed that IFN-induced recruitment of P-TEFb and NELF/DSIF was under the control of BRD4. We suggest a model where BRD4 coordinates both positive and negative regulation of ISG elongation.
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30
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Transcription factor Sp3 represses expression of p21CIP¹ via inhibition of productive elongation by RNA polymerase II. Mol Cell Biol 2013; 33:1582-93. [PMID: 23401853 DOI: 10.1128/mcb.00323-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Like that of many protein-coding genes, expression of the p21(CIP1) cell cycle inhibitor is regulated at the level of transcription elongation. While many transcriptional activators have been shown to stimulate elongation, the mechanisms by which promoter-specific repressors regulate pausing and elongation by RNA polymerase II (RNA PolII) are not well described. Here we report that the transcription factor Sp3 inhibits basal p21(CIP1) gene expression by promoter-bound RNA PolII. Knockdown of Sp3 led to increased p21(CIP1) mRNA levels and reduced occupancy of the negative elongation factor (NELF) at the p21(CIP1) promoter, although the level of binding of the positive transcription elongation factor b (P-TEFb) kinase was not increased. Sp3 depletion correlated with increased H3K36me3 and H2Bub1, two histone modifications associated with transcription elongation. Further, Sp3 was shown to promote the binding of protein phosphatase 1 (PP1) to the p21(CIP1) promoter, leading to reduced H3S10 phosphorylation, a finding consistent with Sp3-dependent regulation of the local balance between kinase and phosphatase activities. Analysis of other targets of Sp3-mediated repression suggests that, in addition to previously described SUMO modification-dependent chromatin-silencing mechanisms, inhibition of the transition of paused RNA PolII to productive elongation, described here for p21(CIP1), is a general mechanism by which transcription factor Sp3 fine-tunes gene expression.
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31
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Transcription elongation factors DSIF and NELF: promoter-proximal pausing and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012. [PMID: 23202475 DOI: 10.1016/j.bbagrm.2012.11.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF) were originally identified as factors responsible for transcriptional inhibition by 5,6-dichloro-1-beta-d-ribofuranosyl-benzimidazole (DRB) and were later found to control transcription elongation, together with P-TEFb, at the promoter-proximal region. Although there is ample evidence that these factors play roles throughout the genome, other data also suggest gene- or tissue-specific roles for these factors. In this review, we discuss how these apparently conflicting data can be reconciled. In light of recent findings, we also discuss the detailed mechanism by which these factors control the elongation process at the molecular level. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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32
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Promoter-proximal pausing of RNA polymerase II: emerging roles in metazoans. Nat Rev Genet 2012; 13:720-31. [PMID: 22986266 DOI: 10.1038/nrg3293] [Citation(s) in RCA: 850] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent years have witnessed a sea change in our understanding of transcription regulation: whereas traditional models focused solely on the events that brought RNA polymerase II (Pol II) to a gene promoter to initiate RNA synthesis, emerging evidence points to the pausing of Pol II during early elongation as a widespread regulatory mechanism in higher eukaryotes. Current data indicate that pausing is particularly enriched at genes in signal-responsive pathways. Here the evidence for pausing of Pol II from recent high-throughput studies will be discussed, as well as the potential interconnected functions of promoter-proximally paused Pol II.
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33
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Core LJ, Waterfall JJ, Gilchrist DA, Fargo DC, Kwak H, Adelman K, Lis JT. Defining the status of RNA polymerase at promoters. Cell Rep 2012; 2:1025-35. [PMID: 23062713 DOI: 10.1016/j.celrep.2012.08.034] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 08/24/2012] [Accepted: 08/30/2012] [Indexed: 10/27/2022] Open
Abstract
Recent genome-wide studies in metazoans have shown that RNA polymerase II (Pol II) accumulates to high densities on many promoters at a rate-limited step in transcription. However, the status of this Pol II remains an area of debate. Here, we compare quantitative outputs of a global run-on sequencing assay and chromatin immunoprecipitation sequencing assays and demonstrate that the majority of the Pol II on Drosophila promoters is transcriptionally engaged; very little exists in a preinitiation or arrested complex. These promoter-proximal polymerases are inhibited from further elongation by detergent-sensitive factors, and knockdown of negative elongation factor, NELF, reduces their levels. These results not only solidify the notion that pausing occurs at most promoters, but demonstrate that it is the major rate-limiting step in early transcription at these promoters. Finally, the divergent elongation complexes seen at mammalian promoters are far less prevalent in Drosophila, and this specificity in orientation correlates with directional core promoter elements, which are abundant in Drosophila.
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Affiliation(s)
- Leighton J Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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34
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Diamant G, Amir-Zilberstein L, Yamaguchi Y, Handa H, Dikstein R. DSIF restricts NF-κB signaling by coordinating elongation with mRNA processing of negative feedback genes. Cell Rep 2012; 2:722-31. [PMID: 23041311 DOI: 10.1016/j.celrep.2012.08.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/30/2012] [Accepted: 08/31/2012] [Indexed: 12/15/2022] Open
Abstract
NF-κB is central for immune response and cell survival, and its deregulation is linked to chronic inflammation and cancer through poorly defined mechanisms. IκBα and A20 are NF-κB target genes and negative feedback regulators. Upon their activation by NF-κB, DSIF is recruited, P-TEFb is released, and their elongating polymerase II (Pol II) C-terminal domain (CTD) remains hypophosphorylated. We show that upon DSIF knockdown, mRNA levels of a subset of NF-κB targets are not diminished; yet much less IκBα and A20 protein are synthesized, and NF-κB activation is abnormally prolonged. Further analysis of IκBα and A20 mRNA revealed that a significant portion is uncapped, unspliced, and retained in the nucleus. Interestingly, the Spt5 C-terminal repeat (CTR) domain involved in elongation stimulation through P-TEFb is dispensable for IκBα and A20 regulation. These findings assign a function for DSIF in cotranscriptional mRNA processing when elongating Pol II is hypophosphorylated and define DSIF as part of the negative feedback regulation of NF-κB.
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Affiliation(s)
- Gil Diamant
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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35
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Negative elongation factor-mediated suppression of RNA polymerase II elongation of Kaposi's sarcoma-associated herpesvirus lytic gene expression. J Virol 2012; 86:9696-707. [PMID: 22740393 DOI: 10.1128/jvi.01012-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Genome-wide chromatin immunoprecipitation assays indicate that the promoter-proximal pausing of RNA polymerase II (RNAPII) is an important postinitiation step for gene regulation. During latent infection, the majority of Kaposi's sarcoma-associated herpesvirus (KSHV) genes is silenced via repressive histone marks on their promoters. Despite the absence of their expression during latency, however, several lytic promoters are enriched with activating histone marks, suggesting that mechanisms other than heterochromatin-mediated suppression contribute to preventing lytic gene expression. Here, we show that the RNAPII-mediated transcription of the KSHV OriLytL, K5, K6, and K7 (OriLytL-K7) lytic genes is paused at the elongation step during latency. Specifically, the RNAPII-mediated transcription is stalled by the host's negative elongation factor (NELF) at the promoter regions of OriLytL-K7 lytic genes during latency, leading to the hyperphosphorylation of the serine 5 residue and the hypophosphorylation of the serine 2 of the C-terminal domain of the RNAPII large subunit, a hallmark of stalled RNAPII. Consequently, depletion of NELF expression induced transition of stalled RNAPII into a productive transcription elongation at the promoter-proximal regions of OriLytL-K7 lytic genes, leading to their RTA-independent expression. Using an RTA-deficient recombinant KSHV, we also showed that expression of the K5, K6, and K7 lytic genes was highly inducible upon external stimuli compared to other lytic genes that lack RNAPII on their promoters during latency. These results indicate that the transcription elongation of KSHV OriLytL-K7 lytic genes is inhibited by NELF during latency, but can also be promptly reactivated in an RTA-independent manner upon external stimuli.
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36
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Mechanisms of HIV Transcriptional Regulation and Their Contribution to Latency. Mol Biol Int 2012; 2012:614120. [PMID: 22701796 PMCID: PMC3371693 DOI: 10.1155/2012/614120] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 04/09/2012] [Indexed: 12/26/2022] Open
Abstract
Long-lived latent HIV-infected cells lead to the rebound of virus replication following antiretroviral treatment interruption and present a major barrier to eliminating HIV infection. These latent reservoirs, which include quiescent memory T cells and tissue-resident macrophages, represent a subset of cells with decreased or inactive proviral transcription. HIV proviral transcription is regulated at multiple levels including transcription initiation, polymerase recruitment, transcription elongation, and chromatin organization. How these biochemical processes are coordinated and their potential role in repressing HIV transcription along with establishing and maintaining latency are reviewed.
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37
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Bioinformatic analysis and post-translational modification crosstalk prediction of lysine acetylation. PLoS One 2011; 6:e28228. [PMID: 22164248 PMCID: PMC3229533 DOI: 10.1371/journal.pone.0028228] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 11/04/2011] [Indexed: 01/31/2023] Open
Abstract
Recent proteomics studies suggest high abundance and a much wider role for lysine acetylation (K-Ac) in cellular functions. Nevertheless, cross influence between K-Ac and other post-translational modifications (PTMs) has not been carefully examined. Here, we used a variety of bioinformatics tools to analyze several available K-Ac datasets. Using gene ontology databases, we demonstrate that K-Ac sites are found in all cellular compartments. KEGG analysis indicates that the K-Ac sites are found on proteins responsible for a diverse and wide array of vital cellular functions. Domain structure prediction shows that K-Ac sites are found throughout a wide variety of protein domains, including those in heat shock proteins and those involved in cell cycle functions and DNA repair. Secondary structure prediction proves that K-Ac sites are preferentially found in ordered structures such as alpha helices and beta sheets. Finally, by mutating K-Ac sites in silico and predicting the effect on nearby phosphorylation sites, we demonstrate that the majority of lysine acetylation sites have the potential to impact protein phosphorylation, methylation, and ubiquitination status. Our work validates earlier smaller-scale studies on the acetylome and demonstrates the importance of PTM crosstalk for regulation of cellular function.
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38
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Mbonye U, Karn J. Control of HIV latency by epigenetic and non-epigenetic mechanisms. Curr HIV Res 2011; 9:554-67. [PMID: 22211660 PMCID: PMC3319922 DOI: 10.2174/157016211798998736] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 10/10/2011] [Accepted: 10/21/2011] [Indexed: 12/17/2022]
Abstract
Intensive antiretroviral therapy successfully suppresses viral replication but is unable to eradicate the virus. HIV persists in a small number of resting memory T cells where HIV has been transcriptionally silenced. This review will focus on recent insights into the HIV transcriptional control mechanisms that provide the biochemical basis for understanding latency. There are no specific repressors of HIV transcription encoded by the virus, instead latency arises when the regulatory feedback mechanism driven by HIV Tat expression is disrupted. Small changes in transcriptional initiation, induced by epigenetic silencing, lead to profound restrictions in Tat levels and force the entry of proviruses into latency. In resting memory T cells, which carry the bulk of the latent viral pool, additional restrictions, especially the limiting cellular levels of the essential Tat cofactor P-TEFb and the transcription initiation factors NF-κB and NFAT ensure that the provirus remains silenced unless the host cell is activated. The detailed understanding of HIV transcription is providing a framework for devising new therapeutic strategies designed to purge the latent viral pool. Importantly, the recognition that there are multiple restrictions imposed on latent proviruses suggest that proviral reactivation will not be achieved when only a single reactivation step is targeted and that any optimal activation strategy will require both removal of epigenetic blocks and the activation of P-TEFb.
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Affiliation(s)
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
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39
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Sun J, Pan H, Lei C, Yuan B, Nair SJ, April C, Parameswaran B, Klotzle B, Fan JB, Ruan J, Li R. Genetic and genomic analyses of RNA polymerase II-pausing factor in regulation of mammalian transcription and cell growth. J Biol Chem 2011; 286:36248-57. [PMID: 21865163 DOI: 10.1074/jbc.m111.269167] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Many mammalian genes are occupied by paused RNA polymerase II (pol II) in the promoter-proximal region on both sides of the transcription start site. However, the impact of pol II pausing on gene expression and cell biology is not fully understood. In this study, we used a Cre-Lox system to conditionally knock out the b subunit of mouse negative elongation factor (Nelf-b), a key pol II-pausing factor, in mouse embryonic fibroblasts. We found that Nelf-b was associated with the promoter-proximal region of the majority of expressed genes, yet genetic ablation of Nelf-b only affected the steady-state mRNA levels of a small percentage of the Nelf-b-associated genes. Interestingly, Nelf-b deletion also increased levels of transcription start site upstream transcripts at multiple negative elongation factor-associated genes. The direct target genes of Nelf-b were highly enriched with those involved in the control of cell growth and cell death. Correspondingly, Nelf-b knock-out mouse embryonic fibroblasts exhibited slower progression from quiescence to proliferation, as well as in a cycling cell population. Furthermore, Nelf-b deletion also resulted in increased apoptosis. Thus, the genetic and genomic studies provide new physiological and molecular insight into Nelf-mediated pol II pausing.
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Affiliation(s)
- Jianlong Sun
- Department of Molecular Medicine/Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA
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40
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Negative elongation factor accelerates the rate at which heat shock genes are shut off by facilitating dissociation of heat shock factor. Mol Cell Biol 2011; 31:4232-43. [PMID: 21859888 DOI: 10.1128/mcb.05930-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Promoter-proximal pausing of RNA polymerase II (Pol II) occurs on thousands of genes in animal cells. This pausing often correlates with the rapid induction of genes, but direct tests of the relationship between pausing and induction rates are lacking. hsp70 and hsp26 in Drosophila are rapidly induced by heat shock. Contrary to current expectations, depletion of negative elongation factor (NELF), a key factor in setting up paused Pol II, reduced pausing but did not interfere with rapid induction. Instead, depletion of NELF delayed the time taken for these genes to shut off during recovery from heat shock. NELF depletion also delayed the dissociation of HSF from hsp70 and hsp26, and a similar delay was observed when cells were depleted of the histone acetyltransferase CBP. CBP has been reported to associate with Pol II, and acetylation of HSF by CBP has been implicated in inhibiting the DNA-binding activity of HSF. We propose that NELF-mediated pausing allows Pol II to direct CBP-mediated acetylation of HSF, thus causing HSF to dissociate from the gene. Activators are typically viewed as controlling Pol II. Our results reveal a possible reciprocal relationship in which paused Pol II influences the activator.
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41
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Millner LM, Doll MA, Cai J, States JC, Hein DW. NATb/NAT1*4 promotes greater arylamine N-acetyltransferase 1 mediated DNA adducts and mutations than NATa/NAT1*4 following exposure to 4-aminobiphenyl. Mol Carcinog 2011; 51:636-46. [PMID: 21837760 DOI: 10.1002/mc.20836] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 06/07/2011] [Accepted: 07/11/2011] [Indexed: 11/05/2022]
Abstract
N-acetyltransferase 1 (NAT1) is a phase II metabolic enzyme responsible for the biotransformation of aromatic and heterocyclic amine carcinogens such as 4-aminobiphenyl (ABP). NAT1 catalyzes N-acetylation of arylamines as well as the O-acetylation of N-hydroxylated arylamines. O-acetylation leads to the formation of electrophilic intermediates that result in DNA adducts and mutations. NAT1 is transcribed from a major promoter, NATb, and an alternative promoter, NATa, resulting in mRNAs with distinct 5'-untranslated regions (UTR). NATa mRNA is expressed primarily in the kidney, liver, trachea, and lung while NATb mRNA has been detected in all tissues studied. To determine if differences in 5'-UTR have functional effect upon NAT1 activity and DNA adducts or mutations following exposure to ABP, pcDNA5/FRT plasmid constructs were prepared for transfection of full-length human mRNAs including the 5'-UTR derived from NATa or NATb, the open reading frame, and 888 nucleotides of the 3'-UTR. Following stable transfection of NATb/NAT1*4 or NATa/NAT1*4 into nucleotide excision repair (NER) deficient Chinese hamster ovary cells, N-acetyltransferase activity (in vitro and in situ), mRNA, and protein expression were higher in NATb/NAT1*4 than NATa/NAT1*4 transfected cells (P < 0.05). Consistent with NAT1 expression and activity, ABP-induced DNA adducts and hypoxanthine phosphoribosyl transferase mutants were significantly higher (P < 0.05) in NATb/NAT1*4 than in NATa/NAT1*4 transfected cells following exposure to ABP. These differences observed between NATa and NATb suggest that the 5'-UTRs are differentially regulated.
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Affiliation(s)
- Lori M Millner
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center and Center for Environmental Genomics and Integrative Biology, University of Louisville, Louisville, Kentucky 40202-1617, USA
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42
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Ishihara S, Schwartz RH. Two-step binding of transcription factors causes sequential chromatin structural changes at the activated IL-2 promoter. THE JOURNAL OF IMMUNOLOGY 2011; 187:3292-9. [PMID: 21832163 DOI: 10.4049/jimmunol.1003173] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Most gene promoters have multiple binding sequences for many transcription factors, but the contribution of each of these factors to chromatin remodeling is still unclear. Although we previously found a dynamic change in the arrangement of nucleosome arrays at the Il2 promoter during T cell activation, its timing preceded that of a decrease in nucleosome occupancy at the promoter. In this article, we show that the initial nucleosome rearrangement was temporally correlated with the binding of NFAT1 and AP-1 (Fos/Jun), whereas the second step occurred in parallel with the recruitment of other transcription factors and RNA polymerase II. Pharmacologic inhibitors for activation of NFAT1 or induction of Fos blocked the initial phase in the sequential changes. This step was not affected, however, by inhibition of c-Jun phosphorylation, which instead blocked the binding of the late transcription factors, the recruitment of CREB-binding protein, and the acetylation of histone H3 at lysine 27. Thus, the sequential recruitment of transcription factors appears to facilitate two separate steps in chromatin remodeling at the Il2 locus.
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Affiliation(s)
- Satoru Ishihara
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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43
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Saha RN, Wissink EM, Bailey ER, Zhao M, Fargo DC, Hwang JY, Daigle KR, Fenn JD, Adelman K, Dudek SM. Rapid activity-induced transcription of Arc and other IEGs relies on poised RNA polymerase II. Nat Neurosci 2011; 14:848-56. [PMID: 21623364 DOI: 10.1038/nn.2839] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 04/07/2011] [Indexed: 12/31/2022]
Abstract
Transcription of immediate early genes (IEGs) in neurons is highly sensitive to neuronal activity, but the mechanism underlying these early transcription events is largely unknown. We found that several IEGs, such as Arc (also known as Arg3.1), are poised for near-instantaneous transcription by the stalling of RNA polymerase II (Pol II) just downstream of the transcription start site in rat neurons. Depletion through RNA interference of negative elongation factor, a mediator of Pol II stalling, reduced the Pol II occupancy of the Arc promoter and compromised the rapid induction of Arc and other IEGs. In contrast, reduction of Pol II stalling did not prevent transcription of IEGs that were expressed later and largely lacked promoter-proximal Pol II stalling. Together, our data strongly indicate that the rapid induction of neuronal IEGs requires poised Pol II and suggest a role for this mechanism in a wide variety of transcription-dependent processes, including learning and memory.
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Affiliation(s)
- Ramendra N Saha
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, USA
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44
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Smith E, Lin C, Shilatifard A. The super elongation complex (SEC) and MLL in development and disease. Genes Dev 2011; 25:661-72. [PMID: 21460034 DOI: 10.1101/gad.2015411] [Citation(s) in RCA: 258] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Transcriptional regulation at the level of elongation is vital for the control of gene expression and metazoan development. The mixed lineage leukemia (MLL) protein and its Drosophila homolog, Trithorax, which exist within COMPASS (complex of proteins associated with Set1)-like complexes, are master regulators of development. They are required for proper homeotic gene expression, in part through methylation of histone H3 on Lys 4. In humans, the MLL gene is involved in a large number of chromosomal translocations that create chimeric proteins, fusing the N terminus of MLL to several proteins that share little sequence similarity. Several frequent translocation partners of MLL were found recently to coexist in a super elongation complex (SEC) that includes known transcription elongation factors such as eleven-nineteen lysine-rich leukemia (ELL) and P-TEFb. Importantly, the SEC is required for HOX gene expression in leukemic cells, suggesting that chromosomal translocations involving MLL could lead to the overexpression of HOX and other genes through the involvement of the SEC. Here, we review the normal developmental roles of MLL and the SEC, and how MLL fusion proteins can mediate leukemogenesis.
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Affiliation(s)
- Edwin Smith
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
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45
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Li J, Gilmour DS. Promoter proximal pausing and the control of gene expression. Curr Opin Genet Dev 2011; 21:231-5. [PMID: 21324670 DOI: 10.1016/j.gde.2011.01.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/18/2011] [Indexed: 12/18/2022]
Abstract
The advent of methods for mapping the location of specific proteins across genomes is substantially enlightening our understanding of gene regulation. One recent discovery is that Pol II is concentrated at the 5' end of thousands of genes in mammalian and Drosophila cells. Before this, much research had focused on understanding how sequence-specific, DNA-binding proteins orchestrate the actions of regulators of chromatin structure and the general transcriptional machinery to control transcription initiation. The concentration of Pol II at the 5' ends of genes indicates that key steps regulating transcription occur after Pol II has associated with a gene's promoter.
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Affiliation(s)
- Jian Li
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
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46
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Tur G, Georgieva EI, Gagete A, López-Rodas G, Rodríguez JL, Franco L. Factor binding and chromatin modification in the promoter of murine Egr1 gene upon induction. Cell Mol Life Sci 2010; 67:4065-77. [PMID: 20582451 PMCID: PMC11115556 DOI: 10.1007/s00018-010-0426-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 05/12/2010] [Accepted: 05/31/2010] [Indexed: 12/22/2022]
Abstract
The influence of chromatin on immediate-early gene expression has been studied in a model of Egr1 induction in intact mouse cells. ChIP analysis of factor and RNA polymerase binding reveals that the gene is constitutively poised for transcription in nonstimulated cells, but a repressing chromatin structure hampers productive transcription. Stimulation with phorbol esters results in a transient activation, which starts at 5 min and peaks at 30 min. Quantitative mapping of promoter occupancy by the different factors shows for the first time that no direct competition between SP1 and EGR1 occurs. The phosphorylation of ELK1 and CREB, which involves both the cascades of MEK1/2 and p38 kinases, is required for gene expression, which ceases following the binding of NAB1 and NAB2 to the promoter. The changes in histone acetylation and the differential recruitment of histone-modifying complexes further show the role of chromatin in the activation of this immediate-early gene.
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Affiliation(s)
- Gema Tur
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
| | - Elena I. Georgieva
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
| | - Andrés Gagete
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
| | - Gerardo López-Rodas
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
| | - José L. Rodríguez
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
| | - Luis Franco
- The Chromatin Laboratory, Department of Biochemistry and Molecular Biology, University of Valencia, Dr Moliner, 50, 46100 Burjassot, Valencia Spain
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Nechaev S, Adelman K. Pol II waiting in the starting gates: Regulating the transition from transcription initiation into productive elongation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:34-45. [PMID: 21081187 DOI: 10.1016/j.bbagrm.2010.11.001] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/06/2010] [Accepted: 11/09/2010] [Indexed: 01/12/2023]
Abstract
Proper regulation of gene expression is essential for the differentiation, development and survival of all cells and organisms. Recent work demonstrates that transcription of many genes, including key developmental and stimulus-responsive genes, is regulated after the initiation step, by pausing of RNA polymerase II during elongation through the promoter-proximal region. Thus, there is great interest in better understanding the events that follow transcription initiation and the ways in which the efficiency of early elongation can be modulated to impact expression of these highly regulated genes. Here we describe our current understanding of the steps involved in the transition from an unstable initially transcribing complex into a highly stable and processive elongation complex. We also discuss the interplay between factors that affect early transcript elongation and the potential physiological consequences for genes that are regulated through transcriptional pausing.
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Affiliation(s)
- Sergei Nechaev
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Krystof V, Chamrád I, Jorda R, Kohoutek J. Pharmacological targeting of CDK9 in cardiac hypertrophy. Med Res Rev 2010; 30:646-66. [PMID: 19757441 DOI: 10.1002/med.20172] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cardiac hypertrophy allows the heart to adapt to workload, but persistent or unphysiological stimulus can result in pump failure. Cardiac hypertrophy is characterized by an increase in the size of differentiated cardiac myocytes. At the molecular level, growth of cells is linked to intensive transcription and translation. Several cyclin-dependent kinases (CDKs) have been identified as principal regulators of transcription, and among these CDK9 is directly associated with cardiac hypertrophy. CDK9 phosphorylates the C-terminal domain of RNA polymerase II and thus stimulates the elongation phase of transcription. Chronic activation of CDK9 causes not only cardiac myocyte enlargement but also confers predisposition to heart failure. Due to the long interest of molecular oncologists and medicinal chemists in CDKs as potential targets of anticancer drugs, a portfolio of small-molecule inhibitors of CDK9 is available. Recent determination of CDK9's crystal structure now allows the development of selective inhibitors and their further optimization in terms of biochemical potency and selectivity. CDK9 may therefore constitute a novel target for drugs against cardiac hypertrophy.
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Affiliation(s)
- Vladimír Krystof
- Faculty of Science, Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany AS CR, Slechtitelů 11, Olomouc 783 71, Czech Republic.
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49
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Wang X, Hang S, Prazak L, Gergen JP. NELF potentiates gene transcription in the Drosophila embryo. PLoS One 2010; 5:e11498. [PMID: 20634899 PMCID: PMC2901382 DOI: 10.1371/journal.pone.0011498] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 06/17/2010] [Indexed: 02/06/2023] Open
Abstract
A hallmark of genes that are subject to developmental regulation of transcriptional elongation is association of the negative elongation factor NELF with the paused RNA polymerase complex. Here we use a combination of biochemical and genetic experiments to investigate the in vivo function of NELF in the Drosophila embryo. NELF associates with different gene promoter regions in correlation with the association of RNA polymerase II (Pol II) and the initial activation of gene expression during the early stages of embryogenesis. Genetic experiments reveal that maternally provided NELF is required for the activation, rather than the repression of reporter genes that emulate the expression of key developmental control genes. Furthermore, the relative requirement for NELF is dictated by attributes of the flanking cis-regulatory information. We propose that NELF-associated paused Pol II complexes provide a platform for high fidelity integration of the combinatorial spatial and temporal information that is central to the regulation of gene expression during animal development.
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Affiliation(s)
- Xiaoling Wang
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Saiyu Hang
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Lisa Prazak
- Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - J. Peter Gergen
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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50
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Chiba K, Yamamoto J, Yamaguchi Y, Handa H. Promoter-proximal pausing and its release: molecular mechanisms and physiological functions. Exp Cell Res 2010; 316:2723-30. [PMID: 20541545 DOI: 10.1016/j.yexcr.2010.05.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/26/2010] [Accepted: 05/30/2010] [Indexed: 10/19/2022]
Abstract
For a long time, not much attention had been paid to post-initiation steps in transcription, because it was widely believed that transcriptional control was brought about almost entirely through the regulation of transcription initiation. However, it has become clear that the process of elongation is also tightly controlled by a collection of regulatory factors called transcription elongation factors and contributes, for example, to rapid induction of immediate-early genes and to the control over the viral life cycle. Transcription elongation has attracted attention also because this process is coupled with various RNA processing events. In this review, we discuss biochemical and physiological aspects of elongation control, particularly focusing on the role of the negative elongation factor NELF.
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Affiliation(s)
- Kunitoshi Chiba
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
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