1
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Hari-Gupta Y, Fili N, dos Santos Á, Cook AW, Gough RE, Reed HCW, Wang L, Aaron J, Venit T, Wait E, Grosse-Berkenbusch A, Gebhardt JCM, Percipalle P, Chew TL, Martin-Fernandez M, Toseland CP. Myosin VI regulates the spatial organisation of mammalian transcription initiation. Nat Commun 2022; 13:1346. [PMID: 35292632 PMCID: PMC8924246 DOI: 10.1038/s41467-022-28962-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/21/2022] [Indexed: 12/19/2022] Open
Abstract
During transcription, RNA Polymerase II (RNAPII) is spatially organised within the nucleus into clusters that correlate with transcription activity. While this is a hallmark of genome regulation in mammalian cells, the mechanisms concerning the assembly, organisation and stability remain unknown. Here, we have used combination of single molecule imaging and genomic approaches to explore the role of nuclear myosin VI (MVI) in the nanoscale organisation of RNAPII. We reveal that MVI in the nucleus acts as the molecular anchor that holds RNAPII in high density clusters. Perturbation of MVI leads to the disruption of RNAPII localisation, chromatin organisation and subsequently a decrease in gene expression. Overall, we uncover the fundamental role of MVI in the spatial regulation of gene expression.
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Affiliation(s)
- Yukti Hari-Gupta
- grid.9759.20000 0001 2232 2818School of Biosciences, University of Kent, Canterbury, UK ,grid.83440.3b0000000121901201Present Address: MRC LMCB, University College London, London, UK
| | - Natalia Fili
- grid.11835.3e0000 0004 1936 9262Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK ,grid.36511.300000 0004 0420 4262Present Address: School of Life Sciences, University of Lincoln, Lincoln, UK
| | - Ália dos Santos
- grid.11835.3e0000 0004 1936 9262Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Alexander W. Cook
- grid.11835.3e0000 0004 1936 9262Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Rosemarie E. Gough
- grid.11835.3e0000 0004 1936 9262Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Hannah C. W. Reed
- grid.9759.20000 0001 2232 2818School of Biosciences, University of Kent, Canterbury, UK
| | - Lin Wang
- grid.76978.370000 0001 2296 6998Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, UK
| | - Jesse Aaron
- grid.443970.dAdvanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA USA
| | - Tomas Venit
- grid.440573.10000 0004 1755 5934Science Division, Biology Program, New York University Abu Dhabi (NYUAD), Abu Dhabi, United Arab Emirates
| | - Eric Wait
- grid.443970.dAdvanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA USA
| | | | | | - Piergiorgio Percipalle
- grid.440573.10000 0004 1755 5934Science Division, Biology Program, New York University Abu Dhabi (NYUAD), Abu Dhabi, United Arab Emirates ,grid.10548.380000 0004 1936 9377Department of Molecular Bioscience, The Wenner Gren Institute, Stockholm University, Stockholm, SE Sweden
| | - Teng-Leong Chew
- grid.443970.dAdvanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA USA
| | - Marisa Martin-Fernandez
- grid.76978.370000 0001 2296 6998Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, UK
| | - Christopher P. Toseland
- grid.11835.3e0000 0004 1936 9262Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
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2
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Uchino S, Ito Y, Sato Y, Handa T, Ohkawa Y, Tokunaga M, Kimura H. Live imaging of transcription sites using an elongating RNA polymerase II-specific probe. J Cell Biol 2022; 221:212888. [PMID: 34854870 PMCID: PMC8647360 DOI: 10.1083/jcb.202104134] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/12/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022] Open
Abstract
In eukaryotic nuclei, most genes are transcribed by RNA polymerase II (RNAP2), whose regulation is a key to understanding the genome and cell function. RNAP2 has a long heptapeptide repeat (Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7), and Ser2 is phosphorylated on an elongation form. To detect RNAP2 Ser2 phosphorylation (RNAP2 Ser2ph) in living cells, we developed a genetically encoded modification-specific intracellular antibody (mintbody) probe. The RNAP2 Ser2ph-mintbody exhibited numerous foci, possibly representing transcription “factories,” and foci were diminished during mitosis and in a Ser2 kinase inhibitor. An in vitro binding assay using phosphopeptides confirmed the mintbody’s specificity. RNAP2 Ser2ph-mintbody foci were colocalized with proteins associated with elongating RNAP2 compared with factors involved in the initiation. These results support the view that mintbody localization represents the sites of RNAP2 Ser2ph in living cells. RNAP2 Ser2ph-mintbody foci showed constrained diffusional motion like chromatin, but they were more mobile than DNA replication domains and p300-enriched foci, suggesting that the elongating RNAP2 complexes are separated from more confined chromatin domains.
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Affiliation(s)
- Satoshi Uchino
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuma Ito
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuko Sato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.,Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsuya Handa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Makio Tokunaga
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroshi Kimura
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.,Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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3
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Kimura H, Sato Y. Imaging transcription elongation dynamics by new technologies unveils the organization of initiation and elongation in transcription factories. Curr Opin Cell Biol 2022; 74:71-79. [DOI: 10.1016/j.ceb.2022.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 01/05/2022] [Accepted: 01/10/2022] [Indexed: 11/27/2022]
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4
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Mobility of Nucleostemin in Live Cells Is Specifically Related to Transcription Inhibition by Actinomycin D and GTP-Binding Motif. Int J Mol Sci 2021; 22:ijms22158293. [PMID: 34361059 PMCID: PMC8347349 DOI: 10.3390/ijms22158293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/24/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
In vertebrates, nucleostemin (NS) is an important marker of proliferation in several types of stem and cancer cells, and it can also interact with the tumor-suppressing transcription factor p53. In the present study, the intra-nuclear diffusional dynamics of native NS tagged with GFP and two GFP-tagged NS mutants with deleted guanosine triphosphate (GTP)-binding domains were analyzed by fluorescence correlation spectroscopy. Free and slow binding diffusion coefficients were evaluated, either under normal culture conditions or under treatment with specific cellular proliferation inhibitors actinomycin D (ActD), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), or trichostatin A (TSA). When treated with ActD, the fractional ratio of the slow diffusion was significantly decreased in the nucleoplasm. The decrease was proportional to ActD treatment duration. In contrast, DRB or TSA treatment did not affect NS diffusion. Interestingly, it was also found that the rate of diffusion of two NS mutants increased significantly even under normal conditions. These results suggest that the mobility of NS in the nucleoplasm is related to the initiation of DNA or RNA replication, and that the GTP-binding motif is also related to the large change of mobility.
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5
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Sugaya K. Chromosome instability caused by mutations in the genes involved in transcription and splicing. RNA Biol 2019; 16:1521-1525. [PMID: 31385554 DOI: 10.1080/15476286.2019.1652523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Mutations in molecules involved in transcription and splicing can cause chromosome instability such as sister chromatid exchanges. We isolated and characterized responsible genes from mammalian temperature-sensitive mutant cells showing chromosome instability. A mutation in the largest subunit of RNA polymerase II affected DNA synthesis in S phase-arrested cells, resulting in abnormal induction of sister chromatid exchanges. The yeast mutant harboring a homologous mutation showed very similar phenotype to that of the mammalian mutant. A mutation in Smu1, which is involved in splicing, also affected DNA synthesis in S and G2 phase-arrested cells, resulting in abnormal induction of sister chromatid exchanges and chromosomal aberrations. These cells showed a connection between defects of RNA metabolism and induction of chromosome instability. Genome instability appeared to be caused by links between RNA metabolism and replication resulting in genomic recombination. RNA metabolism can be regarded as one possible driver of genome modification triggering genome evolution.
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Affiliation(s)
- Kimihiko Sugaya
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST) , Chiba , Japan.,Group of Quantum-state Controlled MRI, QST , Chiba , Japan
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6
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Haijes HA, Koster MJE, Rehmann H, Li D, Hakonarson H, Cappuccio G, Hancarova M, Lehalle D, Reardon W, Schaefer GB, Lehman A, van de Laar IMBH, Tesselaar CD, Turner C, Goldenberg A, Patrier S, Thevenon J, Pinelli M, Brunetti-Pierri N, Prchalová D, Havlovicová M, Vlckova M, Sedláček Z, Lopez E, Ragoussis V, Pagnamenta AT, Kini U, Vos HR, van Es RM, van Schaik RFMA, van Essen TAJ, Kibaek M, Taylor JC, Sullivan J, Shashi V, Petrovski S, Fagerberg C, Martin DM, van Gassen KLI, Pfundt R, Falk MJ, McCormick EM, Timmers HTM, van Hasselt PM. De Novo Heterozygous POLR2A Variants Cause a Neurodevelopmental Syndrome with Profound Infantile-Onset Hypotonia. Am J Hum Genet 2019; 105:283-301. [PMID: 31353023 PMCID: PMC6699192 DOI: 10.1016/j.ajhg.2019.06.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/30/2019] [Indexed: 11/26/2022] Open
Abstract
The RNA polymerase II complex (pol II) is responsible for transcription of all ∼21,000 human protein-encoding genes. Here, we describe sixteen individuals harboring de novo heterozygous variants in POLR2A, encoding RPB1, the largest subunit of pol II. An iterative approach combining structural evaluation and mass spectrometry analyses, the use of S. cerevisiae as a model system, and the assessment of cell viability in HeLa cells allowed us to classify eleven variants as probably disease-causing and four variants as possibly disease-causing. The significance of one variant remains unresolved. By quantification of phenotypic severity, we could distinguish mild and severe phenotypic consequences of the disease-causing variants. Missense variants expected to exert only mild structural effects led to a malfunctioning pol II enzyme, thereby inducing a dominant-negative effect on gene transcription. Intriguingly, individuals carrying these variants presented with a severe phenotype dominated by profound infantile-onset hypotonia and developmental delay. Conversely, individuals carrying variants expected to result in complete loss of function, thus reduced levels of functional pol II from the normal allele, exhibited the mildest phenotypes. We conclude that subtle variants that are central in functionally important domains of POLR2A cause a neurodevelopmental syndrome characterized by profound infantile-onset hypotonia and developmental delay through a dominant-negative effect on pol-II-mediated transcription of DNA.
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Affiliation(s)
- Hanneke A Haijes
- Department of Pediatrics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, 3584 EA Utrecht, the Netherlands; Department of Biomedical Genetics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, 3584 EA Utrecht, the Netherlands; German Cancer Consortium (DKTK) standort Freiburg and German Cancer Research Center (DKFZ), 79106 Heidelberg, Germany
| | - Maria J E Koster
- Regenerative Medicine Center and Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands; German Cancer Consortium (DKTK) standort Freiburg and German Cancer Research Center (DKFZ), 79106 Heidelberg, Germany
| | - Holger Rehmann
- Expertise Center for Structural Biology, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands; Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Oncode Institute, 3584 CT Utrecht, the Netherlands
| | - Dong Li
- Center for Applied Genomics, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Human Genetics, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gerarda Cappuccio
- Department of Translational Medicine, Federico II University, 80126 Naples, Italy; Telethon Institute of Genetics and Medicine, Pozzuoli, 80126 Naples, Italy
| | - Miroslava Hancarova
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, 150 06 Prague, Czech Republic
| | - Daphne Lehalle
- Department of Genetics, Centre Hospitalier Universitaire de Dijon, 21000 Dijon, France
| | - Willie Reardon
- Department of Clinical and Medical Genetics, Our Lady's Hospital for Sick Children, D12 N512 Dublin, Ireland
| | - G Bradley Schaefer
- Department of Pediatrics, Section of Genetics and Metabolism, University of Arkansas for Medical Sciences, Little Rock, Arkansas, AR 72223, USA
| | - Anna Lehman
- Department of Medical Genetics, BC Children's Hospital Research Institute, University of British Columbia, BC V6H 3N1 Vancouver, Canada
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics, Erasmus Medical University Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Coranne D Tesselaar
- Department of Pediatrics, Amphia Hospital Breda, 4818 CK Breda, the Netherlands
| | - Clesson Turner
- Department of Clinical Genetics and Pediatrics, Walter Reed National Military Medical Center, Bethesda, Maryland, MD 20814, USA
| | - Alice Goldenberg
- Department of Genetics, Rouen University Hospital, Centre de Référence Anomalies du Développement, Normandy Centre for Genomic and Personalized Medicine, 76000 Rouen, France
| | - Sophie Patrier
- Department of Pathology, Rouen University Hospital, Centre de Référence Anomalies du Développement, 76000 Rouen, France
| | - Julien Thevenon
- Department of Genetics and Reproduction, Centre Hospitalier Universitaire de Grenoble, 38700 Grenoble, France
| | - Michele Pinelli
- Department of Translational Medicine, Federico II University, 80126 Naples, Italy; Telethon Institute of Genetics and Medicine, Pozzuoli, 80126 Naples, Italy
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, Federico II University, 80126 Naples, Italy; Telethon Institute of Genetics and Medicine, Pozzuoli, 80126 Naples, Italy
| | - Darina Prchalová
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, 150 06 Prague, Czech Republic
| | - Markéta Havlovicová
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, 150 06 Prague, Czech Republic
| | - Markéta Vlckova
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, 150 06 Prague, Czech Republic
| | - Zdeněk Sedláček
- Department of Biology and Medical Genetics, Charles University Second Faculty of Medicine and University Hospital Motol, 150 06 Prague, Czech Republic
| | - Elena Lopez
- Department of Medical Genetics, BC Children's Hospital Research Institute, University of British Columbia, BC V6H 3N1 Vancouver, Canada
| | - Vassilis Ragoussis
- National Institute for Health Research Oxford Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN Oxford, UK
| | - Alistair T Pagnamenta
- National Institute for Health Research Oxford Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN Oxford, UK
| | - Usha Kini
- Department of Genomic Medicine, Oxford Centre for Genomic Medicine, Oxford University Hospitals National Health Service Foundation Trust, OX3 7LE Oxford, UK
| | - Harmjan R Vos
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Oncode Institute, 3584 CT Utrecht, the Netherlands
| | - Robert M van Es
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Oncode Institute, 3584 CT Utrecht, the Netherlands
| | - Richard F M A van Schaik
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Oncode Institute, 3584 CT Utrecht, the Netherlands
| | - Ton A J van Essen
- Department of Clinical Genetics, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Maria Kibaek
- H.C. Andersen Children Hospital, Odense University Hospital, 5000 Odense, Denmark
| | - Jenny C Taylor
- National Institute for Health Research Oxford Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN Oxford, UK
| | - Jennifer Sullivan
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, NC 27710, USA
| | - Vandana Shashi
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, NC 27710, USA
| | - Slave Petrovski
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, NC 27710, USA; AstraZeneca Centre for Genomics Research, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, CB4 0WG Cambridge, United Kingdom; Department of Medicine, the University of Melbourne, VIC 3010 Melbourne, Australia
| | - Christina Fagerberg
- Department of Clinical Genetics, Odense University Hospital, 5000 Odense, Denmark
| | - Donna M Martin
- Departments of Pediatrics and Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, MI 48109, USA
| | - Koen L I van Gassen
- Department of Biomedical Genetics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, 3584 EA Utrecht, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center Nijmegen, 6525 HR Nijmegen, the Netherlands
| | - Marni J Falk
- Division of Human Genetics, the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Mitochondrial Medicine Frontier Program, Division of Human Genetics, the Children's Hospital of Philadelphia, PA 19104, Philadelphia, USA
| | - Elizabeth M McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, the Children's Hospital of Philadelphia, PA 19104, Philadelphia, USA
| | - H T Marc Timmers
- Regenerative Medicine Center and Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands; Department of Urology, University Medical Center Freiburg, University of Freiburg, 79110 Freiburg, Germany
| | - Peter M van Hasselt
- Department of Pediatrics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, 3584 EA Utrecht, the Netherlands.
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7
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Cook PR, Marenduzzo D. Transcription-driven genome organization: a model for chromosome structure and the regulation of gene expression tested through simulations. Nucleic Acids Res 2019; 46:9895-9906. [PMID: 30239812 PMCID: PMC6212781 DOI: 10.1093/nar/gky763] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/14/2018] [Indexed: 12/29/2022] Open
Abstract
Current models for the folding of the human genome see a hierarchy stretching down from chromosome territories, through A/B compartments and topologically-associating domains (TADs), to contact domains stabilized by cohesin and CTCF. However, molecular mechanisms underlying this folding, and the way folding affects transcriptional activity, remain obscure. Here we review physical principles driving proteins bound to long polymers into clusters surrounded by loops, and present a parsimonious yet comprehensive model for the way the organization determines function. We argue that clusters of active RNA polymerases and their transcription factors are major architectural features; then, contact domains, TADs and compartments just reflect one or more loops and clusters. We suggest tethering a gene close to a cluster containing appropriate factors—a transcription factory—increases the firing frequency, and offer solutions to many current puzzles concerning the actions of enhancers, super-enhancers, boundaries and eQTLs (expression quantitative trait loci). As a result, the activity of any gene is directly influenced by the activity of other transcription units around it in 3D space, and this is supported by Brownian-dynamics simulations of transcription factors binding to cognate sites on long polymers.
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Affiliation(s)
- Peter R Cook
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Davide Marenduzzo
- SUPA, School of Physics, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
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8
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Sugaya K. Let's think again about using mammalian temperature-sensitive mutants to investigate functional molecules-The perspectives from the studies on three mutants showing chromosome instability. J Cell Biochem 2018; 119:7143-7150. [PMID: 29943840 DOI: 10.1002/jcb.27205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/24/2018] [Indexed: 11/06/2022]
Abstract
This review evaluates the use of temperature-sensitive (ts) mutants to investigate functional molecules in mammalian cells. A series of studies were performed in which mammalian cells expressing functional molecules were isolated from ts mutants using complementation by the introduction and expression of the responsible protein tagged with the green fluorescent protein. The results showed that chromosome instability and cell-cycle arrest were caused by ts defects in the following three molecules: the largest subunit of RNA polymerase II, a protein involved in splicing, and ubiquitin-activating enzyme. The cells expressing functional protein were then isolated by introducing the responsible gene tagged with the green fluorescent protein to complement the ts phenotype. These cells proved to be useful in analyzing the dynamics of RNA polymerase II in living cells. Analyses of the functional interaction between proteins involved in splicing were also useful in the investigation of ts mutants and their derivatives. In addition, these cells demonstrated the functional localization of ubiquitin-activating enzyme in the nucleus. Mammalian ts mutants continue to show great potential to aid in understanding the functions of the essential molecules in cells. Therefore, it is highly important that studies on the identification and characterization of the genes responsible for the phenotype of a mutant are carried out.
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Affiliation(s)
- Kimihiko Sugaya
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,Group of Quantum-state Controlled MRI, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
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9
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Palozola KC, Liu H, Nicetto D, Zaret KS. Low-Level, Global Transcription during Mitosis and Dynamic Gene Reactivation during Mitotic Exit. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2018; 82:197-205. [PMID: 29348325 DOI: 10.1101/sqb.2017.82.034280] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mitosis is thought to be a period of transcriptional silence due to the compact nature of mitotic chromosomes and the apparent exclusion of RNA Pol II and many transcription factors from mitotic chromatin. Yet accurate reactivation of a cell's specific gene expression program is needed to reestablish functional cell identity after mitosis. The majority of studies on protein regulation and localization during mitosis have relied extensively on antibodies and cross-linking-based approaches that are known to artifactually exclude proteins from mitotic chromatin. Here we show that RNA Pol II localization in mitosis is antibody- and fixation-dependent, and that direct assessment of transcription by pulse-labeling nascent RNA reveals global, low-level mitotic transcription. We also find a hierarchy of gene reactivation as the cells transition from mitosis to their interphase amplitude of gene expression. Resetting of gene transcription during mitotic exit is coincident with enhancer transcription. Our work thus shifts focus from assessing mitotic exit as a binary transcription switch to a more nuanced concert of transcription amplitude and enhancer usage. We suggest that understanding how gene expression patterns are conserved during mitosis rests upon deciphering how transcription is maintained by promoters.
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Affiliation(s)
- Katherine C Palozola
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Hong Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112
| | - Dario Nicetto
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kenneth S Zaret
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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10
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Rademacher A, Erdel F, Trojanowski J, Schumacher S, Rippe K. Real-time observation of light-controlled transcription in living cells. J Cell Sci 2017. [DOI: 10.1242/jcs.205534] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Gene expression is tightly regulated in space and time. To dissect this process with high temporal resolution, we introduce an optogenetic tool termed BLInCR (Blue Light-Induced Chromatin Recruitment) that combines rapid and reversible light-dependent recruitment of effector proteins with a real-time readout for transcription. We used BLInCR to control the activity of a reporter gene cluster in the human osteosarcoma cell line U2OS by reversibly recruiting the viral transactivator VP16. RNA production was detectable ∼2 minutes after VP16 recruitment and readily decreased when VP16 dissociated from the cluster in the absence of light. Quantitative assessment of the activation process revealed biphasic activation kinetics with a pronounced early phase in cells treated with the histone deacetylase inhibitor SAHA. Comparison with kinetic models for transcription activation suggests that the gene cluster undergoes a maturation process when activated. We anticipate that BLInCR will facilitate the study of transcription dynamics in living cells.
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Affiliation(s)
- Anne Rademacher
- German Cancer Research Center (DKFZ) and Bioquant, Division of Chromatin Networks, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Fabian Erdel
- German Cancer Research Center (DKFZ) and Bioquant, Division of Chromatin Networks, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Jorge Trojanowski
- German Cancer Research Center (DKFZ) and Bioquant, Division of Chromatin Networks, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Sabrina Schumacher
- German Cancer Research Center (DKFZ) and Bioquant, Division of Chromatin Networks, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Karsten Rippe
- German Cancer Research Center (DKFZ) and Bioquant, Division of Chromatin Networks, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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11
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Cho WK, Jayanth N, Mullen S, Tan TH, Jung YJ, Cissé II. Super-resolution imaging of fluorescently labeled, endogenous RNA Polymerase II in living cells with CRISPR/Cas9-mediated gene editing. Sci Rep 2016; 6:35949. [PMID: 27782203 PMCID: PMC5080603 DOI: 10.1038/srep35949] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/07/2016] [Indexed: 12/19/2022] Open
Abstract
Live cell imaging of mammalian RNA polymerase II (Pol II) has previously relied on random insertions of exogenous, mutant Pol II coupled with the degradation of endogenous Pol II using a toxin, α-amanitin. Therefore, it has been unclear whether over-expression of labeled Pol II under an exogenous promoter may have played a role in reported Pol II dynamics in vivo. Here we label the endogenous Pol II in mouse embryonic fibroblast (MEF) cells using the CRISPR/Cas9 gene editing system. Using single-molecule based super-resolution imaging in the living cells, we captured endogenous Pol II clusters. Consistent with previous studies, we observed that Pol II clusters were short-lived (cluster lifetime ~8 s) in living cells. Moreover, dynamic responses to serum-stimulation, and drug-mediated transcription inhibition were all in agreement with previous observations in the exogenous Pol II MEF cell line. Our findings suggest that previous exogenously tagged Pol II faithfully recapitulated the endogenous polymerase clustering dynamics in living cells, and our approach may in principle be used to directly label transcription factors for live cell imaging.
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Affiliation(s)
- Won-Ki Cho
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Namrata Jayanth
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Susan Mullen
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Tzer Han Tan
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Yoon J Jung
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Ibrahim I Cissé
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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12
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Serebryannyy LA, Parilla M, Annibale P, Cruz CM, Laster K, Gratton E, Kudryashov D, Kosak ST, Gottardi CJ, de Lanerolle P. Persistent nuclear actin filaments inhibit transcription by RNA polymerase II. J Cell Sci 2016; 129:3412-25. [PMID: 27505898 DOI: 10.1242/jcs.195867] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 12/26/2022] Open
Abstract
Actin is abundant in the nucleus and it is clear that nuclear actin has important functions. However, mystery surrounds the absence of classical actin filaments in the nucleus. To address this question, we investigated how polymerizing nuclear actin into persistent nuclear actin filaments affected transcription by RNA polymerase II. Nuclear filaments impaired nuclear actin dynamics by polymerizing and sequestering nuclear actin. Polymerizing actin into stable nuclear filaments disrupted the interaction of actin with RNA polymerase II and correlated with impaired RNA polymerase II localization, dynamics, gene recruitment, and reduced global transcription and cell proliferation. Polymerizing and crosslinking nuclear actin in vitro similarly disrupted the actin-RNA-polymerase-II interaction and inhibited transcription. These data rationalize the general absence of stable actin filaments in mammalian somatic nuclei. They also suggest a dynamic pool of nuclear actin is required for the proper localization and activity of RNA polymerase II.
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Affiliation(s)
- Leonid A Serebryannyy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Megan Parilla
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Paolo Annibale
- Laboratory of Fluorescence Dynamics, University of California Irvine, Irvine, CA 92697, USA
| | - Christina M Cruz
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Kyle Laster
- Department of Cell and Molecular Biology, Northwestern University, Chicago, IL 60611, USA
| | - Enrico Gratton
- Laboratory of Fluorescence Dynamics, University of California Irvine, Irvine, CA 92697, USA
| | - Dmitri Kudryashov
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Steven T Kosak
- Department of Cell and Molecular Biology, Northwestern University, Chicago, IL 60611, USA
| | - Cara J Gottardi
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Primal de Lanerolle
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA
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13
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Cho WK, Jayanth N, English BP, Inoue T, Andrews JO, Conway W, Grimm JB, Spille JH, Lavis LD, Lionnet T, Cisse II. RNA Polymerase II cluster dynamics predict mRNA output in living cells. eLife 2016; 5. [PMID: 27138339 PMCID: PMC4929003 DOI: 10.7554/elife.13617] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 05/02/2016] [Indexed: 12/11/2022] Open
Abstract
Protein clustering is a hallmark of genome regulation in mammalian cells. However, the dynamic molecular processes involved make it difficult to correlate clustering with functional consequences in vivo. We developed a live-cell super-resolution approach to uncover the correlation between mRNA synthesis and the dynamics of RNA Polymerase II (Pol II) clusters at a gene locus. For endogenous β-actin genes in mouse embryonic fibroblasts, we observe that short-lived (~8 s) Pol II clusters correlate with basal mRNA output. During serum stimulation, a stereotyped increase in Pol II cluster lifetime correlates with a proportionate increase in the number of mRNAs synthesized. Our findings suggest that transient clustering of Pol II may constitute a pre-transcriptional regulatory event that predictably modulates nascent mRNA output. DOI:http://dx.doi.org/10.7554/eLife.13617.001
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Affiliation(s)
- Won-Ki Cho
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Namrata Jayanth
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Brian P English
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Takuma Inoue
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - J Owen Andrews
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - William Conway
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jan-Hendrik Spille
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Timothée Lionnet
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ibrahim I Cisse
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
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14
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Guantes R, Rastrojo A, Neves R, Lima A, Aguado B, Iborra FJ. Global variability in gene expression and alternative splicing is modulated by mitochondrial content. Genome Res 2015; 25:633-44. [PMID: 25800673 PMCID: PMC4417112 DOI: 10.1101/gr.178426.114] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
Abstract
Noise in gene expression is a main determinant of phenotypic variability. Increasing experimental evidence suggests that genome-wide cellular constraints largely contribute to the heterogeneity observed in gene products. It is still unclear, however, which global factors affect gene expression noise and to what extent. Since eukaryotic gene expression is an energy demanding process, differences in the energy budget of each cell could determine gene expression differences. Here, we quantify the contribution of mitochondrial variability (a natural source of ATP variation) to global variability in gene expression. We find that changes in mitochondrial content can account for ∼50% of the variability observed in protein levels. This is the combined result of the effect of mitochondria dosage on transcription and translation apparatus content and activities. Moreover, we find that mitochondrial levels have a large impact on alternative splicing, thus modulating both the abundance and type of mRNAs. A simple mathematical model in which mitochondrial content simultaneously affects transcription rate and splicing site choice can explain the alternative splicing data. The results of this study show that mitochondrial content (and/or probably function) influences mRNA abundance, translation, and alternative splicing, which ultimately affects cellular phenotype.
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Affiliation(s)
- Raul Guantes
- Department of Condensed Matter Physics, Materials Science Institute "Nicolás Cabrera" and Institute of Condensed Matter Physics (IFIMAC), Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Alberto Rastrojo
- Centro Biología Molecular "Severo Ochoa," CSIC-UAM, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Ricardo Neves
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Headington, Oxford OX3 9DS, United Kingdom
| | - Ana Lima
- UC Biotech, Center for Neuroscience and Cell Biology, Biocant, Center of Innovation in Biotechnology, 3060-197 Cantanhede, Portugal
| | - Begoña Aguado
- Centro Biología Molecular "Severo Ochoa," CSIC-UAM, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Francisco J Iborra
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Headington, Oxford OX3 9DS, United Kingdom; Centro Nacional de Biotecnología, CSIC, Campus de Cantoblanco, 28049 Madrid, Spain
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15
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Stasevich TJ, Hayashi-Takanaka Y, Sato Y, Maehara K, Ohkawa Y, Sakata-Sogawa K, Tokunaga M, Nagase T, Nozaki N, McNally JG, Kimura H. Regulation of RNA polymerase II activation by histone acetylation in single living cells. Nature 2014; 516:272-5. [PMID: 25252976 DOI: 10.1038/nature13714] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 07/25/2014] [Indexed: 12/31/2022]
Abstract
In eukaryotic cells, post-translational histone modifications have an important role in gene regulation. Starting with early work on histone acetylation, a variety of residue-specific modifications have now been linked to RNA polymerase II (RNAP2) activity, but it remains unclear if these markers are active regulators of transcription or just passive byproducts. This is because studies have traditionally relied on fixed cell populations, meaning temporal resolution is limited to minutes at best, and correlated factors may not actually be present in the same cell at the same time. Complementary approaches are therefore needed to probe the dynamic interplay of histone modifications and RNAP2 with higher temporal resolution in single living cells. Here we address this problem by developing a system to track residue-specific histone modifications and RNAP2 phosphorylation in living cells by fluorescence microscopy. This increases temporal resolution to the tens-of-seconds range. Our single-cell analysis reveals histone H3 lysine-27 acetylation at a gene locus can alter downstream transcription kinetics by as much as 50%, affecting two temporally separate events. First acetylation enhances the search kinetics of transcriptional activators, and later the acetylation accelerates the transition of RNAP2 from initiation to elongation. Signatures of the latter can be found genome-wide using chromatin immunoprecipitation followed by sequencing. We argue that this regulation leads to a robust and potentially tunable transcriptional response.
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Affiliation(s)
- Timothy J Stasevich
- 1] Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan [2] Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870, USA [3] Transcription Imaging Consortium, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
| | - Yoko Hayashi-Takanaka
- 1] Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan [2] Japan Science and Technology Agency (JST), Core Research for Evolutional Science and Technology (CREST), Kawaguchi, Saitama, 332-0012, Japan [3] Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Yuko Sato
- 1] Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan [2] Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Kazumitsu Maehara
- Department of Advanced Medical Initiatives, Faculty of Medicine, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yasuyuki Ohkawa
- 1] Japan Science and Technology Agency (JST), Core Research for Evolutional Science and Technology (CREST), Kawaguchi, Saitama, 332-0012, Japan [2] Department of Advanced Medical Initiatives, Faculty of Medicine, Kyushu University, Fukuoka, 812-8582, Japan
| | - Kumiko Sakata-Sogawa
- 1] Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan [2] RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, 230-0045, Japan
| | - Makio Tokunaga
- 1] Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan [2] RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, 230-0045, Japan
| | - Takahiro Nagase
- Department of Biotechnology Research, Kazusa DNA Research Institute, Chiba, 292-0818, Japan
| | | | - James G McNally
- 1] Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA [2] Institute for Soft Matter and Functional Materials, Helmholtz Zentrum Berlin, Berlin, 14109, Germany
| | - Hiroshi Kimura
- 1] Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan [2] Japan Science and Technology Agency (JST), Core Research for Evolutional Science and Technology (CREST), Kawaguchi, Saitama, 332-0012, Japan [3] Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
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16
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Imaging RNA Polymerase II transcription sites in living cells. Curr Opin Genet Dev 2014; 25:126-30. [PMID: 24794700 DOI: 10.1016/j.gde.2014.01.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 01/05/2014] [Accepted: 01/06/2014] [Indexed: 12/20/2022]
Abstract
Over the past twenty years, exciting developments in optical and molecular imaging approaches have allowed researchers to examine with unprecedented resolution the spatial organization of transcription sites in the nucleus. An attractive model that has developed from these studies is that active genes cluster to preformed transcription factories that contain multiple active RNA polymerases and transcription factor proteins required for efficient mRNA biogenesis. However, this model has been extensively debated in part due to the fact transcription factories and their features have only been documented in fixed cells. In this review, we will focus on recent live-cell imaging studies that are changing our understanding of transcription factories.
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17
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Cisse II, Izeddin I, Causse SZ, Boudarene L, Senecal A, Muresan L, Dugast-Darzacq C, Hajj B, Dahan M, Darzacq X. Real-time dynamics of RNA polymerase II clustering in live human cells. Science 2013; 341:664-7. [PMID: 23828889 DOI: 10.1126/science.1239053] [Citation(s) in RCA: 326] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Transcription is reported to be spatially compartmentalized in nuclear transcription factories with clusters of RNA polymerase II (Pol II). However, little is known about when these foci assemble or their relative stability. We developed a quantitative single-cell approach to characterize protein spatiotemporal organization, with single-molecule sensitivity in live eukaryotic cells. We observed that Pol II clusters form transiently, with an average lifetime of 5.1 (± 0.4) seconds, which refutes the notion that they are statically assembled substructures. Stimuli affecting transcription yielded orders-of-magnitude changes in the dynamics of Pol II clusters, which implies that clustering is regulated and plays a role in the cell's ability to effect rapid response to external signals. Our results suggest that transient crowding of enzymes may aid in rate-limiting steps of gene regulation.
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Affiliation(s)
- Ibrahim I Cisse
- Functional Imaging of Transcription, CNRS UMR8197, Ecole Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, 75005 France
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18
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Southall TD, Gold KS, Egger B, Davidson CM, Caygill EE, Marshall OJ, Brand AH. Cell-type-specific profiling of gene expression and chromatin binding without cell isolation: assaying RNA Pol II occupancy in neural stem cells. Dev Cell 2013; 26:101-12. [PMID: 23792147 PMCID: PMC3714590 DOI: 10.1016/j.devcel.2013.05.020] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/20/2013] [Accepted: 05/24/2013] [Indexed: 12/20/2022]
Abstract
Cell-type-specific transcriptional profiling often requires the isolation of specific cell types from complex tissues. We have developed “TaDa,” a technique that enables cell-specific profiling without cell isolation. TaDa permits genome-wide profiling of DNA- or chromatin-binding proteins without cell sorting, fixation, or affinity purification. The method is simple, sensitive, highly reproducible, and transferable to any model system. We show that TaDa can be used to identify transcribed genes in a cell-type-specific manner with considerable temporal precision, enabling the identification of differential gene expression between neuroblasts and the neuroepithelial cells from which they derive. We profile the genome-wide binding of RNA polymerase II in these adjacent, clonally related stem cells within intact Drosophila brains. Our data reveal expression of specific metabolic genes in neuroepithelial cells, but not in neuroblasts, and highlight gene regulatory networks that may pattern neural stem cell fates. TaDa is a method for cell-type-specific profiling of chromatin binding proteins TaDa does not require cell sorting, fixation, or affinity purification This is a highly sensitive and robust technique for transcriptional profiling We report differential RNA Pol II binding in clonally related stem cells
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Affiliation(s)
- Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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19
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Papantonis A, Cook PR. Transcription factories: genome organization and gene regulation. Chem Rev 2013; 113:8683-705. [PMID: 23597155 DOI: 10.1021/cr300513p] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Argyris Papantonis
- Sir William Dunn School of Pathology, University of Oxford , South Parks Road, Oxford OX1 3RE, United Kingdom
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20
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Schwertman P, Lagarou A, Dekkers DHW, Raams A, van der Hoek AC, Laffeber C, Hoeijmakers JHJ, Demmers JAA, Fousteri M, Vermeulen W, Marteijn JA. UV-sensitive syndrome protein UVSSA recruits USP7 to regulate transcription-coupled repair. Nat Genet 2012; 44:598-602. [PMID: 22466611 DOI: 10.1038/ng.2230] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/29/2012] [Indexed: 02/07/2023]
Abstract
Transcription-coupled nucleotide-excision repair (TC-NER) is a subpathway of NER that efficiently removes the highly toxic RNA polymerase II blocking lesions in DNA. Defective TC-NER gives rise to the human disorders Cockayne syndrome and UV-sensitive syndrome (UV(S)S). NER initiating factors are known to be regulated by ubiquitination. Using a SILAC-based proteomic approach, we identified UVSSA (formerly known as KIAA1530) as part of a UV-induced ubiquitinated protein complex. Knockdown of UVSSA resulted in TC-NER deficiency. UVSSA was found to be the causative gene for UV(S)S, an unresolved NER deficiency disorder. The UVSSA protein interacts with elongating RNA polymerase II, localizes specifically to UV-induced lesions, resides in chromatin-associated TC-NER complexes and is implicated in stabilizing the TC-NER master organizing protein ERCC6 (also known as CSB) by delivering the deubiquitinating enzyme USP7 to TC-NER complexes. Together, these findings indicate that UVSSA-USP7–mediated stabilization of ERCC6 represents a critical regulatory mechanism of TC-NER in restoring gene expression.
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Affiliation(s)
- Petra Schwertman
- Department of Genetics and Netherlands Proteomics Centre, Centre for Biomedical Genetics, Erasmus Medical Centre, Rotterdam, The Netherlands
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21
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Daniels DL, Méndez J, Mosley AL, Ramisetty SR, Murphy N, Benink H, Wood KV, Urh M, Washburn MP. Examining the complexity of human RNA polymerase complexes using HaloTag technology coupled to label free quantitative proteomics. J Proteome Res 2012; 11:564-75. [PMID: 22149079 DOI: 10.1021/pr200459c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Efficient determination of protein interactions and cellular localization remains a challenge in higher order eukaryotes and creates a need for robust technologies for functional proteomics studies. To address this, the HaloTag technology was developed for highly efficient and rapid isolation of intracellular complexes and correlative in vivo cellular imaging. Here we demonstrate the strength of this technology by simultaneous capture of human eukaryotic RNA polymerases (RNAP) I, II, and III using a shared subunit, POLR2H, fused to the HaloTag. Affinity purifications showed successful isolation, as determined using quantitative proteomics, of all RNAP core subunits, even at expression levels near endogenous. Transient known RNAP II interacting partners were identified as well as three previously uncharacterized interactors. These interactions were validated and further functionally characterized using cellular imaging. The multiple capabilities of the HaloTag technology demonstrate the ability to efficiently isolate highly challenging multiprotein complexes, discover new interactions, and characterize cellular localization.
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Affiliation(s)
- Danette L Daniels
- Promega Corporation , 2800 Woods Hollow Road, Madison, Wisconsin 53711, United States.
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22
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Meldi L, Brickner JH. Compartmentalization of the nucleus. Trends Cell Biol 2011; 21:701-8. [PMID: 21900010 PMCID: PMC3970429 DOI: 10.1016/j.tcb.2011.08.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 12/14/2022]
Abstract
The nucleus is a spatially organized compartment. The most obvious way in which this is achieved is at the level of chromosomes. The positioning of chromosomes with respect to nuclear landmarks and with respect to each other is both non-random and cell-type specific. This suggests that cells possess molecular mechanisms to influence the folding and disposition of chromosomes within the nucleus. The localization of many proteins is also heterogeneous within the nucleus. Therefore, chromosome folding and the localization of proteins leads to a model in which individual genes are positioned in distinct protein environments that can affect their transcriptional state. We focus here on the spatial organization of the nucleus and how it impacts upon gene expression.
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Affiliation(s)
- Lauren Meldi
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
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23
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Boulon S, Pradet-Balade B, Verheggen C, Molle D, Boireau S, Georgieva M, Azzag K, Robert MC, Ahmad Y, Neel H, Lamond AI, Bertrand E. HSP90 and its R2TP/Prefoldin-like cochaperone are involved in the cytoplasmic assembly of RNA polymerase II. Mol Cell 2010; 39:912-924. [PMID: 20864038 DOI: 10.1016/j.molcel.2010.08.023] [Citation(s) in RCA: 216] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 05/12/2010] [Accepted: 06/16/2010] [Indexed: 01/09/2023]
Abstract
RNA polymerases are key multisubunit cellular enzymes. Microscopy studies indicated that RNA polymerase I assembles near its promoter. However, the mechanism by which RNA polymerase II is assembled from its 12 subunits remains unclear. We show here that RNA polymerase II subunits Rpb1 and Rpb3 accumulate in the cytoplasm when assembly is prevented and that nuclear import of Rpb1 requires the presence of all subunits. Using MS-based quantitative proteomics, we characterized assembly intermediates. These included a cytoplasmic complex containing subunits Rpb1 and Rpb8 associated with the HSP90 cochaperone hSpagh (RPAP3) and the R2TP/Prefoldin-like complex. Remarkably, HSP90 activity stabilized incompletely assembled Rpb1 in the cytoplasm. Our data indicate that RNA polymerase II is built in the cytoplasm and reveal quality-control mechanisms that link HSP90 to the nuclear import of fully assembled enzymes. hSpagh also bound the free RPA194 subunit of RNA polymerase I, suggesting a general role in assembling RNA polymerases.
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Affiliation(s)
- Séverine Boulon
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Bérengère Pradet-Balade
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Céline Verheggen
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Dorothée Molle
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Stéphanie Boireau
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Marya Georgieva
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Karim Azzag
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Marie-Cécile Robert
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Yasmeen Ahmad
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Henry Neel
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France
| | - Angus I Lamond
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
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das Neves RP, Jones NS, Andreu L, Gupta R, Enver T, Iborra FJ. Connecting variability in global transcription rate to mitochondrial variability. PLoS Biol 2010; 8:e1000560. [PMID: 21179497 PMCID: PMC3001896 DOI: 10.1371/journal.pbio.1000560] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 10/28/2010] [Indexed: 11/18/2022] Open
Abstract
Populations of genetically identical eukaryotic cells show significant cell-to-cell variability in gene expression. However, we lack a good understanding of the origins of this variation. We have found marked cell-to-cell variability in average cellular rates of transcription. We also found marked cell-to-cell variability in the amount of cellular mitochondrial mass. We undertook fusion studies that suggested that variability in transcription rate depends on small diffusible factors. Following this, in vitro studies showed that transcription rate has a sensitive dependence on [ATP] but not on the concentration of other nucleotide triphosphates (NTPs). Further experiments that perturbed populations by changing nutrient levels and available [ATP] suggested this connection holds in vivo. We found evidence that cells with higher mitochondrial mass, or higher total membrane potential, have a faster rate of transcription per unit volume of nuclear material. We also found evidence that transcription rate variability is substantially modulated by the presence of anti- or prooxidants. Daughter studies showed that a cause of variability in mitochondrial content is apparently stochastic segregation of mitochondria at division. We conclude by noting that daughters that stochastically inherit a lower mitochondrial mass than their sisters have relatively longer cell cycles. Our findings reveal a link between variability in energy metabolism and variability in transcription rate.
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Affiliation(s)
- Ricardo Pires das Neves
- Medical Research Council Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
- Biocant Center of Innovation and Biotechnology, Cantanhede, Portugal
- Center for Neuroscience and Cell Biology University of Coimbra, Coimbra, Portugal
| | - Nick S. Jones
- Department of Physics and Biochemistry, Oxford Centre for Integrative Systems Biology, CABDyN Complexity Centre, Oxford, United Kingdom
| | - Lorena Andreu
- Medical Research Council Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Rajeev Gupta
- Medical Research Council Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Tariq Enver
- Medical Research Council Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
| | - Francisco J. Iborra
- Medical Research Council Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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25
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Diefenbacher ME, Litfin M, Herrlich P, Kassel O. The nuclear isoform of the LIM domain protein Trip6 integrates activating and repressing signals at the promoter-bound glucocorticoid receptor. Mol Cell Endocrinol 2010; 320:58-66. [PMID: 20153803 DOI: 10.1016/j.mce.2010.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 01/28/2010] [Accepted: 02/07/2010] [Indexed: 01/08/2023]
Abstract
Trip6 belongs to a family of cytosolic LIM domain proteins involved in cell adhesion and migration. Recent findings show that these proteins also regulate transcription. We have previously reported that nTrip6, a nuclear isoform of Trip6, acts as a co-activator for AP-1 and NF-kappaB transcription factors. Here we report that nTrip6 is an essential regulator of glucocorticoid receptor (GR) transcriptional activity. nTrip6 is recruited to GR-bound promoters through an interaction with GR, and increases GR-mediated transcription. nTrip6 is also essential for the transrepression of GR by NF-kappaB and AP-1. The interaction of nTrip6 with NF-kappaB and AP-1 at a GR-bound promoter is required for the repression. Thus, nTrip6 serves as the molecular mediator of the crosstalk between nuclear receptors and other transcription factors in that it assembles these factors at promoters. Our results reveal an essential role for LIM domain proteins in the integration of positive and negative signals at target promoters.
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Affiliation(s)
- Markus E Diefenbacher
- Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Karlsruhe, Germany
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26
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Stavreva DA, Wiench M, John S, Conway-Campbell BL, McKenna MA, Pooley JR, Johnson TA, Voss TC, Lightman SL, Hager GL. Ultradian hormone stimulation induces glucocorticoid receptor-mediated pulses of gene transcription. Nat Cell Biol 2009; 11:1093-102. [PMID: 19684579 DOI: 10.1038/ncb1922] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 05/22/2009] [Indexed: 01/10/2023]
Abstract
Studies on glucocorticoid receptor (GR) action typically assess gene responses by long-term stimulation with synthetic hormones. As corticosteroids are released from adrenal glands in a circadian and high-frequency (ultradian) mode, such treatments may not provide an accurate assessment of physiological hormone action. Here we demonstrate that ultradian hormone stimulation induces cyclic GR-mediated transcriptional regulation, or gene pulsing, both in cultured cells and in animal models. Equilibrium receptor-occupancy of regulatory elements precisely tracks the ligand pulses. Nascent RNA transcripts from GR-regulated genes are released in distinct quanta, demonstrating a profound difference between the transcriptional programs induced by ultradian and constant stimulation. Gene pulsing is driven by rapid GR exchange with response elements and by GR recycling through the chaperone machinery, which promotes GR activation and reactivation in response to the ultradian hormone release, thus coupling promoter activity to the naturally occurring fluctuations in hormone levels. The GR signalling pathway has been optimized for a prompt and timely response to fluctuations in hormone levels, indicating that biologically accurate regulation of gene targets by GR requires an ultradian mode of hormone stimulation.
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Affiliation(s)
- Diana A Stavreva
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-5055, USA
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27
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Darzacq X, Yao J, Larson DR, Causse SZ, Bosanac L, de Turris V, Ruda VM, Lionnet T, Zenklusen D, Guglielmi B, Tjian R, Singer RH. Imaging transcription in living cells. Annu Rev Biophys 2009; 38:173-96. [PMID: 19416065 DOI: 10.1146/annurev.biophys.050708.133728] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The advent of new technologies for the imaging of living cells has made it possible to determine the properties of transcription, the kinetics of polymerase movement, the association of transcription factors, and the progression of the polymerase on the gene. We report here the current state of the field and the progress necessary to achieve a more complete understanding of the various steps in transcription. Our Consortium is dedicated to developing and implementing the technology to further this understanding.
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Affiliation(s)
- Xavier Darzacq
- Janelia Farm Research Consortium on Imaging Transcription, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA.
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28
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Abstract
Transcription is a fundamental step in gene expression, yet it remains poorly understood at a cellular level. Visualization of transcription sites and active genes has led to the suggestion that transcription occurs at discrete sites in the nucleus, termed transcription factories, where multiple active RNA polymerases are concentrated and anchored to a nuclear substructure. However, this concept is not universally accepted. This Review discusses the experimental evidence in support of the transcription factory model and the evidence that argues against such a spatially structured view of transcription. The transcription factory model has implications for the regulation of transcription initiation and elongation, for the organization of genes in the genome, for the co-regulation of genes and for genome instability.
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Affiliation(s)
- Heidi Sutherland
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Crewe Road, Edinburgh EH4 2XU, UK
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29
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Hongo E, Ishihara Y, Sugaya K, Sugaya K. Characterization of cells expressing RNA polymerase II tagged with green fluorescent protein: effect of ionizing irradiation on RNA synthesis. Int J Radiat Biol 2009; 84:778-87. [PMID: 18821392 DOI: 10.1080/09553000802345936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To isolate and to characterize cells expressing RNA polymerase II tagged with green fluorescent protein for analyses of the effects of ionizing radiation on transcription in living cells. MATERIALS AND METHODS We introduced an alpha-amanitin-resistant mutation into a vector encoding the largest subunit of RNA polymerase II tagged with green fluorescent protein (GFP-pol). Cell lines stably expressing functional GFP-pol were isolated under selection with alpha-amanitin from a Chinese hamster cell line, CHO-K1, and a radiation-sensitive mutant CHO cell line, XR-1. RESULTS We tested the functionality of the fusion protein in vivo by determining RNA synthesis activity by incorporation of nucleoside analogues. Both CHO-K1 and XR-1 cells expressing GFP-pol had properties similar to those of their respective parental cell lines, indicating that GFP-pol is functional. CONCLUSIONS These stable lines might prove useful for analyses of the roles of transcription after ionizing radiation.
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Affiliation(s)
- Etsuko Hongo
- Radiation Effect Mechanisms Research Group, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
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Escargueil AE, Poindessous V, Soares DG, Sarasin A, Cook PR, Larsen AK. Influence of irofulven, a transcription-coupled repair-specific antitumor agent, on RNA polymerase activity, stability and dynamics in living mammalian cells. J Cell Sci 2008; 121:1275-83. [PMID: 18388315 DOI: 10.1242/jcs.023259] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Transcription-coupled repair (TCR) plays a key role in the repair of DNA lesions induced by bulky adducts and is initiated when the elongating RNA polymerase II (Pol II) stalls at DNA lesions. This is accompanied by alterations in Pol II activity and stability. We have previously shown that the monofunctional adducts formed by irofulven (6-hydroxymethylacylfulvene) are exclusively recognized by TCR, without involvement of global genome repair (GGR), making irofulven a unique tool to characterize TCR-associated processes in vivo. Here, we characterize the influence of irofulven on Pol II activity, stability and mobility in living mammalian cells. Our results demonstrate that irofulven induces specific inhibition of nucleoplasmic RNA synthesis, an important decrease of Pol II mobility, coupled to the accumulation of initiating polymerase and a time-dependent loss of the engaged enzyme, associated with its polyubiquitylation. Both proteasome-mediated degradation of the stalled polymerase and new protein synthesis are necessary to allow Pol II recycling into preinitiating complexes. Together, our findings provide novel insights into the subsequent fate of the stalled RNA polymerase II and demonstrate the essential role of the recycling process for transcriptional reinitiation and viability of mammalian cells.
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Affiliation(s)
- Alexandre E Escargueil
- Laboratory of Cancer Biology and Therapeutics, Centre de Recherche Saint-Antoine, Paris, France
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31
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Diefenbacher M, Sekula S, Heilbock C, Maier JV, Litfin M, van Dam H, Castellazzi M, Herrlich P, Kassel O. Restriction to Fos family members of Trip6-dependent coactivation and glucocorticoid receptor-dependent trans-repression of activator protein-1. Mol Endocrinol 2008; 22:1767-80. [PMID: 18535250 DOI: 10.1210/me.2007-0574] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The term activator protein (AP)-1 describes homodimeric and heterodimeric transcription factors composed of members of the Jun, Fos, and cAMP response element-binding protein (CREB)/activating transcription factor (ATF) families of proteins. Distinct AP-1 dimers, for instance the prototypical c-Jun:c-Fos and c-Jun:ATF2 dimers, are differentially regulated by signaling pathways and bind related yet distinct response elements in the regulatory regions of AP-1 target genes. Little is known about the dimer-specific regulation of AP-1 activity at the promoter of its target genes. We have previously shown that nTrip6, the nuclear isoform of the LIM domain protein Trip6, acts as an AP-1 coactivator. Moreover, nTrip6 is an essential component of glucocorticoid receptor (GR)-mediated trans-repression of AP-1, in that it mediates the tethering of GR to the promoter-bound AP-1. We have now discovered a striking specificity of nTrip6 actions determined by the binding preference of its LIM domains. We show that nTrip6 interacts only with Fos family members. Consequently, nTrip6 is a selective coactivator for AP-1 dimers containing Fos. nTrip6 also assembles activated GR to c-Jun:c-Fos-driven promoters. Neither nTrip6 nor GR are recruited to a promoter occupied by c-Jun:ATF2. Thus, only Fos-containing dimers are trans-repressed by GR. Thus, the dimer composition of AP-1 determines the mechanism of both the positive and negative regulation of AP-1 transcriptional activity. Interestingly, on a second level of action, GR represses the increase in transcriptional activity of c-Jun:ATF2 induced by c-Jun N-terminal kinase (JNK)-dependent phosphorylation. This repression depends on GR-mediated induction of MAPK phosphatase 1 (MKP-1) expression, which results in c-Jun N-terminal kinase inactivation.
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Affiliation(s)
- Markus Diefenbacher
- Institut für Toxikologie und Genetik, Forschungszentrum Karlsruhe, Hermann-von-Helmholtz Platz 1, D- 76344 Eggenstein-Leopoldshafen, Germany
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32
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Pombo A. Advances in imaging the interphase nucleus using thin cryosections. Histochem Cell Biol 2007; 128:97-104. [PMID: 17636315 DOI: 10.1007/s00418-007-0310-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2007] [Indexed: 01/01/2023]
Abstract
The mammalian genome is partitioned amongst various chromosomes and encodes for approximately 30,000 protein-coding genes. Gene expression occurs after exit from mitosis, when chromosomes partially decondense within the cell nucleus to allow the enzymatic activities that work on chromatin to access each gene in a regulated fashion. Differential patterns of gene expression evolve during cell differentiation to give rise to the over 200 cell types in higher eukaryotes. The architectural organisation of the genome inside the interphase cell nucleus, and associated enzymatic activities, reveals dynamic and functional compartmentalization of the genome. In this review, I highlight the advantages of Tokuyasu cryosectioning on the investigation of nuclear structure and function.
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Affiliation(s)
- Ana Pombo
- Nuclear Organisation Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.
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33
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Sugaya K, Hongo E, Ishihara Y, Tsuji H. The conserved role of Smu1 in splicing is characterized in its mammalian temperature-sensitive mutant. J Cell Sci 2006; 119:4944-51. [PMID: 17105761 DOI: 10.1242/jcs.03288] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Temperature-sensitive CHO-K1 mutant cell line tsTM18 exhibits chromosomal instability and cell-cycle arrest at S and G2 phases with decreased DNA synthesis at the nonpermissive temperature, 39 degrees C. We previously identified an amino acid substitution in Smu1 that underlies the temperature-sensitive phenotypes of tsTM18 cells. In the present study, we confirmed that Smu1 is associated with the temperature-sensitive defect of tsTM18 by RNA interference. We also found an early temperature effect in DNA synthesis. Because genetic studies of nematodes revealed that smu-1 is involved in splicing of the unc52/perlecan pre-mRNA, we analysed the perlecan transcript in tsTM18 cells by reverse transcription-polymerase chain reaction (RT-PCR). The perlecan PCR product amplified from RNA of tsTM18 cells cultured at 39 degrees C appeared to be a mixture of variants. Sequence analysis identified at least six variants that result from alternative splicing and intron retention. Comparison of the results of perlecan RT-PCR analysis with those of analysis of four other genes suggested that the splicing defect in the perlecan gene is unique and that it is conserved through evolution.
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Affiliation(s)
- Kimihiko Sugaya
- Radiation Effect Mechanisms Research Group, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan.
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34
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Custódio N, Antoniou M, Carmo-Fonseca M. Abundance of the largest subunit of RNA polymerase II in the nucleus is regulated by nucleo-cytoplasmic shuttling. Exp Cell Res 2006; 312:2557-67. [PMID: 16765347 DOI: 10.1016/j.yexcr.2006.04.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Revised: 04/15/2006] [Accepted: 04/19/2006] [Indexed: 12/15/2022]
Abstract
Eukaryotic RNA polymerase II is a complex enzyme composed of 12 distinct subunits that is present in cells in low abundance. Transcription of mRNA by RNA polymerase II involves a phosphorylation/dephosphorylation cycle of the carboxyl-terminal domain (CTD) of the enzyme's largest subunit. We have generated stable murine cell lines expressing an alpha-amanitin-resistant form of the largest subunit of RNA polymerase II (RNA Pol II LS). These cells maintained transcriptional activity in the presence of alpha-amanitin, indicating that the exogenous protein was functional. We observed that over-expressed RNA Pol II LS was predominantly hypophosphorylated, soluble and accumulated in the cytoplasm in a CRM1-dependent manner. Our results further showed that the transcriptionally active form of RNA Pol II LS containing phosphoserine in position 2 of the CTD repeats was restricted to the nucleus and its levels remained remarkably constant. We propose that nucleo-cytoplasmic shuttling of RNA Pol II LS may provide a mechanism to control the pool of RNA polymerase subunits that is accessible for assembly of a functional enzyme in the nucleus.
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Affiliation(s)
- Noélia Custódio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
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35
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Shav-Tal Y. The living test-tube: imaging of real-time gene expression. SOFT MATTER 2006; 2:361-370. [PMID: 32680249 DOI: 10.1039/b600234j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cells are dynamic entities. Not only are some cells motile but there is constant motion of organelles, proteins, nucleic acids and other molecules within every living cell. These complex molecular pathways control the life cycle of a cell and all come down to the basic players of the gene expression pathway: DNA, RNA and protein. It is therefore imperative to study biological processes as they naturally occur-in living cells, and to unravel the biophysical rules that govern intracellular dynamics. Towards this end, genetically encoded fluorescent proteins have become one of the major tools available for the study of kinetic processes taking place in real-time. This review will focus on the technical developments available for the study of gene activity in living cells and will summarize the novel biological information extracted from these approaches.
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Affiliation(s)
- Yaron Shav-Tal
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
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36
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Xie SQ, Martin S, Guillot PV, Bentley DL, Pombo A. Splicing speckles are not reservoirs of RNA polymerase II, but contain an inactive form, phosphorylated on serine2 residues of the C-terminal domain. Mol Biol Cell 2006; 17:1723-33. [PMID: 16467386 PMCID: PMC1415300 DOI: 10.1091/mbc.e05-08-0726] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 01/26/2006] [Accepted: 01/30/2006] [Indexed: 11/11/2022] Open
Abstract
"Splicing speckles" are major nuclear domains rich in components of the splicing machinery and polyA(+) RNA. Although speckles contain little detectable transcriptional activity, they are found preferentially associated with specific mRNA-coding genes and gene-rich R bands, and they accumulate some unspliced pre-mRNAs. RNA polymerase II transcribes mRNAs and is required for splicing, with some reports suggesting that the inactive complexes are stored in splicing speckles. Using ultrathin cryosections to improve optical resolution and preserve nuclear structure, we find that all forms of polymerase II are present, but not enriched, within speckles. Inhibition of polymerase activity shows that speckles do not act as major storage sites for inactive polymerase II complexes but that they contain a stable pool of polymerase II phosphorylated on serine(2) residues of the C-terminal domain, which is transcriptionally inactive and may have roles in spliceosome assembly or posttranscriptional splicing of pre-mRNAs. Paraspeckle domains lie adjacent to speckles, but little is known about their protein content or putative roles in the expression of the speckle-associated genes. We find that paraspeckles are transcriptionally inactive but contain polymerase II, which remains stably associated upon transcriptional inhibition, when paraspeckles reorganize around nucleoli in the form of caps.
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Affiliation(s)
- Sheila Q Xie
- Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, United Kingdom
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37
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Bosisio D, Marazzi I, Agresti A, Shimizu N, Bianchi ME, Natoli G. A hyper-dynamic equilibrium between promoter-bound and nucleoplasmic dimers controls NF-kappaB-dependent gene activity. EMBO J 2006; 25:798-810. [PMID: 16467852 PMCID: PMC1383558 DOI: 10.1038/sj.emboj.7600977] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 12/19/2005] [Indexed: 12/14/2022] Open
Abstract
Because of its very high affinity for DNA, NF-kappaB is believed to make long-lasting contacts with cognate sites and to be essential for the nucleation of very stable enhanceosomes. However, the kinetic properties of NF-kappaB interaction with cognate sites in vivo are unknown. Here, we show that in living cells NF-kappaB is immobilized onto high-affinity binding sites only transiently, and that complete NF-kappaB turnover on active chromatin occurs in less than 30 s. Therefore, promoter-bound NF-kappaB is in dynamic equilibrium with nucleoplasmic dimers; promoter occupancy and transcriptional activity oscillate synchronously with nucleoplasmic NF-kappaB and independently of promoter occupancy by other sequence-specific transcription factors. These data indicate that changes in the nuclear concentration of NF-kappaB directly impact on promoter function and that promoters sample nucleoplasmic levels of NF-kappaB over a timescale of seconds, thus rapidly re-tuning their activity. We propose a revision of the enhanceosome concept in this dynamic framework.
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Affiliation(s)
- Daniela Bosisio
- Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Ivan Marazzi
- Institute for Research in Biomedicine, Bellinzona, Switzerland
| | | | - Noriaki Shimizu
- Faculty of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Marco E Bianchi
- San Raffaele University, Milan, Italy
- San Raffaele University, Via Olgettina 58, 20132, Milan, Italy. Tel.: +39 02 26434 763; Fax: +39 02 26434 861; E-mail:
| | - Gioacchino Natoli
- European Institute of Oncology, Milan, Italy
- Department of Experimental Oncology, European Institute of Oncology, Via Ripamonti 435, 20141, Milan, Italy. Tel.: +39 02 5748 9953; Fax: +39 02 5748 9851; E-mail:
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38
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Abstract
Understanding the different molecular mechanisms responsible for gene expression has been a central interest of molecular biologists for several decades. Transcription, the initial step of gene expression, consists of converting the genetic code into a dynamic messenger RNA that will specify a required cellular function following translocation to the cytoplasm and translation. We now possess an in-depth understanding of the mechanism and regulations of transcription. By contrast, an understanding of the dynamics of an individual gene's expression in real time is just beginning to emerge following recent technological developments.
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Affiliation(s)
- Xavier Darzacq
- Department of Anatomy, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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39
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Voss TC, Demarco IA, Booker CF, Day RN. Corepressor subnuclear organization is regulated by estrogen receptor via a mechanism that requires the DNA-binding domain. Mol Cell Endocrinol 2005; 231:33-47. [PMID: 15713534 DOI: 10.1016/j.mce.2004.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 12/09/2004] [Accepted: 12/09/2004] [Indexed: 10/25/2022]
Abstract
The restriction of transcription factors to certain domains within the cell nucleus must serve an important regulatory function. The silencing mediator of retinoic acid and thyroid hormone (SMRT) and other members of the corepressor complex are enriched in spherical intranuclear foci, and repress estrogen receptor alpha (ERalpha)-dependent transcriptional activity. When fluorescent protein (FP)-labeled SMRT and ERalpha were co-expressed, the proteins co-localized. The subnuclear organization and positioning of the complexes, however, depended on the ligand state of the receptor. Automated image analysis was used to quantify the ERalpha-dependent change in SMRT organization in randomly selected living cell populations. The results demonstrate that the subnuclear positioning of SMRT is influenced by the ligand-bound ERalpha, and this activity is dependent on the ratio of the co-expressed ERalpha and SMRT. A deletion mutant of ERalpha showed that the receptor DNA-binding domain was necessary for the ligand-dependent positioning of SMRT. These results define important organizational mechanisms that underlie nuclear receptor regulation of gene expression.
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Affiliation(s)
- Ty C Voss
- Departments of Medicine and Cell Biology, University of Virginia, Charlottesville, VA, USA
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40
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Chen D, Dundr M, Wang C, Leung A, Lamond A, Misteli T, Huang S. Condensed mitotic chromatin is accessible to transcription factors and chromatin structural proteins. ACTA ACUST UNITED AC 2004; 168:41-54. [PMID: 15623580 PMCID: PMC2171683 DOI: 10.1083/jcb.200407182] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
During mitosis, chromosomes are highly condensed and transcription is silenced globally. One explanation for transcriptional repression is the reduced accessibility of transcription factors. To directly test this hypothesis and to investigate the dynamics of mitotic chromatin, we evaluate the exchange kinetics of several RNA polymerase I transcription factors and nucleosome components on mitotic chromatin in living cells. We demonstrate that these factors rapidly exchange on and off ribosomal DNA clusters and that the kinetics of exchange varies at different phases of mitosis. In addition, the nucleosome component H1c-GFP also shows phase-specific exchange rates with mitotic chromatin. Furthermore, core histone components exchange at detectable levels that are elevated during anaphase and telophase, temporally correlating with H3-K9 acetylation and recruitment of RNA polymerase II before the onset of bulk RNA synthesis at mitotic exit. Our findings indicate that mitotic chromosomes in general and ribosomal genes in particular, although highly condensed, are accessible to transcription factors and chromatin proteins. The phase-specific exchanges of nucleosome components during late mitotic phases are consistent with an emerging model of replication independent core histone replacement.
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Affiliation(s)
- Danyang Chen
- Department of Cell and Molecular Biology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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41
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Janicki SM, Tsukamoto T, Salghetti SE, Tansey WP, Sachidanandam R, Prasanth KV, Ried T, Shav-Tal Y, Bertrand E, Singer RH, Spector DL. From silencing to gene expression: real-time analysis in single cells. Cell 2004; 116:683-98. [PMID: 15006351 PMCID: PMC4942132 DOI: 10.1016/s0092-8674(04)00171-0] [Citation(s) in RCA: 535] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 01/21/2004] [Accepted: 01/23/2004] [Indexed: 12/29/2022]
Abstract
We have developed an inducible system to visualize gene expression at the levels of DNA, RNA and protein in living cells. The system is composed of a 200 copy transgene array integrated into a euchromatic region of chromosome 1 in human U2OS cells. The condensed array is heterochromatic as it is associated with HP1, histone H3 methylated at lysine 9, and several histone methyltransferases. Upon transcriptional induction, HP1alpha is depleted from the locus and the histone variant H3.3 is deposited suggesting that histone exchange is a mechanism through which heterochromatin is transformed into a transcriptionally active state. RNA levels at the transcription site increase immediately after the induction of transcription and the rate of synthesis slows over time. Using this system, we are able to correlate changes in chromatin structure with the progression of transcriptional activation allowing us to obtain a real-time integrative view of gene expression.
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Affiliation(s)
- Susan M Janicki
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724 USA
| | | | - Simone E Salghetti
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724 USA
| | - William P Tansey
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724 USA
| | - Ravi Sachidanandam
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724 USA
| | | | - Thomas Ried
- Genetics Branch, Center for Cancer Research/National Cancer Institute/NIH, 50 South Drive, Bethesda, MD 20892 USA
| | - Yaron Shav-Tal
- Departments of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461 USA
| | - Edouard Bertrand
- Institut de Genetique Moleculaire de Montpellier-CNRS, 1919 Route de Mende, 34293 Montpellier, France
| | - Robert H Singer
- Departments of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461 USA
| | - David L Spector
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724 USA
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42
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Affiliation(s)
- Hiroshi Kimura
- Horizontal Medical Research Organization, School of Medicine, Kyoto University, Kyoto 606-8510, Japan
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43
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Abstract
RNA polymerase II transcribes most eukaryotic genes. Its catalytic subunit was tagged with green fluorescent protein and expressed in Chinese hamster cells bearing a mutation in the same subunit; it complemented the defect and so was functional. Photobleaching revealed two kinetic fractions of polymerase in living nuclei: approximately 75% moved rapidly, but approximately 25% was transiently immobile (association t1/2 approximately 20 min) and transcriptionally active, as incubation with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole eliminated it. No immobile but inactive fraction was detected, providing little support for the existence of a stable holoenzyme, or the slow stepwise assembly of a preinitiation complex on promoters or the nuclear substructure. Actinomycin D decreased the rapidly moving fraction, suggesting that engaged polymerases stall at intercalated molecules while others initiate. When wild-type cells containing only the endogenous enzyme were incubated with [3H]uridine, nascent transcripts became saturated with tritium with similar kinetics (t1/2 approximately 14 min). These data are consistent with a polymerase being mobile for one half to five sixths of a transcription cycle, and rapid assembly into the preinitiation complex. Then, most expressed transcription units would spend significant times unassociated with engaged polymerases.
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Affiliation(s)
- Hiroshi Kimura
- Sir William Dunn School of Pathology, Oxford OX1 3RE, UK
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44
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Becker M, Baumann C, John S, Walker DA, Vigneron M, McNally JG, Hager GL. Dynamic behavior of transcription factors on a natural promoter in living cells. EMBO Rep 2002; 3:1188-94. [PMID: 12446572 PMCID: PMC1308318 DOI: 10.1093/embo-reports/kvf244] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Through the use of photobleaching techniques, we examined the dynamic interaction of three members of the transcription apparatus with a target promoter in living cells. The glucocorticoid receptor (GR) interacting protein 1 (GRIP-1) exhibits a half maximal time for fluorescent recovery (tau(R)) of 5 s, reflecting the same rapid exchange as observed for GR. In contrast, the large subunit (RPB1) of RNA polymerase II (pol II) required 13 min for complete fluorescence recovery, consistent with its function as a processive enzyme. We also observe a complex induction profile for the kinetics of GR-stimulated transcription. Our results indicate that GR and GRIP-1 as components of the activating complex are in a dynamic equilibrium with the promoter, and must return to the template many times during the course of transcriptional activation.
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Affiliation(s)
- Matthias Becker
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
| | - Christopher Baumann
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
| | - Sam John
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
| | - Dawn A. Walker
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
| | - Marc Vigneron
- CR1 INSERM, UMR 7100 CNRS-ULP E.S.B.S., 1 bld Sébastien Brant, 67400 Illkirch, France
| | - James G. McNally
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
| | - Gordon L. Hager
- Laboratory of Receptor Biology and Gene Expression, Building
41 Room B602, Center for Cancer Research, National Cancer Institute,
NIH, Bethesda, MD 20892-5055, USA
- Tel: +1 301 496 9867; Fax: +1 301 496 4951;
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45
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Cook PR. Predicting three-dimensional genome structure from transcriptional activity. Nat Genet 2002; 32:347-52. [PMID: 12410231 DOI: 10.1038/ng1102-347] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Accepted: 09/10/2002] [Indexed: 11/09/2022]
Affiliation(s)
- Peter R Cook
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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46
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Sugaya K, Sasanuma S, Cook PR, Mita K. A mutation in the largest (catalytic) subunit of RNA polymerase II and its relation to the arrest of the cell cycle in G(1) phase. Gene 2001; 274:77-81. [PMID: 11674999 DOI: 10.1016/s0378-1119(01)00615-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Transcriptional activity of RNA polymerase II is modulated during the cell cycle. We previously identified a temperature-sensitive mutation in the largest (catalytic) subunit of RNA polymerase II (RPB1) that causes cell cycle arrest and genome instability. We now characterize a different cell line that has a temperature-sensitive defect in cell cycle progression, and find that it also has a mutation in RPB1. The temperature-sensitive mutant, tsAF8, of the Syrian hamster cell line, BHK21, arrests at the non-permissive temperature in the mid-G(1) phase. We show that RPB1 in tsAF8--which is found exclusively in the nucleus at the permissive temperature--is also found in the cytoplasm at the non-permissive temperature. Comparison of the DNA sequences of the RPB1 gene in the wild-type and mutant shows the mutant phenotype results from a (hemizygous) C-to-A variation at nucleotide 944 in one RPB1 allele; this gives rise to an ala-to-asp substitution at residue 315 in the protein. Aligning the amino acid sequences from various species reveals that ala(315) is highly conserved in eukaryotes.
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Affiliation(s)
- K Sugaya
- Genome Research Group, National Institute of Radiological Sciences, 4-9-1, Anagawa, Chiba, 263-8555, Japan.
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