1
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Su BG, Vos SM. Distinct negative elongation factor conformations regulate RNA polymerase II promoter-proximal pausing. Mol Cell 2024; 84:1243-1256.e5. [PMID: 38401543 PMCID: PMC10997474 DOI: 10.1016/j.molcel.2024.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/17/2023] [Accepted: 01/25/2024] [Indexed: 02/26/2024]
Abstract
Metazoan gene expression regulation involves pausing of RNA polymerase (Pol II) in the promoter-proximal region of genes and is stabilized by DSIF and NELF. Upon depletion of elongation factors, NELF appears to accompany elongating Pol II past pause sites; however, prior work indicates that NELF prevents Pol II elongation. Here, we report cryoelectron microscopy structures of Pol II-DSIF-NELF complexes with NELF in two distinct conformations corresponding to paused and poised states. The paused NELF state supports Pol II stalling, whereas the poised NELF state enables transcription elongation as it does not support a tilted RNA-DNA hybrid. Further, the poised NELF state can accommodate TFIIS binding to Pol II, allowing for Pol II reactivation at paused or backtracking sites. Finally, we observe that the NELF-A tentacle interacts with the RPB2 protrusion and is necessary for pausing. Our results define how NELF can support pausing, reactivation, and elongation by Pol II.
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Affiliation(s)
- Bonnie G Su
- Department of Biology, Massachusetts Institute of Technology, Building 68, 31 Ames St., Cambridge, MA 02139, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, Building 68, 31 Ames St., Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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2
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Yang KB, Rasouly A, Epshtein V, Martinez C, Nguyen T, Shamovsky I, Nudler E. Persistence of backtracking by human RNA polymerase II. Mol Cell 2024; 84:897-909.e4. [PMID: 38340716 DOI: 10.1016/j.molcel.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/20/2023] [Accepted: 01/22/2024] [Indexed: 02/12/2024]
Abstract
RNA polymerase II (RNA Pol II) can backtrack during transcription elongation, exposing the 3' end of nascent RNA. Nascent RNA sequencing can approximate the location of backtracking events that are quickly resolved; however, the extent and genome-wide distribution of more persistent backtracking are unknown. Consequently, we developed a method to directly sequence the extruded, "backtracked" 3' RNA. Our data show that RNA Pol II slides backward more than 20 nt in human cells and can persist in this backtracked state. Persistent backtracking mainly occurs where RNA Pol II pauses near promoters and intron-exon junctions and is enriched in genes involved in translation, replication, and development, where gene expression is decreased if these events are unresolved. Histone genes are highly prone to persistent backtracking, and the resolution of such events is likely required for timely expression during cell division. These results demonstrate that persistent backtracking can potentially affect diverse gene expression programs.
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Affiliation(s)
- Kevin B Yang
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Aviram Rasouly
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, NYU Langone Health, New York, NY 10016, USA
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Criseyda Martinez
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Thao Nguyen
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ilya Shamovsky
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, NYU Langone Health, New York, NY 10016, USA.
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3
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Yang KB, Rasouly A, Epshtein V, Martinez C, Nguyen T, Shamovsky I, Nudler E. Persistence of backtracking by human RNA polymerase II. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571520. [PMID: 38168453 PMCID: PMC10760130 DOI: 10.1101/2023.12.13.571520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
RNA polymerase II (pol II) can backtrack during transcription elongation, exposing the 3' end of nascent RNA. Nascent RNA sequencing can approximate the location of backtracking events that are quickly resolved; however, the extent and genome wide distribution of more persistent backtracking is unknown. Consequently, we developed a novel method to directly sequence the extruded, "backtracked" 3' RNA. Our data shows that pol II slides backwards more than 20 nucleotides in human cells and can persist in this backtracked state. Persistent backtracking mainly occurs where pol II pauses near promoters and intron-exon junctions, and is enriched in genes involved in translation, replication, and development, where gene expression is decreased if these events are unresolved. Histone genes are highly prone to persistent backtracking, and the resolution of such events is likely required for timely expression during cell division. These results demonstrate that persistent backtracking has the potential to affect diverse gene expression programs.
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4
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Pal S, Biswas D. Promoter-proximal regulation of gene transcription: Key factors involved and emerging role of general transcription factors in assisting productive elongation. Gene 2023:147571. [PMID: 37331491 DOI: 10.1016/j.gene.2023.147571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
The pausing of RNA polymerase II (Pol II) at the promoter-proximal sites is a key rate-limiting step in gene expression. Cells have dedicated a specific set of proteins that sequentially establish pause and then release the Pol II from promoter-proximal sites. A well-controlled pausing and subsequent release of Pol II is crucial for thefine tuning of expression of genes including signal-responsive and developmentally-regulated ones. The release of paused Pol II broadly involves its transition from initiation to elongation. In this review article, we will discuss the phenomenon of Pol II pausing, the underlying mechanism, and also the role of different known factors, with an emphasis on general transcription factors, involved in this overall regulation. We will further discuss some recent findings suggesting a possible role (underexplored) of initiation factors in assisting the transition of transcriptionally-engaged paused Pol II into productive elongation.
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Affiliation(s)
- Sujay Pal
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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5
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Marquardt S, Petrillo E, Manavella PA. Cotranscriptional RNA processing and modification in plants. THE PLANT CELL 2023; 35:1654-1670. [PMID: 36259932 PMCID: PMC10226594 DOI: 10.1093/plcell/koac309] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/14/2022] [Indexed: 05/30/2023]
Abstract
The activities of RNA polymerases shape the epigenetic landscape of genomes with profound consequences for genome integrity and gene expression. A fundamental event during the regulation of eukaryotic gene expression is the coordination between transcription and RNA processing. Most primary RNAs mature through various RNA processing and modification events to become fully functional. While pioneering results positioned RNA maturation steps after transcription ends, the coupling between the maturation of diverse RNA species and their transcription is becoming increasingly evident in plants. In this review, we discuss recent advances in our understanding of the crosstalk between RNA Polymerase II, IV, and V transcription and nascent RNA processing of both coding and noncoding RNAs.
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Affiliation(s)
- Sebastian Marquardt
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Ezequiel Petrillo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Buenos Aires, C1428EHA, Argentina
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe 3000, Argentina
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6
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Obermeyer S, Stöckl R, Schnekenburger T, Kapoor H, Stempfl T, Schwartz U, Grasser KD. TFIIS Is Crucial During Early Transcript Elongation for Transcriptional Reprogramming in Response to Heat Stress. J Mol Biol 2023; 435:167917. [PMID: 36502880 DOI: 10.1016/j.jmb.2022.167917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022]
Abstract
In addition to the stage of transcriptional initiation, the production of mRNAs is regulated during elongation. Accordingly, the synthesis of mRNAs by RNA polymerase II (RNAPII) in the chromatin context is modulated by various transcript elongation factors. TFIIS is an elongation factor that stimulates the transcript cleavage activity of RNAPII to reactivate stalled elongation complexes at barriers to transcription including nucleosomes. Since Arabidopsis tfIIs mutants grow normally under standard conditions, we have exposed them to heat stress (HS), revealing that tfIIs plants are highly sensitive to elevated temperatures. Transcriptomic analyses demonstrate that particularly HS-induced genes are expressed at lower levels in tfIIs than in wildtype. Mapping the distribution of elongating RNAPII uncovered that in tfIIs plants RNAPII accumulates at the +1 nucleosome of genes that are upregulated upon HS. The promoter-proximal RNAPII accumulation in tfIIs under HS conditions conforms to that observed upon inhibition of the RNAPII transcript cleavage activity. Further analysis of the RNAPII accumulation downstream of transcriptional start sites illustrated that RNAPII stalling occurs at +1 nucleosomes that are depleted in the histone variant H2A.Z upon HS. Therefore, assistance of early transcript elongation by TFIIS is required for reprogramming gene expression to establish plant thermotolerance.
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Affiliation(s)
- Simon Obermeyer
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Richard Stöckl
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Tobias Schnekenburger
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Henna Kapoor
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Thomas Stempfl
- Center of Excellence for Fluorescent Bioanalytics (KFB), University of Regensburg, Am Biopark 9, D-93053 Regensburg, Germany
| | - Uwe Schwartz
- NGS Analysis Centre, Biology and Pre-Clinical Medicine, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany.
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7
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Blombach F, Fouqueau T, Matelska D, Smollett K, Werner F. Promoter-proximal elongation regulates transcription in archaea. Nat Commun 2021; 12:5524. [PMID: 34535658 PMCID: PMC8448881 DOI: 10.1038/s41467-021-25669-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 08/25/2021] [Indexed: 01/17/2023] Open
Abstract
Recruitment of RNA polymerase and initiation factors to the promoter is the only known target for transcription activation and repression in archaea. Whether any of the subsequent steps towards productive transcription elongation are involved in regulation is not known. We characterised how the basal transcription machinery is distributed along genes in the archaeon Saccharolobus solfataricus. We discovered a distinct early elongation phase where RNA polymerases sequentially recruit the elongation factors Spt4/5 and Elf1 to form the transcription elongation complex (TEC) before the TEC escapes into productive transcription. TEC escape is rate-limiting for transcription output during exponential growth. Oxidative stress causes changes in TEC escape that correlate with changes in the transcriptome. Our results thus establish that TEC escape contributes to the basal promoter strength and facilitates transcription regulation. Impaired TEC escape coincides with the accumulation of initiation factors at the promoter and recruitment of termination factor aCPSF1 to the early TEC. This suggests two possible mechanisms for how TEC escape limits transcription, physically blocking upstream RNA polymerases during transcription initiation and premature termination of early TECs.
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Affiliation(s)
- Fabian Blombach
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK.
| | - Thomas Fouqueau
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Dorota Matelska
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Katherine Smollett
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Finn Werner
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK.
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8
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Kerschbaum S, Wegrostek C, Riegel E, Czerny T. Senescence in a cell culture model for burn wounds. Exp Mol Pathol 2021; 122:104674. [PMID: 34437877 DOI: 10.1016/j.yexmp.2021.104674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/25/2021] [Accepted: 08/15/2021] [Indexed: 11/29/2022]
Abstract
Thermal injuries cause severe damage on the cellular and tissue level and are considered especially challenging in the clinical routine. Complex interactions of different cell types and pathways dictate the formation of burn wounds. Thus, complications like burn wound progression, where so far viable tissue becomes necrotic and the size and depth of the wound increases, are difficult to explain, mainly due to the lack of simple model systems. We tested the behavior of human fibroblasts after heat treatment. A prominent response of the cells is to activate the heat shock response (HSR), which is one of the primary emergency mechanisms of the cell to proteotoxic stress factors such as heat. However, after a powerful but not lethal heat shock we observed a delayed activation of the HSR. Extending this model system, we further investigated these static cells and observed the emergence of senescent cells. In particular, the cells became β-galactosidase positive, increased p16 levels and developed a senescence-associated secretory phenotype (SASP). The secretion of cytokines like IL-6 is reminiscent of burn wounds and generates a bystander effect in so far non-senescent cells. In agreement with burn wounds, a wave of cytokine secretion enhanced by invading immune cells could explain complications like burn wound progression. A simple cell culture model can thus be applied for the analysis of highly complex conditions in human tissues.
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Affiliation(s)
- Sarah Kerschbaum
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Christina Wegrostek
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Elisabeth Riegel
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Thomas Czerny
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria.
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9
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Negative elongation factor regulates muscle progenitor expansion for efficient myofiber repair and stem cell pool repopulation. Dev Cell 2021; 56:1014-1029.e7. [PMID: 33735618 DOI: 10.1016/j.devcel.2021.02.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 01/08/2021] [Accepted: 02/19/2021] [Indexed: 11/24/2022]
Abstract
Negative elongation factor (NELF) is a critical transcriptional regulator that stabilizes paused RNA polymerase to permit rapid gene expression changes in response to environmental cues. Although NELF is essential for embryonic development, its role in adult stem cells remains unclear. In this study, through a muscle-stem-cell-specific deletion, we showed that NELF is required for efficient muscle regeneration and stem cell pool replenishment. In mechanistic studies using PRO-seq, single-cell trajectory analyses and myofiber cultures revealed that NELF works at a specific stage of regeneration whereby it modulates p53 signaling to permit massive expansion of muscle progenitors. Strikingly, transplantation experiments indicated that these progenitors are also necessary for stem cell pool repopulation, implying that they are able to return to quiescence. Thus, we identified a critical role for NELF in the expansion of muscle progenitors in response to injury and revealed that progenitors returning to quiescence are major contributors to the stem cell pool repopulation.
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10
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Dollinger R, Gilmour DS. Regulation of Promoter Proximal Pausing of RNA Polymerase II in Metazoans. J Mol Biol 2021; 433:166897. [PMID: 33640324 DOI: 10.1016/j.jmb.2021.166897] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
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Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 462 North Frear, University Park, PA 16802, USA.
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 465A North Frear, University Park, PA 16802, USA.
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11
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Noe Gonzalez M, Blears D, Svejstrup JQ. Causes and consequences of RNA polymerase II stalling during transcript elongation. Nat Rev Mol Cell Biol 2021; 22:3-21. [PMID: 33208928 DOI: 10.1038/s41580-020-00308-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
The journey of RNA polymerase II (Pol II) as it transcribes a gene is anything but a smooth ride. Transcript elongation is discontinuous and can be perturbed by intrinsic regulatory barriers, such as promoter-proximal pausing, nucleosomes, RNA secondary structures and the underlying DNA sequence. More substantial blocking of Pol II translocation can be caused by other physiological circumstances and extrinsic obstacles, including other transcribing polymerases, the replication machinery and several types of DNA damage, such as bulky lesions and DNA double-strand breaks. Although numerous different obstacles cause Pol II stalling or arrest, the cell somehow distinguishes between them and invokes different mechanisms to resolve each roadblock. Resolution of Pol II blocking can be as straightforward as temporary backtracking and transcription elongation factor S-II (TFIIS)-dependent RNA cleavage, or as drastic as premature transcription termination or degradation of polyubiquitylated Pol II and its associated nascent RNA. In this Review, we discuss the current knowledge of how these different Pol II stalling contexts are distinguished by the cell, how they overlap with each other, how they are resolved and how, when unresolved, they can cause genome instability.
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Affiliation(s)
- Melvin Noe Gonzalez
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Blears
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK.
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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12
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Abstract
RNA polymerase II (Pol II) transcribes all protein-coding genes and many noncoding RNAs in eukaryotic genomes. Although Pol II is a complex, 12-subunit enzyme, it lacks the ability to initiate transcription and cannot consistently transcribe through long DNA sequences. To execute these essential functions, an array of proteins and protein complexes interact with Pol II to regulate its activity. In this review, we detail the structure and mechanism of over a dozen factors that govern Pol II initiation (e.g., TFIID, TFIIH, and Mediator), pausing, and elongation (e.g., DSIF, NELF, PAF, and P-TEFb). The structural basis for Pol II transcription regulation has advanced rapidly in the past decade, largely due to technological innovations in cryoelectron microscopy. Here, we summarize a wealth of structural and functional data that have enabled a deeper understanding of Pol II transcription mechanisms; we also highlight mechanistic questions that remain unanswered or controversial.
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Affiliation(s)
- Allison C Schier
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
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13
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Fant CB, Levandowski CB, Gupta K, Maas ZL, Moir J, Rubin JD, Sawyer A, Esbin MN, Rimel JK, Luyties O, Marr MT, Berger I, Dowell RD, Taatjes DJ. TFIID Enables RNA Polymerase II Promoter-Proximal Pausing. Mol Cell 2020; 78:785-793.e8. [PMID: 32229306 DOI: 10.1016/j.molcel.2020.03.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/15/2019] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
RNA polymerase II (RNAPII) transcription is governed by the pre-initiation complex (PIC), which contains TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, RNAPII, and Mediator. After initiation, RNAPII enzymes pause after transcribing less than 100 bases; precisely how RNAPII pausing is enforced and regulated remains unclear. To address specific mechanistic questions, we reconstituted human RNAPII promoter-proximal pausing in vitro, entirely with purified factors (no extracts). As expected, NELF and DSIF increased pausing, and P-TEFb promoted pause release. Unexpectedly, the PIC alone was sufficient to reconstitute pausing, suggesting RNAPII pausing is an inherent PIC function. In agreement, pausing was lost upon replacement of the TFIID complex with TATA-binding protein (TBP), and PRO-seq experiments revealed widespread disruption of RNAPII pausing upon acute depletion (t = 60 min) of TFIID subunits in human or Drosophila cells. These results establish a TFIID requirement for RNAPII pausing and suggest pause regulatory factors may function directly or indirectly through TFIID.
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Affiliation(s)
- Charli B Fant
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | | | - Kapil Gupta
- School of Biochemistry, Bristol Research Centre for Synthetic Biology, University of Bristol, Bristol, UK
| | - Zachary L Maas
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - John Moir
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Jonathan D Rubin
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Andrew Sawyer
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Meagan N Esbin
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Jenna K Rimel
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Olivia Luyties
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Michael T Marr
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Imre Berger
- School of Biochemistry, Bristol Research Centre for Synthetic Biology, University of Bristol, Bristol, UK
| | - Robin D Dowell
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA; BioFrontiers Institute, University of Colorado, Boulder, CO, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
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14
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Huang W, Cheng C, Liu J, Zhang X, Ren C, Jiang X, Chen T, Cheng K, Li H, Hu C. Fine Mapping of the High-pH Tolerance and Growth Trait-Related Quantitative Trait Loci (QTLs) and Identification of the Candidate Genes in Pacific White Shrimp (Litopenaeus vannamei). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:1-18. [PMID: 31758429 DOI: 10.1007/s10126-019-09932-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
High-pH tolerance and growth are important traits for the shrimp culture industry in areas with saline-alkali water. In the present study, an F1 full-sib family of Pacific white shrimp (Litopenaeus vannamei) was generated with a new "semidirectional cross" method, and double-digest restriction site-associated DNA sequencing (ddRAD-Seq) technology was applied to genotype the 2 parents and 148 progenies. A total of 3567 high-quality markers were constructed for the genetic linkage map, and the total map length was 4161.555 centimorgans (cM), showing 48 linkage groups (LGs) with an average interlocus length of 1.167 cM. With a constrained logarithm of odds (LOD) score ≥ 2.50, 12 high-pH tolerance and 2 growth (body weight) QTLs were located. L. vannamei genomic scaffolds were used to assist with the detection of 21 stress- and 5 growth-related scaffold genes. According to the high-pH transcriptome data of our previous study, 6 candidate high-pH response genes were discovered, and 5 of these 6 genes were consistently expressed with the high-pH transcriptome data, validating the locations of the high-pH tolerance trait-related QTLs in this study. This paper is the first report of fine-mapping high-pH tolerance and growth (body weight) trait QTLs in one L. vannamei genetic map. Our results will further benefit marker-assisted selection work and might be useful for promoting genomic research on the shrimp L. vannamei.
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Affiliation(s)
- Wen Huang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
- Institution of South China Sea Ecology and Environmental Engineering (ISEE), Chinese Academy of Sciences, Guangzhou, 510301, China.
| | - Chuhang Cheng
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinshang Liu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Guangdong Jinyang Biotechnology co. LTD, Maoming, 525027, China
| | - Xin Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunhua Ren
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao Jiang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Ting Chen
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Kaimin Cheng
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Yuehai Feed Group co., LTD, Zhanjiang, 524017, China
| | - Huo Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
- Guangdong Jinyang Biotechnology co. LTD, Maoming, 525027, China
| | - Chaoqun Hu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB)/Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
- Institution of South China Sea Ecology and Environmental Engineering (ISEE), Chinese Academy of Sciences, Guangzhou, 510301, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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15
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Wissink EM, Vihervaara A, Tippens ND, Lis JT. Nascent RNA analyses: tracking transcription and its regulation. Nat Rev Genet 2019; 20:705-723. [PMID: 31399713 PMCID: PMC6858503 DOI: 10.1038/s41576-019-0159-6] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2019] [Indexed: 12/19/2022]
Abstract
The programmes that direct an organism's development and maintenance are encoded in its genome. Decoding of this information begins with regulated transcription of genomic DNA into RNA. Although transcription and its control can be tracked indirectly by measuring stable RNAs, it is only by directly measuring nascent RNAs that the immediate regulatory changes in response to developmental, environmental, disease and metabolic signals are revealed. Multiple complementary methods have been developed to quantitatively track nascent transcription genome-wide at nucleotide resolution, all of which have contributed novel insights into the mechanisms of gene regulation and transcription-coupled RNA processing. Here we critically evaluate the array of strategies used for investigating nascent transcription and discuss the recent conceptual advances they have provided.
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Affiliation(s)
- Erin M Wissink
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Anniina Vihervaara
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Nathaniel D Tippens
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Tri-Institutional Training Program in Computational Biology and Medicine, New York, NY, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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16
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The hunt for RNA polymerase II elongation factors: a historical perspective. Nat Struct Mol Biol 2019; 26:771-776. [PMID: 31439940 DOI: 10.1038/s41594-019-0283-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/18/2019] [Indexed: 02/07/2023]
Abstract
The discovery of the three eukaryotic nuclear RNA polymerases paved the way for serious biochemical investigations of eukaryotic transcription and the identification of eukaryotic transcription factors. Here we describe this adventure from our vantage point, with a focus on the hunt for factors that regulate elongation by RNA polymerase II.
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17
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Gressel S, Schwalb B, Cramer P. The pause-initiation limit restricts transcription activation in human cells. Nat Commun 2019; 10:3603. [PMID: 31399571 PMCID: PMC6689055 DOI: 10.1038/s41467-019-11536-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 07/18/2019] [Indexed: 01/01/2023] Open
Abstract
Eukaryotic gene transcription is often controlled at the level of RNA polymerase II (Pol II) pausing in the promoter-proximal region. Pausing Pol II limits the frequency of transcription initiation ('pause-initiation limit'), predicting that the pause duration must be decreased for transcriptional activation. To test this prediction, we conduct a genome-wide kinetic analysis of the heat shock response in human cells. We show that the pause-initiation limit restricts transcriptional activation at most genes. Gene activation generally requires the activity of the P-TEFb kinase CDK9, which decreases the duration of Pol II pausing and thereby enables an increase in the productive initiation frequency. The transcription of enhancer elements is generally not pause limited and can be activated without CDK9 activity. Our results define the kinetics of Pol II transcriptional regulation in human cells at all gene classes during a natural transcription response.
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Affiliation(s)
- Saskia Gressel
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.
| | - Patrick Cramer
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.
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18
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Abdelkareem M, Saint-André C, Takacs M, Papai G, Crucifix C, Guo X, Ortiz J, Weixlbaumer A. Structural Basis of Transcription: RNA Polymerase Backtracking and Its Reactivation. Mol Cell 2019; 75:298-309.e4. [PMID: 31103420 PMCID: PMC7611809 DOI: 10.1016/j.molcel.2019.04.029] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/14/2019] [Accepted: 04/21/2019] [Indexed: 12/14/2022]
Abstract
Regulatory sequences or erroneous incorporations during DNA transcription cause RNA polymerase backtracking and inactivation in all kingdoms of life. Reactivation requires RNA transcript cleavage. Essential transcription factors (GreA and GreB, or TFIIS) accelerate this reaction. We report four cryo-EM reconstructions of Escherichia coli RNA polymerase representing the entire reaction pathway: (1) a backtracked complex; a backtracked complex with GreB (2) before and (3) after RNA cleavage; and (4) a reactivated, substrate-bound complex with GreB before RNA extension. Compared with eukaryotes, the backtracked RNA adopts a different conformation. RNA polymerase conformational changes cause distinct GreB states: a fully engaged GreB before cleavage; a disengaged GreB after cleavage; and a dislodged, loosely bound GreB removed from the active site to allow RNA extension. These reconstructions provide insight into the catalytic mechanism and dynamics of RNA cleavage and extension and suggest how GreB targets backtracked complexes without interfering with canonical transcription.
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Affiliation(s)
- Mo'men Abdelkareem
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Charlotte Saint-André
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Maria Takacs
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Gabor Papai
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Corinne Crucifix
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Xieyang Guo
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Julio Ortiz
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France
| | - Albert Weixlbaumer
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Strasbourg, France; Université de Strasbourg, Strasbourg, France; CNRS UMR7104, Strasbourg, France; INSERM U1258, 67404 Illkirch Cedex, France.
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19
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Bradley CC, Gordon AJE, Halliday JA, Herman C. Transcription fidelity: New paradigms in epigenetic inheritance, genome instability and disease. DNA Repair (Amst) 2019; 81:102652. [PMID: 31326363 DOI: 10.1016/j.dnarep.2019.102652] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA transcription errors are transient, yet frequent, events that do have consequences for the cell. However, until recently we lacked the tools to empirically measure and study these errors. Advances in RNA library preparation and next generation sequencing (NGS) have allowed the spectrum of transcription errors to be empirically measured over the entire transcriptome and in nascent transcripts. Combining these powerful methods with forward and reverse genetic strategies has refined our understanding of transcription factors known to enhance RNA accuracy and will enable the discovery of new candidates. Furthermore, these approaches will shed additional light on the complex interplay between transcription fidelity and other DNA transactions, such as replication and repair, and explore a role for transcription errors in cellular evolution and disease.
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Affiliation(s)
- Catherine C Bradley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, 77030, USA; Robert and Janice McNair Foundation/ McNair Medical Institute M.D./Ph.D. Scholars Program, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, 77030, USA.
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20
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Abstract
In this review, Core et al. discuss the recent advances in our understanding of the early steps in Pol II transcription, highlighting the events and factors involved in the establishment and release of paused Pol II. They also discuss a number of unanswered questions about the regulation and function of Pol II pausing. Precise spatio–temporal control of gene activity is essential for organismal development, growth, and survival in a changing environment. Decisive steps in gene regulation involve the pausing of RNA polymerase II (Pol II) in early elongation, and the controlled release of paused polymerase into productive RNA synthesis. Here we describe the factors that enable pausing and the events that trigger Pol II release into the gene. We also discuss open questions in the field concerning the stability of paused Pol II, nucleosomes as obstacles to elongation, and potential roles of pausing in defining the precision and dynamics of gene expression.
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Affiliation(s)
- Leighton Core
- Department of Molecular and Cell Biology, Institute of Systems Genomics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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21
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Peck SA, Hughes KD, Victorino JF, Mosley AL. Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1529. [PMID: 30848101 PMCID: PMC6570551 DOI: 10.1002/wrna.1529] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 12/20/2022]
Abstract
Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jose F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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22
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Farnung L, Vos SM, Cramer P. Structure of transcribing RNA polymerase II-nucleosome complex. Nat Commun 2018; 9:5432. [PMID: 30575770 PMCID: PMC6303367 DOI: 10.1038/s41467-018-07870-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/05/2018] [Indexed: 01/08/2023] Open
Abstract
Transcription of eukaryotic protein-coding genes requires passage of RNA polymerase II (Pol II) through nucleosomes, but it is unclear how this is achieved. Here we report the cryo-EM structure of transcribing Saccharomyces cerevisiae Pol II engaged with a downstream nucleosome core particle at an overall resolution of 4.4 Å. Pol II and the nucleosome are observed in a defined relative orientation that is not predicted. Pol II contacts both sides of the nucleosome dyad using its clamp head and lobe domains. Structural comparisons reveal that the elongation factors TFIIS, DSIF, NELF, SPT6, and PAF1 complex can be accommodated on the Pol II surface in the presence of the oriented nucleosome. Our results provide a starting point for analysing the mechanisms of chromatin transcription. Eukaryotic transcription requires passage of RNA polymerase II (Pol II) through chromatin, which is impaired by nucleosomes. Here the authors report the cryo-EM structure of transcribing Pol II engaged with a downstream nucleosome core particle at an overall resolution of 4.4 Å, providing insights into the mechanism of chromatin transcription.
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Affiliation(s)
- Lucas Farnung
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Seychelle M Vos
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany.
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23
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Widespread Backtracking by RNA Pol II Is a Major Effector of Gene Activation, 5' Pause Release, Termination, and Transcription Elongation Rate. Mol Cell 2018; 73:107-118.e4. [PMID: 30503775 DOI: 10.1016/j.molcel.2018.10.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/10/2018] [Accepted: 10/17/2018] [Indexed: 10/27/2022]
Abstract
In addition to phosphodiester bond formation, RNA polymerase II has an RNA endonuclease activity, stimulated by TFIIS, which rescues complexes that have arrested and backtracked. How TFIIS affects transcription under normal conditions is poorly understood. We identified backtracking sites in human cells using a dominant-negative TFIIS (TFIISDN) that inhibits RNA cleavage and stabilizes backtracked complexes. Backtracking is most frequent within 2 kb of start sites, consistent with slow elongation early in transcription, and in 3' flanking regions where termination is enhanced by TFIISDN, suggesting that backtracked pol II is a favorable substrate for termination. Rescue from backtracking by RNA cleavage also promotes escape from 5' pause sites, prevents premature termination of long transcripts, and enhances activation of stress-inducible genes. TFIISDN slowed elongation rates genome-wide by half, suggesting that rescue of backtracked pol II by TFIIS is a major stimulus of elongation under normal conditions.
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24
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Turtola M, Mäkinen JJ, Belogurov GA. Active site closure stabilizes the backtracked state of RNA polymerase. Nucleic Acids Res 2018; 46:10870-10887. [PMID: 30256972 PMCID: PMC6237748 DOI: 10.1093/nar/gky883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/30/2018] [Accepted: 09/19/2018] [Indexed: 01/02/2023] Open
Abstract
All cellular RNA polymerases (RNAP) occasionally backtrack along the template DNA as part of transcriptional proofreading and regulation. Here, we studied the mechanism of RNAP backtracking by one nucleotide using two complementary approaches that allowed us to precisely measure the occupancy and lifetime of the backtracked state. Our data show that the stability of the backtracked state is critically dependent on the closure of the RNAP active site by a mobile domain, the trigger loop (TL). The lifetime and occupancy of the backtracked state measurably decreased by substitutions of the TL residues that interact with the nucleoside triphosphate (NTP) substrate, whereas amino acid substitutions that stabilized the closed active site increased the lifetime and occupancy. These results suggest that the same conformer of the TL closes the active site during catalysis of nucleotide incorporation into the nascent RNA and backtracking by one nucleotide. In support of this hypothesis, we construct a model of the 1-nt backtracked complex with the closed active site and the backtracked nucleotide in the entry pore area known as the E-site. We further propose that 1-nt backtracking mimics the reversal of the NTP substrate loading into the RNAP active site during on-pathway elongation.
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Affiliation(s)
- Matti Turtola
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
| | - Janne J Mäkinen
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
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25
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Vos SM, Farnung L, Urlaub H, Cramer P. Structure of paused transcription complex Pol II-DSIF-NELF. Nature 2018; 560:601-606. [PMID: 30135580 PMCID: PMC6245578 DOI: 10.1038/s41586-018-0442-2] [Citation(s) in RCA: 227] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/17/2018] [Indexed: 11/24/2022]
Abstract
Metazoan gene regulation often involves the pausing of RNA polymerase II (Pol II) in the promoter-proximal region. Paused Pol II is stabilized by the protein complexes DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF). Here we report the cryo-electron microscopy structure of a paused transcription elongation complex containing Sus scrofa Pol II and Homo sapiens DSIF and NELF at 3.2 Å resolution. The structure reveals a tilted DNA-RNA hybrid that impairs binding of the nucleoside triphosphate substrate. NELF binds the polymerase funnel, bridges two mobile polymerase modules, and contacts the trigger loop, thereby restraining Pol II mobility that is required for pause release. NELF prevents binding of the anti-pausing transcription elongation factor IIS (TFIIS). Additionally, NELF possesses two flexible 'tentacles' that can contact DSIF and exiting RNA. These results define the paused state of Pol II and provide the molecular basis for understanding the function of NELF during promoter-proximal gene regulation.
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Affiliation(s)
- Seychelle M Vos
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany
| | - Lucas Farnung
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany
| | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Bioanalytical Mass Spectrometry, Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics Group, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany.
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26
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TCEA1 regulates the proliferative potential of mouse myeloid cells. Exp Cell Res 2018; 370:551-560. [PMID: 30009791 DOI: 10.1016/j.yexcr.2018.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 01/15/2023]
Abstract
Leukemia is a malignance with complex pathogenesis and poor prognosis. Discovery of noval regulators amenable to leukemia could be of value to gain insight into the pathogenesis, diagnosis and prognosis of leukemia. Here, we conducted a large-scale shRNA library screening for functional regulators in the development of myeloid cells in primary cells. We identified eighteen candidate regulators in the primary screening. Those genes cover a wide range of cellular functions, including gene expression regulation, intracellular signaling transduction, nucleotide excision repair, cell cycle control and transcription regulation. In both primary screening and validation, shRNAs targeting Tcea1, encoding the transcription elongation factor A (SII) 1, exhibited the greatest influence on the proliferative potential of cells. Knocking down the expression of Tcea1 in the 32Dcl3 myeloid cell line led to enhanced proliferation of myeloid cells and blockage of myeloid differentiation induced by G-CSF. In addition, silence of Tcea1 inhibited apoptosis of myeloid cells. Thus, Tcea1 was identified as a gene which can influence the proliferative potential, survival and differentiation of myeloid cells. These findings have implications for how transcriptional elongation influences myeloid cell development and leukemic transformation.
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27
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Gao WW, Xiao RQ, Zhang WJ, Hu YR, Peng BL, Li WJ, He YH, Shen HF, Ding JC, Huang QX, Ye TY, Li Y, Liu ZY, Ding R, Rosenfeld MG, Liu W. JMJD6 Licenses ERα-Dependent Enhancer and Coding Gene Activation by Modulating the Recruitment of the CARM1/MED12 Co-activator Complex. Mol Cell 2018; 70:340-357.e8. [PMID: 29628309 PMCID: PMC6258263 DOI: 10.1016/j.molcel.2018.03.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 02/12/2018] [Accepted: 03/02/2018] [Indexed: 12/18/2022]
Abstract
Whereas the actions of enhancers in gene transcriptional regulation are well established, roles of JmjC-domain-containing proteins in mediating enhancer activation remain poorly understood. Here, we report that recruitment of the JmjC-domain-containing protein 6 (JMJD6) to estrogen receptor alpha (ERα)-bound active enhancers is required for RNA polymerase II recruitment and enhancer RNA production on enhancers, resulting in transcriptional pause release of cognate estrogen target genes. JMJD6 is found to interact with MED12 in the mediator complex to regulate its recruitment. Unexpectedly, JMJD6 is necessary for MED12 to interact with CARM1, which methylates MED12 at multiple arginine sites and regulates its chromatin binding. Consistent with its role in transcriptional activation, JMJD6 is required for estrogen/ERα-induced breast cancer cell growth and tumorigenesis. Our data have uncovered a critical regulator of estrogen/ERα-induced enhancer coding gene activation and breast cancer cell potency, providing a potential therapeutic target of ER-positive breast cancers.
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Affiliation(s)
- Wei-Wei Gao
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Rong-Quan Xiao
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Wen-Juan Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Yi-Ren Hu
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Bing-Ling Peng
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Wen-Juan Li
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Yao-Hui He
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Hai-Feng Shen
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Jian-Cheng Ding
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Qi-Xuan Huang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Tian-Yi Ye
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Ying Li
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Zhi-Ying Liu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Rong Ding
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department of Medicine, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Wen Liu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China; State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China.
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28
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Catarino RR, Stark A. Assessing sufficiency and necessity of enhancer activities for gene expression and the mechanisms of transcription activation. Genes Dev 2018; 32:202-223. [PMID: 29491135 PMCID: PMC5859963 DOI: 10.1101/gad.310367.117] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Enhancers are important genomic regulatory elements directing cell type-specific transcription. They assume a key role during development and disease, and their identification and functional characterization have long been the focus of scientific interest. The advent of next-generation sequencing and clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-based genome editing has revolutionized the means by which we study enhancer biology. In this review, we cover recent developments in the prediction of enhancers based on chromatin characteristics and their identification by functional reporter assays and endogenous DNA perturbations. We discuss that the two latter approaches provide different and complementary insights, especially in assessing enhancer sufficiency and necessity for transcription activation. Furthermore, we discuss recent insights into mechanistic aspects of enhancer function, including findings about cofactor requirements and the role of post-translational histone modifications such as monomethylation of histone H3 Lys4 (H3K4me1). Finally, we survey how these approaches advance our understanding of transcription regulation with respect to promoter specificity and transcriptional bursting and provide an outlook covering open questions and promising developments.
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Affiliation(s)
- Rui R Catarino
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
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Zhang Y, Dakic A, Chen R, Dai Y, Schlegel R, Liu X. Direct HPV E6/Myc interactions induce histone modifications, Pol II phosphorylation, and hTERT promoter activation. Oncotarget 2017; 8:96323-96339. [PMID: 29221209 PMCID: PMC5707103 DOI: 10.18632/oncotarget.22036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 09/15/2017] [Indexed: 11/25/2022] Open
Abstract
Human Papillomavirus Viruses (HPVs) are associated with the majority of human cervical and anal cancers and 10-30% of head and neck squamous carcinomas. E6 oncoprotein from high risk HPVs interacts with the p53 tumor suppressor protein to facilitate its degradation and increases telomerase activity for extending the life span of host cells. We published previously that the Myc cellular transcription factor associates with the high-risk HPV E6 protein in vivo and participates in the transactivation of the hTERT promoter. In the present study, we further analyzed the role of E6 and the Myc-Max-Mad network in regulating the hTERT promoter. We confirmed that E6 and Myc interact independently and that Max can also form a complex with E6. However, the E6/Max complex is observed only in the presence of Myc, suggesting that E6 associates with Myc/Max dimers. Consistent with the hypothesis that Myc is required for E6 induction of the hTERT promoter, Myc antagonists (Mad or Mnt) significantly blocked E6-mediated transactivation of the hTERT promoter. Analysis of Myc mutants demonstrated that both the transactivation domain and HLH domain of Myc protein were required for binding E6 and for the consequent transactivation of the hTERT promoter, by either Myc or E6. We also showed that E6 increased phosphorylation of Pol II on the hTERT promoter and induced epigenetic histone modifications of the hTERT promoter. More important, knockdown of Myc expression dramatically decreased engagement of acetyl-histones and Pol II at the hTERT promoter in E6-expressing cells. Thus, E6/Myc interaction triggers the transactivation of the hTERT promoter by modulating both histone modifications, Pol II phosphorylation and promoter engagement, suggesting a novel mechanism for telomerase activation and a new target for HPV- associated human cancer.
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Affiliation(s)
- Yiyu Zhang
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Aleksandra Dakic
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Renxiang Chen
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Yuhai Dai
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Richard Schlegel
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Xuefeng Liu
- Department of Pathology, Center for Cell Reprogramming, Georgetown University Medical Center, Washington, DC 20057, USA
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Yang H, Basquin D, Pauli D, Oliver B. Drosophila melanogaster positive transcriptional elongation factors regulate metabolic and sex-biased expression in adults. BMC Genomics 2017; 18:384. [PMID: 28521739 PMCID: PMC5436443 DOI: 10.1186/s12864-017-3755-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/03/2017] [Indexed: 11/22/2022] Open
Abstract
Background Transcriptional elongation is a generic function, but is also regulated to allow rapid transcription responses. Following relatively long initiation and promoter clearance, RNA polymerase II can pause and then rapidly elongate following recruitment of positive elongation factors. Multiple elongation complexes exist, but the role of specific components in adult Drosophila is underexplored. Results We conducted RNA-seq experiments to analyze the effect of RNAi knockdown of Suppressor of Triplolethal and lilliputian. We similarly analyzed the effect of expressing a dominant negative Cyclin-dependent kinase 9 allele. We observed that almost half of the genes expressed in adults showed reduced expression, supporting a broad role for the three tested genes in steady-state transcript abundance. Expression profiles following lilliputian and Suppressor of Triplolethal RNAi were nearly identical raising the possibility that they are obligatory co-factors. Genes showing reduced expression due to these RNAi treatments were short and enriched for genes encoding metabolic or enzymatic functions. The dominant-negative Cyclin-dependent kinase 9 profiles showed both overlapping and specific differential expression, suggesting involvement in multiple complexes. We also observed hundreds of genes with sex-biased differential expression following treatment. Conclusion Transcriptional profiles suggest that Lilliputian and Suppressor of Triplolethal are obligatory cofactors in the adult and that they can also function with Cyclin-dependent kinase 9 at a subset of loci. Our results suggest that transcriptional elongation control is especially important for rapidly expressed genes to support digestion and metabolism, many of which have sex-biased function. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3755-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Haiwang Yang
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA.
| | - Denis Basquin
- Department of Genetics & Evolution, Sciences III, University of Geneva, Boulevard d'Yvoy 4, CH 1205, Geneva, Switzerland
| | - Daniel Pauli
- Department of Genetics & Evolution, Sciences III, University of Geneva, Boulevard d'Yvoy 4, CH 1205, Geneva, Switzerland
| | - Brian Oliver
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA
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Resto M, Kim BH, Fernandez AG, Abraham BJ, Zhao K, Lewis BA. O-GlcNAcase Is an RNA Polymerase II Elongation Factor Coupled to Pausing Factors SPT5 and TIF1β. J Biol Chem 2016; 291:22703-22713. [PMID: 27601472 DOI: 10.1074/jbc.m116.751420] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 08/29/2016] [Indexed: 12/24/2022] Open
Abstract
We describe here the identification and functional characterization of the enzyme O-GlcNAcase (OGA) as an RNA polymerase II elongation factor. Using in vitro transcription elongation assays, we show that OGA activity is required for elongation in a crude nuclear extract system, whereas in a purified system devoid of OGA the addition of rOGA inhibited elongation. Furthermore, OGA is physically associated with the known RNA polymerase II (pol II) pausing/elongation factors SPT5 and TRIM28-KAP1-TIF1β, and a purified OGA-SPT5-TIF1β complex has elongation properties. Lastly, ChIP-seq experiments show that OGA maps to the transcriptional start site/5' ends of genes, showing considerable overlap with RNA pol II, SPT5, TRIM28-KAP1-TIF1β, and O-GlcNAc itself. These data all point to OGA as a component of the RNA pol II elongation machinery regulating elongation genome-wide. Our results add a novel and unexpected dimension to the regulation of elongation by the insertion of O-GlcNAc cycling into the pol II elongation regulatory dynamics.
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Affiliation(s)
- Melissa Resto
- From the Transcriptional Regulation and Biochemistry Unit, Metabolism Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 30893
| | - Bong-Hyun Kim
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland 21702
| | - Alfonso G Fernandez
- From the Transcriptional Regulation and Biochemistry Unit, Metabolism Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 30893
| | - Brian J Abraham
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, and.,Laboratory of Epigenome Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Keji Zhao
- Laboratory of Epigenome Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Brian A Lewis
- From the Transcriptional Regulation and Biochemistry Unit, Metabolism Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 30893,
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Tsai SY, Chang YL, Swamy KBS, Chiang RL, Huang DH. GAGA factor, a positive regulator of global gene expression, modulates transcriptional pausing and organization of upstream nucleosomes. Epigenetics Chromatin 2016; 9:32. [PMID: 27468311 PMCID: PMC4962548 DOI: 10.1186/s13072-016-0082-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/20/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genome-wide studies in higher eukaryotes have revealed the presence of paused RNA polymerase II (RNA-Pol) at about 30-50 bp downstream of the transcription start site of genes involved in developmental control, cell proliferation and intercellular signaling. Promoter-proximal pausing is believed to represent a critical step in transcriptional regulation. GAGA sequence motifs have frequently been found in the upstream region of paused genes in Drosophila, implicating a prevalent binding factor, GAF, in transcriptional pausing. RESULTS Using newly isolated mutants that retain only ~3 % normal GAF level, we analyzed its impacts on transcriptional regulation in whole animals. We first examined the abundance of three major isoforms of RNA-Pol on Hsp70 during heat shock. By cytogenetic analyses on polytene chromosomes and chromatin immunoprecipitation (ChIP), we show that paused RNA-Pol of Hsp70 is substantially reduced in mutants. Conversely, a global increase in paused RNA-Pol is observed when GAF is over-expressed. Coupled analyses of transcriptome and GAF genomic distribution show that 269 genes enriched for upstream GAF binding are down-regulated in mutants. Interestingly, ~15 % of them encode transcriptional factors, which might control ~2000 additional genes down-regulated in mutants. Further examination of RNA-Pol distribution in GAF targets reveals that a positive correlation exists between promoter-proximal RNA-Pol density and GAF occupancy in WT, but not in mutants. Comparison of nucleosome profiles indicates that nucleosome occupancy is preferentially attenuated by GAF in the upstream region that strongly favors nucleosome assembly. Using a dominant eye phenotype caused by GAF over-expression, we detect significant genetic interactions between GAF and the nucleosome remodeler NURF, the pausing factor NELF, and BAB1 whose binding sites are enriched specifically in genes displaying GAF-dependent pausing. CONCLUSION Our results provide direct evidence to support a critical role of GAF in global gene expression, transcriptional pausing and upstream nucleosome organization of a group of genes. By cooperating with factors acting at different levels, GAF orchestrates a series of events from local nucleosome displacement to paused transcription. The use of whole animals containing broad tissue types attests the physiological relevance of this regulatory network.
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Affiliation(s)
- Shih-Ying Tsai
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei Taiwan, ROC ; Molecular Cell Biology, Taiwan International Graduate Program, Institute of Molecular Biology, Academia Sinica, Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
| | - Yuh-Long Chang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei Taiwan, ROC
| | - Krishna B S Swamy
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei Taiwan, ROC
| | - Ruei-Lin Chiang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei Taiwan, ROC
| | - Der-Hwa Huang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei Taiwan, ROC
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Abstract
Termination of RNA polymerase II (RNAPII) transcription is a fundamental step of gene expression that involves the release of the nascent transcript and dissociation of RNAPII from the DNA template. As transcription termination is intimately linked to RNA 3' end processing, termination pathways have a key decisive influence on the fate of the transcribed RNA. Quite remarkably, when reaching the 3' end of genes, a substantial fraction of RNAPII fail to terminate transcription, requiring the contribution of alternative or "fail-safe" mechanisms of termination to release the polymerase. This point of view covers redundant mechanisms of transcription termination and how they relate to conventional termination models. In particular, we expand on recent findings that propose a reverse torpedo model of termination, in which the 3'5' exonucleolytic activity of the RNA exosome targets transcription events associated with paused and backtracked RNAPII.
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Affiliation(s)
- Jean-François Lemay
- a Department of Biochemistry ; Faculté de Médecine et des Sciences de la Santé; Université de Sherbrooke; Pavillon de Recherche Appliquée sur le Cancer (PRAC) ; Sherbrooke, Quebec
| | - François Bachand
- a Department of Biochemistry ; Faculté de Médecine et des Sciences de la Santé; Université de Sherbrooke; Pavillon de Recherche Appliquée sur le Cancer (PRAC) ; Sherbrooke, Quebec
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Senti KA, Jurczak D, Sachidanandam R, Brennecke J. piRNA-guided slicing of transposon transcripts enforces their transcriptional silencing via specifying the nuclear piRNA repertoire. Genes Dev 2015; 29:1747-62. [PMID: 26302790 PMCID: PMC4561483 DOI: 10.1101/gad.267252.115] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this study, Senti et al investigate how cytoplasmic post-transcriptional silencing influences transcriptional silencing in the nucleus. They show that Piwi-bound piRNA populations depend almost exclusively on prior piRNA-guided transcript slicing, thus providing further insight into the regulation of piRNA biogenesis in the developing Drosophila ovary. PIWI clade Argonaute proteins silence transposon expression in animal gonads. Their target specificity is defined by bound ∼23- to 30-nucleotide (nt) PIWI-interacting RNAs (piRNAs) that are processed from single-stranded precursor transcripts via two distinct pathways. Primary piRNAs are defined by the endonuclease Zucchini, while biogenesis of secondary piRNAs depends on piRNA-guided transcript cleavage and results in piRNA amplification. Here, we analyze the interdependencies between these piRNA biogenesis pathways in developing Drosophila ovaries. We show that secondary piRNA-guided target slicing is the predominant mechanism that specifies transcripts—including those from piRNA clusters—as primary piRNA precursors and defines the spectrum of Piwi-bound piRNAs in germline cells. Post-transcriptional silencing in the cytoplasm therefore enforces nuclear transcriptional target silencing, which ensures the tight suppression of transposons during oogenesis. As target slicing also defines the nuclear piRNA pool during mouse spermatogenesis, our findings uncover an unexpected conceptual similarity between the mouse and fly piRNA pathways.
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Affiliation(s)
- Kirsten-André Senti
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Daniel Jurczak
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Ravi Sachidanandam
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029, USA
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
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35
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Imashimizu M, Shimamoto N, Oshima T, Kashlev M. Transcription elongation. Heterogeneous tracking of RNA polymerase and its biological implications. Transcription 2015; 5:e28285. [PMID: 25764114 PMCID: PMC4214235 DOI: 10.4161/trns.28285] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Regulation of transcription elongation via pausing of RNA polymerase has multiple physiological roles. The pausing mechanism depends on the sequence heterogeneity of the DNA being transcribed, as well as on certain interactions of polymerase with specific DNA sequences. In order to describe the mechanism of regulation, we introduce the concept of heterogeneity into the previously proposed alternative models of elongation, power stroke and Brownian ratchet. We also discuss molecular origins and physiological significances of the heterogeneity.
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36
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Nojima T, Gomes T, Grosso ARF, Kimura H, Dye MJ, Dhir S, Carmo-Fonseca M, Proudfoot NJ. Mammalian NET-Seq Reveals Genome-wide Nascent Transcription Coupled to RNA Processing. Cell 2015; 161:526-540. [PMID: 25910207 PMCID: PMC4410947 DOI: 10.1016/j.cell.2015.03.027] [Citation(s) in RCA: 385] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/24/2014] [Accepted: 02/25/2015] [Indexed: 11/18/2022]
Abstract
Transcription is a highly dynamic process. Consequently, we have developed native elongating transcript sequencing technology for mammalian chromatin (mNET-seq), which generates single-nucleotide resolution, nascent transcription profiles. Nascent RNA was detected in the active site of RNA polymerase II (Pol II) along with associated RNA processing intermediates. In particular, we detected 5'splice site cleavage by the spliceosome, showing that cleaved upstream exon transcripts are associated with Pol II CTD phosphorylated on the serine 5 position (S5P), which is accumulated over downstream exons. Also, depletion of termination factors substantially reduces Pol II pausing at gene ends, leading to termination defects. Notably, termination factors play an additional promoter role by restricting non-productive RNA synthesis in a Pol II CTD S2P-specific manner. Our results suggest that CTD phosphorylation patterns established for yeast transcription are significantly different in mammals. Taken together, mNET-seq provides dynamic and detailed snapshots of the complex events underlying transcription in mammals.
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Affiliation(s)
- Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Tomás Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana Rita Fialho Grosso
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Hiroshi Kimura
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 226-8501Yokohama, Japan
| | - Michael J Dye
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Somdutta Dhir
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal.
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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37
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Abstract
The immunoglobulin diversification processes of somatic hypermutation and class switch recombination critically rely on transcription-coupled targeting of activation-induced cytidine deaminase (AID) to Ig loci in activated B lymphocytes. AID catalyzes deamination of cytidine deoxynucleotides on exposed single-stranded DNA. In addition to driving immunoglobulin diversity, promiscuous targeting of AID mutagenic activity poses a deleterious threat to genomic stability. Recent genome-wide studies have uncovered pervasive AID activity throughout the B cell genome. It is increasingly apparent that AID activity is frequently targeted to genomic loci undergoing early transcription termination where RNA exosome promotes the resolution of stalled transcription complexes via cotranscriptional RNA degradation mechanisms. Here, we review aspects and consequences of eukaryotic transcription that lead to early termination, RNA exosome recruitment, and ultimately targeting of AID mutagenic activity.
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Affiliation(s)
- Evangelos Pefanis
- Department of Microbiology & Immunology, College of Physicians and Surgeons, Columbia University, New York, USA.
| | - Uttiya Basu
- Department of Microbiology & Immunology, College of Physicians and Surgeons, Columbia University, New York, USA.
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38
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Samarakkody A, Abbas A, Scheidegger A, Warns J, Nnoli O, Jokinen B, Zarns K, Kubat B, Dhasarathy A, Nechaev S. RNA polymerase II pausing can be retained or acquired during activation of genes involved in the epithelial to mesenchymal transition. Nucleic Acids Res 2015; 43:3938-49. [PMID: 25820424 PMCID: PMC4417172 DOI: 10.1093/nar/gkv263] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 03/17/2015] [Indexed: 12/26/2022] Open
Abstract
Promoter-proximal RNA polymerase II (Pol II) pausing is implicated in the regulation of gene transcription. However, the mechanisms of pausing including its dynamics during transcriptional responses remain to be fully understood. We performed global analysis of short capped RNAs and Pol II Chromatin Immunoprecipitation sequencing in MCF-7 breast cancer cells to map Pol II pausing across the genome, and used permanganate footprinting to specifically follow pausing during transcriptional activation of several genes involved in the epithelial to mesenchymal transition (EMT). We find that the gene for EMT master regulator Snail (SNAI1), but not Slug (SNAI2), shows evidence of Pol II pausing before activation. Transcriptional activation of the paused SNAI1 gene is accompanied by a further increase in Pol II pausing signal, whereas activation of non-paused SNAI2 gene results in the acquisition of a typical pausing signature. The increase in pausing signal reflects increased transcription initiation without changes in Pol II pausing. Activation of the heat shock HSP70 gene involves pausing release that speeds up Pol II turnover, but does not change pausing location. We suggest that Pol II pausing is retained during transcriptional activation and can further undergo regulated release in a signal-specific manner.
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Affiliation(s)
- Ann Samarakkody
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Ata Abbas
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Adam Scheidegger
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Jessica Warns
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Oscar Nnoli
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Bradley Jokinen
- Department of Computer Sciences, University of North Dakota, Grand Forks, ND 58202, USA
| | - Kris Zarns
- Department of Computer Sciences, University of North Dakota, Grand Forks, ND 58202, USA
| | - Brooke Kubat
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Archana Dhasarathy
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
| | - Sergei Nechaev
- Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND 58202, USA
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Jordán-Pla A, Gupta I, de Miguel-Jiménez L, Steinmetz LM, Chávez S, Pelechano V, Pérez-Ortín JE. Chromatin-dependent regulation of RNA polymerases II and III activity throughout the transcription cycle. Nucleic Acids Res 2014; 43:787-802. [PMID: 25550430 PMCID: PMC4333398 DOI: 10.1093/nar/gku1349] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The particular behaviour of eukaryotic RNA polymerases along different gene regions and amongst distinct gene functional groups is not totally understood. To cast light onto the alternative active or backtracking states of RNA polymerase II, we have quantitatively mapped active RNA polymerases at a high resolution following a new biotin-based genomic run-on (BioGRO) technique. Compared with conventional profiling with chromatin immunoprecipitation, the analysis of the BioGRO profiles in Saccharomyces cerevisiae shows that RNA polymerase II has unique activity profiles at both gene ends, which are highly dependent on positioned nucleosomes. This is the first demonstration of the in vivo influence of positioned nucleosomes on transcription elongation. The particular features at the 5' end and around the polyadenylation site indicate that this polymerase undergoes extensive specific-activity regulation in the initial and final transcription elongation phases. The genes encoding for ribosomal proteins show distinctive features at both ends. BioGRO also provides the first nascentome analysis for RNA polymerase III, which indicates that transcription of tRNA genes is poorly regulated at the individual copy level. The present study provides a novel perspective of the transcription cycle that incorporates inactivation/reactivation as an important aspect of RNA polymerase dynamics.
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Affiliation(s)
- Antonio Jordán-Pla
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
| | - Ishaan Gupta
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Lola de Miguel-Jiménez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany Stanford University School of Medicine, Department of Genetics, Stanford, CA 94305, USA Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA
| | - Sebastián Chávez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Vicent Pelechano
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
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40
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Puri D, Gala H, Mishra R, Dhawan J. High-wire act: the poised genome and cellular memory. FEBS J 2014; 282:1675-91. [PMID: 25440020 DOI: 10.1111/febs.13165] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/22/2014] [Accepted: 11/27/2014] [Indexed: 12/12/2022]
Abstract
Emerging evidence aided by genome-wide analysis of chromatin and transcriptional states has shed light on the mechanisms by which stem cells achieve cellular memory. The epigenetic and transcriptional plasticity governing stem cell behavior is highlighted by the identification of 'poised' genes, which permit cells to maintain readiness to undertake alternate developmental fates. This review focuses on two crucial mechanisms of gene poising: bivalent chromatin marks and RNA polymerase II stalling. We provide the context for these mechanisms by exploring the current consensus on the regulation of chromatin states, especially in quiescent adult stem cells, where poised genes are critical for recapitulating developmental choices, leading to regenerative function.
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Affiliation(s)
- Deepika Puri
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
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41
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Weber CM, Ramachandran S, Henikoff S. Nucleosomes are context-specific, H2A.Z-modulated barriers to RNA polymerase. Mol Cell 2014; 53:819-30. [PMID: 24606920 DOI: 10.1016/j.molcel.2014.02.014] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/04/2013] [Accepted: 01/28/2014] [Indexed: 01/03/2023]
Abstract
Nucleosomes are barriers to transcription in vitro; however, their effects on RNA polymerase in vivo are unknown. Here we describe a simple and general strategy to comprehensively map the positions of elongating and arrested RNA polymerase II (RNAPII) at nucleotide resolution. We find that the entry site of the first (+1) nucleosome is a barrier to RNAPII for essentially all genes, including those undergoing regulated pausing farther upstream. In contrast to the +1 nucleosome, gene body nucleosomes are low barriers and cause RNAPII stalling both at the entry site and near the dyad axis. The extent of the +1 nucleosome barrier correlates with nucleosome occupancy but anticorrelates with enrichment of histone variant H2A.Z. Importantly, depletion of H2A.Z from a nucleosome position results in a higher barrier to RNAPII. Our results suggest that nucleosomes present significant, context-specific barriers to RNAPII in vivo that can be tuned by the incorporation of H2A.Z.
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Affiliation(s)
- Christopher M Weber
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Srinivas Ramachandran
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Steven Henikoff
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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42
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Maxwell CS, Kruesi WS, Core LJ, Kurhanewicz N, Waters CT, Lewarch CL, Antoshechkin I, Lis JT, Meyer BJ, Baugh LR. Pol II docking and pausing at growth and stress genes in C. elegans. Cell Rep 2014; 6:455-66. [PMID: 24485661 PMCID: PMC4026043 DOI: 10.1016/j.celrep.2014.01.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 11/01/2013] [Accepted: 01/06/2014] [Indexed: 11/25/2022] Open
Abstract
Fluctuations in nutrient availability profoundly impact gene expression. Previous work revealed postrecruitment regulation of RNA polymerase II (Pol II) during starvation and recovery in Caenorhabditis elegans, suggesting that promoter-proximal pausing promotes rapid response to feeding. To test this hypothesis, we measured Pol II elongation genome wide by two complementary approaches and analyzed elongation in conjunction with Pol II binding and expression. We confirmed bona fide pausing during starvation and also discovered Pol II docking. Pausing occurs at active stress-response genes that become downregulated in response to feeding. In contrast, "docked" Pol II accumulates without initiating upstream of inactive growth genes that become rapidly upregulated upon feeding. Beyond differences in function and expression, these two sets of genes have different core promoter motifs, suggesting alternative transcriptional machinery. Our work suggests that growth and stress genes are both regulated postrecruitment during starvation but at initiation and elongation, respectively, coordinating gene expression with nutrient availability.
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Affiliation(s)
- Colin S Maxwell
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - William S Kruesi
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Leighton J Core
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Nicole Kurhanewicz
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Colin T Waters
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Caitlin L Lewarch
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA
| | - Igor Antoshechkin
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Barbara J Meyer
- Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - L Ryan Baugh
- Department of Biology, Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA.
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43
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Abstract
Most transcription factors specify the subset of genes that will be actively transcribed in the cell by stimulating transcription initiation at these genes, but MYC has a fundamentally different role. MYC binds E-box sites in the promoters of active genes and stimulates recruitment of the elongation factor P-TEFb and thus transcription elongation. Consequently, rather than specifying the set of genes that will be transcribed in any particular cell, MYC's predominant role is to increase the production of transcripts from active genes. This increase in the transcriptional output of the cell's existing gene expression program, called transcriptional amplification, has a profound effect on proliferation and other behaviors of a broad range of cells. Transcriptional amplification may reduce rate-limiting constraints for tumor cell proliferation and explain MYC's broad oncogenic activity among diverse tissues.
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Affiliation(s)
- Peter B Rahl
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142
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44
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Affiliation(s)
- Jiannan Guo
- Biochemistry Department, University of Iowa , Iowa City, Iowa 52242, United States
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45
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Dönertas D, Sienski G, Brennecke J. Drosophila Gtsf1 is an essential component of the Piwi-mediated transcriptional silencing complex. Genes Dev 2013; 27:1693-705. [PMID: 23913922 DOI: 10.1101/gad.221150.113] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The PIWI-interacting RNA (piRNA) pathway is a small RNA silencing system that keeps selfish genetic elements such as transposons under control in animal gonads. Several lines of evidence indicate that nuclear PIWI family proteins guide transcriptional silencing of their targets, yet the composition of the underlying silencing complex is unknown. Here we demonstrate that the double CHHC zinc finger protein gametocyte-specific factor 1 (Gtsf1) is an essential factor for Piwi-mediated transcriptional repression in Drosophila. Cells lacking Gtsf1 contain nuclear Piwi loaded with piRNAs, yet Piwi's silencing capacity is ablated. Gtsf1 interacts directly with a small subpool of nuclear Piwi, and loss of Gtsf1 phenocopies loss of Piwi in terms of deregulation of transposons, loss of H3K9 trimethylation (H3K9me3) marks at euchromatic transposon insertions, and deregulation of genes in proximity to repressed transposons. We propose that only a small fraction of nuclear Piwi is actively engaged in target silencing and that Gtsf1 is an essential component of the underlying Piwi-centered silencing complex.
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Affiliation(s)
- Derya Dönertas
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences IMBA, 1030 Vienna, Austria
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46
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Abstract
The Mediator complex is a multi-subunit assembly that appears to be required for regulating expression of most RNA polymerase II (pol II) transcripts, which include protein-coding and most non-coding RNA genes. Mediator and pol II function within the pre-initiation complex (PIC), which consists of Mediator, pol II, TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH and is approximately 4.0 MDa in size. Mediator serves as a central scaffold within the PIC and helps regulate pol II activity in ways that remain poorly understood. Mediator is also generally targeted by sequence-specific, DNA-binding transcription factors (TFs) that work to control gene expression programs in response to developmental or environmental cues. At a basic level, Mediator functions by relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression. Thus, Mediator is essential for converting biological inputs (communicated by TFs) to physiological responses (via changes in gene expression). In this review, we summarize an expansive body of research on the Mediator complex, with an emphasis on yeast and mammalian complexes. We focus on the basics that underlie Mediator function, such as its structure and subunit composition, and describe its broad regulatory influence on gene expression, ranging from chromatin architecture to transcription initiation and elongation, to mRNA processing. We also describe factors that influence Mediator structure and activity, including TFs, non-coding RNAs and the CDK8 module.
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Affiliation(s)
- Zachary C Poss
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO , USA
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47
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Millán-Zambrano G, Rodríguez-Gil A, Peñate X, de Miguel-Jiménez L, Morillo-Huesca M, Krogan N, Chávez S. The prefoldin complex regulates chromatin dynamics during transcription elongation. PLoS Genet 2013; 9:e1003776. [PMID: 24068951 PMCID: PMC3777993 DOI: 10.1371/journal.pgen.1003776] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 07/23/2013] [Indexed: 12/13/2022] Open
Abstract
Transcriptional elongation requires the concerted action of several factors that allow RNA polymerase II to advance through chromatin in a highly processive manner. In order to identify novel elongation factors, we performed systematic yeast genetic screening based on the GLAM (Gene Length-dependent Accumulation of mRNA) assay, which is used to detect defects in the expression of long transcription units. Apart from well-known transcription elongation factors, we identified mutants in the prefoldin complex subunits, which were among those that caused the most dramatic phenotype. We found that prefoldin, so far involved in the cytoplasmic co-translational assembly of protein complexes, is also present in the nucleus and that a subset of its subunits are recruited to chromatin in a transcription-dependent manner. Prefoldin influences RNA polymerase II the elongation rate in vivo and plays an especially important role in the transcription elongation of long genes and those whose promoter regions contain a canonical TATA box. Finally, we found a specific functional link between prefoldin and histone dynamics after nucleosome remodeling, which is consistent with the extensive network of genetic interactions between this factor and the machinery regulating chromatin function. This study establishes the involvement of prefoldin in transcription elongation, and supports a role for this complex in cotranscriptional histone eviction. Transcription is the biological process that allows genes to be copied into RNA; the molecule that can be read by the cell in order to fabricate its structural components, proteins. Transcription is carried out by RNA polymerases, but these molecular machines need auxiliary factors to guide them through the genome and to help them during the RNA synthesis process. We searched for novel auxiliary factors using a genetic procedure and found a set of potential novel transcriptional players. Among them, we encountered a highly unexpected result: a factor, called prefoldin, so far exclusively involved in the folding of proteins during their fabrication. We confirmed that prefoldin binds transcribed genes and plays an important role during gene transcription. We also further investigated this transcriptional role and found that prefoldin is important for unpacking genes, thus facilitating the advance of the RNA polymerases along them.
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Affiliation(s)
- Gonzalo Millán-Zambrano
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Alfonso Rodríguez-Gil
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Xenia Peñate
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Lola de Miguel-Jiménez
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Macarena Morillo-Huesca
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Nevan Krogan
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, United States of America
| | - Sebastián Chávez
- Departmento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- * E-mail:
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48
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Abstract
Elongation is becoming increasingly recognized as a critical step in eukaryotic transcriptional regulation. Although traditional genetic and biochemical studies have identified major players of transcriptional elongation, our understanding of the importance and roles of these factors is evolving rapidly through the recent advances in genome-wide and single-molecule technologies. Here, we focus on how elongation can modulate the transcriptional outcome through the rate-liming step of RNA polymerase II (Pol II) pausing near promoters and how the participating factors were identified. Among the factors we describe are the pausing factors--NELF (negative elongation factor) and DSIF (DRB sensitivity-inducing factor)--and P-TEFb (positive elongation factor b), which is the key player in pause release. We also describe the high-resolution view of Pol II pausing and propose nonexclusive models for how pausing is achieved. We then discuss Pol II elongation through the bodies of genes and the roles of FACT and SPT6, factors that allow Pol II to move through nucleosomes.
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Affiliation(s)
- Hojoong Kwak
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703; ,
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49
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Correct assembly of RNA polymerase II depends on the foot domain and is required for multiple steps of transcription in Saccharomyces cerevisiae. Mol Cell Biol 2013; 33:3611-26. [PMID: 23836886 DOI: 10.1128/mcb.00262-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Recent papers have provided insight into the cytoplasmic assembly of RNA polymerase II (RNA pol II) and its transport to the nucleus. However, little is known about the mechanisms governing its nuclear assembly, stability, degradation, and recycling. We demonstrate that the foot of RNA pol II is crucial for the assembly and stability of the complex, by ensuring the correct association of Rpb1 with Rpb6 and of the dimer Rpb4-Rpb7 (Rpb4/7). Mutations at the foot affect the assembly and stability of the enzyme, a defect that is offset by RPB6 overexpression, in coordination with Rpb1 degradation by an Asr1-independent mechanism. Correct assembly is a prerequisite for the proper maintenance of several transcription steps. In fact, assembly defects alter transcriptional activity and the amount of enzyme associated with the genes, affect C-terminal domain (CTD) phosphorylation, interfere with the mRNA-capping machinery, and possibly increase the amount of stalled RNA pol II. In addition, our data show that TATA-binding protein (TBP) occupancy does not correlate with RNA pol II occupancy or transcriptional activity, suggesting a functional relationship between assembly, Mediator, and preinitiation complex (PIC) stability. Finally, our data help clarify the mechanisms governing the assembly and stability of RNA pol II.
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50
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Abstract
The mechanisms by which B cells somatically engineer their genomes to generate the vast diversity of antibodies required to challenge the nearly infinite number of antigens that immune systems encounter are of tremendous clinical and academic interest. The DNA cytidine deaminase activation-induced deaminase (AID) catalyzes two of these mechanisms: class switch recombination (CSR) and somatic hypermutation (SHM). Recent discoveries indicate a significant promiscuous targeting of this B-cell mutator enzyme genome-wide. Here we discuss the various regulatory elements that control AID activity and prevent AID from inducing genomic instability and thereby initiating oncogenesis.
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Affiliation(s)
- Celia Keim
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - David Kazadi
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Gerson Rothschild
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Uttiya Basu
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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