1
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van Breugel ME, Gerber A, van Leeuwen F. The choreography of chromatin in RNA polymerase III regulation. Biochem Soc Trans 2024; 52:1173-1189. [PMID: 38666598 DOI: 10.1042/bst20230770] [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: 03/07/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 06/27/2024]
Abstract
Regulation of eukaryotic gene expression involves a dynamic interplay between the core transcriptional machinery, transcription factors, and chromatin organization and modification. While this applies to transcription by all RNA polymerase complexes, RNA polymerase III (RNAPIII) seems to be atypical with respect to its mechanisms of regulation. One distinctive feature of most RNAPIII transcribed genes is that they are devoid of nucleosomes, which relates to the high levels of transcription. Moreover, most of the regulatory sequences are not outside but within the transcribed open chromatin regions. Yet, several lines of evidence suggest that chromatin factors affect RNAPIII dynamics and activity and that gene sequence alone does not explain the observed regulation of RNAPIII. Here we discuss the role of chromatin modification and organization of RNAPIII transcribed genes and how they interact with the core transcriptional RNAPIII machinery and regulatory DNA elements in and around the transcribed genes.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
| | - Alan Gerber
- Department of Neurosurgery, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam 1081HV, The Netherlands
- Cancer Center Amsterdam, Cancer Biology, Amsterdam 1081HV, The Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, The Netherlands
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2
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Song E, Han S, Hohng S, Kang C. Compatibility of termination mechanisms in bacterial transcription with inference on eukaryotic models. Biochem Soc Trans 2024; 52:887-897. [PMID: 38533838 DOI: 10.1042/bst20231229] [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: 01/19/2024] [Revised: 03/18/2024] [Accepted: 03/18/2024] [Indexed: 03/28/2024]
Abstract
Transcription termination has evolved to proceed through diverse mechanisms. For several classes of terminators, multiple models have been debatably proposed. Recent single-molecule studies on bacterial terminators have resolved several long-standing controversies. First, termination mode or outcome is twofold rather than single. RNA is released alone before DNA or together with DNA from RNA polymerase (RNAP), i.e. with RNA release for termination, RNAP retains on or dissociates off DNA, respectively. The concomitant release, described in textbooks, results in one-step decomposition of transcription complexes, and this 'decomposing termination' prevails at ρ factor-dependent terminators. Contrastingly, the sequential release was recently discovered abundantly from RNA hairpin-dependent intrinsic terminations. RNA-only release allows RNAP to diffuse on DNA in both directions and recycle for reinitiation. This 'recycling termination' enables one-dimensional reinitiation, which would be more expeditious than three-dimensional reinitiation by RNAP dissociated at decomposing termination. Second, while both recycling and decomposing terminations occur at a hairpin-dependent terminator, four termination mechanisms compatibly operate at a ρ-dependent terminator with ρ in alternative modes and even intrinsically without ρ. RNA-bound catch-up ρ mediates recycling termination first and decomposing termination later, while RNAP-prebound stand-by ρ invokes only decomposing termination slowly. Without ρ, decomposing termination occurs slightly and sluggishly. These four mechanisms operate on distinct timescales, providing orderly fail-safes. The stand-by mechanism is benefited by terminational pause prolongation and modulated by accompanying riboswitches more greatly than the catch-up mechanisms. Conclusively, any mechanism alone is insufficient to perfect termination, and multiple mechanisms operate compatibly to achieve maximum possible efficiency under separate controls.
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Affiliation(s)
- Eunho Song
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun Han
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Sungchul Hohng
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Changwon Kang
- Department of Biological Sciences, and KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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3
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Wang S, Han Z, Strick TR. Single-molecule characterization of Sen1 translocation properties provides insights into eukaryotic factor-dependent transcription termination. Nucleic Acids Res 2024; 52:3249-3261. [PMID: 38261990 PMCID: PMC11013386 DOI: 10.1093/nar/gkae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/25/2024] Open
Abstract
Sen1 is an essential helicase for factor-dependent transcription termination in Saccharomyces cerevisiae, whose molecular-motor mechanism has not been well addressed. Here, we use single-molecule experimentation to better understand the molecular-motor determinants of its action on RNA polymerase II (Pol II) complex. We quantify Sen1 translocation activity on single-stranded DNA (ssDNA), finding elevated translocation rates, high levels of processivity and ATP affinities. Upon deleting the N- and C-terminal domains, or further deleting different parts of the prong subdomain, which is an essential element for transcription termination, Sen1 displays changes in its translocation properties, such as slightly reduced translocation processivities, enhanced translocation rates and statistically identical ATP affinities. Although these parameters fulfil the requirements for Sen1 translocating along the RNA transcript to catch up with a stalled Pol II complex, we observe significant reductions in the termination efficiencies as well as the factions of the formation of the previously described topological intermediate prior to termination, suggesting that the prong may preserve an interaction with Pol II complex during factor-dependent termination. Our results underscore a more detailed rho-like mechanism of Sen1 and a critical interaction between Sen1 and Pol II complex for factor-dependent transcription termination in eukaryotes.
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Affiliation(s)
- Shuang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
- Songshan Lake Materials Laboratory, 523808 Dongguan, Guangdong, China
- Molecular Motors and Machines group, Ecole normale supérieure, Institut de Biologie de l’Ecole normale supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France
| | - Zhong Han
- Metabolism and Function of RNA in the Nucleus, Institut Jacques Monod, CNRS, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France
| | - Terence R Strick
- Molecular Motors and Machines group, Ecole normale supérieure, Institut de Biologie de l’Ecole normale supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France
- Programme Equipe Labellisées, Ligue Contre le Cancer, 75013 Paris, France
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4
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Giannini M, Porrua O. Senataxin: A key actor in RNA metabolism, genome integrity and neurodegeneration. Biochimie 2024; 217:10-19. [PMID: 37558082 DOI: 10.1016/j.biochi.2023.08.001] [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: 05/08/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023]
Abstract
The RNA/DNA helicase senataxin (SETX) has been involved in multiple crucial processes related to genome expression and integrity such us transcription termination, the regulation of transcription-replication conflicts and the resolution of R-loops. SETX has been the focus of numerous studies since the discovery that mutations in its coding gene are the root cause of two different neurodegenerative diseases: Ataxia with Oculomotor Apraxia type 2 (AOA2) and a juvenile form of Amyotrophic Lateral Sclerosis (ALS4). A plethora of cellular phenotypes have been described as the result of SETX deficiency, yet the precise molecular function of SETX as well as the molecular pathways leading from SETX mutations to AOA2 and ALS4 pathologies have remained unclear. However, recent data have shed light onto the biochemical activities and biological roles of SETX, thus providing new clues to understand the molecular consequences of SETX mutation. In this review we summarize near two decades of scientific effort to elucidate SETX function, we discuss strengths and limitations of the approaches and models used thus far to investigate SETX-associated diseases and suggest new possible research avenues for the study of AOA2 and ALS4 pathogenesis.
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Affiliation(s)
- Marta Giannini
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Odil Porrua
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France.
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5
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van Breugel ME, van Kruijsbergen I, Mittal C, Lieftink C, Brouwer I, van den Brand T, Kluin RJC, Hoekman L, Menezes RX, van Welsem T, Del Cortona A, Malik M, Beijersbergen RL, Lenstra TL, Verstrepen KJ, Pugh BF, van Leeuwen F. Locus-specific proteome decoding reveals Fpt1 as a chromatin-associated negative regulator of RNA polymerase III assembly. Mol Cell 2023; 83:4205-4221.e9. [PMID: 37995691 DOI: 10.1016/j.molcel.2023.10.037] [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: 04/18/2023] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
Transcription of tRNA genes by RNA polymerase III (RNAPIII) is tuned by signaling cascades. The emerging notion of differential tRNA gene regulation implies the existence of additional regulatory mechanisms. However, tRNA gene-specific regulators have not been described. Decoding the local chromatin proteome of a native tRNA gene in yeast revealed reprogramming of the RNAPIII transcription machinery upon nutrient perturbation. Among the dynamic proteins, we identified Fpt1, a protein of unknown function that uniquely occupied RNAPIII-regulated genes. Fpt1 binding at tRNA genes correlated with the efficiency of RNAPIII eviction upon nutrient perturbation and required the transcription factors TFIIIB and TFIIIC but not RNAPIII. In the absence of Fpt1, eviction of RNAPIII was reduced, and the shutdown of ribosome biogenesis genes was impaired upon nutrient perturbation. Our findings provide support for a chromatin-associated mechanism required for RNAPIII eviction from tRNA genes and tuning the physiological response to changing metabolic demands.
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Affiliation(s)
- Maria Elize van Breugel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ila van Kruijsbergen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Chitvan Mittal
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Cor Lieftink
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Ineke Brouwer
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Teun van den Brand
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roelof J C Kluin
- Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Liesbeth Hoekman
- Proteomics Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Renée X Menezes
- Biostatistics Centre and Division of Psychosocial Research and Epidemiology, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tibor van Welsem
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Andrea Del Cortona
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - Muddassir Malik
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis and Robotics and Screening Center, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Genomics Core Facility, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Division of Gene Regulation, Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066 CX, the Netherlands
| | - Kevin J Verstrepen
- VIB-KU Leuven Center for Microbiology, KU Leuven, 3001 Heverlee-Leuven, Belgium
| | - B Franklin Pugh
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam 1066 CX, the Netherlands; Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands.
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6
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Yang DL, Huang K, Deng D, Zeng Y, Wang Z, Zhang Y. DNA-dependent RNA polymerases in plants. THE PLANT CELL 2023; 35:3641-3661. [PMID: 37453082 PMCID: PMC10533338 DOI: 10.1093/plcell/koad195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 06/09/2023] [Accepted: 05/29/2023] [Indexed: 07/18/2023]
Abstract
DNA-dependent RNA polymerases (Pols) transfer the genetic information stored in genomic DNA to RNA in all organisms. In eukaryotes, the typical products of nuclear Pol I, Pol II, and Pol III are ribosomal RNAs, mRNAs, and transfer RNAs, respectively. Intriguingly, plants possess two additional Pols, Pol IV and Pol V, which produce small RNAs and long noncoding RNAs, respectively, mainly for silencing transposable elements. The five plant Pols share some subunits, but their distinct functions stem from unique subunits that interact with specific regulatory factors in their transcription cycles. Here, we summarize recent advances in our understanding of plant nucleus-localized Pols, including their evolution, function, structures, and transcription cycles.
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Affiliation(s)
- Dong-Lei Yang
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Kun Huang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Deyin Deng
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Lin’an, Hangzhou 311300, China
| | - Yuan Zeng
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhenxing Wang
- College of Horticulture, National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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7
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Han Z, Moore GA, Mitter R, Lopez Martinez D, Wan L, Dirac Svejstrup AB, Rueda DS, Svejstrup JQ. DNA-directed termination of RNA polymerase II transcription. Mol Cell 2023; 83:3253-3267.e7. [PMID: 37683646 PMCID: PMC7615648 DOI: 10.1016/j.molcel.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/27/2023] [Accepted: 08/09/2023] [Indexed: 09/10/2023]
Abstract
RNA polymerase II (RNAPII) transcription involves initiation from a promoter, transcriptional elongation through the gene, and termination in the terminator region. In bacteria, terminators often contain specific DNA elements provoking polymerase dissociation, but RNAPII transcription termination is thought to be driven entirely by protein co-factors. We used biochemical reconstitution, single-molecule studies, and genome-wide analysis in yeast to study RNAPII termination. Transcription into natural terminators by pure RNAPII results in spontaneous termination at specific sequences containing T-tracts. Single-molecule analysis indicates that termination involves pausing without backtracking. The "torpedo" Rat1-Rai1 exonuclease (XRN2 in humans) greatly stimulates spontaneous termination but is ineffectual on other paused RNAPIIs. By contrast, elongation factor Spt4-Spt5 (DSIF) suppresses termination. Genome-wide analysis further indicates that termination occurs by transcript cleavage at the poly(A) site exposing a new 5' RNA-end that allows Rat1-Rai1 loading, which then catches up with destabilized RNAPII at specific termination sites to end transcription.
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Affiliation(s)
- Zhong Han
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - George A Moore
- Single Molecule Imaging group, MRC-London Institute of Medical Sciences, and Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Richard Mitter
- Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David Lopez Martinez
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Li Wan
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - A Barbara Dirac Svejstrup
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David S Rueda
- Single Molecule Imaging group, MRC-London Institute of Medical Sciences, and Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Jesper Q Svejstrup
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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8
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Choudhary R, Niska-Blakie J, Adhil M, Liberi G, Achar YJ, Giannattasio M, Foiani M. Sen1 and Rrm3 ensure permissive topological conditions for replication termination. Cell Rep 2023; 42:112747. [PMID: 37405920 DOI: 10.1016/j.celrep.2023.112747] [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: 10/01/2022] [Revised: 04/17/2023] [Accepted: 06/20/2023] [Indexed: 07/07/2023] Open
Abstract
Replication forks terminate at TERs and telomeres. Forks that converge or encounter transcription generate topological stress. Combining genetics, genomics, and transmission electron microscopy, we find that Rrm3hPif1 and Sen1hSenataxin helicases assist termination at TERs; Sen1 specifically acts at telomeres. rrm3 and sen1 genetically interact and fail to terminate replication, exhibiting fragility at termination zones (TERs) and telomeres. sen1rrm3 accumulates RNA-DNA hybrids and X-shaped gapped or reversed converging forks at TERs; sen1, but not rrm3, builds up RNA polymerase II (RNPII) at TERs and telomeres. Rrm3 and Sen1 restrain Top1 and Top2 activities, preventing toxic accumulation of positive supercoil at TERs and telomeres. We suggest that Rrm3 and Sen1 coordinate the activities of Top1 and Top2 when forks encounter transcription head on or codirectionally, respectively, thus preventing the slowing down of DNA and RNA polymerases. Hence Rrm3 and Sen1 are indispensable to generate permissive topological conditions for replication termination.
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Affiliation(s)
- Ramveer Choudhary
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Joanna Niska-Blakie
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Mohamood Adhil
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Giordano Liberi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza," CNR, Pavia, Italy
| | | | - Michele Giannattasio
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, Via Festa del Perdono, 7, 20122 Milan, Italy
| | - Marco Foiani
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, Via Festa del Perdono, 7, 20122 Milan, Italy.
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9
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Naesens L, Haerynck F, Gack MU. The RNA polymerase III-RIG-I axis in antiviral immunity and inflammation. Trends Immunol 2023; 44:435-449. [PMID: 37149405 PMCID: PMC10461603 DOI: 10.1016/j.it.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 05/08/2023]
Abstract
Nucleic acid sensors survey subcellular compartments for atypical or mislocalized RNA or DNA, ultimately triggering innate immune responses. Retinoic acid-inducible gene-I (RIG-I) is part of the family of cytoplasmic RNA receptors that can detect viruses. A growing literature demonstrates that mammalian RNA polymerase III (Pol III) transcribes certain viral or cellular DNA sequences into immunostimulatory RIG-I ligands, which elicits antiviral or inflammatory responses. Dysregulation of the Pol III-RIG-I sensing axis can lead to human diseases including severe viral infection outcomes, autoimmunity, and tumor progression. Here, we summarize the newly emerging role of viral and host-derived Pol III transcripts in immunity and also highlight recent advances in understanding how mammalian cells prevent unwanted immune activation by these RNAs to maintain homeostasis.
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Affiliation(s)
- Leslie Naesens
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium; Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
| | - Filomeen Haerynck
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium; Primary Immunodeficiency Research Lab, Center for Primary Immunodeficiency, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium
| | - Michaela U Gack
- Florida Research and Innovation Center, Cleveland Clinic, Port St. Lucie, FL, USA.
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10
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Song E, Hwang S, Munasingha PR, Seo YS, Kang J, Kang C, Hohng S. Transcriptional pause extension benefits the stand-by rather than catch-up Rho-dependent termination. Nucleic Acids Res 2023; 51:2778-2789. [PMID: 36762473 PMCID: PMC10085680 DOI: 10.1093/nar/gkad051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/30/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
Transcriptional pause is essential for all types of termination. In this single-molecule study on bacterial Rho factor-dependent terminators, we confirm that the three Rho-dependent termination routes operate compatibly together in a single terminator, and discover that their termination efficiencies depend on the terminational pauses in unexpected ways. Evidently, the most abundant route is that Rho binds nascent RNA first and catches up with paused RNA polymerase (RNAP) and this catch-up Rho mediates simultaneous releases of transcript RNA and template DNA from RNAP. The fastest route is that the catch-up Rho effects RNA-only release and leads to 1D recycling of RNAP on DNA. The slowest route is that the RNAP-prebound stand-by Rho facilitates only the simultaneous rather than sequential releases. Among the three routes, only the stand-by Rho's termination efficiency positively correlates with pause duration, contrary to a long-standing speculation, invariably in the absence or presence of NusA/NusG factors, competitor RNAs or a crowding agent. Accordingly, the essential terminational pause does not need to be long for the catch-up Rho's terminations, and long pauses benefit only the stand-by Rho's terminations. Furthermore, the Rho-dependent termination of mgtA and ribB riboswitches is controlled mainly by modulation of the stand-by rather than catch-up termination.
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Affiliation(s)
- Eunho Song
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Seungha Hwang
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Palinda Ruvan Munasingha
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yeon-Soo Seo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jin Young Kang
- Correspondence may also be addressed to Jin Young Kang. Tel: +82 42 350 2831;
| | - Changwon Kang
- Correspondence may also be addressed to Changwon Kang. Tel: +82 42 350 2610;
| | - Sungchul Hohng
- To whom correspondence should be addressed. Tel: +82 2 880 6593;
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11
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Xie J, Libri D, Porrua O. Mechanisms of eukaryotic transcription termination at a glance. J Cell Sci 2023; 136:286227. [PMID: 36594557 DOI: 10.1242/jcs.259873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Transcription termination is the final step of a transcription cycle, which induces the release of the transcript at the termination site and allows the recycling of the polymerase for the next round of transcription. Timely transcription termination is critical for avoiding interferences between neighbouring transcription units as well as conflicts between transcribing RNA polymerases (RNAPs) and other DNA-associated processes, such as replication or DNA repair. Understanding the mechanisms by which the very stable transcription elongation complex is dismantled is essential for appreciating how physiological gene expression is maintained and also how concurrent processes that occur synchronously on the DNA are coordinated. Although the strategies employed by the different classes of eukaryotic RNAPs are traditionally considered to be different, novel findings point to interesting commonalities. In this Cell Science at a Glance and the accompanying poster, we review the current understanding about the mechanisms of transcription termination by the three eukaryotic RNAPs.
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Affiliation(s)
- Juanjuan Xie
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Domenico Libri
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Odil Porrua
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
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12
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Girbig M, Xie J, Grötsch H, Libri D, Porrua O, Müller CW. Architecture of the yeast Pol III pre-termination complex and pausing mechanism on poly(dT) termination signals. Cell Rep 2022; 40:111316. [PMID: 36070694 DOI: 10.1016/j.celrep.2022.111316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 07/01/2022] [Accepted: 08/15/2022] [Indexed: 12/20/2022] Open
Abstract
RNA polymerase (Pol) III is specialized to transcribe short, abundant RNAs, for which it terminates transcription on polythymine (dT) stretches on the non-template (NT) strand. When Pol III reaches the termination signal, it pauses and forms the pre-termination complex (PTC). Here, we report cryoelectron microscopy (cryo-EM) structures of the yeast Pol III PTC and complementary functional states at resolutions of 2.7-3.9 Å. Pol III recognizes the poly(dT) termination signal with subunit C128 that forms a hydrogen-bond network with the NT strand and, thereby, induces pausing. Mutating key interacting residues interferes with transcription termination in vitro, impairs yeast growth, and causes global termination defects in vivo, confirming our structural results. Additional cryo-EM analysis reveals that C53-C37, a Pol III subcomplex and key termination factor, participates indirectly in Pol III termination. We propose a mechanistic model of Pol III transcription termination and rationalize why Pol III, unlike Pol I and Pol II, terminates on poly(dT) signals.
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Affiliation(s)
- Mathias Girbig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Juanjuan Xie
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Helga Grötsch
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Domenico Libri
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Odil Porrua
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany.
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