1
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Ye J, Kan CH, Yang X, Ma C. Inhibition of bacterial RNA polymerase function and protein-protein interactions: a promising approach for next-generation antibacterial therapeutics. RSC Med Chem 2024; 15:1471-1487. [PMID: 38784472 PMCID: PMC11110800 DOI: 10.1039/d3md00690e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/25/2024] [Indexed: 05/25/2024] Open
Abstract
The increasing prevalence of multidrug-resistant pathogens necessitates the urgent development of new antimicrobial agents with innovative modes of action for the next generation of antimicrobial therapy. Bacterial transcription has been identified and widely studied as a viable target for antimicrobial development. The main focus of these studies has been the discovery of inhibitors that bind directly to the core enzyme of RNA polymerase (RNAP). Over the past two decades, substantial advancements have been made in understanding the properties of protein-protein interactions (PPIs) and gaining structural insights into bacterial RNAP and its associated factors. This has led to the crucial role of computational methods in aiding the identification of new PPI inhibitors to affect the RNAP function. In this context, bacterial transcriptional PPIs present promising, albeit challenging, targets for the creation of new antimicrobials. This review will succinctly outline the structural foundation of bacterial transcription networks and provide a summary of the known small molecules that target transcription PPIs.
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Affiliation(s)
- Jiqing Ye
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Kowloon Hong Kong SAR China
- School of Pharmacy, Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University Hefei 230032 China
| | - Cheuk Hei Kan
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital Shatin Hong Kong SAR China
| | - Xiao Yang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital Shatin Hong Kong SAR China
| | - Cong Ma
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University Kowloon Hong Kong SAR China
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2
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Bu F, Wang X, Li M, Ma L, Wang C, Hu Y, Cao Z, Liu B. Cryo-EM Structure of Porphyromonas gingivalis RNA Polymerase. J Mol Biol 2024; 436:168568. [PMID: 38583515 DOI: 10.1016/j.jmb.2024.168568] [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: 03/11/2024] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Porphyromonas gingivalis, an anaerobic CFB (Cytophaga, Fusobacterium, and Bacteroides) group bacterium, is the keystone pathogen of periodontitis and has been implicated in various systemic diseases. Increased antibiotic resistance and lack of effective antibiotics necessitate a search for new intervention strategies. Here we report a 3.5 Å resolution cryo-EM structure of P. gingivalis RNA polymerase (RNAP). The structure displays new structural features in its ω subunit and multiple domains in β and β' subunits, which differ from their counterparts in other bacterial RNAPs. Superimpositions with E. coli RNAP holoenzyme and initiation complex further suggest that its ω subunit may contact the σ4 domain, thereby possibly contributing to the assembly and stabilization of initiation complexes. In addition to revealing the unique features of P. gingivalis RNAP, our work offers a framework for future studies of transcription regulation in this important pathogen, as well as for structure-based drug development.
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Affiliation(s)
- Fan Bu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Xiaoxuan Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Mengke Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Li Ma
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Chuan Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.
| | - Zhengguo Cao
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
| | - Bin Liu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN, USA.
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3
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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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4
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Said N, Finazzo M, Hilal T, Wang B, Selinger TL, Gjorgjevikj D, Artsimovitch I, Wahl MC. Sm-like protein Rof inhibits transcription termination factor ρ by binding site obstruction and conformational insulation. Nat Commun 2024; 15:3186. [PMID: 38622114 PMCID: PMC11018626 DOI: 10.1038/s41467-024-47439-6] [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: 09/08/2023] [Accepted: 04/01/2024] [Indexed: 04/17/2024] Open
Abstract
Transcription termination factor ρ is a hexameric, RNA-dependent NTPase that can adopt active closed-ring and inactive open-ring conformations. The Sm-like protein Rof, a homolog of the RNA chaperone Hfq, inhibits ρ-dependent termination in vivo but recapitulation of this activity in vitro has proven difficult and the precise mode of Rof action is presently unknown. Here, our cryo-EM structures of ρ-Rof and ρ-RNA complexes show that Rof undergoes pronounced conformational changes to bind ρ at the protomer interfaces, undercutting ρ conformational dynamics associated with ring closure and occluding extended primary RNA-binding sites that are also part of interfaces between ρ and RNA polymerase. Consistently, Rof impedes ρ ring closure, ρ-RNA interactions and ρ association with transcription elongation complexes. Structure-guided mutagenesis coupled with functional assays confirms that the observed ρ-Rof interface is required for Rof-mediated inhibition of cell growth and ρ-termination in vitro. Bioinformatic analyses reveal that Rof is restricted to Pseudomonadota and that the ρ-Rof interface is conserved. Genomic contexts of rof differ between Enterobacteriaceae and Vibrionaceae, suggesting distinct modes of Rof regulation. We hypothesize that Rof and other cellular anti-terminators silence ρ under diverse, but yet to be identified, stress conditions when unrestrained transcription termination by ρ may be detrimental.
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Affiliation(s)
- Nelly Said
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany
| | - Mark Finazzo
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Tarek Hilal
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany
- Research Center of Electron Microscopy and Core Facility BioSupraMol, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstr. 36a, D-14195 Berlin, Germany
| | - Bing Wang
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Tim Luca Selinger
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany
| | - Daniela Gjorgjevikj
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany
- Department of Medicine, MRC Laboratory of Molecular Biology, University of Cambridge, Cambridge CB2 0QH, United Kingdom
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 6, D-14195 Berlin, Germany.
- Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany.
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5
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Zhang J, Zhang S, Zhou W, Zhang X, Li G, Li R, Lin X, Chen Z, Liu F, Shen P, Zhou X, Gao Y, Chen Z, Chao Y, Wang C. A widely conserved protein Rof inhibits transcription termination factor Rho and promotes Salmonella virulence program. Nat Commun 2024; 15:3187. [PMID: 38622116 PMCID: PMC11018607 DOI: 10.1038/s41467-024-47438-7] [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: 09/06/2023] [Accepted: 03/18/2024] [Indexed: 04/17/2024] Open
Abstract
Transcription is crucial for the expression of genetic information and its efficient and accurate termination is required for all living organisms. Rho-dependent termination could rapidly terminate unwanted premature RNAs and play important roles in bacterial adaptation to changing environments. Although Rho has been discovered for about five decades, the regulation mechanisms of Rho-dependent termination are still not fully elucidated. Here we report that Rof is a conserved antiterminator and determine the cryogenic electron microscopy structure of Rho-Rof antitermination complex. Rof binds to the open-ring Rho hexamer and inhibits the initiation of Rho-dependent termination. Rof's N-terminal α-helix undergoes conformational changes upon binding with Rho, and is key in facilitating Rof-Rho interactions. Rof binds to Rho's primary binding site (PBS) and excludes Rho from binding with PBS ligand RNA at the initiation step. Further in vivo analyses in Salmonella Typhimurium show that Rof is required for virulence gene expression and host cell invasion, unveiling a physiological function of Rof and transcription termination in bacterial pathogenesis.
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Affiliation(s)
- Jing Zhang
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Shuo Zhang
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wei Zhou
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China
| | - Xiang Zhang
- The Fifth People's Hospital, Institutes of Biomedical Sciences, School of Public Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Guanjin Li
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruoxuan Li
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xingyu Lin
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ziying Chen
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
- The Fifth People's Hospital, Institutes of Biomedical Sciences, School of Public Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Fang Liu
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China
| | - Pan Shen
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China
| | - Xiaogen Zhou
- College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Yue Gao
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing, China.
| | - Zhenguo Chen
- The Fifth People's Hospital, Institutes of Biomedical Sciences, School of Public Health, School of Basic Medical Sciences, Fudan University, Shanghai, China.
| | - Yanjie Chao
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- Key Laboratory of RNA Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
| | - Chengyuan Wang
- CAS Key Laboratory of Molecular Virology and Immunology, Center for Microbes, Development and Health (CMDH), Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
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6
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Zuber PK, Said N, Hilal T, Wang B, Loll B, González-Higueras J, Ramírez-Sarmiento CA, Belogurov GA, Artsimovitch I, Wahl MC, Knauer SH. Concerted transformation of a hyper-paused transcription complex and its reinforcing protein. Nat Commun 2024; 15:3040. [PMID: 38589445 PMCID: PMC11001881 DOI: 10.1038/s41467-024-47368-4] [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: 08/22/2023] [Accepted: 03/28/2024] [Indexed: 04/10/2024] Open
Abstract
RfaH, a paralog of the universally conserved NusG, binds to RNA polymerases (RNAP) and ribosomes to activate expression of virulence genes. In free, autoinhibited RfaH, an α-helical KOW domain sequesters the RNAP-binding site. Upon recruitment to RNAP paused at an ops site, KOW is released and refolds into a β-barrel, which binds the ribosome. Here, we report structures of ops-paused transcription elongation complexes alone and bound to the autoinhibited and activated RfaH, which reveal swiveled, pre-translocated pause states stabilized by an ops hairpin in the non-template DNA. Autoinhibited RfaH binds and twists the ops hairpin, expanding the RNA:DNA hybrid to 11 base pairs and triggering the KOW release. Once activated, RfaH hyper-stabilizes the pause, which thus requires anti-backtracking factors for escape. Our results suggest that the entire RfaH cycle is solely determined by the ops and RfaH sequences and provide insights into mechanisms of recruitment and metamorphosis of NusG homologs across all life.
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Affiliation(s)
- Philipp K Zuber
- Biochemistry IV-Biophysical Chemistry, Universität Bayreuth, Bayreuth, Germany
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Nelly Said
- Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Tarek Hilal
- Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
- Research Center of Electron Microscopy and Core Facility BioSupraMol, Freie Universität Berlin, Berlin, Germany
| | - Bing Wang
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Bernhard Loll
- Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Jorge González-Higueras
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID, Millennium Science Initiative Program, Millennium Institute for Integrative Biology, Santiago, Chile
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID, Millennium Science Initiative Program, Millennium Institute for Integrative Biology, Santiago, Chile
| | | | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
| | - Markus C Wahl
- Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany.
- Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany.
| | - Stefan H Knauer
- Biochemistry IV-Biophysical Chemistry, Universität Bayreuth, Bayreuth, Germany.
- Bristol-Myers Squibb GmbH & Co. KGaA, Munich, Germany.
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7
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Shine M, Gordon J, Schärfen L, Zigackova D, Herzel L, Neugebauer KM. Co-transcriptional gene regulation in eukaryotes and prokaryotes. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00706-2. [PMID: 38509203 DOI: 10.1038/s41580-024-00706-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2024] [Indexed: 03/22/2024]
Abstract
Many steps of RNA processing occur during transcription by RNA polymerases. Co-transcriptional activities are deemed commonplace in prokaryotes, in which the lack of membrane barriers allows mixing of all gene expression steps, from transcription to translation. In the past decade, an extraordinary level of coordination between transcription and RNA processing has emerged in eukaryotes. In this Review, we discuss recent developments in our understanding of co-transcriptional gene regulation in both eukaryotes and prokaryotes, comparing methodologies and mechanisms, and highlight striking parallels in how RNA polymerases interact with the machineries that act on nascent RNA. The development of RNA sequencing and imaging techniques that detect transient transcription and RNA processing intermediates has facilitated discoveries of transcription coordination with splicing, 3'-end cleavage and dynamic RNA folding and revealed physical contacts between processing machineries and RNA polymerases. Such studies indicate that intron retention in a given nascent transcript can prevent 3'-end cleavage and cause transcriptional readthrough, which is a hallmark of eukaryotic cellular stress responses. We also discuss how coordination between nascent RNA biogenesis and transcription drives fundamental aspects of gene expression in both prokaryotes and eukaryotes.
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Affiliation(s)
- Morgan Shine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jackson Gordon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lydia Herzel
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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8
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Ghosh T, Jahangirnejad S, Chauvier A, Stringer AM, Korepanov AP, Côté JP, Wade JT, Lafontaine DA. Direct and indirect control of Rho-dependent transcription termination by the Escherichia coli lysC riboswitch. RNA (NEW YORK, N.Y.) 2024; 30:381-391. [PMID: 38253429 PMCID: PMC10946432 DOI: 10.1261/rna.079779.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024]
Abstract
Bacterial riboswitches are molecular structures that play a crucial role in controlling gene expression to maintain cellular balance. The Escherichia coli lysC riboswitch has been previously shown to regulate gene expression through translation initiation and mRNA decay. Recent research suggests that lysC gene expression is also influenced by Rho-dependent transcription termination. Through a series of in silico, in vitro, and in vivo experiments, we provide experimental evidence that the lysC riboswitch directly and indirectly modulates Rho transcription termination. Our study demonstrates that Rho-dependent transcription termination plays a significant role in the cotranscriptional regulation of lysC expression. Together with previous studies, our work suggests that lysC expression is governed by a lysine-sensing riboswitch that regulates translation initiation, transcription termination, and mRNA degradation. Notably, both Rho and RNase E target the same region of the RNA molecule, implying that RNase E may degrade Rho-terminated transcripts, providing a means to selectively eliminate these incomplete messenger RNAs. Overall, this study sheds light on the complex regulatory mechanisms used by bacterial riboswitches, emphasizing the role of transcription termination in the control of gene expression and mRNA stability.
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Affiliation(s)
- Tithi Ghosh
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
| | - Shirin Jahangirnejad
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
| | - Adrien Chauvier
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
| | - Anne M Stringer
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA
| | - Alexey P Korepanov
- Expression Génétique Microbienne, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jean Phillippe Côté
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
| | - Joseph T Wade
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York 12201, USA
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1K 2R1
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9
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Warren Norris MAH, Plaskon DM, Tamayo R. Phase Variation of Flagella and Toxins in Clostridioides difficile is Mediated by Selective Rho-dependent Termination. J Mol Biol 2024; 436:168456. [PMID: 38278436 PMCID: PMC10942720 DOI: 10.1016/j.jmb.2024.168456] [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: 10/26/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
Clostridioides difficile is an intestinal pathogen that exhibits phase variation of flagella and toxins through inversion of the flagellar (flg) switch controlling flagellar and toxin gene expression. The transcription termination factor Rho preferentially inhibits swimming motility of bacteria with the 'flg-OFF' switch sequence. How C. difficile Rho mediates this selectivity was unknown. C. difficile Rho contains an N-terminal insertion domain (NID) which is found in a subset of Rho orthologues and confers diverse functions. Here we determined how Rho distinguishes between flg-ON and -OFF mRNAs and the roles of the NID and other domains of C. difficile Rho. Using in vitro ATPase assays, we determined that Rho specifically binds a region containing the left inverted repeat of the flg switch, but only of flg-OFF mRNA, indicating that differential termination is mediated by selective Rho binding. Using a suite of in vivo and in vitro assays in C. difficile, we determined that the NID is essential for Rho termination of flg-OFF mRNA, likely by influencing the ability to form stable hexamers, and the RNA binding domain is critical for flg-OFF specific termination. This work gives insight into the novel mechanism by which Rho interacts with flg mRNA to mediate phase variation of flagella and toxins in C. difficile and broadens our understanding of Rho-mediated termination in an organism with an AT-rich genome.
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Affiliation(s)
- Mercedes A H Warren Norris
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Dylan M Plaskon
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
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10
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Bhardwaj K, Kalita A, Verma N, Prakash A, Thakur R, Dutta D. Rho-dependent termination enables cellular pH homeostasis. J Bacteriol 2024; 206:e0035623. [PMID: 38169297 PMCID: PMC10810219 DOI: 10.1128/jb.00356-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
The termination factor Rho, an ATP-dependent RNA translocase, preempts pervasive transcription processes, thereby rendering genome integrity in bacteria. Here, we show that the loss of Rho function raised the intracellular pH to >8.0 in Escherichia coli. The loss of Rho function upregulates tryptophanase-A (TnaA), an enzyme that catabolizes tryptophan to produce indole, pyruvate, and ammonia. We demonstrate that the enhanced TnaA function had produced the conjugate base ammonia, raising the cellular pH in the Rho-dependent termination defective strains. On the other hand, the constitutively overexpressed Rho lowered the cellular pH to about 6.2, independent of cellular ammonia levels. Since Rho overexpression may increase termination activities, the decrease in cellular pH could result from an excess H+ ion production during ATP hydrolysis by overproduced Rho. Furthermore, we performed in vivo termination assays to show that the efficiency of Rho-dependent termination was increased at both acidic and basic pH ranges. Given that the Rho level remained unchanged, the alkaline pH increases the termination efficiency by stimulating Rho's catalytic activity. We conducted the Rho-mediated RNA release assay from a stalled elongation complex to show an efficient RNA release at alkaline pH, compared to the neutral or acidic pH, that supports our in vivo observation. Whereas acidic pH appeared to increase the termination function by elevating the cellular level of Rho. This study is the first to link Rho function to the cellular pH homeostasis in bacteria. IMPORTANCE The current study shows that the loss or gain of Rho-dependent termination alkalizes or acidifies the cytoplasm, respectively. In the case of loss of Rho function, the tryptophanase-A enzyme is upregulated, and degrades tryptophan, producing ammonia to alkalize cytoplasm. We hypothesize that Rho overproduction by deleting its autoregulatory DNA portion increases termination function, causing excessive ATP hydrolysis to produce H+ ions and cytoplasmic acidification. Therefore, this study is the first to unravel a relationship between Rho function and intrinsic cellular pH homeostasis. Furthermore, the Rho level increases in the absence of autoregulation, causing cytoplasmic acidification. As intracellular pH plays a critical role in enzyme function, such a connection between Rho function and alkalization will have far-reaching implications for bacterial physiology.
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Affiliation(s)
- Kanika Bhardwaj
- CSIR Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Arunima Kalita
- CSIR Institute of Microbial Technology, Chandigarh, India
| | - Neha Verma
- CSIR Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Anand Prakash
- CSIR Institute of Microbial Technology, Chandigarh, India
| | - Ruchika Thakur
- CSIR Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Dipak Dutta
- CSIR Institute of Microbial Technology, Chandigarh, India
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11
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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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12
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Said N, Finazzo M, Hilal T, Wang B, Selinger TL, Gjorgjevikj D, Artsimovitch I, Wahl MC. Sm-like protein Rof inhibits transcription termination factor ρ by binding site obstruction and conformational insulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555460. [PMID: 37693585 PMCID: PMC10491184 DOI: 10.1101/2023.08.30.555460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Transcription termination factor ρ is a hexameric, RNA-dependent NTPase that can adopt active closed-ring and inactive open-ring conformations. The Sm-like protein Rof, a homolog of the RNA chaperone Hfq, inhibits ρ-dependent termination in vivo but recapitulation of this activity in vitro has proven difficult and the precise mode of Rof action is presently unknown. Our electron microscopic structures of ρ-Rof and ρ-RNA complexes show that Rof undergoes pronounced conformational changes to bind ρ at the protomer interfaces, undercutting ρ conformational dynamics associated with ring closure and occluding extended primary RNA-binding sites that are also part of interfaces between ρ and RNA polymerase. Consistently, Rof impedes ρ ring closure, ρ-RNA interactions, and ρ association with transcription elongation complexes. Structure-guided mutagenesis coupled with functional assays confirmed that the observed ρ-Rof interface is required for Rof-mediated inhibition of cell growth and ρ-termination in vitro. Bioinformatic analyses revealed that Rof is restricted to Pseudomonadota and that the ρ-Rof interface is conserved. Genomic contexts of rof differ between Enterobacteriaceae and Vibrionaceae, suggesting distinct modes of Rof regulation. We hypothesize that Rof and other cellular anti-terminators silence ρ under diverse, but yet to be identified, stress conditions when unrestrained transcription termination by ρ would be lethal.
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Affiliation(s)
- Nelly Said
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
| | - Mark Finazzo
- The Ohio State University, Department of Microbiology and Center for RNA Biology, Columbus, OH, USA
| | - Tarek Hilal
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy and Core Facility BioSupraMol, Fabeckstr. 36a, 14195 Berlin, Germany
| | - Bing Wang
- The Ohio State University, Department of Microbiology and Center for RNA Biology, Columbus, OH, USA
| | - Tim Luca Selinger
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
| | - Daniela Gjorgjevikj
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
| | - Irina Artsimovitch
- The Ohio State University, Department of Microbiology and Center for RNA Biology, Columbus, OH, USA
| | - Markus C. Wahl
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
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13
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Wang B, Said N, Hilal T, Finazzo M, Wahl MC, Artsimovitch I. Transcription termination factor ρ polymerizes under stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.18.553922. [PMID: 37645988 PMCID: PMC10462130 DOI: 10.1101/2023.08.18.553922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Bacterial RNA helicase ρ is a genome sentinel that terminates synthesis of damaged and junk RNAs that are not translated by the ribosome. Co-transcriptional RNA surveillance by ρ is essential for quality control of the transcriptome during optimal growth. However, it is unclear how bacteria protect their RNAs from overzealous ρ during dormancy or stress, conditions common in natural habitats. Here we used cryogenic electron microscopy, biochemical, and genetic approaches to show that residue substitutions, ADP, or ppGpp promote hyper-oligomerization of Escherichia coli ρ. Our results demonstrate that nucleotides bound at subunit interfaces control ρ switching from active hexamers to inactive higher-order oligomers and extended filaments. Polymers formed upon exposure to antibiotics or ppGpp disassemble when stress is relieved, thereby directly linking termination activity to cellular physiology. Inactivation of ρ through hyper-oligomerization is a regulatory strategy shared by RNA polymerases, ribosomes, and metabolic enzymes across all life.
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Affiliation(s)
- Bing Wang
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Nelly Said
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
| | - Tarek Hilal
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy and Core Facility BioSupraMol, Fabeckstr. 36a, 14195 Berlin, Germany
| | - Mark Finazzo
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Markus C. Wahl
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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14
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Hwang S, Kang JY. To burst or hide. Structure 2023; 31:893-894. [PMID: 37541191 DOI: 10.1016/j.str.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/07/2023] [Accepted: 07/11/2023] [Indexed: 08/06/2023]
Abstract
The transcription activator of the λ phage, CII, determines whether the phage will undergo the lytic or the lysogenic pathway. In a report by Zhao et al. in this issue of Structure, the cryo-EM structure of the λCII-dependent transcription activation complex reveals how λCII activates the PRE promoter to turn on the lysogenic pathway.
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Affiliation(s)
- Seungha Hwang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jin Young Kang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
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15
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Petroni E, Esnault C, Tetreault D, Dale RK, Storz G, Adams PP. Extensive diversity in RNA termination and regulation revealed by transcriptome mapping for the Lyme pathogen Borrelia burgdorferi. Nat Commun 2023; 14:3931. [PMID: 37402717 DOI: 10.1038/s41467-023-39576-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/16/2023] [Indexed: 07/06/2023] Open
Abstract
Transcription termination is an essential and dynamic process that can tune gene expression in response to diverse molecular signals. Yet, the genomic positions, molecular mechanisms, and regulatory consequences of termination have only been studied thoroughly in model bacteria. Here, we use several RNA-seq approaches to map RNA ends for the transcriptome of the spirochete Borrelia burgdorferi - the etiological agent of Lyme disease. We identify complex gene arrangements and operons, untranslated regions and small RNAs. We predict intrinsic terminators and experimentally test examples of Rho-dependent transcription termination. Remarkably, 63% of RNA 3' ends map upstream of or internal to open reading frames (ORFs), including genes involved in the unique infectious cycle of B. burgdorferi. We suggest these RNAs result from premature termination, processing and regulatory events such as cis-acting regulation. Furthermore, the polyamine spermidine globally influences the generation of truncated mRNAs. Collectively, our findings provide insights into transcription termination and uncover an abundance of potential RNA regulators in B. burgdorferi.
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Affiliation(s)
- Emily Petroni
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Caroline Esnault
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Daniel Tetreault
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Ryan K Dale
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Philip P Adams
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA.
- Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD, 20892, USA.
- Independent Research Scholar Program, Intramural Research Program, National Institutes of Health, Bethesda, MD, 20892, USA.
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16
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Chauvier A, Porta JC, Deb I, Ellinger E, Meze K, Frank AT, Ohi MD, Walter NG. Structural basis for control of bacterial RNA polymerase pausing by a riboswitch and its ligand. Nat Struct Mol Biol 2023; 30:902-913. [PMID: 37264140 PMCID: PMC10523900 DOI: 10.1038/s41594-023-01002-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/20/2023] [Indexed: 06/03/2023]
Abstract
Folding of nascent transcripts can be modulated by the RNA polymerase (RNAP) that carries out their transcription, and vice versa. A pause of RNAP during transcription of a preQ1 riboswitch (termed que-PEC) is stabilized by a previously characterized template consensus sequence and the ligand-free conformation of the nascent RNA. Ligand binding to the riboswitch induces RNAP pause release and downstream transcription termination; however, the mechanism by which riboswitch folding modulates pausing is unclear. Here, we report single-particle cryo-electron microscopy reconstructions of que-PEC in ligand-free and ligand-bound states. In the absence of preQ1, the RNA transcript is in an unexpected hyper-translocated state, preventing downstream nucleotide incorporation. Strikingly, on ligand binding, the riboswitch rotates around its helical axis, expanding the surrounding RNAP exit channel and repositioning the transcript for elongation. Our study reveals the tight coupling by which nascent RNA structures and their ligands can functionally regulate the macromolecular transcription machinery.
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Affiliation(s)
- Adrien Chauvier
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Jason C Porta
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Indrajit Deb
- Biophysics Program, University of Michigan, Ann Arbor, MI, USA
- Drug Discovery Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Emily Ellinger
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Katarina Meze
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Aaron T Frank
- Biophysics Program, University of Michigan, Ann Arbor, MI, USA
- Arrakis Therapeutics, Waltham, MA, USA
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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17
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Strobel EJ. Isolation of E. coli RNA polymerase transcription elongation complexes by selective solid-phase photoreversible immobilization. Methods Enzymol 2023; 691:223-250. [PMID: 37914448 PMCID: PMC10950060 DOI: 10.1016/bs.mie.2023.03.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The ability to prepare defined transcription elongation complexes (TECs) is a fundamental tool for investigating the interplay between RNA polymerases (RNAPs) and nascent RNA. To facilitate the preparation of defined TECs that contain arbitrarily long and complex transcripts, we developed a procedure for isolating roadblocked E. coli TECs from an in vitro transcription reaction using solid-phase photoreversible immobilization. Our approach uses a modified DNA template that contains both a 5' photocleavable biotin tag and an internal biotin-TEG transcription stall site. Because the footprint of a TEC at the stall site sequesters the biotin-TEG tag, DNA template molecules that contain a TEC can be reversibly immobilized on streptavidin-coated magnetic beads by the 5' photocleavable biotin tag. In contrast, DNA template molecules that do not contain a TEC are retained on the beads because the biotin-TEG tag is exposed and can bind streptavidin. In this way, DNA template molecules that contain a TEC are gently separated from free DNA and DNA that contains non-productive transcription complexes. This procedure yields precisely positioned TECs that are >95% pure with >30% yield relative to the amount of input DNA template. The resulting complexes are >99% stable for at least 3 h and can be used for biochemical investigations of nascent RNA structure and function in the context of E. coli RNAP. The procedure is likely generalizable to any RNAP that arrests at and sequesters the internal biotin-TEG stall site.
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Affiliation(s)
- Eric J Strobel
- Department of Biological Sciences, The University at Buffalo, Buffalo, NY, United States.
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18
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Zhang Y, Han W, Wang L, Wang H, Jia Q, Chen T, Wang S, Li M. Correlative Escherichia coli Transcription Rate and Bubble Conformation Remodeled by NusA and NusG. J Phys Chem B 2023; 127:2909-2917. [PMID: 36977198 DOI: 10.1021/acs.jpcb.2c08771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Transcription is highly regulated by a variety of transcription factors, among which NusA and NusG act contradictorily in Escherichia coli (E. coli) that NusA stabilizes a paused RNA polymerase (RNAP) and NusG suppresses it. The mechanism of the NusA and NusG regulations on RNAP transcription has been addressed, but their effect on the conformational changes of the transcription bubble correlated with transcription kinetics remains elusive. By using single-molecule magnetic trap, we identify a reduction in the transcription rate of ∼40% events by NusA. Although the rest ∼60% of transcription events exhibit unaffected transcription rates, a NusA-enhanced standard deviation of the transcription rate is observed. NusA remodeling also increases the extent of DNA unwinding in the transcription bubble by 1-2 base pairs, which can be reduced by NusG. The NusG remodeling is more significant on the RNAP molecules with reduced transcription rates rather than those without. Our results provide a quantitative view on the mechanisms of transcriptional regulation by NusA and NusG factors.
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Affiliation(s)
- Yuqiong Zhang
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Weijing Han
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Lisha Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Hao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qi Jia
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Tongsheng Chen
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
| | - Shuang Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ming Li
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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19
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Ahmad E, Mitra A, Ahmed W, Mahapatra V, Hegde SR, Sala C, Cole ST, Nagaraja V. Rho-dependent transcription termination is the dominant mechanism in Mycobacterium tuberculosis. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194923. [PMID: 36822574 DOI: 10.1016/j.bbagrm.2023.194923] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/31/2023] [Accepted: 02/14/2023] [Indexed: 02/24/2023]
Abstract
Intrinsic and Rho-dependent transcription termination mechanisms regulate gene expression and recycle RNA polymerase in bacteria. Both the modes are well studied in Escherichia coli, and a few other organisms. The understanding of Rho function is limited in most other bacteria including mycobacteria. Here, we highlight the dominance of Rho-dependent termination in mycobacteria and validate Rho as a key regulatory factor. The lower abundance of intrinsic terminators, high cellular levels of Rho, and its genome-wide association with a majority of transcriptionally active genes indicate the pronounced role of Rho-mediated termination in Mycobacterium tuberculosis (Mtb). Rho modulates the termination of RNA synthesis for both protein-coding and stable RNA genes in Mtb. Concordantly, the depletion of Rho in mycobacteria impact its growth and enhances the transcription read-through at 3' ends of the transcription units. We demonstrate that MtbRho is catalytically active in the presence of RNA with varied secondary structures. These properties suggest an evolutionary adaptation of Rho as the efficient and preponderant mode of transcription termination in mycobacteria.
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Affiliation(s)
- Ezaz Ahmad
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Varsha Mahapatra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Shubhada R Hegde
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru 560100, India
| | - Claudia Sala
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, 53100 Siena, Italy
| | | | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India.
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20
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Wang X, N MPA, Jeon HJ, He J, Lim HM. Identification of a Rho-Dependent Termination Site In Vivo Using Synthetic Small RNA. Microbiol Spectr 2023; 11:e0395022. [PMID: 36651730 PMCID: PMC9927376 DOI: 10.1128/spectrum.03950-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023] Open
Abstract
Rho promotes Rho-dependent termination (RDT) at the Rho-dependent terminator, producing a variable-length region without secondary structure at the 3' end of mRNA. Determining the exact RDT site in vivo is challenging, because the 3' end of mRNA is rapidly removed after RDT by 3'-to-5' exonuclease processing. Here, we applied synthetic small RNA (sysRNA) to identify the RDT region in vivo by exploiting its complementary base-pairing ability to target mRNA. Through the combined analyses of rapid amplification of cDNA 3' ends, primer extension, and capillary electrophoresis, we could precisely map and quantify mRNA 3' ends. We found that complementary double-stranded RNA (dsRNA) formed between sysRNA and mRNA was efficiently cleaved by RNase III in the middle of the dsRNA region. The formation of dsRNA appeared to protect the cleaved RNA 3' ends from rapid degradation by 3'-to-5' exonuclease, thereby stabilizing the mRNA 3' end. We further verified that the signal intensity at the 3' end was positively correlated with the amount of mRNA. By constructing a series of sysRNAs with close target sites and comparing the difference in signal intensity at the 3' end of wild-type and Rho-impaired strains, we finally identified a region of increased mRNA expression within the 21-bp range, which was determined as the RDT region. Our results demonstrated the ability to use sysRNA as a novel tool to identify RDT regions in vivo and expand the range of applications of sysRNA. IMPORTANCE sysRNA, which was formerly widely employed, has steadily lost popularity as more novel techniques for suppressing gene expression come into existence because of issues such as unstable inhibition effect and low inhibition efficiency. However, it remains an interesting topic as a regulatory tool due to its ease of design and low metabolic burden on cells. Here, for the first time, we discovered a new method to identify RDT regions in vivo using sysRNA. This new feature is important because since the discovery of the Rho protein in 1969, specific identification of RDT sites in vivo has been difficult due to the rapid processing of RNA 3' ends by exonucleases, and sysRNA might provide a new approach to address this challenge.
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Affiliation(s)
- Xun Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People’s Republic of China
| | - Monford Paul Abishek N
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Heung Jin Jeon
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
- Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People’s Republic of China
| | - Heon M. Lim
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
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21
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Murayama Y, Ehara H, Aoki M, Goto M, Yokoyama T, Sekine SI. Structural basis of the transcription termination factor Rho engagement with transcribing RNA polymerase from Thermus thermophilus. SCIENCE ADVANCES 2023; 9:eade7093. [PMID: 36753546 PMCID: PMC9908020 DOI: 10.1126/sciadv.ade7093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Transcription termination is an essential step in transcription by RNA polymerase (RNAP) and crucial for gene regulation. For many bacterial genes, transcription termination is mediated by the adenosine triphosphate-dependent RNA translocase/helicase Rho, which causes RNA/DNA dissociation from the RNAP elongation complex (EC). However, the structural basis of the interplay between Rho and RNAP remains obscure. Here, we report the cryo-electron microscopy structure of the Thermus thermophilus RNAP EC engaged with Rho. The Rho hexamer binds RNAP through the carboxyl-terminal domains, which surround the RNA exit site of RNAP, directing the nascent RNA seamlessly from the RNA exit to its central channel. The β-flap tip at the RNA exit is critical for the Rho-dependent RNA release, and its deletion causes an alternative Rho-RNAP binding mode, which is irrelevant to termination. The Rho binding site overlaps with the binding sites of other macromolecules, such as ribosomes, providing a general basis of gene regulation.
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Affiliation(s)
- Yuko Murayama
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mari Aoki
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mie Goto
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takeshi Yokoyama
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shun-ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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22
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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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23
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Termination factor Rho mediates transcriptional reprogramming of Bacillus subtilis stationary phase. PLoS Genet 2023; 19:e1010618. [PMID: 36735730 PMCID: PMC9931155 DOI: 10.1371/journal.pgen.1010618] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/15/2023] [Accepted: 01/14/2023] [Indexed: 02/04/2023] Open
Abstract
Transcription termination factor Rho is known for its ubiquitous role in suppression of pervasive, mostly antisense, transcription. In the model Gram-positive bacterium Bacillus subtilis, de-repression of pervasive transcription by inactivation of rho revealed the role of Rho in the regulation of post-exponential differentiation programs. To identify other aspects of the regulatory role of Rho during adaptation to starvation, we have constructed a B. subtilis strain (Rho+) that expresses rho at a relatively stable high level in order to compensate for its decrease in the wild-type cells entering stationary phase. The RNAseq analysis of Rho+, WT and Δrho strains (expression profiles can be visualized at http://genoscapist.migale.inrae.fr/seb_rho/) shows that Rho over-production enhances the termination efficiency of Rho-sensitive terminators, thus reducing transcriptional read-through and antisense transcription genome-wide. Moreover, the Rho+ strain exhibits global alterations of sense transcription with the most significant changes observed for the AbrB, CodY, and stringent response regulons, forming the pathways governing the transition to stationary phase. Subsequent physiological analyses demonstrated that maintaining rho expression at a stable elevated level modifies stationary phase-specific physiology of B. subtilis cells, weakens stringent response, and thereby negatively affects the cellular adaptation to nutrient limitations and other stresses, and blocks the development of genetic competence and sporulation. These results highlight the Rho-specific termination of transcription as a novel element controlling stationary phase. The release of this control by decreasing Rho levels during the transition to stationary phase appears crucial for the functionality of complex gene networks ensuring B. subtilis survival in stationary phase.
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24
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Structural basis of Rho-dependent transcription termination. Nature 2023; 614:367-374. [PMID: 36697824 PMCID: PMC9911385 DOI: 10.1038/s41586-022-05658-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/14/2022] [Indexed: 01/26/2023]
Abstract
Rho is a ring-shaped hexameric ATP-dependent molecular motor. Together with the transcription elongation factor NusG, Rho mediates factor-dependent transcription termination and transcription-translation-coupling quality control in Escherichia coli1-4. Here we report the preparation of complexes that are functional in factor-dependent transcription termination from Rho, NusG, RNA polymerase (RNAP), and synthetic nucleic acid scaffolds, and we report cryogenic electron microscopy structures of the complexes. The structures show that functional factor-dependent pre-termination complexes contain a closed-ring Rho hexamer; have RNA threaded through the central channel of Rho; have 60 nucleotides of RNA interacting sequence-specifically with the exterior of Rho and 6 nucleotides of RNA interacting sequence-specifically with the central channel of Rho; have Rho oriented relative to RNAP such that ATP-dependent translocation by Rho exerts mechanical force on RNAP; and have NusG bridging Rho and RNAP. The results explain five decades of research on Rho and provide a foundation for understanding Rho's function.
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25
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Protein structure terminates doubt about how transcription stops. Nature 2023; 614:237-238. [PMID: 36697726 DOI: 10.1038/d41586-023-00121-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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26
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Morichaud Z, Trapani S, Vishwakarma RK, Chaloin L, Lionne C, Lai-Kee-Him J, Bron P, Brodolin K. Structural basis of the mycobacterial stress-response RNA polymerase auto-inhibition via oligomerization. Nat Commun 2023; 14:484. [PMID: 36717560 PMCID: PMC9886945 DOI: 10.1038/s41467-023-36113-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 01/16/2023] [Indexed: 01/31/2023] Open
Abstract
Self-assembly of macromolecules into higher-order symmetric structures is fundamental for the regulation of biological processes. Higher-order symmetric structure self-assembly by the gene expression machinery, such as bacterial DNA-dependent RNA polymerase (RNAP), has never been reported before. Here, we show that the stress-response σB factor from the human pathogen, Mycobacterium tuberculosis, induces the RNAP holoenzyme oligomerization into a supramolecular complex composed of eight RNAP units. Cryo-electron microscopy revealed a pseudo-symmetric structure of the RNAP octamer in which RNAP protomers are captured in an auto-inhibited state and display an open-clamp conformation. The structure shows that σB is sequestered by the RNAP flap and clamp domains. The transcriptional activator RbpA prevented octamer formation by promoting the initiation-competent RNAP conformation. Our results reveal that a non-conserved region of σ is an allosteric controller of transcription initiation and demonstrate how basal transcription factors can regulate gene expression by modulating the RNAP holoenzyme assembly and hibernation.
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Affiliation(s)
- Zakia Morichaud
- Institut de Recherche en Infectiologie de Montpellier, Univ Montpellier, CNRS, Montpellier, 34293, France
| | - Stefano Trapani
- Centre de Biologie Structurale, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Rishi K Vishwakarma
- Institut de Recherche en Infectiologie de Montpellier, Univ Montpellier, CNRS, Montpellier, 34293, France.,Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Laurent Chaloin
- Institut de Recherche en Infectiologie de Montpellier, Univ Montpellier, CNRS, Montpellier, 34293, France
| | - Corinne Lionne
- Centre de Biologie Structurale, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | | | - Patrick Bron
- Centre de Biologie Structurale, Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Konstantin Brodolin
- Institut de Recherche en Infectiologie de Montpellier, Univ Montpellier, CNRS, Montpellier, 34293, France. .,INSERM, Montpellier, France.
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27
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Petroni E, Esnault C, Tetreault D, Dale RK, Storz G, Adams PP. Extensive diversity in RNA termination and regulation revealed by transcriptome mapping for the Lyme pathogen B. burgdorferi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522626. [PMID: 36712141 PMCID: PMC9881889 DOI: 10.1101/2023.01.04.522626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Transcription termination is an essential and dynamic process that can tune gene expression in response to diverse molecular signals. Yet, the genomic positions, molecular mechanisms, and regulatory consequences of termination have only been studied thoroughly in model bacteria. We employed complementary RNA-seq approaches to map RNA ends for the transcriptome of the spirochete Borrelia burgdorferi - the etiological agent of Lyme disease. By systematically mapping B. burgdorferi RNA ends at single nucleotide resolution, we delineated complex gene arrangements and operons and mapped untranslated regions (UTRs) and small RNAs (sRNAs). We experimentally tested modes of B. burgdorferi transcription termination and compared our findings to observations in E. coli , P. aeruginosa , and B. subtilis . We discovered 63% of B. burgdorferi RNA 3' ends map upstream or internal to open reading frames (ORFs), suggesting novel mechanisms of regulation. Northern analysis confirmed the presence of stable 5' derived RNAs from mRNAs encoding gene products involved in the unique infectious cycle of B. burgdorferi . We suggest these RNAs resulted from premature termination and regulatory events, including forms of cis- acting regulation. For example, we documented that the polyamine spermidine globally influences the generation of truncated mRNAs. In one case, we showed that high spermidine concentrations increased levels of RNA fragments derived from an mRNA encoding a spermidine import system, with a concomitant decrease in levels of the full- length mRNA. Collectively, our findings revealed new insight into transcription termination and uncovered an abundance of potential RNA regulators.
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Affiliation(s)
- Emily Petroni
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Caroline Esnault
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Daniel Tetreault
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Ryan K. Dale
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Philip P. Adams
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.,Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892, USA.,Independent Research Scholar Program, Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA.,correspondence:
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28
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Abstract
In bacteria, transcription and translation take place in the same cellular compartment. Therefore, a messenger RNA can be translated as it is being transcribed, a process known as transcription-translation coupling. This process was already recognized at the dawn of molecular biology, yet the interplay between the two key players, the RNA polymerase and ribosome, remains elusive. Genetic data indicate that an RNA sequence can be translated shortly after it has been transcribed. The closer both processes are in time, the less accessible the RNA sequence is between the RNA polymerase and ribosome. This temporal coupling has important consequences for gene regulation. Biochemical and structural studies have detailed several complexes between the RNA polymerase and ribosome. The in vivo relevance of this physical coupling has not been formally demonstrated. We discuss how both temporal and physical coupling may mesh to produce the phenomenon we know as transcription-translation coupling.
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Affiliation(s)
- Gregor M Blaha
- Department of Biochemistry, University of California, Riverside, California, USA;
| | - Joseph T Wade
- Wadsworth Center, New York State Department of Health, Albany, New York, USA;
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
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29
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Intrinsic and Rho-dependent termination cooperate for efficient transcription termination at 3’ untranslated regions. Biochem Biophys Res Commun 2022; 628:123-132. [DOI: 10.1016/j.bbrc.2022.08.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/10/2022] [Accepted: 08/22/2022] [Indexed: 11/22/2022]
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30
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Mandell ZF, Vishwakarma RK, Yakhnin H, Murakami KS, Kashlev M, Babitzke P. Comprehensive transcription terminator atlas for Bacillus subtilis. Nat Microbiol 2022; 7:1918-1931. [PMID: 36192538 PMCID: PMC10024249 DOI: 10.1038/s41564-022-01240-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/26/2022] [Indexed: 01/12/2023]
Abstract
The transcriptome-wide contributions of Rho-dependent and intrinsic (Rho-independent) transcription termination mechanisms in bacteria are unclear. By sequencing released transcripts in a wild-type strain and strains containing deficiencies in NusA, NusG and/or Rho (10 strains), we produced an atlas of terminators for the model Gram-positive bacterium Bacillus subtilis. We found that NusA and NusG stimulate 77% and 19% of all intrinsic terminators, respectively, and that both proteins participate in Rho-dependent termination. We also show that Rho stimulates termination at 10% of the intrinsic terminators in vivo. We recapitulated Rho-stimulated intrinsic termination at 5 terminators in vitro and found that Rho requires the KOW domain of NusG to stimulate this process at one of these terminators. Computational analyses of our atlas using RNAstructure, MEME suite and DiffLogo, combined with in vitro transcription experiments, revealed that Rho stimulates intrinsic terminators with weak hairpins and/or U-rich tracts by remodelling the RNA upstream of the intrinsic terminator to prevent the formation of RNA structures that could otherwise compete with the terminator hairpin. We also identified 56 putative examples of 'hybrid Rho-dependent termination', wherein classical Rho-dependent termination occurs after readthrough of a Rho-stimulated intrinsic terminator.
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Affiliation(s)
- Zachary F Mandell
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
- Department of Molecular Biology and Genetics and Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Rishi K Vishwakarma
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Helen Yakhnin
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Mikhail Kashlev
- NCI RNA Biology Laboratory, Center for Cancer Research, NCI, Frederick, MD, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA.
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31
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Dey S, Batisse C, Shukla J, Webster MW, Takacs M, Saint-André C, Weixlbaumer A. Structural insights into RNA-mediated transcription regulation in bacteria. Mol Cell 2022; 82:3885-3900.e10. [DOI: 10.1016/j.molcel.2022.09.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/07/2022] [Accepted: 09/19/2022] [Indexed: 11/06/2022]
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32
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Yin Z, Bird JG, Kaelber JT, Nickels BE, Ebright RH. In transcription antitermination by Qλ, NusA induces refolding of Qλ to form a nozzle that extends the RNA polymerase RNA-exit channel. Proc Natl Acad Sci U S A 2022; 119:e2205278119. [PMID: 35951650 PMCID: PMC9388147 DOI: 10.1073/pnas.2205278119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/08/2022] [Indexed: 01/24/2023] Open
Abstract
Lambdoid bacteriophage Q proteins are transcription antipausing and antitermination factors that enable RNA polymerase (RNAP) to read through pause and termination sites. Q proteins load onto RNAP engaged in promoter-proximal pausing at a Q binding element (QBE) and adjacent sigma-dependent pause element to yield a Q-loading complex, and they translocate with RNAP as a pausing-deficient, termination-deficient Q-loaded complex. In previous work, we showed that the Q protein of bacteriophage 21 (Q21) functions by forming a nozzle that narrows and extends the RNAP RNA-exit channel, preventing formation of pause and termination RNA hairpins. Here, we report atomic structures of four states on the pathway of antitermination by the Q protein of bacteriophage λ (Qλ), a Q protein that shows no sequence similarity to Q21 and that, unlike Q21, requires the transcription elongation factor NusA for efficient antipausing and antitermination. We report structures of Qλ, the Qλ-QBE complex, the NusA-free pre-engaged Qλ-loading complex, and the NusA-containing engaged Qλ-loading complex. The results show that Qλ, like Q21, forms a nozzle that narrows and extends the RNAP RNA-exit channel, preventing formation of RNA hairpins. However, the results show that Qλ has no three-dimensional structural similarity to Q21, employs a different mechanism of QBE recognition than Q21, and employs a more complex process for loading onto RNAP than Q21, involving recruitment of Qλ to form a pre-engaged loading complex, followed by NusA-facilitated refolding of Qλ to form an engaged loading complex. The results establish that Qλ and Q21 are not structural homologs and are solely functional analogs.
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Affiliation(s)
- Zhou Yin
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Jeremy G. Bird
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Jason T. Kaelber
- Rutgers Cryo-EM and Nanoimaging Facility, Rutgers University, Piscataway, NJ 08854
| | - Bryce E. Nickels
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Richard H. Ebright
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
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33
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Marshall CJ, Qayyum MZ, Walker JE, Murakami KS, Santangelo TJ. The structure and activities of the archaeal transcription termination factor Eta detail vulnerabilities of the transcription elongation complex. Proc Natl Acad Sci U S A 2022; 119:e2207581119. [PMID: 35917344 PMCID: PMC9371683 DOI: 10.1073/pnas.2207581119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Transcription must be properly regulated to ensure dynamic gene expression underlying growth, development, and response to environmental cues. Regulation is imposed throughout the transcription cycle, and while many efforts have detailed the regulation of transcription initiation and early elongation, the termination phase of transcription also plays critical roles in regulating gene expression. Transcription termination can be driven by only a few proteins in each domain of life. Detailing the mechanism(s) employed provides insight into the vulnerabilities of transcription elongation complexes (TECs) that permit regulated termination to control expression of many genes and operons. Here, we describe the biochemical activities and crystal structure of the superfamily 2 helicase Eta, one of two known factors capable of disrupting archaeal transcription elongation complexes. Eta retains a twin-translocase core domain common to all superfamily 2 helicases and a well-conserved C terminus wherein individual amino acid substitutions can critically abrogate termination activities. Eta variants that perturb ATPase, helicase, single-stranded DNA and double-stranded DNA translocase and termination activities identify key regions of the C terminus of Eta that, when combined with modeling Eta-TEC interactions, provide a structural model of Eta-mediated termination guided in part by structures of Mfd and the bacterial TEC. The susceptibility of TECs to disruption by termination factors that target the upstream surface of RNA polymerase and potentially drive termination through forward translocation and allosteric mechanisms that favor opening of the clamp to release the encapsulated nucleic acids emerges as a common feature of transcription termination mechanisms.
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Affiliation(s)
- Craig J. Marshall
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - M. Zuhaib Qayyum
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Julie E. Walker
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Katsuhiko S. Murakami
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
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34
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Mandell ZF, Zemba D, Babitzke P. Factor-stimulated intrinsic termination: getting by with a little help from some friends. Transcription 2022; 13:96-108. [PMID: 36154805 PMCID: PMC9715273 DOI: 10.1080/21541264.2022.2127602] [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: 07/11/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 01/12/2023] Open
Abstract
Transcription termination is known to occur via two mechanisms in bacteria, intrinsic termination (also frequently referred to as Rho-independent or factor-independent termination) and Rho-dependent termination. Based primarily on in vitro studies using Escherichia coli RNA polymerase, it was generally assumed that intrinsic termination and Rho-dependent termination are distinct mechanisms and that the signals required for intrinsic termination are present primarily within the nucleic acids. In this review, we detail recent findings from studies in Bacillus subtilis showing that intrinsic termination in this organism is highly stimulated by NusA, NusG, and even Rho. In NusA-stimulated intrinsic termination, NusA facilitates the formation of weak terminator hairpins and compensates for distal U-rich tract interruptions. In NusG-stimulated intrinsic termination, NusG stabilizes a sequence-dependent pause at the point of termination, which extends the time frame for RNA hairpins with weak terminal base pairs to form in either a NusA-stimulated or a NusA-independent fashion. In Rho-stimulated intrinsic termination, Rho prevents the formation of antiterminator-like RNA structures that could otherwise compete with the terminator hairpin. Combined, NusA, NusG, and Rho stimulate approximately 97% of all intrinsic terminators in B. subtilis. Thus, the general view that intrinsic termination is primarily a factor-independent process needs to be revised to account for recent findings. Moreover, the historical distinction between Rho-dependent and intrinsic termination is overly simplistic and needs to be modernized.
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Affiliation(s)
- Zachary F. Mandell
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States
- Department of Molecular Biology and Genetics and Department of Biology, Johns Hopkins University, Baltimore, MD, United State
| | - Dani Zemba
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States
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35
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Mohamed AA, Vazquez Nunez R, Vos SM. Structural advances in transcription elongation. Curr Opin Struct Biol 2022; 75:102422. [PMID: 35816930 DOI: 10.1016/j.sbi.2022.102422] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/22/2022] [Accepted: 06/02/2022] [Indexed: 11/03/2022]
Abstract
Transcription is the first step of gene expression and involves RNA polymerases. After transcription initiation, RNA polymerase enters elongation followed by transcription termination at the end of the gene. Only recently, structures of transcription elongation complexes bound to key transcription elongation factors have been determined in bacterial and eukaryotic systems. These structures have revealed numerous insights including the basis for transcriptional pausing, RNA polymerase interaction with large complexes such as the ribosome and the spliceosome, and the transition into productive elongation. Here, we review these structures and describe areas for future research.
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Affiliation(s)
- Abdallah A Mohamed
- Massachusetts Institute of Technology, Department of Biology, 31 Ames St., Cambridge, MA 02142, USA. https://twitter.com/AMohamed_98
| | - Roberto Vazquez Nunez
- Massachusetts Institute of Technology, Department of Biology, 31 Ames St., Cambridge, MA 02142, USA. https://twitter.com/rjareth
| | - Seychelle M Vos
- Massachusetts Institute of Technology, Department of Biology, 31 Ames St., Cambridge, MA 02142, USA.
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36
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Molina JA, Galaz-Davison P, Komives EA, Artsimovitch I, Ramírez-Sarmiento CA. Allosteric couplings upon binding of RfaH to transcription elongation complexes. Nucleic Acids Res 2022; 50:6384-6397. [PMID: 35670666 PMCID: PMC9226497 DOI: 10.1093/nar/gkac453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/07/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
In every domain of life, NusG-like proteins bind to the elongating RNA polymerase (RNAP) to support processive RNA synthesis and to couple transcription to ongoing cellular processes. Structures of factor-bound transcription elongation complexes (TECs) reveal similar contacts to RNAP, consistent with a shared mechanism of action. However, NusG homologs differ in their regulatory roles, modes of recruitment, and effects on RNA synthesis. Some of these differences could be due to conformational changes in RNAP and NusG-like proteins, which cannot be captured in static structures. Here, we employed hydrogen-deuterium exchange mass spectrometry to investigate changes in local and non-local structural dynamics of Escherichia coli NusG and its paralog RfaH, which have opposite effects on expression of xenogenes, upon binding to TEC. We found that NusG and RfaH regions that bind RNAP became solvent-protected in factor-bound TECs, whereas RNAP regions that interact with both factors showed opposite deuterium uptake changes when bound to NusG or RfaH. Additional changes far from the factor-binding site were observed only with RfaH. Our results provide insights into differences in structural dynamics exerted by NusG and RfaH during binding to TEC, which may explain their different functional outcomes and allosteric regulation of transcriptional pausing by RfaH.
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Affiliation(s)
- José Alejandro Molina
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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37
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In vivo regulation of bacterial Rho-dependent transcription termination by the nascent RNA. J Biol Chem 2022; 298:102001. [PMID: 35500654 PMCID: PMC9160355 DOI: 10.1016/j.jbc.2022.102001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/23/2022] [Accepted: 04/25/2022] [Indexed: 11/22/2022] Open
Abstract
Bacterial Rho is a RNA-dependent ATPase that functions in the termination of DNA transcription. However, the in vivo nature of the bacterial Rho-dependent terminators, as well as the mechanism of the Rho-dependent termination process, are not fully understood. Here, we measured the in vivo termination efficiencies of 72 Rho-dependent terminators in E. coli by systematically performing qRT-PCR analyses of cDNA prepared from mid-log phase bacterial cultures. We found that these terminators exhibited a wide range of efficiencies, and many behaved differently in vivo compared to the predicted or experimentally determined efficiencies in vitro. Rho-utilization sites (rut sites) present in the RNA terminator sequences are characterized by the presence of C-rich/G-poor sequences, or C>G bubbles. We found that weaker terminators exhibited a robust correlation with the properties (size, length, density, etc.) of these C>G bubbles of their respective rut sites, while stronger terminators lack this correlation, suggesting a limited role of rut sequences in controlling in vivo termination efficiencies. We also found that in vivo termination efficiencies are dependent on the rates of ATP hydrolysis as well as Rho-translocation on the nascent RNA. We demonstrate that weaker terminators, in addition to having rut sites with diminished C>G bubble sizes, are dependent on the Rho-auxiliary factor, NusG, in vivo. From these results, we concluded that in vivo Rho-dependent termination follows a nascent RNA-dependent pathway, where Rho-translocation along the RNA is essential and rut sequences may recruit Rho in vivo, but Rho-rut binding strengths do not regulate termination efficiencies.
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38
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Mittermeier M, Wang B, Said N, Gjorgjevikj D, Wahl MC, Artsimovitch I. A non-native C-terminal extension of the β' subunit compromises RNA polymerase and Rho functions. Mol Microbiol 2022; 117:871-885. [PMID: 35049093 PMCID: PMC9018486 DOI: 10.1111/mmi.14879] [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: 11/16/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 11/30/2022]
Abstract
Escherichia coli RfaH abrogates Rho-mediated polarity in lipopolysaccharide core biosynthesis operons, and ΔrfaH cells are hypersensitive to antibiotics, bile salts, and detergents. Selection for rfaH suppressors that restore growth on SDS identified a temperature-sensitive mutant in which 46 C-terminal residues of the RNA polymerase (RNAP) β' subunit are replaced with 23 residues carrying a net positive charge. Based on similarity to rpoC397, which confers a temperature-sensitive phenotype and resistance to bacteriophages, we named this mutant rpoC397*. We show that SDS resistance depends on a single nonpolar residue within the C397* tail, whereas basic residues are dispensable. In line with its mimicry of RfaH, C397* RNAP is resistant to Rho but responds to pause signals, NusA, and NusG in vitro similarly to the wild-type enzyme and binds to Rho and Nus factors in vivo. Strikingly, the deletion of rpoZ, which encodes the ω "chaperone" subunit, restores rpoC397* growth at 42°C but has no effect on SDS sensitivity. Our results suggest that the C397* tail traps the ω subunit in an inhibitory state through direct contacts and hinders Rho-dependent termination through long-range interactions. We propose that the dynamic and hypervariable β'•ω module controls RNA synthesis in response to niche-specific signals.
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Affiliation(s)
- Maura Mittermeier
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Bing Wang
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Nelly Said
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Daniela Gjorgjevikj
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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39
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Martinez B, Bharati BK, Epshtein V, Nudler E. Pervasive Transcription-coupled DNA repair in E. coli. Nat Commun 2022; 13:1702. [PMID: 35354807 PMCID: PMC8967931 DOI: 10.1038/s41467-022-28871-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 02/14/2022] [Indexed: 11/18/2022] Open
Abstract
Global Genomic Repair (GGR) and Transcription-Coupled Repair (TCR) have been viewed, respectively, as major and minor sub-pathways of the nucleotide excision repair (NER) process that removes bulky lesions from the genome. Here we applied a next generation sequencing assay, CPD-seq, in E. coli to measure the levels of cyclobutane pyrimidine dimer (CPD) lesions before, during, and after UV-induced genotoxic stress, and, therefore, to determine the rate of genomic recovery by NER at a single nucleotide resolution. We find that active transcription is necessary for the repair of not only the template strand (TS), but also the non-template strand (NTS), and that the bulk of TCR is independent of Mfd – a DNA translocase that is thought to be necessary and sufficient for TCR in bacteria. We further show that repair of both TS and NTS is enhanced by increased readthrough past Rho-dependent terminators. We demonstrate that UV-induced genotoxic stress promotes global antitermination so that TCR is more accessible to the antisense, intergenic, and other low transcribed regions. Overall, our data suggest that GGR and TCR are essentially the same process required for complete repair of the bacterial genome. Transcription-Coupled DNA repair has been classically defined as the preferential repair of the template strand (TS) over the non-template strand (NTS). Here the authors challenge this classic model of TCR by using a genome-wide repair assay, CPD-seq, as well as RNA-seq, to show that TCR occurs across the entire E. coli genome – including NTS and intergenic regions.
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Affiliation(s)
- Britney Martinez
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Binod K Bharati
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, 10016, USA.,Howard Hughes Medical Institute, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, 10016, USA. .,Howard Hughes Medical Institute, NYU Grossman School of Medicine, New York, New York, 10016, USA.
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40
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Rho-dependent transcription termination proceeds via three routes. Nat Commun 2022; 13:1663. [PMID: 35351884 PMCID: PMC8964686 DOI: 10.1038/s41467-022-29321-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 03/09/2022] [Indexed: 01/26/2023] Open
Abstract
Rho is a general transcription termination factor in bacteria, but many aspects of its mechanism of action are unclear. Diverse models have been proposed for the initial interaction between the RNA polymerase (RNAP) and Rho (catch-up and stand-by pre-terminational models); for the terminational release of the RNA transcript (RNA shearing, RNAP hyper-translocation or displacing, and allosteric models); and for the post-terminational outcome (whether the RNAP dissociates or remains bound to the DNA). Here, we use single-molecule fluorescence assays to study those three steps in transcription termination mediated by E. coli Rho. We find that different mechanisms previously proposed for each step co-exist, but apparently occur on various timescales and tend to lead to specific outcomes. Our results indicate that three kinetically distinct routes take place: (1) the catch-up mode leads first to RNA shearing for RNAP recycling on DNA, and (2) later to RNAP displacement for decomposition of the transcriptional complex; (3) the last termination usually follows the stand-by mode with displacing for decomposing. This three-route model would help reconcile current controversies on the mechanisms. Rho is a general transcription termination factor in bacteria. Here, Song et al. use single-molecule fluorescence assays to provide evidence that Rho-mediated transcription termination can occur via three kinetically different routes.
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41
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Zhu C, Guo X, Dumas P, Takacs M, Abdelkareem M, Vanden Broeck A, Saint-André C, Papai G, Crucifix C, Ortiz J, Weixlbaumer A. Transcription factors modulate RNA polymerase conformational equilibrium. Nat Commun 2022; 13:1546. [PMID: 35318334 PMCID: PMC8940904 DOI: 10.1038/s41467-022-29148-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 03/01/2022] [Indexed: 01/26/2023] Open
Abstract
RNA polymerase (RNAP) frequently pauses during the transcription of DNA to RNA to regulate gene expression. Transcription factors NusA and NusG modulate pausing, have opposing roles, but can bind RNAP simultaneously. Here we report cryo-EM reconstructions of Escherichia coli RNAP bound to NusG, or NusA, or both. RNAP conformational changes, referred to as swivelling, correlate with transcriptional pausing. NusA facilitates RNAP swivelling to further increase pausing, while NusG counteracts this role. Their structural effects are consistent with biochemical results on two categories of transcriptional pauses. In addition, the structures suggest a cooperative mechanism of NusA and NusG during Rho-mediated transcription termination. Our results provide a structural rationale for the stochastic nature of pausing and termination and how NusA and NusG can modulate it. Pausing of RNA polymerase (RNAP) and transcription is regulated by the NusA and NusG transcription factors in bacteria. Here the authors provide structural evidence for how they interact with RNAP to carry out their pausing roles and also reveal functions for NusA and NusG in transcription termination.
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Affiliation(s)
- Chengjin Zhu
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Xieyang Guo
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France.,GlaxoSmithKline, Gunnels Wood Road, Stevenage, Herts, SG1 2NY, UK
| | - Philippe Dumas
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Maria Takacs
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Mo'men Abdelkareem
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Arnaud Vanden Broeck
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Charlotte Saint-André
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Gabor Papai
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Corinne Crucifix
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France
| | - Julio Ortiz
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France.,Université de Strasbourg, 67404, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France.,Forschungszentrum Jülich, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich, Germany
| | - Albert Weixlbaumer
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404, Illkirch, France. .,Université de Strasbourg, 67404, Illkirch, France. .,Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France. .,Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France.
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42
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RfaH May Oppose Silencing by H-NS and YmoA Proteins during Transcription Elongation. J Bacteriol 2022; 204:e0059921. [PMID: 35258322 DOI: 10.1128/jb.00599-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) silence xenogenes by blocking RNA polymerase binding to promoters and hindering transcript elongation. In Escherichia coli, H-NS and its homolog SptA interact with YmoA proteins Hha and YdgT to assemble nucleoprotein filaments that facilitate transcription termination by Rho, which acts in synergy with NusG. Countersilencing during initiation is facilitated by proteins that exclude NAPs from promoter regions, but auxiliary factors that alleviate silencing during elongation are not known. A specialized NusG paralog, RfaH, activates lipopolysaccharide core biosynthesis operons, enabling survival in the presence of detergents and antibiotics. RfaH strongly inhibits Rho-dependent termination by reducing RNA polymerase pausing, promoting translation, and competing with NusG. We hypothesize that RfaH also acts as a countersilencer of NAP/YmoA filaments. We show that deletions of hns and hha+ydgT suppress the growth defects of ΔrfaH by alleviating Rho-mediated polarity within the waa operon. The absence of YmoA proteins exacerbates cellular defects caused by reduced Rho levels or Rho inhibition by bicyclomycin but has negligible effects at a strong model Rho-dependent terminator. Our findings that the distribution of Hha and RfaH homologs is strongly correlated supports a model in which they comprise a silencing/countersilencing pair that controls expression of chromosomal and plasmid-encoded xenogenes. IMPORTANCE Horizontally acquired DNA drives bacterial evolution, but its unregulated expression may harm the recipient. Xenogeneic silencers recognize foreign genes and inhibit their transcription. However, some xenogenes, such as those encoding lipo- and exopolysaccharides, confer resistance to antibiotics, bile salts, and detergents, necessitating the existence of countersilencing fitness mechanisms. Here, we present evidence that Escherichia coli antiterminator RfaH alleviates silencing of the chromosomal waa operon and propose that plasmid-encoded RfaH homologs promote dissemination of antibiotic resistance genes through conjugation.
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43
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Roles of zinc-binding domain of bacterial RNA polymerase in transcription. Trends Biochem Sci 2022; 47:710-724. [DOI: 10.1016/j.tibs.2022.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/27/2022] [Accepted: 03/07/2022] [Indexed: 01/07/2023]
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44
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Cryo-EM structure of transcription termination factor Rho from Mycobacterium tuberculosis reveals bicyclomycin resistance mechanism. Commun Biol 2022; 5:120. [PMID: 35140348 PMCID: PMC8828861 DOI: 10.1038/s42003-022-03069-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/21/2022] [Indexed: 01/17/2023] Open
Abstract
The bacterial Rho factor is a ring-shaped motor triggering genome-wide transcription termination and R-loop dissociation. Rho is essential in many species, including in Mycobacterium tuberculosis where rho gene inactivation leads to rapid death. Yet, the M. tuberculosis Rho [MtbRho] factor displays poor NTPase and helicase activities, and resistance to the natural Rho inhibitor bicyclomycin [BCM] that remain unexplained. To address these issues, we solved the cryo-EM structure of MtbRho at 3.3 Å resolution. The MtbRho hexamer is poised into a pre-catalytic, open-ring state wherein specific contacts stabilize ATP in intersubunit ATPase pockets, thereby explaining the cofactor preference of MtbRho. We reveal a leucine-to-methionine substitution that creates a steric bulk in BCM binding cavities near the positions of ATP γ-phosphates, and confers resistance to BCM at the expense of motor efficiency. Our work contributes to explain the unusual features of MtbRho and provides a framework for future antibiotic development. Cryo-EM shows that M. tuberculosis Rho-factor adopts an open, ring-shaped hexamer conformation and a steric bulk in the cavity for bicyclomycin binding, which explains resistance to the antibiotic.
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Regulation of Heterogenous LexA Expression in Staphylococcus aureus by an Antisense RNA Originating from Transcriptional Read-Through upon Natural Mispairings in the sbrB Intrinsic Terminator. Int J Mol Sci 2022; 23:ijms23010576. [PMID: 35009002 PMCID: PMC8745188 DOI: 10.3390/ijms23010576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/30/2021] [Accepted: 01/01/2022] [Indexed: 12/10/2022] Open
Abstract
Bacterial genomes are pervasively transcribed, generating a wide variety of antisense RNAs (asRNAs). Many of them originate from transcriptional read-through events (TREs) during the transcription termination process. Previous transcriptome analyses revealed that the lexA gene from Staphylococcus aureus, which encodes the main SOS response regulator, is affected by the presence of an asRNA. Here, we show that the lexA antisense RNA (lexA-asRNA) is generated by a TRE on the intrinsic terminator (TTsbrB) of the sbrB gene, which is located downstream of lexA, in the opposite strand. Transcriptional read-through occurs by a natural mutation that destabilizes the TTsbrB structure and modifies the efficiency of the intrinsic terminator. Restoring the mispairing mutation in the hairpin of TTsbrB prevented lexA-asRNA transcription. The level of lexA-asRNA directly correlated with cellular stress since the expressions of sbrB and lexA-asRNA depend on the stress transcription factor SigB. Comparative analyses revealed strain-specific nucleotide polymorphisms within TTsbrB, suggesting that this TT could be prone to accumulating natural mutations. A genome-wide analysis of TREs suggested that mispairings in TT hairpins might provide wider transcriptional connections with downstream genes and, ultimately, transcriptomic variability among S. aureus strains.
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46
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Suppressor Mutants: History and Today's Applications. EcoSal Plus 2021; 9:eESP00372020. [PMID: 34910591 DOI: 10.1128/ecosalplus.esp-0037-2020] [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: 11/20/2022]
Abstract
For decades, biologist have exploited the near boundless advantages that molecular and genetic tools and analysis provide for our ability to understand biological systems. One of these genetic tools, suppressor analysis, has proven invaluable in furthering our understanding of biological processes and pathways and in discovering unknown interactions between genes and gene products. The power of suppressor analysis lies in its ability to discover genetic interactions in an unbiased manner, often leading to surprising discoveries. With advancements in technology, high-throughput approaches have aided in large-scale identification of suppressors and have helped provide insight into the core functional mechanisms through which suppressors act. In this review, we examine some of the fundamental discoveries that have been made possible through analysis of suppressor mutations. In addition, we cover the different types of suppressor mutants that can be isolated and the biological insights afforded by each type. Moreover, we provide considerations for the design of experiments to isolate suppressor mutants and for strategies to identify intergenic suppressor mutations. Finally, we provide guidance and example protocols for the isolation and mapping of suppressor mutants.
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47
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Abstract
Ring-shaped hexameric helicases are essential motor proteins that separate duplex nucleic acid strands for DNA replication, recombination, and transcriptional regulation. Two evolutionarily distinct lineages of these enzymes, predicated on RecA and AAA+ ATPase folds, have been identified and characterized to date. Hexameric helicases couple NTP hydrolysis with conformational changes that move nucleic acid substrates through a central pore in the enzyme. How hexameric helicases productively engage client DNA or RNA segments and use successive rounds of NTPase activity to power translocation and unwinding have been longstanding questions in the field. Recent structural and biophysical findings are beginning to reveal commonalities in NTP hydrolysis and substrate translocation by diverse hexameric helicase families. Here, we review these molecular mechanisms and highlight aspects of their function that are yet to be understood.
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48
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Dynamic competition between a ligand and transcription factor NusA governs riboswitch-mediated transcription regulation. Proc Natl Acad Sci U S A 2021; 118:2109026118. [PMID: 34782462 DOI: 10.1073/pnas.2109026118] [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] [Accepted: 10/11/2021] [Indexed: 11/18/2022] Open
Abstract
Cotranscriptional RNA folding is widely assumed to influence the timely control of gene expression, but our understanding remains limited. In bacteria, the fluoride (F-)-sensing riboswitch is a transcriptional control element essential to defend against toxic F- levels. Using this model riboswitch, we find that its ligand F- and essential bacterial transcription factor NusA compete to bind the cotranscriptionally folding RNA, opposing each other's modulation of downstream pausing and termination by RNA polymerase. Single-molecule fluorescence assays probing active transcription elongation complexes discover that NusA unexpectedly binds highly reversibly, frequently interrogating the complex for emerging, cotranscriptionally folding RNA duplexes. NusA thus fine-tunes the transcription rate in dependence of the ligand-responsive higher-order structure of the riboswitch. At the high NusA concentrations found intracellularly, this dynamic modulation is expected to lead to adaptive bacterial transcription regulation with fast response times.
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49
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Qayyum MZ, Molodtsov V, Renda A, Murakami KS. Structural basis of RNA polymerase recycling by the Swi2/Snf2 family of ATPase RapA in Escherichia coli. J Biol Chem 2021; 297:101404. [PMID: 34774797 PMCID: PMC8666675 DOI: 10.1016/j.jbc.2021.101404] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 11/02/2021] [Accepted: 11/09/2021] [Indexed: 01/27/2023] Open
Abstract
After transcription termination, cellular RNA polymerases (RNAPs) are occasionally trapped on DNA, impounded in an undefined post-termination complex (PTC), limiting the free RNAP pool and subsequently leading to inefficient transcription. In Escherichia coli, a Swi2/Snf2 family of ATPase called RapA is known to be involved in countering such inefficiency through RNAP recycling; however, the precise mechanism of this recycling is unclear. To better understand its mechanism, here we determined the structures of two sets of E. coli RapA–RNAP complexes, along with the RNAP core enzyme and the elongation complex, using cryo-EM. These structures revealed the large conformational changes of RNAP and RapA upon their association that has been implicated in the hindrance of PTC formation. Our results along with DNA-binding assays reveal that although RapA binds RNAP away from the DNA-binding main channel, its binding can allosterically close the RNAP clamp, thereby preventing its nonspecific DNA binding and PTC formation. Taken together, we propose that RapA acts as a guardian of RNAP by which RapA prevents nonspecific DNA binding of RNAP without affecting the binding of promoter DNA recognition σ factor, thereby enhancing RNAP recycling.
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Affiliation(s)
- M Zuhaib Qayyum
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Vadim Molodtsov
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew Renda
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Center for Structural Biology, Pennsylvania State University, University Park, Pennsylvania, USA.
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Abstract
To exert their functions, RNAs adopt diverse structures, ranging from simple secondary to complex tertiary and quaternary folds. In vivo, RNA folding starts with RNA transcription, and a wide variety of processes are coupled to co-transcriptional RNA folding events, including the regulation of fundamental transcription dynamics, gene regulation by mechanisms like attenuation, RNA processing or ribonucleoprotein particle formation. While co-transcriptional RNA folding and associated co-transcriptional processes are by now well accepted as pervasive regulatory principles in all organisms, investigations into the role of the transcription machinery in co-transcriptional folding processes have so far largely focused on effects of the order in which RNA regions are produced and of transcription kinetics. Recent structural and structure-guided functional analyses of bacterial transcription complexes increasingly point to an additional role of RNA polymerase and associated transcription factors in supporting co-transcriptional RNA folding by fostering or preventing strategic contacts to the nascent transcripts. In general, the results support the view that transcription complexes can act as RNA chaperones, a function that has been suggested over 30 years ago. Here, we discuss transcription complexes as RNA chaperones based on recent examples from bacterial transcription.
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Affiliation(s)
- Nelly Said
- Freie Universität Berlin, Department Biology, Chemistry, Pharmacy, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany
| | - Markus C Wahl
- Freie Universität Berlin, Department Biology, Chemistry, Pharmacy, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Berlin, Germany.,Helmholtz-Zentrum Berlin Für Materialien Und Energie, Macromolecular Crystallography, Berlin, Germany
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