1
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Fang C, Huang K, Wu X, Zhang H, Gu Z, Wang J, Zhang Y. Transcription elongation of the plant RNA polymerase IV is prone to backtracking. SCIENCE ADVANCES 2024; 10:eadq3087. [PMID: 39178250 PMCID: PMC11343019 DOI: 10.1126/sciadv.adq3087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/22/2024] [Indexed: 08/25/2024]
Abstract
RNA polymerase IV (Pol IV) forms a complex with RNA-directed RNA polymerase 2 (RDR2) to produce double-stranded RNA (dsRNA) precursors essential for plant gene silencing. In the "backtracking-triggered RNA channeling" model, Pol IV backtracks and delivers its transcript's 3' terminus to RDR2, which synthesizes dsRNA. However, the mechanisms underlying Pol IV backtracking and RNA protection from cleavage are unclear. Here, we determined cryo-electron microscopy structures of Pol IV elongation complexes at four states of its nucleotide addition cycle (NAC): posttranslocation, guanosine triphosphate-bound, pretranslocation, and backtracked states. The structures reveal that Pol IV maintains an open DNA cleft and kinked bridge helix in all NAC states, loosely interacts with the nucleoside triphosphate substrate, and barely contacts proximal backtracked nucleotides. Biochemical data indicate that Pol IV is inefficient in forward translocation and RNA cleavage. These findings suggest that Pol IV transcription elongation is prone to backtracking and incapable of RNA hydrolysis, ensuring efficient dsRNA production by Pol IV-RDR2.
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Affiliation(s)
- Chengli Fang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Kun Huang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Xiaoxian Wu
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hongwei Zhang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhanxi Gu
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiawei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, 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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2
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Nova IC, Craig JM, Mazumder A, Laszlo AH, Derrington IM, Noakes MT, Brinkerhoff H, Yang S, Vahedian-Movahed H, Li L, Zhang Y, Bowman JL, Huang JR, Mount JW, Ebright RH, Gundlach JH. Nanopore tweezers show fractional-nucleotide translocation in sequence-dependent pausing by RNA polymerase. Proc Natl Acad Sci U S A 2024; 121:e2321017121. [PMID: 38990947 PMCID: PMC11260103 DOI: 10.1073/pnas.2321017121] [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: 11/30/2023] [Accepted: 05/23/2024] [Indexed: 07/13/2024] Open
Abstract
RNA polymerases (RNAPs) carry out the first step in the central dogma of molecular biology by transcribing DNA into RNA. Despite their importance, much about how RNAPs work remains unclear, in part because the small (3.4 Angstrom) and fast (~40 ms/nt) steps during transcription were difficult to resolve. Here, we used high-resolution nanopore tweezers to observe the motion of single Escherichia coli RNAP molecules as it transcribes DNA ~1,000 times improved temporal resolution, resolving single-nucleotide and fractional-nucleotide steps of individual RNAPs at saturating nucleoside triphosphate concentrations. We analyzed RNAP during processive transcription elongation and sequence-dependent pausing at the yrbL elemental pause sequence. Each time RNAP encounters the yrbL elemental pause sequence, it rapidly interconverts between five translocational states, residing predominantly in a half-translocated state. The kinetics and force-dependence of this half-translocated state indicate it is a functional intermediate between pre- and post-translocated states. Using structural and kinetics data, we show that, in the half-translocated and post-translocated states, sequence-specific protein-DNA interaction occurs between RNAP and a guanine base at the downstream end of the transcription bubble (core recognition element). Kinetic data show that this interaction stabilizes the half-translocated and post-translocated states relative to the pre-translocated state. We develop a kinetic model for RNAP at the yrbL pause and discuss this in the context of key structural features.
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Affiliation(s)
- Ian C. Nova
- Department of Physics, University of Washington, Seattle, WA98195
| | | | - Abhishek Mazumder
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ08854
| | - Andrew H. Laszlo
- Department of Physics, University of Washington, Seattle, WA98195
| | | | | | | | - Shuya Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ08854
| | | | - Lingting Li
- Key Laboratory of Synthetic Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai200032, China
| | | | - Jesse R. Huang
- Department of Physics, University of Washington, Seattle, WA98195
| | | | - Richard H. Ebright
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ08854
| | - Jens H. Gundlach
- Department of Physics, University of Washington, Seattle, WA98195
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3
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Hosseini SH, Roussel MR. Analytic delay distributions for a family of gene transcription models. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2024; 21:6225-6262. [PMID: 39176425 DOI: 10.3934/mbe.2024273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2024]
Abstract
Models intended to describe the time evolution of a gene network must somehow include transcription, the DNA-templated synthesis of RNA, and translation, the RNA-templated synthesis of proteins. In eukaryotes, the DNA template for transcription can be very long, often consisting of tens of thousands of nucleotides, and lengthy pauses may punctuate this process. Accordingly, transcription can last for many minutes, in some cases hours. There is a long history of introducing delays in gene expression models to take the transcription and translation times into account. Here we study a family of detailed transcription models that includes initiation, elongation, and termination reactions. We establish a framework for computing the distribution of transcription times, and work out these distributions for some typical cases. For elongation, a fixed delay is a good model provided elongation is fast compared to initiation and termination, and there are no sites where long pauses occur. The initiation and termination phases of the model then generate a nontrivial delay distribution, and elongation shifts this distribution by an amount corresponding to the elongation delay. When initiation and termination are relatively fast, the distribution of elongation times can be approximated by a Gaussian. A convolution of this Gaussian with the initiation and termination time distributions gives another analytic approximation to the transcription time distribution. If there are long pauses during elongation, because of the modularity of the family of models considered, the elongation phase can be partitioned into reactions generating a simple delay (elongation through regions where there are no long pauses), and reactions whose distribution of waiting times must be considered explicitly (initiation, termination, and motion through regions where long pauses are likely). In these cases, the distribution of transcription times again involves a nontrivial part and a shift due to fast elongation processes.
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Affiliation(s)
- S Hossein Hosseini
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Marc R Roussel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
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4
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Midha T, Mallory JD, Kolomeisky AB, Igoshin OA. Synergy among Pausing, Intrinsic Proofreading, and Accessory Proteins Results in Optimal Transcription Speed and Tolerable Accuracy. J Phys Chem Lett 2023; 14:3422-3429. [PMID: 37010247 DOI: 10.1021/acs.jpclett.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Cleavage of dinucleotides after the misincorporational pauses serves as a proofreading mechanism that increases transcriptional elongation accuracy. The accuracy is further improved by accessory proteins such as GreA and TFIIS. However, it is not clear why RNAP pauses and why cleavage-factor-assisted proofreading is necessary despite transcriptional errors in vitro being of the same order as those in downstream translation. Here, we developed a chemical-kinetic model that incorporates most relevant features of transcriptional proofreading and uncovers how the balance between speed and accuracy is achieved. We found that long pauses are essential for high accuracy, whereas cleavage-factor-stimulated proofreading optimizes speed. Moreover, in comparison to the cleavage of a single nucleotide or three nucleotides, RNAP backtracking and dinucleotide cleavage improve both speed and accuracy. Our results thereby show how the molecular mechanism and the kinetic parameters of the transcriptional process were evolutionarily optimized to achieve maximal speed and tolerable accuracy.
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Affiliation(s)
- Tripti Midha
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Joel D Mallory
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Oleg A Igoshin
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
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5
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Johnson RS, Strausbauch M, McCloud C. An NTP-driven mechanism for the nucleotide addition cycle of Escherichia coli RNA polymerase during transcription. PLoS One 2022; 17:e0273746. [PMID: 36282801 PMCID: PMC9595533 DOI: 10.1371/journal.pone.0273746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/15/2022] [Indexed: 11/06/2022] Open
Abstract
The elementary steps of transcription as catalyzed by E. coli RNA polymerase during one and two rounds of the nucleotide addition cycle (NAC) were resolved in rapid kinetic studies. Modelling of stopped-flow kinetic data of pyrophosphate release in a coupled enzyme assay during one round of the NAC indicates that the rate of pyrophosphate release is significantly less than that for nucleotide incorporation. Upon modelling of the stopped-flow kinetic data for pyrophosphate release during two rounds of the NAC, it was observed that the presence of the next nucleotide for incorporation increases the rate of release of the first pyrophosphate equivalent; incorrect nucleotides for incorporation had no effect on the rate of pyrophosphate release. Although the next nucleotide for incorporation increases the rate of pyrophosphate release, it is still significantly less than the rate of incorporation of the first nucleotide. The results from the stopped-flow kinetic studies were confirmed by using quench-flow followed by thin-layer chromatography (QF-TLC) with only the first nucleotide for incorporation labeled on the gamma phosphate with 32P to monitor pyrophosphate release. Collectively, the results are consistent with an NTP-driven model for the NAC in which the binding of the next cognate nucleotide for incorporation causes a synergistic conformational change in the enzyme that triggers the more rapid release of pyrophosphate, translocation of the enzyme along the DNA template strand and nucleotide incorporation.
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Affiliation(s)
- Ronald S. Johnson
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- * E-mail:
| | - Mark Strausbauch
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Christopher McCloud
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
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6
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Qian J, Dunlap D, Finzi L. Thermodynamic model of bacterial transcription. Phys Rev E 2022; 106:044406. [PMID: 36397483 PMCID: PMC9803584 DOI: 10.1103/physreve.106.044406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 09/20/2022] [Indexed: 01/03/2023]
Abstract
Transcriptional pausing is highly regulated by the template DNA and nascent transcript sequences. Here, we propose a thermodynamic model of transcriptional pausing, based on the thermal energy of transcription bubbles and nascent RNA structures, to describe the kinetics of the reaction pathways between active translocation, elemental, backtracked, and hairpin-stabilized pauses. The model readily predicts experimentally detected pauses in high-resolution optical-tweezer measurements of transcription. Unlike other models, it also predicts the effect of tension and the GreA transcription factor on pausing.
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Affiliation(s)
- Jin Qian
- Physics Department, Emory University
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7
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Kor R, Mohammad-Rafiee F. Theoretical study of RNA-polymerase behavior considering the backtracking state. SOFT MATTER 2022; 18:5979-5988. [PMID: 35920142 DOI: 10.1039/d2sm00232a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The dynamical behavior of the RNA polymerase in the transcription process is vital to gene expression. During the transcription process, the 3' end of the transcribed RNA can be dislocated from the active site of the enzyme and as a result, the RNA polymerase goes to the backtracked state. Here, we develop a theoretical model to study the transcription process considering the backtracking state. We aim at describing the behavior of the enzyme in the backtracking state in the presence of an external force, which leads to two possibilities: (i) rescuing from the backtracking state and, (ii) the arresting of the enzyme. We study the probability and the rate of the mentioned processes. In addition, we find that entering the backtracking state behaves like the Brownian ratchet mechanism. This model could shed some light on the modeling of the transcription process and further studies on the energy landscape of the backtracking channel and the gene regulation.
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Affiliation(s)
- Razieh Kor
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
| | - Farshid Mohammad-Rafiee
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
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8
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Plaskon D, Evensen C, Henderson K, Palatnik B, Ishikuri T, Wang HC, Doughty S, Thomas Record M. Step-by-Step Regulation of Productive and Abortive Transcription Initiation by Pyrophosphorolysis. J Mol Biol 2022; 434:167621. [DOI: 10.1016/j.jmb.2022.167621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
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9
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Sahoo M, N A, Baral PR, Klumpp S. Accuracy and speed of elongation in a minimal model of DNA replication. Phys Rev E 2021; 104:034417. [PMID: 34654207 DOI: 10.1103/physreve.104.034417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/08/2021] [Indexed: 11/07/2022]
Abstract
Being a dual purpose enzyme, the DNA polymerase is responsible for elongation of the newly formed DNA strand as well as cleaving the erroneous growth in case of a misincorporation. The efficiency of replication depends on the coordination of the polymerization and exonuclease activity of DNA polymerase. Here, we propose and analyze a minimal kinetic model of DNA replication and determine exact expressions for the velocity of elongation and the accuracy of replication. We first analyze the case without exonuclease activity. In that case, accuracy is determined by a kinetic competition between stepping and unbinding, with discrimination between correct and incorrect nucleotides in both transitions. We then include exonuclease activity and ask how different modes of additional discrimination in the exonuclease pathway can improve the accuracy while limiting the detrimental effect of exonuclease on the speed of replication. In this way, we ask how the kinetic parameters of the model have to be set to coordinate the two activities of the enzyme for high accuracy and high speed. The analysis also shows that the design of a replication system does not universally have to follow the speed-accuracy trade-off rule, although it does in the biologically realized parameter range. The accuracy of the process is mainly controlled by the crucial role of stepping after erroneous incorporation, which has impact on both polymerase and exonuclease activities of DNA polymerase.
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Affiliation(s)
- M Sahoo
- Department of Physics, University of Kerala, Kariavattom Campus 695581, India.,School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram-695551, India
| | - Arsha N
- Department of Physics, University of Kerala, Kariavattom Campus 695581, India
| | - P R Baral
- School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram-695551, India
| | - S Klumpp
- Institute for the Dynamics of Complex Systems, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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10
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Abstract
Cellular life depends on transcription of DNA by RNA polymerase to express genetic information. RNA polymerase has evolved not just to read information from DNA and write it to RNA but also to sense and process information from the cellular and extracellular environments. Much of this information processing occurs during transcript elongation, when transcriptional pausing enables regulatory decisions. Transcriptional pauses halt RNA polymerase in response to DNA and RNA sequences and structures at locations and times that help coordinate interactions with small molecules and transcription factors important for regulation. Four classes of transcriptional pause signals are now evident after decades of study: elemental pauses, backtrack pauses, hairpin-stabilized pauses, and regulator-stabilized pauses. In this review, I describe current understanding of the molecular mechanisms of these four classes of pause signals, remaining questions about how RNA polymerase responds to pause signals, and the many exciting directions now open to understand pausing and the regulation of transcript elongation on a genome-wide scale. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Robert Landick
- Department of Biochemistry and Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA;
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11
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Kilic Z, Sgouralis I, Pressé S. Residence time analysis of RNA polymerase transcription dynamics: A Bayesian sticky HMM approach. Biophys J 2021; 120:1665-1679. [PMID: 33705761 DOI: 10.1016/j.bpj.2021.02.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 02/08/2021] [Accepted: 02/18/2021] [Indexed: 01/09/2023] Open
Abstract
The time spent by a single RNA polymerase (RNAP) at specific locations along the DNA, termed "residence time," reports on the initiation, elongation, and termination stages of transcription. At the single-molecule level, this information can be obtained from dual ultrastable optical trapping experiments, revealing a transcriptional elongation of RNAP interspersed with residence times of variable duration. Successfully discriminating between long and short residence times was used by previous approaches to learn about RNAP's transcription elongation dynamics. Here, we propose an approach based on the Bayesian sticky hidden Markov model that treats all residence times for an Escherichia coli RNAP on an equal footing without a priori discriminating between long and short residence times. Furthermore, our method has two additional advantages: we provide full distributions around key point statistics and directly treat the sequence dependence of RNAP's elongation rate. By applying our approach to experimental data, we find assigned relative probabilities on long versus short residence times, force-dependent average residence time transcription elongation dynamics, ∼10% drop in the average backtracking durations in the presence of GreB, and ∼20% drop in the average residence time as a function of applied force in the presence of RNaseA.
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Affiliation(s)
- Zeliha Kilic
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona
| | - Ioannis Sgouralis
- Department of Mathematics, University of Tennessee, Knoxville, Tennessee
| | - Steve Pressé
- Center for Biological Physics, Department of Physics and School of Molecular Sciences, Arizona State University, Tempe, Arizona. spresse@%20asu.edu
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12
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Qian J, Dunlap D, Finzi L. Basic mechanisms and kinetics of pause-interspersed transcript elongation. Nucleic Acids Res 2021; 49:15-24. [PMID: 33330935 PMCID: PMC7797061 DOI: 10.1093/nar/gkaa1182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 11/13/2022] Open
Abstract
RNA polymerase pausing during elongation is an important mechanism in the regulation of gene expression. Pausing along DNA templates is thought to be induced by distinct signals encoded in the nucleic acid sequence and halt elongation complexes to allow time for necessary co-transcriptional events. Pausing signals have been classified as those producing short-lived elemental, long-lived backtracked, or hairpin-stabilized pauses. In recent years, structural microbiology and single-molecule studies have significantly advanced our understanding of the paused states, but the dynamics of these states are still uncertain, although several models have been proposed to explain the experimentally observed pausing behaviors. This review summarizes present knowledge about the paused states, discusses key discrepancies among the kinetic models and their basic assumptions, and highlights the importance and challenges in constructing theoretical models that may further our biochemical understanding of transcriptional pausing.
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Affiliation(s)
- Jin Qian
- Physics, Emory University, Atlanta, GA 30307, USA
| | - David Dunlap
- Physics, Emory University, Atlanta, GA 30307, USA
| | - Laura Finzi
- Physics, Emory University, Atlanta, GA 30307, USA
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13
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Yang D, Liu W, Deng X, Xie W, Chen H, Zhong Z, Ma J. GC-Content Dependence of Elastic and Overstretching Properties of DNA:RNA Hybrid Duplexes. Biophys J 2020; 119:852-861. [PMID: 32738216 DOI: 10.1016/j.bpj.2020.06.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/22/2020] [Accepted: 06/18/2020] [Indexed: 01/25/2023] Open
Abstract
DNA:RNA hybrid duplex plays important roles in various biological processes. Both its structural stability and interactions with proteins are highly sequence dependent. In this study, we utilize homebuilt optical tweezers to investigate how GC contents in the sequence influence the structural and mechanical properties of DNA:RNA hybrid by measuring its contour length, elasticities, and overstretching dynamics. Our results support that the DNA:RNA hybrid adopts a conformation between the A- and B-form helix, and the GC content does not affect its structural and elastic parameters obviously when varying from 40 to 60% before the overstretching transition of DNA:RNA hybrid occurs. In the overstretching transition, however, our study unravels significant heterogeneity and strong sequence dependence, suggesting the presence of a highly dynamic competition between the two processes, namely the S-form duplex formation (nonhysteretic) and the unpeeling (hysteretic). Analyzing the components left in DNA:RNA hybrid after the overstretching transition suggests that the RNA strand is more easily unpeeled than the DNA strand, whereas an increase in the GC content from 40 to 60% can significantly reduce unpeeling. Large hysteresis is observed between the stretching and relaxation processes, which is also quantitatively correlated with the percentage of unpeeling in the DNA:RNA duplex. Increasing in both the salt concentration and GC content can effectively reduce the hysteresis with the latter being more significant. Together, our study reveals that the mechanical properties of DNA:RNA hybrid duplexes are significantly different from double-stranded DNA and double-stranded RNA, and its overstretching behavior is highly sequence dependent. These results should be taken into account in the future studies on DNA:RNA-hybrid-related functional structures and motor proteins.
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Affiliation(s)
- Dongni Yang
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong, China; State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenzhao Liu
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong, China; State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiangyu Deng
- State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wei Xie
- State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Hu Chen
- Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Lab for Soft Functional Materials Research, Department of Physics, Xiamen University, Xiamen, Fujian, China
| | - Zhensheng Zhong
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong, China; State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, Guangdong, China.
| | - Jie Ma
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong, China; State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, Guangdong, China.
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14
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Gaspard P. Template-directed growth of copolymers. CHAOS (WOODBURY, N.Y.) 2020; 30:043114. [PMID: 32357651 DOI: 10.1063/1.5145100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
The theory of multistate template-directed reversible copolymerization is developed by extending the method based on iterated function systems to matrices, taking into account the possibility of multiple activation states instead of a single one for the growth process. In this extended theory, the mean growth velocity is obtained with an iterated matrix function system and the probabilities of copolymer sequences are given by matrix products defined along the template. The theory allows us to understand the effects of template heterogeneity, which include a fractal distribution of local growth velocities far enough from equilibrium, and a regime of sublinear growth in time close to equilibrium.
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Affiliation(s)
- Pierre Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles (U.L.B.), Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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15
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Nakajima RT, Costa PR, Lemke N. Cooperative and sequence-dependent model for RNAP dynamics: Application to ribosomal gene transcription. J Theor Biol 2020; 488:110134. [PMID: 31874133 DOI: 10.1016/j.jtbi.2019.110134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 11/11/2019] [Accepted: 12/19/2019] [Indexed: 11/29/2022]
Abstract
Escherichia coli ribosomal genes are a well-established experimental model used to investigate the transcription process. These genes are essential to cell physiology and are therefore strongly expressed. Multiple transcription units collaborate in rrn expression. Experiments involving electron microscopy have shown the non-uniform density of the RNA polymerases transcribing these ribosomal operons. Here, we investigate RNAP collaborative transcription in E. coli ribosomal genes using a stochastic sequence-dependent model that included interactions among the RNAPs. We achieved results consistent with experimental data using a model with variable parametrization for genic and intergenic regions, compared with previous attempts that used uniform parameters for genic and intergenic regions. Our model also showed that cooperative behaviour reduced the dwell times in pause sites predicted by the single-round approach but induced a new pausing event at an upstream position. This work may stimulate new experimental research and provide other scenarios to test our model predictions.
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Affiliation(s)
- Rafael Takahiro Nakajima
- Institute of Biosciences, UNESP - Univ Estadual Paulista, Department of Physics and Biophysics, Botucatu, 18618-689, Brazil.
| | - Pedro Rafael Costa
- Institute of Biosciences, UNESP - Univ Estadual Paulista, Department of Physics and Biophysics, Botucatu, 18618-689, Brazil.
| | - Ney Lemke
- Institute of Biosciences, UNESP - Univ Estadual Paulista, Department of Physics and Biophysics, Botucatu, 18618-689, Brazil.
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16
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Douglas J, Kingston R, Drummond AJ. Bayesian inference and comparison of stochastic transcription elongation models. PLoS Comput Biol 2020; 16:e1006717. [PMID: 32059006 PMCID: PMC7046298 DOI: 10.1371/journal.pcbi.1006717] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/27/2020] [Accepted: 12/13/2019] [Indexed: 02/06/2023] Open
Abstract
Transcription elongation can be modelled as a three step process, involving polymerase translocation, NTP binding, and nucleotide incorporation into the nascent mRNA. This cycle of events can be simulated at the single-molecule level as a continuous-time Markov process using parameters derived from single-molecule experiments. Previously developed models differ in the way they are parameterised, and in their incorporation of partial equilibrium approximations. We have formulated a hierarchical network comprised of 12 sequence-dependent transcription elongation models. The simplest model has two parameters and assumes that both translocation and NTP binding can be modelled as equilibrium processes. The most complex model has six parameters makes no partial equilibrium assumptions. We systematically compared the ability of these models to explain published force-velocity data, using approximate Bayesian computation. This analysis was performed using data for the RNA polymerase complexes of E. coli, S. cerevisiae and Bacteriophage T7. Our analysis indicates that the polymerases differ significantly in their translocation rates, with the rates in T7 pol being fast compared to E. coli RNAP and S. cerevisiae pol II. Different models are applicable in different cases. We also show that all three RNA polymerases have an energetic preference for the posttranslocated state over the pretranslocated state. A Bayesian inference and model selection framework, like the one presented in this publication, should be routinely applicable to the interrogation of single-molecule datasets. Transcription is a critical biological process which occurs in all living organisms. It involves copying the organism’s genetic material into messenger RNA (mRNA) which directs protein synthesis on the ribosome. Transcription is performed by RNA polymerases which have been extensively studied using both ensemble and single-molecule techniques. Single-molecule data provides unique insights into the molecular behaviour of RNA polymerases. Transcription at the single-molecule level can be computationally simulated as a continuous-time Markov process and the model outputs compared with experimental data. In this study we use Bayesian techniques to perform a systematic comparison of 12 stochastic models of transcriptional elongation. We demonstrate how equilibrium approximations can strengthen or weaken the model, and show how Bayesian techniques can identify necessary or unnecessary model parameters. We describe a framework to a) simulate, b) perform inference on, and c) compare models of transcription elongation.
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Affiliation(s)
- Jordan Douglas
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Centre for Computational Evolution, School of Computer Science, University of Auckland, Auckland, New Zealand
- * E-mail:
| | - Richard Kingston
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Alexei J. Drummond
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Centre for Computational Evolution, School of Computer Science, University of Auckland, Auckland, New Zealand
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17
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Prajapati RK, Rosenqvist P, Palmu K, Mäkinen JJ, Malinen AM, Virta P, Metsä-Ketelä M, Belogurov GA. Oxazinomycin arrests RNA polymerase at the polythymidine sequences. Nucleic Acids Res 2019; 47:10296-10312. [PMID: 31495891 PMCID: PMC6821320 DOI: 10.1093/nar/gkz782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/13/2019] [Accepted: 08/31/2019] [Indexed: 02/06/2023] Open
Abstract
Oxazinomycin is a C-nucleoside antibiotic that is produced by Streptomyces hygroscopicus and closely resembles uridine. Here, we show that the oxazinomycin triphosphate is a good substrate for bacterial and eukaryotic RNA polymerases (RNAPs) and that a single incorporated oxazinomycin is rapidly extended by the next nucleotide. However, the incorporation of several successive oxazinomycins or a single oxazinomycin in a certain sequence context arrested a fraction of the transcribing RNAP. The addition of Gre RNA cleavage factors eliminated the transcriptional arrest at a single oxazinomycin and shortened the nascent RNAs arrested at the polythymidine sequences suggesting that the transcriptional arrest was caused by backtracking of RNAP along the DNA template. We further demonstrate that the ubiquitous C-nucleoside pseudouridine is also a good substrate for RNA polymerases in a triphosphorylated form but does not inhibit transcription of the polythymidine sequences. Our results collectively suggest that oxazinomycin functions as a Trojan horse substrate and its inhibitory effect is attributable to the oxygen atom in the position corresponding to carbon five of the uracil ring.
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Affiliation(s)
- Ranjit K Prajapati
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Petja Rosenqvist
- Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
| | - Kaisa Palmu
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Janne J Mäkinen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Anssi M Malinen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Pasi Virta
- Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
| | - Mikko Metsä-Ketelä
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
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18
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Kang JY, Mishanina TV, Landick R, Darst SA. Mechanisms of Transcriptional Pausing in Bacteria. J Mol Biol 2019; 431:4007-4029. [PMID: 31310765 DOI: 10.1016/j.jmb.2019.07.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/08/2019] [Accepted: 07/08/2019] [Indexed: 12/21/2022]
Abstract
Pausing by RNA polymerase (RNAP) during transcription regulates gene expression in all domains of life. In this review, we recap the history of transcriptional pausing discovery, summarize advances in our understanding of the underlying causes of pausing since then, and describe new insights into the pausing mechanisms and pause modulation by transcription factors gained from structural and biochemical experiments. The accumulated evidence to date suggests that upon encountering a pause signal in the nucleic-acid sequence being transcribed, RNAP rearranges into an elemental, catalytically inactive conformer unable to load NTP substrate. The conformation, and as a consequence lifetime, of an elemental paused RNAP is modulated by backtracking, nascent RNA structure, binding of transcription regulators, or a combination of these mechanisms. We conclude the review by outlining open questions and directions for future research in the field of transcriptional pausing.
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Affiliation(s)
- Jin Young Kang
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejon 34141, Republic of Korea.
| | - Tatiana V Mishanina
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA.
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Seth A Darst
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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19
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Belogurov GA, Artsimovitch I. The Mechanisms of Substrate Selection, Catalysis, and Translocation by the Elongating RNA Polymerase. J Mol Biol 2019; 431:3975-4006. [PMID: 31153902 DOI: 10.1016/j.jmb.2019.05.042] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/24/2019] [Accepted: 05/24/2019] [Indexed: 11/15/2022]
Abstract
Multi-subunit DNA-dependent RNA polymerases synthesize all classes of cellular RNAs, ranging from short regulatory transcripts to gigantic messenger RNAs. RNA polymerase has to make each RNA product in just one try, even if it takes millions of successive nucleotide addition steps. During each step, RNA polymerase selects a correct substrate, adds it to a growing chain, and moves one nucleotide forward before repeating the cycle. However, RNA synthesis is anything but monotonous: RNA polymerase frequently pauses upon encountering mechanical, chemical and torsional barriers, sometimes stepping back and cleaving off nucleotides from the growing RNA chain. A picture in which these intermittent dynamics enable processive, accurate, and controllable RNA synthesis is emerging from complementary structural, biochemical, computational, and single-molecule studies. Here, we summarize our current understanding of the mechanism and regulation of the on-pathway transcription elongation. We review the details of substrate selection, catalysis, proofreading, and translocation, focusing on rate-limiting steps, structural elements that modulate them, and accessory proteins that appear to control RNA polymerase translocation.
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Affiliation(s)
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
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20
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Long C, E. C, Da LT, Yu J. A Viral T7 RNA Polymerase Ratcheting Along DNA With Fidelity Control. Comput Struct Biotechnol J 2019; 17:638-644. [PMID: 31193497 PMCID: PMC6535458 DOI: 10.1016/j.csbj.2019.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/25/2019] [Accepted: 05/04/2019] [Indexed: 12/02/2022] Open
Abstract
RNA polymerase (RNAP) from bacteriophage T7 is a representative single-subunit viral RNAP that can transcribe with high promoter activities without assistances from transcription factors. We accordingly studied this small transcription machine computationally as a model system to understand underlying mechanisms of mechano-chemical coupling and fidelity control in the RNAP transcription elongation. Here we summarize our computational work from several recent publications to demonstrate first how T7 RNAP translocates via Brownian alike motions along DNA right after the catalytic product release. Then we show how the backward translocation motions are prevented at post-translocation upon successful nucleotide incorporation, which is also subject to stepwise nucleotide selection and acts as a pawl for "selective ratcheting". The structural dynamics and energetics features revealed from our atomistic molecular dynamics (MD) simulations and related analyses on the single-subunit T7 RNAP thus provided detailed and quantitative characterizations on the Brownian-ratchet working scenario of a prototypical transcription machine with sophisticated nucleotide selectivity for fidelity control. The presented mechanisms can be more or less general for structurally similar viral or mitochondrial RNAPs and some of DNA polymerases, or even for the RNAP engine of the more complicated transcription machinery in higher organisms.
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Affiliation(s)
- Chunhong Long
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Chao E.
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Lin-Tai Da
- Shanghai Center for Systems Biomedicine, Shanghai JiaoTong University, Shanghai 200240, China
| | - Jin Yu
- Beijing Computational Science Research Center, Beijing, 100193, China
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21
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Belitsky V, Schütz G. RNA Polymerase interactions and elongation rate. J Theor Biol 2019; 462:370-380. [DOI: 10.1016/j.jtbi.2018.11.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 11/30/2022]
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22
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Transcription factor regulation of RNA polymerase's torque generation capacity. Proc Natl Acad Sci U S A 2019; 116:2583-2588. [PMID: 30635423 DOI: 10.1073/pnas.1807031116] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During transcription, RNA polymerase (RNAP) supercoils DNA as it translocates. The resulting torsional stress in DNA can accumulate and, in the absence of regulatory mechanisms, becomes a barrier to RNAP elongation, causing RNAP stalling, backtracking, and transcriptional arrest. Here we investigate whether and how a transcription factor may regulate both torque-induced Escherichia coli RNAP stalling and the torque generation capacity of RNAP. Using a unique real-time angular optical trapping assay, we found that RNAP working against a resisting torque was highly prone to extensive backtracking. We then investigated transcription in the presence of GreB, a transcription factor known to rescue RNAP from the backtracked state. We found that GreB greatly suppressed RNAP backtracking and remarkably increased the torque that RNAP was able to generate by 65%, from 11.2 pN⋅nm to 18.5 pN·nm. Variance analysis of the real-time positional trajectories of RNAP after a stall revealed the kinetic parameters of backtracking and GreB rescue. These results demonstrate that backtracking is the primary mechanism by which torsional stress limits transcription and that the transcription factor GreB effectively enhances the torsional capacity of RNAP. These findings suggest a broader role for transcription factors in regulating RNAP functionality and elongation.
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23
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Saba J, Chua XY, Mishanina TV, Nayak D, Windgassen TA, Mooney RA, Landick R. The elemental mechanism of transcriptional pausing. eLife 2019; 8:e40981. [PMID: 30618376 PMCID: PMC6336406 DOI: 10.7554/elife.40981] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022] Open
Abstract
Transcriptional pausing underlies regulation of cellular RNA biogenesis. A consensus pause sequence that acts on RNA polymerases (RNAPs) from bacteria to mammals halts RNAP in an elemental paused state from which longer-lived pauses can arise. Although the structural foundations of pauses prolonged by backtracking or nascent RNA hairpins are recognized, the fundamental mechanism of the elemental pause is less well-defined. Here we report a mechanistic dissection that establishes the elemental pause signal (i) is multipartite; (ii) causes a modest conformational shift that puts γ-proteobacterial RNAP in an off-pathway state in which template base loading but not RNA translocation is inhibited; and (iii) allows RNAP to enter pretranslocated and one-base-pair backtracked states easily even though the half-translocated state observed in paused cryo-EM structures rate-limits pause escape. Our findings provide a mechanistic basis for the elemental pause and a framework to understand how pausing is modulated by sequence, cellular conditions, and regulators.
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Affiliation(s)
- Jason Saba
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Xien Yu Chua
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Tatiana V Mishanina
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Dhananjaya Nayak
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Tricia A Windgassen
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Rachel Anne Mooney
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
| | - Robert Landick
- Department of BiochemistryUniversity of Wisconsin-MadisonMadisonUnited States
- Department of BacteriologyUniversity of Wisconsin-MadisonMadisonUnited States
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24
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Belitsky V, Schütz GM. Stationary RNA polymerase fluctuations during transcription elongation. Phys Rev E 2019; 99:012405. [PMID: 30780341 DOI: 10.1103/physreve.99.012405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Indexed: 06/09/2023]
Abstract
We study fluctuation effects of nonsteric molecular interactions between RNA polymerase (RNAP) motors that move simultaneously on the same DNA track during transcription elongation. Based on a stochastic model that allows for the exact analytical computation of the stationary distribution of RNAPs as a function of their density, interaction strength, nucleoside triphosphate concentration, and rate of pyrophosphate release we predict an almost geometric headway distribution of subsequent RNAP transcribing on the same DNA segment. The localization length which characterizes the decay of the headway distribution depends directly only the average density of RNAP and the interaction strength, but not on specific single-RNAP properties. Density correlations are predicted to decay exponentially with the distance (in units of DNA base pairs), with a correlation length that is significantly shorter than the localization length.
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Affiliation(s)
- V Belitsky
- Instituto de Matemática e Estátistica, Universidade de São Paulo, Rua do Matão, 1010, CEP 05508-090 São Paulo, São Paulo, Brazil
| | - G M Schütz
- Institute of Complex Systems II, Theoretical Soft Matter and Biophysics, Forschungszentrum Jülich, 52425 Jülich, Germany
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25
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Turtola M, Mäkinen JJ, Belogurov GA. Active site closure stabilizes the backtracked state of RNA polymerase. Nucleic Acids Res 2018; 46:10870-10887. [PMID: 30256972 PMCID: PMC6237748 DOI: 10.1093/nar/gky883] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/30/2018] [Accepted: 09/19/2018] [Indexed: 01/02/2023] Open
Abstract
All cellular RNA polymerases (RNAP) occasionally backtrack along the template DNA as part of transcriptional proofreading and regulation. Here, we studied the mechanism of RNAP backtracking by one nucleotide using two complementary approaches that allowed us to precisely measure the occupancy and lifetime of the backtracked state. Our data show that the stability of the backtracked state is critically dependent on the closure of the RNAP active site by a mobile domain, the trigger loop (TL). The lifetime and occupancy of the backtracked state measurably decreased by substitutions of the TL residues that interact with the nucleoside triphosphate (NTP) substrate, whereas amino acid substitutions that stabilized the closed active site increased the lifetime and occupancy. These results suggest that the same conformer of the TL closes the active site during catalysis of nucleotide incorporation into the nascent RNA and backtracking by one nucleotide. In support of this hypothesis, we construct a model of the 1-nt backtracked complex with the closed active site and the backtracked nucleotide in the entry pore area known as the E-site. We further propose that 1-nt backtracking mimics the reversal of the NTP substrate loading into the RNAP active site during on-pathway elongation.
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Affiliation(s)
- Matti Turtola
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
| | - Janne J Mäkinen
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
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26
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Le TT, Wang MD. Molecular Highways—Navigating Collisions of DNA Motor Proteins. J Mol Biol 2018; 430:4513-4524. [DOI: 10.1016/j.jmb.2018.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 01/09/2023]
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27
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Unarta IC, Zhu L, Tse CKM, Cheung PPH, Yu J, Huang X. Molecular mechanisms of RNA polymerase II transcription elongation elucidated by kinetic network models. Curr Opin Struct Biol 2018; 49:54-62. [PMID: 29414512 DOI: 10.1016/j.sbi.2018.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 12/30/2022]
Abstract
Transcription elongation cycle (TEC) of RNA polymerase II (Pol II) is a process of adding a nucleoside triphosphate to the growing messenger RNA chain. Due to the long timescale events in Pol II TEC, an advanced computational technique, such as Markov State Model (MSM), is needed to provide atomistic mechanism and reaction rates. The combination of MSM and experimental results can be used to build a kinetic network model (KNM) of the whole TEC. This review provides a brief protocol to build MSM and KNM of the whole TEC, along with the latest findings of MSM and other computational studies of Pol II TEC. Lastly, we offer a perspective on potentially using a sequence dependent KNM to predict genome-wide transcription error.
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Affiliation(s)
- Ilona Christy Unarta
- Bioengineering Graduate Program, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong
| | - Lizhe Zhu
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Carmen Ka Man Tse
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Peter Pak-Hang Cheung
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong
| | - Jin Yu
- Beijing Computational Science Research Center, Beijing 100084, China
| | - Xuhui Huang
- Center of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong; Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.
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28
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Le TT, Yang Y, Tan C, Suhanovsky MM, Fulbright RM, Inman JT, Li M, Lee J, Perelman S, Roberts JW, Deaconescu AM, Wang MD. Mfd Dynamically Regulates Transcription via a Release and Catch-Up Mechanism. Cell 2017; 172:344-357.e15. [PMID: 29224782 DOI: 10.1016/j.cell.2017.11.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/21/2017] [Accepted: 11/09/2017] [Indexed: 11/25/2022]
Abstract
The bacterial Mfd ATPase is increasingly recognized as a general transcription factor that participates in the resolution of transcription conflicts with other processes/roadblocks. This function stems from Mfd's ability to preferentially act on stalled RNA polymerases (RNAPs). However, the mechanism underlying this preference and the subsequent coordination between Mfd and RNAP have remained elusive. Here, using a novel real-time translocase assay, we unexpectedly discovered that Mfd translocates autonomously on DNA. The speed and processivity of Mfd dictate a "release and catch-up" mechanism to efficiently patrol DNA for frequently stalled RNAPs. Furthermore, we showed that Mfd prevents RNAP backtracking or rescues a severely backtracked RNAP, allowing RNAP to overcome stronger obstacles. However, if an obstacle's resistance is excessive, Mfd dissociates the RNAP, clearing the DNA for other processes. These findings demonstrate a remarkably delicate coordination between Mfd and RNAP, allowing efficient targeting and recycling of Mfd and expedient conflict resolution.
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Affiliation(s)
- Tung T Le
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Yi Yang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Chuang Tan
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Margaret M Suhanovsky
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | | | - James T Inman
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Ming Li
- Department of Chemistry, Cornell University, Ithaca, NY 14853, USA
| | - Jaeyoon Lee
- Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA
| | - Sarah Perelman
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Jeffrey W Roberts
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Alexandra M Deaconescu
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Michelle D Wang
- Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA; Physics Department & LASSP, Cornell University, Ithaca, NY 14853, USA.
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29
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Mellenius H, Ehrenberg M. Transcriptional accuracy modeling suggests two-step proofreading by RNA polymerase. Nucleic Acids Res 2017; 45:11582-11593. [PMID: 29036494 PMCID: PMC5714138 DOI: 10.1093/nar/gkx849] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/10/2017] [Accepted: 09/22/2017] [Indexed: 01/01/2023] Open
Abstract
We suggest a novel two-step proofreading mechanism with two sequential rounds of proofreading selection in mRNA transcription. It is based on the previous experimental observations that the proofreading RNA polymerase cleaves off transcript fragments of at least 2 nt and that transcript elongation after a nucleotide misincorporation is anomalously slow. Taking these results into account, we extend the description of the accuracy of template guided nucleotide selection beyond previous models of RNA polymerase-dependent DNA transcription. The model derives the accuracy of initial and proofreading base selection from experimentally estimated nearest-neighbor parameters. It is also used to estimate the small accuracy enhancement of polymerase revisiting of previous positions following transcript cleavage.
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Affiliation(s)
- Harriet Mellenius
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 752 37, Sweden
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 752 37, Sweden
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30
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Abstract
The kinetic equations of DNA replication are shown to be exactly solved in terms of iterated function systems, running along the template sequence and giving the statistical properties of the copy sequences, as well as the kinetic and thermodynamic properties of the replication process. With this method, different effects due to sequence heterogeneity can be studied, in particular, a transition between linear and sublinear growths in time of the copies, and a transition between continuous and fractal distributions of the local velocities of the DNA polymerase along the template. The method is applied to the human mitochondrial DNA polymerase γ without and with exonuclease proofreading.
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Affiliation(s)
- Pierre Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université libre de Bruxelles (ULB), Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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31
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Mustaev A, Roberts J, Gottesman M. Transcription elongation. Transcription 2017; 8:150-161. [PMID: 28301288 PMCID: PMC5501382 DOI: 10.1080/21541264.2017.1289294] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 12/23/2022] Open
Abstract
This review is focused on recent progress in understanding how Escherichia coli RNAP polymerase translocates along the DNA template and the factors that affect this movement. We discuss the fundamental aspects of RNAP translocation, template signals that influence forward or backward movement, and host or phage factors that modulate translocation.
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Affiliation(s)
- Arkady Mustaev
- PHRI Center, NJMS, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Jeffrey Roberts
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Max Gottesman
- Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY, USA
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32
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Lukačišin M, Landon M, Jajoo R. Sequence-specific thermodynamic properties of nucleic acids influence both transcriptional pausing and backtracking in yeast. PLoS One 2017; 12:e0174066. [PMID: 28301878 PMCID: PMC5354634 DOI: 10.1371/journal.pone.0174066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 03/02/2017] [Indexed: 01/22/2023] Open
Abstract
RNA Polymerase II pauses and backtracks during transcription, with many consequences for gene expression and cellular physiology. Here, we show that the energy required to melt double-stranded nucleic acids in the transcription bubble predicts pausing in Saccharomyces cerevisiae far more accurately than nucleosome roadblocks do. In addition, the same energy difference also determines when the RNA polymerase backtracks instead of continuing to move forward. This data-driven model corroborates—in a genome wide and quantitative manner—previous evidence that sequence-dependent thermodynamic features of nucleic acids influence both transcriptional pausing and backtracking.
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Affiliation(s)
- Martin Lukačišin
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States of America
- IST Austria, Klosterneuburg, Austria
| | - Matthieu Landon
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States of America
- Department of Genetics, Harvard Medical School, Boston, MA, United States of America
- Ecole des Mines de Paris, Mines Paristech, Paris, France
| | - Rishi Jajoo
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States of America
- * E-mail:
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33
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Gaspard P. Template-Directed Copolymerization, Random Walks along Disordered Tracks, and Fractals. PHYSICAL REVIEW LETTERS 2016; 117:238101. [PMID: 27982621 DOI: 10.1103/physrevlett.117.238101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Indexed: 06/06/2023]
Abstract
In biology, template-directed copolymerization is the fundamental mechanism responsible for the synthesis of DNA, RNA, and proteins. More than 50 years have passed since the discovery of DNA structure and its role in coding genetic information. Yet, the kinetics and thermodynamics of information processing in DNA replication, transcription, and translation remain poorly understood. Challenging issues are the facts that DNA or RNA sequences constitute disordered media for the motion of polymerases or ribosomes while errors occur in copying the template. Here, it is shown that these issues can be addressed and sequence heterogeneity effects can be quantitatively understood within a framework revealing universal aspects of information processing at the molecular scale. In steady growth regimes, the local velocities of polymerases or ribosomes along the template are distributed as the continuous or fractal invariant set of a so-called iterated function system, which determines the copying error probabilities. The growth may become sublinear in time with a scaling exponent that can also be deduced from the iterated function system.
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Affiliation(s)
- Pierre Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université libre de Bruxelles (ULB), Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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34
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Control of transcriptional pausing by biased thermal fluctuations on repetitive genomic sequences. Proc Natl Acad Sci U S A 2016; 113:E7409-E7417. [PMID: 27830653 DOI: 10.1073/pnas.1607760113] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the process of transcription elongation, RNA polymerase (RNAP) pauses at highly nonrandom positions across genomic DNA, broadly regulating transcription; however, molecular mechanisms responsible for the recognition of such pausing positions remain poorly understood. Here, using a combination of statistical mechanical modeling and high-throughput sequencing and biochemical data, we evaluate the effect of thermal fluctuations on the regulation of RNAP pausing. We demonstrate that diffusive backtracking of RNAP, which is biased by repetitive DNA sequence elements, causes transcriptional pausing. This effect stems from the increased microscopic heterogeneity of an elongation complex, and thus is entropy-dominated. This report shows a linkage between repetitive sequence elements encoded in the genome and regulation of RNAP pausing driven by thermal fluctuations.
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35
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Xu H, Skinner SO, Sokac AM, Golding I. Stochastic Kinetics of Nascent RNA. PHYSICAL REVIEW LETTERS 2016; 117:128101. [PMID: 27667861 PMCID: PMC5033037 DOI: 10.1103/physrevlett.117.128101] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The stochastic kinetics of transcription is typically inferred from the distribution of RNA numbers in individual cells. However, cellular RNA reflects additional processes downstream of transcription, hampering this analysis. In contrast, nascent (actively transcribed) RNA closely reflects the kinetics of transcription. We present a theoretical model for the stochastic kinetics of nascent RNA, which we solve to obtain the probability distribution of nascent RNA per gene. The model allows us to evaluate the kinetic parameters of transcription from single-cell measurements of nascent RNA. The model also predicts surprising discontinuities in the distribution of nascent RNA, a feature which we verify experimentally.
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Affiliation(s)
- Heng Xu
- Center for Theoretical Biological Physics, Rice University, Houston,
Texas, USA
- Center for the Physics of Living Cells, University of Illinois at
Urbana-Champaign, Urbana, Illinois, USA
- Verna & Marrs McLean Department of Biochemistry and Molecular
Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Samuel O. Skinner
- Center for Theoretical Biological Physics, Rice University, Houston,
Texas, USA
- Center for the Physics of Living Cells, University of Illinois at
Urbana-Champaign, Urbana, Illinois, USA
- Verna & Marrs McLean Department of Biochemistry and Molecular
Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Anna Marie Sokac
- Verna & Marrs McLean Department of Biochemistry and Molecular
Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Ido Golding
- Center for Theoretical Biological Physics, Rice University, Houston,
Texas, USA
- Center for the Physics of Living Cells, University of Illinois at
Urbana-Champaign, Urbana, Illinois, USA
- Verna & Marrs McLean Department of Biochemistry and Molecular
Biology, Baylor College of Medicine, Houston, Texas, USA
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36
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Zhang J, Landick R. A Two-Way Street: Regulatory Interplay between RNA Polymerase and Nascent RNA Structure. Trends Biochem Sci 2016; 41:293-310. [PMID: 26822487 DOI: 10.1016/j.tibs.2015.12.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 02/06/2023]
Abstract
The vectorial (5'-to-3' at varying velocity) synthesis of RNA by cellular RNA polymerases (RNAPs) creates a rugged kinetic landscape, demarcated by frequent, sometimes long-lived, pauses. In addition to myriad gene-regulatory roles, these pauses temporally and spatially program the co-transcriptional, hierarchical folding of biologically active RNAs. Conversely, these RNA structures, which form inside or near the RNA exit channel, interact with the polymerase and adjacent protein factors to influence RNA synthesis by modulating pausing, termination, antitermination, and slippage. Here, we review the evolutionary origin, mechanistic underpinnings, and regulatory consequences of this interplay between RNAP and nascent RNA structure. We categorize and rationalize the extensive linkage between the transcriptional machinery and its product, and provide a framework for future studies.
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Affiliation(s)
- Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
| | - Robert Landick
- Departments of Biochemistry and Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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37
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Bordoy AE, Chatterjee A. Cis-Antisense Transcription Gives Rise to Tunable Genetic Switch Behavior: A Mathematical Modeling Approach. PLoS One 2015. [PMID: 26222133 PMCID: PMC4519249 DOI: 10.1371/journal.pone.0133873] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Antisense transcription has been extensively recognized as a regulatory mechanism for gene expression across all kingdoms of life. Despite the broad importance and extensive experimental determination of cis-antisense transcription, relatively little is known about its role in controlling cellular switching responses. Growing evidence suggests the presence of non-coding cis-antisense RNAs that regulate gene expression via antisense interaction. Recent studies also indicate the role of transcriptional interference in regulating expression of neighboring genes due to traffic of RNA polymerases from adjacent promoter regions. Previous models investigate these mechanisms independently, however, little is understood about how cells utilize coupling of these mechanisms in advantageous ways that could also be used to design novel synthetic genetic devices. Here, we present a mathematical modeling framework for antisense transcription that combines the effects of both transcriptional interference and cis-antisense regulation. We demonstrate the tunability of transcriptional interference through various parameters, and that coupling of transcriptional interference with cis-antisense RNA interaction gives rise to hypersensitive switches in expression of both antisense genes. When implementing additional positive and negative feed-back loops from proteins encoded by these genes, the system response acquires a bistable behavior. Our model shows that combining these multiple-levels of regulation allows fine-tuning of system parameters to give rise to a highly tunable output, ranging from a simple-first order response to biologically complex higher-order response such as tunable bistable switch. We identify important parameters affecting the cellular switch response in order to provide the design principles for tunable gene expression using antisense transcription. This presents an important insight into functional role of antisense transcription and its importance towards design of synthetic biological switches.
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Affiliation(s)
- Antoni E. Bordoy
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, United States of America
| | - Anushree Chatterjee
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, United States of America
- BioFrontiers institute, University of Colorado Boulder, Boulder, CO, United States of America
- * E-mail:
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38
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Skancke J, Bar N, Kuiper M, Hsu LM. Sequence-Dependent Promoter Escape Efficiency Is Strongly Influenced by Bias for the Pretranslocated State during Initial Transcription. Biochemistry 2015; 54:4267-75. [PMID: 26083830 DOI: 10.1021/acs.biochem.5b00272] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abortive transcription initiation can be rate-limiting for promoter escape and therefore represents a barrier to productive gene expression. The mechanism for abortive initiation is unknown, but the amount of abortive transcript is known to vary with the composition of the initial transcribed sequence (ITS). Here, we used a thermodynamic model of translocation combined with experimental validation to investigate the relationship between ITS and promoter escape on a set of phage T5 N25 promoters. We found a strong, negative correlation between RNAP's propensity to occupy the pretranslocated state during initial transcription and the efficiency of promoter escape (r = -0.67; p < 10(-6)). This correlation was almost entirely caused by free energy changes due to variation in the RNA 3' dinucleotide sequence at each step, implying that this sequence element controls the disposition of initial transcribing complexes. We tested our model experimentally by constructing a set of novel N25-ITS promoter variants; quantitative transcription analysis again showed a strong correlation (r = -0.81; p < 10(-6)). Our results support a model in which sequence-directed bias for the pretranslocated state during scrunching results in increased backtracking, which limits the efficiency of promoter escape. This provides an answer to the long-standing issue of how sequence composition of the ITS affects promoter escape efficiency.
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Affiliation(s)
- Jørgen Skancke
- †Department of Chemical Engineering, Norwegian University of Science and Technology, Sem Sælandsvei 4, 7491 Trondheim, Norway
| | - Nadav Bar
- †Department of Chemical Engineering, Norwegian University of Science and Technology, Sem Sælandsvei 4, 7491 Trondheim, Norway
| | - Martin Kuiper
- ‡Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Lilian M Hsu
- §Program in Biochemistry, Mount Holyoke College, South Hadley, Massachusetts 01075, United States
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Imashimizu M, Takahashi H, Oshima T, McIntosh C, Bubunenko M, Court DL, Kashlev M. Visualizing translocation dynamics and nascent transcript errors in paused RNA polymerases in vivo. Genome Biol 2015; 16:98. [PMID: 25976475 PMCID: PMC4457086 DOI: 10.1186/s13059-015-0666-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/05/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Transcription elongation is frequently interrupted by pausing signals in DNA, with downstream effects on gene expression. Transcription errors also induce prolonged pausing, which can lead to a destabilized genome by interfering with DNA replication. Mechanisms of pausing associated with translocation blocks and misincorporation have been characterized in vitro, but not in vivo. RESULTS We investigate the pausing pattern of RNA polymerase (RNAP) in Escherichia coli by a novel approach, combining native elongating transcript sequencing (NET-seq) with RNase footprinting of the transcripts (RNET-seq). We reveal that the G-dC base pair at the 5' end of the RNA-DNA hybrid interferes with RNAP translocation. The distance between the 5' G-dC base pair and the 3' end of RNA fluctuates over a three-nucleotide width. Thus, the G-dC base pair can induce pausing in post-translocated, pre-translocated, and backtracked states of RNAP. Additionally, a CpG sequence of the template DNA strand spanning the active site of RNAP inhibits elongation and induces G-to-A errors, which leads to backtracking of RNAP. Gre factors efficiently proofread the errors and rescue the backtracked complexes. We also find that pausing events are enriched in the 5' untranslated region and antisense transcription of mRNA genes and are reduced in rRNA genes. CONCLUSIONS In E. coli, robust transcriptional pausing involves RNAP interaction with G-dC at the upstream end of the RNA-DNA hybrid, which interferes with translocation. CpG DNA sequences induce transcriptional pausing and G-to-A errors.
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Affiliation(s)
- Masahiko Imashimizu
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan.
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Ikoma, Nara, 630-0192, Japan.
| | - Carl McIntosh
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Bubunenko
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Donald L Court
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Kashlev
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
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40
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DNA template dependent accuracy variation of nucleotide selection in transcription. PLoS One 2015; 10:e0119588. [PMID: 25799551 PMCID: PMC4370716 DOI: 10.1371/journal.pone.0119588] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022] Open
Abstract
It has been commonly assumed that the effect of erroneous transcription of DNA genes into messenger RNAs on peptide sequence errors are masked by much more frequent errors of mRNA translation to protein. We present a theoretical model of transcriptional accuracy. It uses experimentally estimated standard free energies of double-stranded DNA and RNA/DNA hybrids and predicts a DNA template dependent transcriptional accuracy variation spanning several orders of magnitude. The model also identifies high-error as well a high-accuracy transcription motifs. The source of the large accuracy span is the context dependent variation of the stacking free energy of pairs of correct and incorrect base pairs in the ever moving transcription bubble. Our model predictions have direct experimental support from recent single molecule based identifications of transcriptional errors in the C. elegans transcriptome. Our conclusions challenge the general view that amino acid substitution errors in proteins are mainly caused by translational errors. It suggests instead that transcriptional error hotspots are the dominating source of peptide sequence errors in some DNA template contexts, while mRNA translation is the major cause of protein errors in other contexts.
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41
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Mejia YX, Nudler E, Bustamante C. Trigger loop folding determines transcription rate of Escherichia coli's RNA polymerase. Proc Natl Acad Sci U S A 2015; 112:743-8. [PMID: 25552559 PMCID: PMC4311812 DOI: 10.1073/pnas.1421067112] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Two components of the RNA polymerase (RNAP) catalytic center, the bridge helix and the trigger loop (TL), have been linked with changes in elongation rate and pausing. Here, single molecule experiments with the WT and two TL-tip mutants of the Escherichia coli enzyme reveal that tip mutations modulate RNAP's pause-free velocity, identifying TL conformational changes as one of two rate-determining steps in elongation. Consistent with this observation, we find a direct correlation between helix propensity of the modified amino acid and pause-free velocity. Moreover, nucleotide analogs affect transcription rate, suggesting that their binding energy also influences TL folding. A kinetic model in which elongation occurs in two steps, TL folding on nucleoside triphosphate (NTP) binding followed by NTP incorporation/pyrophosphate release, quantitatively accounts for these results. The TL plays no role in pause recovery remaining unfolded during a pause. This model suggests a finely tuned mechanism that balances transcription speed and fidelity.
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Affiliation(s)
- Yara X Mejia
- Jason L. Choy Laboratory of Single-Molecule Biophysics, the California Institute of Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology and Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016
| | - Carlos Bustamante
- Jason L. Choy Laboratory of Single-Molecule Biophysics, the California Institute of Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720; Department of Molecular and Cell Biology, Department of Physics, Department of Chemistry, Biophysics Graduate Group and Howard Hughes Medical Institute, University of California, Berkeley, CA 94720; and Kavli Energy Nanosciences Institute at Berkeley, Berkeley, CA 94720
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42
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Yu J, Da LT, Huang X. Constructing kinetic models to elucidate structural dynamics of a complete RNA polymerase II elongation cycle. Phys Biol 2014; 12:016004. [DOI: 10.1088/1478-3975/12/1/016004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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43
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Fange D, Mellenius H, Dennis PP, Ehrenberg M. Thermodynamic modeling of variations in the rate of RNA chain elongation of E. coli rrn operons. Biophys J 2014; 106:55-64. [PMID: 24411237 DOI: 10.1016/j.bpj.2013.11.4487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/07/2013] [Accepted: 11/25/2013] [Indexed: 11/15/2022] Open
Abstract
Previous electron-microscopic imaging has shown high RNA polymerase occupation densities in the 16S and 23S encoding regions and low occupation densities in the noncoding leader, spacer, and trailer regions of the rRNA (rrn) operons in E. coli. This indicates slower transcript elongation within the coding regions and faster elongation within the noncoding regions of the operon. Inactivation of four of the seven rrn operons increases the transcript initiation frequency at the promoters of the three intact operons and reduces the time for RNA polymerase to traverse the operon. We have used the DNA sequence-dependent standard free energy variation of the transcription complex to model the experimentally observed changes in the elongation rate along the rrnB operon. We also model the stimulation of the average transcription rate over the whole operon by increasing rate of transcript initiation. Monte Carlo simulations, taking into account initiation of transcription, translocation, and backward and forward tracking of RNA polymerase, partially reproduce the observed transcript elongation rate variations along the rrn operon and fully account for the increased average rate in response to increased frequency of transcript initiation.
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Affiliation(s)
- David Fange
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Harriet Mellenius
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Patrick P Dennis
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
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44
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Vvedenskaya IO, Vahedian-Movahed H, Bird JG, Knoblauch JG, Goldman SR, Zhang Y, Ebright RH, Nickels BE. Interactions between RNA polymerase and the "core recognition element" counteract pausing. Science 2014; 344:1285-9. [PMID: 24926020 DOI: 10.1126/science.1253458] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Transcription elongation is interrupted by sequences that inhibit nucleotide addition and cause RNA polymerase (RNAP) to pause. Here, by use of native elongating transcript sequencing (NET-seq) and a variant of NET-seq that enables analysis of mutant RNAP derivatives in merodiploid cells (mNET-seq), we analyze transcriptional pausing genome-wide in vivo in Escherichia coli. We identify a consensus pause-inducing sequence element, G₋₁₀Y₋₁G(+1) (where -1 corresponds to the position of the RNA 3' end). We demonstrate that sequence-specific interactions between RNAP core enzyme and a core recognition element (CRE) that stabilize transcription initiation complexes also occur in transcription elongation complexes and facilitate pause read-through by stabilizing RNAP in a posttranslocated register. Our findings identify key sequence determinants of transcriptional pausing and establish that RNAP-CRE interactions modulate pausing.
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Affiliation(s)
- Irina O Vvedenskaya
- Department of Genetics and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Hanif Vahedian-Movahed
- Department of Chemistry and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Jeremy G Bird
- Department of Genetics and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA. Department of Chemistry and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Jared G Knoblauch
- Department of Genetics and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Seth R Goldman
- Department of Genetics and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Yu Zhang
- Department of Chemistry and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Richard H Ebright
- Department of Chemistry and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA.
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA.
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45
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Dangkulwanich M, Ishibashi T, Bintu L, Bustamante C. Molecular mechanisms of transcription through single-molecule experiments. Chem Rev 2014; 114:3203-23. [PMID: 24502198 PMCID: PMC3983126 DOI: 10.1021/cr400730x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Manchuta Dangkulwanich
- Jason L. Choy Laboratory of Single-Molecule
Biophysics, Department of Chemistry, California Institute
for Quantitative Biosciences, Department of Physics, and Department of Molecular and Cell
Biology, Howard Hughes Medical Institute,
and Kavli Energy NanoSciences Institute, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Toyotaka Ishibashi
- Jason L. Choy Laboratory of Single-Molecule
Biophysics, Department of Chemistry, California Institute
for Quantitative Biosciences, Department of Physics, and Department of Molecular and Cell
Biology, Howard Hughes Medical Institute,
and Kavli Energy NanoSciences Institute, University of California,
Berkeley, Berkeley, California 94720, United States
- Division
of Life Science, Hong Kong University of
Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
| | - Lacramioara Bintu
- Jason L. Choy Laboratory of Single-Molecule
Biophysics, Department of Chemistry, California Institute
for Quantitative Biosciences, Department of Physics, and Department of Molecular and Cell
Biology, Howard Hughes Medical Institute,
and Kavli Energy NanoSciences Institute, University of California,
Berkeley, Berkeley, California 94720, United States
- Department
of Bioengineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Carlos Bustamante
- Jason L. Choy Laboratory of Single-Molecule
Biophysics, Department of Chemistry, California Institute
for Quantitative Biosciences, Department of Physics, and Department of Molecular and Cell
Biology, Howard Hughes Medical Institute,
and Kavli Energy NanoSciences Institute, University of California,
Berkeley, Berkeley, California 94720, United States
- Physical
Biosciences Division, Lawrence Berkeley
National Laboratory, Berkeley, California 94720, United States
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46
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Yuzenkova Y, Roghanian M, Bochkareva A, Zenkin N. Tagetitoxin inhibits transcription by stabilizing pre-translocated state of the elongation complex. Nucleic Acids Res 2013; 41:9257-65. [PMID: 23935117 PMCID: PMC3814378 DOI: 10.1093/nar/gkt708] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/16/2013] [Accepted: 07/18/2013] [Indexed: 01/30/2023] Open
Abstract
Transcription elongation consists of repetition of the nucleotide addition cycle: phosphodiester bond formation, translocation and binding of the next nucleotide. Inhibitor of multi-subunit RNA polymerase tagetitoxin (TGT) enigmatically slows down addition of nucleotides in a sequence-dependent manner, only at certain positions of the template. Here, we show that TGT neither affects chemistry of RNA synthesis nor induces backward translocation, nor competes with the nucleoside triphosphate (NTP) in the active center. Instead, TGT increases the stability of the pre-translocated state of elongation complex, thus slowing down addition of the following nucleotide. We show that the extent of inhibition directly depends on the intrinsic stability of the pre-translocated state. The dependence of translocation equilibrium on the transcribed sequence results in a wide distribution (~1-10(3)-fold) of inhibitory effects of TGT at different positions of the template, thus explaining sequence-specificity of TGT action. We provide biochemical evidence that, in pre-translocated state, TGT stabilizes folded conformation of the Trigger Loop, which inhibits forward and backward translocation of the complex. The results suggest that Trigger Loop folding in the pre-translocated state may serve to reduce back-tracking of the elongation complex. Overall, we propose that translocation may be a limiting and highly regulated step of RNA synthesis.
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Affiliation(s)
- Yulia Yuzenkova
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne NE2 4AX, UK
| | | | | | - Nikolay Zenkin
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne NE2 4AX, UK
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47
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External conditions inversely change the RNA polymerase II elongation rate and density in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1248-55. [PMID: 24103494 DOI: 10.1016/j.bbagrm.2013.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/23/2022]
Abstract
Elongation speed is a key parameter in RNA polymerase II (RNA pol II) activity. It affects the transcription rate, while it is conditioned by the physicochemical environment it works in at the same time. For instance, it is well-known that temperature affects the biochemical reactions rates. Therefore in free-living organisms that are able to grow at various environmental temperatures, such as the yeast Saccharomyces cerevisiae, evolution should have not only shaped the structural and functional properties of this key enzyme, but should have also provided mechanisms and pathways to adapt its activity to the optimal performance required. We studied the changes in RNA pol II elongation speed caused by alternations in growth temperature in yeast to find that they strictly follow the Arrhenius equation, and that they also provoke an almost inverse proportional change in RNA pol II density within the optimal growth temperature range (26-37 °C). Moreover, we discovered that yeast cells control the transcription initiation rate by changing the total amount of available RNA pol II.
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48
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Intermittent Transcription Dynamics for the Rapid Production of Long Transcripts of High Fidelity. Cell Rep 2013; 5:521-30. [DOI: 10.1016/j.celrep.2013.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 02/01/2013] [Accepted: 09/05/2013] [Indexed: 11/23/2022] Open
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49
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Forties RA, Ma J, Wang MD. On the move. eLife 2013; 2:e01414. [PMID: 24073329 PMCID: PMC3782732 DOI: 10.7554/elife.01414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Single-molecule experiments have shed new light on the mechanisms responsible for the movement of RNA polymerase along DNA during transcription.
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Affiliation(s)
- Robert A Forties
- Department of Physics-Laboratory of Atomic and Solid State Physics and the Howard Hughes Medical Institute, Cornell University, Ithaca, United States
| | - Jie Ma
- Department of Physics-Laboratory of Atomic and Solid State Physics and the Howard Hughes Medical Institute, Cornell University, Ithaca, United States
| | - Michelle D Wang
- Department of Physics-Laboratory of Atomic and Solid State Physics and the Howard Hughes Medical Institute, Cornell University, Ithaca, United States
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Dangkulwanich M, Ishibashi T, Liu S, Kireeva ML, Lubkowska L, Kashlev M, Bustamante CJ. Complete dissection of transcription elongation reveals slow translocation of RNA polymerase II in a linear ratchet mechanism. eLife 2013; 2:e00971. [PMID: 24066225 PMCID: PMC3778554 DOI: 10.7554/elife.00971] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/13/2013] [Indexed: 12/31/2022] Open
Abstract
During transcription elongation, RNA polymerase has been assumed to attain equilibrium between pre- and post-translocated states rapidly relative to the subsequent catalysis. Under this assumption, recent single-molecule studies proposed a branched Brownian ratchet mechanism that necessitates a putative secondary nucleotide binding site on the enzyme. By challenging individual yeast RNA polymerase II with a nucleosomal barrier, we separately measured the forward and reverse translocation rates. Surprisingly, we found that the forward translocation rate is comparable to the catalysis rate. This finding reveals a linear, non-branched ratchet mechanism for the nucleotide addition cycle in which translocation is one of the rate-limiting steps. We further determined all the major on- and off-pathway kinetic parameters in the elongation cycle. The resulting translocation energy landscape shows that the off-pathway states are favored thermodynamically but not kinetically over the on-pathway states, conferring the enzyme its propensity to pause and furnishing the physical basis for transcriptional regulation. DOI:http://dx.doi.org/10.7554/eLife.00971.001.
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Affiliation(s)
- Manchuta Dangkulwanich
- Jason L Choy Laboratory of Single-Molecule Biophysics , University of California, Berkeley , Berkeley , United States ; Department of Chemistry , University of California, Berkeley , Berkeley , United States
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