1
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Zuiddam M, Shakiba B, Schiessel H. Multiplexing mechanical and translational cues on genes. Biophys J 2022; 121:4311-4324. [PMID: 36230003 PMCID: PMC9703045 DOI: 10.1016/j.bpj.2022.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 07/06/2022] [Accepted: 10/07/2022] [Indexed: 12/14/2022] Open
Abstract
The genetic code gives precise instructions on how to translate codons into amino acids. Due to the degeneracy of the genetic code-18 out of 20 amino acids are encoded for by more than one codon-more information can be stored in a basepair sequence. Indeed, various types of additional information have been discussed in the literature, e.g., the positioning of nucleosomes along eukaryotic genomes and the modulation of the translating efficiency in ribosomes to influence cotranslational protein folding. The purpose of this study is to show that it is indeed possible to carry more than one additional layer of information on top of a gene. In particular, we show how much translation efficiency and nucleosome positioning can be adjusted simultaneously without changing the encoded protein. We achieve this by mapping genes on weighted graphs that contain all synonymous genes, and then finding shortest paths through these graphs. This enables us, for example, to readjust the disrupted translational efficiency profile after a gene has been introduced from one organism (e.g., human) into another (e.g., yeast) without greatly changing the nucleosome landscape intrinsically encoded by the DNA molecule.
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Affiliation(s)
- Martijn Zuiddam
- Institute Lorentz for Theoretical Physics, Leiden University, Leiden, the Netherlands
| | - Bahareh Shakiba
- Institute Lorentz for Theoretical Physics, Leiden University, Leiden, the Netherlands
| | - Helmut Schiessel
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany.
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2
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Das M, Kantz H. Role of thermal fluctuations in biological copying mechanisms. Phys Rev E 2021; 103:032110. [PMID: 33862776 DOI: 10.1103/physreve.103.032110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 02/18/2021] [Indexed: 11/07/2022]
Abstract
During transcription, translation, or self-replication of DNA or RNA, information is transferred to the newly formed species from its predecessor. These processes can be interpreted as (generalized) biological copying mechanism as the new biological entities like DNA, RNA, or proteins are representing the information of their parent bodies uniquely. The accuracy of these copying processes is essential, since errors in the copied code can reduce the functionality of the next generation. Such errors might result from perturbations on these processes. Most important in this context is the temperature of the medium, i.e., thermal noise. Although a reasonable amount of experimental studies have been carried out on this important issue, theoretical understanding is truly sparse. In the present work, we illustrate a model study which is able to focus on the effect of the temperature on the process of biological copying mechanisms, as well as on mutation. We find for our paradigmatic models that, in a quite general scenario, the copying processes are most accurate at an intermediate temperature range; i.e., there exists an optimum temperature where mutation is most unlikely. This allows us to interpret the observations for some biological species with the aid of our model study.
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Affiliation(s)
- Moupriya Das
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Holger Kantz
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
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3
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Abstract
Kinetic proofreading is an error correction mechanism present in the processes of the central dogma and beyond and typically requires the free energy of nucleotide hydrolysis for its operation. Though the molecular players of many biological proofreading schemes are known, our understanding of how energy consumption is managed to promote fidelity remains incomplete. In our work, we introduce an alternative conceptual scheme called "the piston model of proofreading" in which enzyme activation through hydrolysis is replaced with allosteric activation achieved through mechanical work performed by a piston on regulatory ligands. Inspired by Feynman's ratchet and pawl mechanism, we consider a mechanical engine designed to drive the piston actions powered by a lowering weight, whose function is analogous to that of ATP synthase in cells. Thanks to its mechanical design, the piston model allows us to tune the "knobs" of the driving engine and probe the graded changes and trade-offs between speed, fidelity, and energy dissipation. It provides an intuitive explanation of the conditions necessary for optimal proofreading and reveals the unexpected capability of allosteric molecules to beat the Hopfield limit of fidelity by leveraging the diversity of states available to them. The framework that we have built for the piston model can also serve as a basis for additional studies of driven biochemical systems.
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Affiliation(s)
- Vahe Galstyan
- Biochemistry and Molecular Biophysics Option , California Institute of Technology , Pasadena , California 91125 , United States
| | - Rob Phillips
- Department of Physics , California Institute of Technology , Pasadena , California 91125 , United States.,Department of Applied Physics , California Institute of Technology , Pasadena , California 91125 , United States.,Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
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4
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Blossey R, Schiessel H. Histone mark recognition controls nucleosome translocation via a kinetic proofreading mechanism: Confronting theory and high-throughput experiments. Phys Rev E 2019; 99:060401. [PMID: 31330635 DOI: 10.1103/physreve.99.060401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Indexed: 12/13/2022]
Abstract
Chromatin remodelers are multidomain enzymatic motor complexes that displace nucleosomes along DNA and hence "remodel chromatin structure," i.e., they dynamically reorganize nucleosome positions in both gene activation and gene repression. Recently, experimental insights from structural biology methods and remodeling assays have substantially advanced the understanding of these key chromatin components. Here we confront the kinetic proofreading scenario of chromatin remodeling, which proposes a mechanical link between histone residue modifications and the ATP-dependent action of remodelers, with recent experiments. We show that recent high-throughput data on nucleosome libraries assayed with remodelers from the Imitation Switch family are in accord with our earlier predictions of the kinetic proofreading scenario. We make suggestions for experimentally verifiable predictions of the kinetic proofreading scenarios for remodelers from other families.
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Affiliation(s)
- Ralf Blossey
- Université de Lille, CNRS, UMR8576 Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), F-59000 Lille, France
| | - Helmut Schiessel
- Institute Lorentz for Theoretical Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
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5
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Roldán É, Vivo P. Exact distributions of currents and frenesy for Markov bridges. Phys Rev E 2019; 100:042108. [PMID: 31770868 DOI: 10.1103/physreve.100.042108] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Indexed: 02/01/2023]
Abstract
We consider discrete-time Markov bridges, chains whose initial and final states coincide. We derive exact finite-time formulae for the joint probability distributions of additive functionals of trajectories. We apply our theory to time-integrated currents and frenesy of enzymatic reactions, which may include absolutely irreversible transitions. We discuss the information that frenesy carries about the currents and show that bridges may violate known uncertainty relations in certain cases. Numerical simulations are in perfect agreement with our theory.
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Affiliation(s)
- Édgar Roldán
- ICTP-The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Pierpaolo Vivo
- Department of Mathematics, King's College London, Strand, London WC2R 2LS, United Kingdom
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6
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Mawla AM, Huising MO. Navigating the Depths and Avoiding the Shallows of Pancreatic Islet Cell Transcriptomes. Diabetes 2019; 68:1380-1393. [PMID: 31221802 PMCID: PMC6609986 DOI: 10.2337/dbi18-0019] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 04/29/2019] [Indexed: 12/24/2022]
Abstract
Islet gene expression has been widely studied to better understand the transcriptional features that define a healthy β-cell. Transcriptomes of FACS-purified α-, β-, and δ-cells using bulk RNA-sequencing have facilitated our understanding of the complex network of cross talk between islet cells and its effects on β-cell function. However, these approaches were by design not intended to resolve heterogeneity between individual cells. Several recent studies used single-cell RNA sequencing (scRNA-Seq) to report considerable heterogeneity within mouse and human β-cells. In this Perspective, we assess how this newfound ability to assess gene expression at single-cell resolution has enhanced our understanding of β-cell heterogeneity. We conduct a comprehensive assessment of several single human β-cell transcriptome data sets and ask if the heterogeneity reported by these studies showed overlap and concurred with previously known examples of β-cell heterogeneity. We also illustrate the impact of the inevitable limitations of working at or below the limit of detection of gene expression at single cell resolution and their consequences for the quality of single-islet cell transcriptome data. Finally, we offer some guidance on when to opt for scRNA-Seq and when bulk sequencing approaches may be better suited.
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Affiliation(s)
- Alex M Mawla
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, Davis, CA
| | - Mark O Huising
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, Davis, CA
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA
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7
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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: 8.6] [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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8
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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: 1.1] [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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9
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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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10
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Lisica A, Grill SW. Optical tweezers studies of transcription by eukaryotic RNA polymerases. Biomol Concepts 2017; 8:1-11. [PMID: 28222010 DOI: 10.1515/bmc-2016-0028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/10/2017] [Indexed: 11/15/2022] Open
Abstract
Transcription is the first step in the expression of genetic information and it is carried out by large macromolecular enzymes called RNA polymerases. Transcription has been studied for many years and with a myriad of experimental techniques, ranging from bulk studies to high-resolution transcript sequencing. In this review, we emphasise the advantages of using single-molecule techniques, particularly optical tweezers, to study transcription dynamics. We give an overview of the latest results in the single-molecule transcription field, focusing on transcription by eukaryotic RNA polymerases. Finally, we evaluate recent quantitative models that describe the biophysics of RNA polymerase translocation and backtracking dynamics.
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Affiliation(s)
- Ana Lisica
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
| | - Stephan W Grill
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
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11
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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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12
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Roldán É, Lisica A, Sánchez-Taltavull D, Grill SW. Stochastic resetting in backtrack recovery by RNA polymerases. Phys Rev E 2016; 93:062411. [PMID: 27415302 DOI: 10.1103/physreve.93.062411] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 11/07/2022]
Abstract
Transcription is a key process in gene expression, in which RNA polymerases produce a complementary RNA copy from a DNA template. RNA polymerization is frequently interrupted by backtracking, a process in which polymerases perform a random walk along the DNA template. Recovery of polymerases from the transcriptionally inactive backtracked state is determined by a kinetic competition between one-dimensional diffusion and RNA cleavage. Here we describe backtrack recovery as a continuous-time random walk, where the time for a polymerase to recover from a backtrack of a given depth is described as a first-passage time of a random walker to reach an absorbing state. We represent RNA cleavage as a stochastic resetting process and derive exact expressions for the recovery time distributions and mean recovery times from a given initial backtrack depth for both continuous and discrete-lattice descriptions of the random walk. We show that recovery time statistics do not depend on the discreteness of the DNA lattice when the rate of one-dimensional diffusion is large compared to the rate of cleavage.
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Affiliation(s)
- Édgar Roldán
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,Center for Advancing Electronics Dresden, cfaed, Dresden, Germany.,GISC - Grupo Interdisciplinar de Sistemas Complejos, Madrid, Spain
| | - Ana Lisica
- BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | | | - Stephan W Grill
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
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13
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Gaspard P. Kinetics and thermodynamics of exonuclease-deficient DNA polymerases. Phys Rev E 2016; 93:042419. [PMID: 27176340 DOI: 10.1103/physreve.93.042419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Indexed: 05/02/2023]
Abstract
A kinetic theory is developed for exonuclease-deficient DNA polymerases, based on the experimental observation that the rates depend not only on the newly incorporated nucleotide, but also on the previous one, leading to the growth of Markovian DNA sequences from a Bernoullian template. The dependencies on nucleotide concentrations and template sequence are explicitly taken into account. In this framework, the kinetic and thermodynamic properties of DNA replication, in particular, the mean growth velocity, the error probability, and the entropy production are calculated analytically in terms of the rate constants and the concentrations. Theory is compared with numerical simulations for the DNA polymerases of T7 viruses and human mitochondria.
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Affiliation(s)
- Pierre Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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14
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Abstract
During DNA transcription, RNA polymerases often adopt inactive backtracked states. Recovery from backtracks can occur by 1D diffusion or cleavage of backtracked RNA, but how polymerases make this choice is unknown. Here, we use single-molecule optical tweezers experiments and stochastic theory to show that the choice of a backtrack recovery mechanism is determined by a kinetic competition between 1D diffusion and RNA cleavage. Notably, RNA polymerase I (Pol I) and Pol II recover from shallow backtracks by 1D diffusion, use RNA cleavage to recover from intermediary depths, and are unable to recover from extensive backtracks. Furthermore, Pol I and Pol II use distinct mechanisms to avoid nonrecoverable backtracking. Pol I is protected by its subunit A12.2, which decreases the rate of 1D diffusion and enables transcript cleavage up to 20 nt. In contrast, Pol II is fully protected through association with the cleavage stimulatory factor TFIIS, which enables rapid recovery from any depth by RNA cleavage. Taken together, we identify distinct backtrack recovery strategies of Pol I and Pol II, shedding light on the evolution of cellular functions of these key enzymes.
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15
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Dulin D, Vilfan ID, Berghuis BA, Poranen MM, Depken M, Dekker NH. Backtracking behavior in viral RNA-dependent RNA polymerase provides the basis for a second initiation site. Nucleic Acids Res 2015; 43:10421-9. [PMID: 26496948 PMCID: PMC4666362 DOI: 10.1093/nar/gkv1098] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/11/2015] [Indexed: 12/02/2022] Open
Abstract
Transcription in RNA viruses is highly dynamic, with a variety of pauses interrupting nucleotide addition by RNA-dependent RNA polymerase (RdRp). For example, rare but lengthy pauses (>20 s) have been linked to backtracking for viral single-subunit RdRps. However, while such backtracking has been well characterized for multi-subunit RNA polymerases (RNAPs) from bacteria and yeast, little is known about the details of viral RdRp backtracking and its biological roles. Using high-throughput magnetic tweezers, we quantify the backtracking by RdRp from the double-stranded (ds) RNA bacteriophage Φ6, a model system for RdRps. We characterize the probability of entering long backtracks as a function of force and propose a model in which the bias toward backtracking is determined by the base paring at the dsRNA fork. We further discover that extensive backtracking provides access to a new 3′-end that allows for the de novo initiation of a second RdRp. This previously unidentified behavior provides a new mechanism for rapid RNA synthesis using coupled RdRps and hints at a possible regulatory pathway for gene expression during viral RNA transcription.
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Affiliation(s)
- David Dulin
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Igor D Vilfan
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Bojk A Berghuis
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Minna M Poranen
- Department of Biosciences, University of Helsinki, Viikki Biocenter 1, P.O. Box 56 (Viikinkaari 9), 00014 Helsinki, Finland
| | - Martin Depken
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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16
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Lang AH, Fisher CK, Mora T, Mehta P. Thermodynamics of statistical inference by cells. PHYSICAL REVIEW LETTERS 2014; 113:148103. [PMID: 25325665 DOI: 10.1103/physrevlett.113.148103] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Indexed: 06/04/2023]
Abstract
The deep connection between thermodynamics, computation, and information is now well established both theoretically and experimentally. Here, we extend these ideas to show that thermodynamics also places fundamental constraints on statistical estimation and learning. To do so, we investigate the constraints placed by (nonequilibrium) thermodynamics on the ability of biochemical signaling networks to estimate the concentration of an external signal. We show that accuracy is limited by energy consumption, suggesting that there are fundamental thermodynamic constraints on statistical inference.
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Affiliation(s)
- Alex H Lang
- Physics Department, Boston University, Boston, Massachusetts 02215, USA
| | - Charles K Fisher
- Physics Department, Boston University, Boston, Massachusetts 02215, USA
| | - Thierry Mora
- Laboratoire de physique statistique, CNRS, UPMC and École normale supérieure, 75005 Paris, France
| | - Pankaj Mehta
- Physics Department, Boston University, Boston, Massachusetts 02215, USA
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17
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Gingrich TR, Vaikuntanathan S, Geissler PL. Heterogeneity-induced large deviations in activity and (in some cases) entropy production. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:042123. [PMID: 25375454 DOI: 10.1103/physreve.90.042123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Indexed: 06/04/2023]
Abstract
We solve a simple model that supports a dynamic phase transition and show conditions for the existence of the transition. Using methods of large deviation theory we analytically compute the probability distribution for activity and entropy production rates of the trajectories on a large ring with a single heterogeneous link. The corresponding joint rate function demonstrates two dynamical phases--one localized and the other delocalized, but the marginal rate functions do not always exhibit the underlying transition. Symmetries in dynamic order parameters influence the observation of a transition, such that distributions for certain dynamic order parameters need not reveal an underlying dynamical bistability. Solution of our model system furthermore yields the form of the effective Markov transition matrices that generate dynamics in which the two dynamical phases are at coexistence. We discuss the implications of the transition for the response of bacterial cells to antibiotic treatment, arguing that even simple models of a cell cycle lacking an explicit bistability in configuration space will exhibit a bistability of dynamical phases.
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Affiliation(s)
- Todd R Gingrich
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | | | - Phillip L Geissler
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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18
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Transcription factors IIS and IIF enhance transcription efficiency by differentially modifying RNA polymerase pausing dynamics. Proc Natl Acad Sci U S A 2014; 111:3419-24. [PMID: 24550488 DOI: 10.1073/pnas.1401611111] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Transcription factors IIS (TFIIS) and IIF (TFIIF) are known to stimulate transcription elongation. Here, we use a single-molecule transcription elongation assay to study the effects of both factors. We find that these transcription factors enhance overall transcription elongation by reducing the lifetime of transcriptional pauses and that TFIIF also decreases the probability of pause entry. Furthermore, we observe that both factors enhance the processivity of RNA polymerase II through the nucleosomal barrier. The effects of TFIIS and TFIIF are quantitatively described using the linear Brownian ratchet kinetic model for transcription elongation and the backtracking model for transcriptional pauses, modified to account for the effects of the transcription factors. Our findings help elucidate the molecular mechanisms by which transcription factors modulate gene expression.
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