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Pukhrambam C, Molodtsov V, Kooshkbaghi M, Tareen A, Vu H, Skalenko KS, Su M, Yin Z, Winkelman JT, Kinney JB, Ebright RH, Nickels BE. Structural and mechanistic basis of σ-dependent transcriptional pausing. Proc Natl Acad Sci U S A 2022; 119:e2201301119. [PMID: 35653571 PMCID: PMC9191641 DOI: 10.1073/pnas.2201301119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/26/2022] [Indexed: 12/20/2022] Open
Abstract
In σ-dependent transcriptional pausing, the transcription initiation factor σ, translocating with RNA polymerase (RNAP), makes sequence-specific protein–DNA interactions with a promoter-like sequence element in the transcribed region, inducing pausing. It has been proposed that, in σ-dependent pausing, the RNAP active center can access off-pathway “backtracked” states that are substrates for the transcript-cleavage factors of the Gre family and on-pathway “scrunched” states that mediate pause escape. Here, using site-specific protein–DNA photocrosslinking to define positions of the RNAP trailing and leading edges and of σ relative to DNA at the λPR′ promoter, we show directly that σ-dependent pausing in the absence of GreB in vitro predominantly involves a state backtracked by 2–4 bp, and σ-dependent pausing in the presence of GreB in vitro and in vivo predominantly involves a state scrunched by 2–3 bp. Analogous experiments with a library of 47 (∼16,000) transcribed-region sequences show that the state scrunched by 2–3 bp—and only that state—is associated with the consensus sequence, T−3N−2Y−1G+1, (where −1 corresponds to the position of the RNA 3′ end), which is identical to the consensus for pausing in initial transcription and which is related to the consensus for pausing in transcription elongation. Experiments with heteroduplex templates show that sequence information at position T−3 resides in the DNA nontemplate strand. A cryoelectron microscopy structure of a complex engaged in σ-dependent pausing reveals positions of DNA scrunching on the DNA nontemplate and template strands and suggests that position T−3 of the consensus sequence exerts its effects by facilitating scrunching.
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Affiliation(s)
- Chirangini Pukhrambam
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Vadim Molodtsov
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Mahdi Kooshkbaghi
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Ammar Tareen
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Hoa Vu
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Kyle S. Skalenko
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Min Su
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Zhou Yin
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Jared T. Winkelman
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Justin B. Kinney
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Richard H. Ebright
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Bryce E. Nickels
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
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Skalenko KS, Li L, Zhang Y, Vvedenskaya IO, Winkelman JT, Cope AL, Taylor DM, Shah P, Ebright RH, Kinney JB, Zhang Y, Nickels BE. Promoter-sequence determinants and structural basis of primer-dependent transcription initiation in Escherichia coli. Proc Natl Acad Sci U S A 2021; 118:e2106388118. [PMID: 34187896 PMCID: PMC8271711 DOI: 10.1073/pnas.2106388118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chemical modifications of RNA 5'-ends enable "epitranscriptomic" regulation, influencing multiple aspects of RNA fate. In transcription initiation, a large inventory of substrates compete with nucleoside triphosphates for use as initiating entities, providing an ab initio mechanism for altering the RNA 5'-end. In Escherichia coli cells, RNAs with a 5'-end hydroxyl are generated by use of dinucleotide RNAs as primers for transcription initiation, "primer-dependent initiation." Here, we use massively systematic transcript end readout (MASTER) to detect and quantify RNA 5'-ends generated by primer-dependent initiation for ∼410 (∼1,000,000) promoter sequences in E. coli The results show primer-dependent initiation in E. coli involves any of the 16 possible dinucleotide primers and depends on promoter sequences in, upstream, and downstream of the primer binding site. The results yield a consensus sequence for primer-dependent initiation, YTSS-2NTSS-1NTSSWTSS+1, where TSS is the transcription start site, NTSS-1NTSS is the primer binding site, Y is pyrimidine, and W is A or T. Biochemical and structure-determination studies show that the base pair (nontemplate-strand base:template-strand base) immediately upstream of the primer binding site (Y:RTSS-2, where R is purine) exerts its effect through the base on the DNA template strand (RTSS-2) through interchain base stacking with the RNA primer. Results from analysis of a large set of natural, chromosomally encoded Ecoli promoters support the conclusions from MASTER. Our findings provide a mechanistic and structural description of how TSS-region sequence hard-codes not only the TSS position but also the potential for epitranscriptomic regulation through primer-dependent transcription initiation.
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Affiliation(s)
- Kyle S Skalenko
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
| | - Lingting Li
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yuanchao Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA 19041
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Irina O Vvedenskaya
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
| | - Jared T Winkelman
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Alexander L Cope
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Deanne M Taylor
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA 19041
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Premal Shah
- Department of Genetics, Rutgers University, Piscataway, NJ 08854
| | - Richard H Ebright
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854
| | - Justin B Kinney
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Bryce E Nickels
- Department of Genetics, Rutgers University, Piscataway, NJ 08854;
- Waksman Institute, Rutgers University, Piscataway, NJ 08854
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3
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Yu L, Winkelman JT, Pukhrambam C, Strick TR, Nickels BE, Ebright RH. The mechanism of variability in transcription start site selection. eLife 2017; 6:32038. [PMID: 29168694 PMCID: PMC5730371 DOI: 10.7554/elife.32038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/22/2017] [Indexed: 01/24/2023] Open
Abstract
During transcription initiation, RNA polymerase (RNAP) binds to promoter DNA, unwinds promoter DNA to form an RNAP-promoter open complex (RPo) containing a single-stranded ‘transcription bubble,’ and selects a transcription start site (TSS). TSS selection occurs at different positions within the promoter region, depending on promoter sequence and initiating-substrate concentration. Variability in TSS selection has been proposed to involve DNA ‘scrunching’ and ‘anti-scrunching,’ the hallmarks of which are: (i) forward and reverse movement of the RNAP leading edge, but not trailing edge, relative to DNA, and (ii) expansion and contraction of the transcription bubble. Here, using in vitro and in vivo protein-DNA photocrosslinking and single-molecule nanomanipulation, we show bacterial TSS selection exhibits both hallmarks of scrunching and anti-scrunching, and we define energetics of scrunching and anti-scrunching. The results establish the mechanism of TSS selection by bacterial RNAP and suggest a general mechanism for TSS selection by bacterial, archaeal, and eukaryotic RNAP. Genes store the information needed to build and repair cells. This information is written in a chemical code within the structure of DNA molecules. To make use of the information, cells copy sections of a gene into a DNA-like molecule called RNA. An enzyme called RNA polymerase makes RNA molecules from DNA templates in a process called transcription. RNA polymerase can only make RNA by attaching to DNA and separating the two strands of the DNA double helix. This creates a short region of single-stranded DNA known as a “transcription bubble”. RNA polymerase can start transcription at different distances from the sites where it initially attaches to DNA, depending on the DNA sequence and the cell’s environment. It had not been known how RNA polymerase selects different transcription start sites in different cases. One hypothesis had been that differences in the size of the transcription bubble – the amount of unwound single-stranded DNA – could be responsible for differences in transcription start sites. For example, RNA polymerase could increase the size of the bubble through a process called “DNA scrunching”, in which RNA polymerase pulls in and unwinds extra DNA from further along the gene. Yu, Winkelman et al. looked for indicators of DNA scrunching to see whether it contributes to the selection of transcription start sites. By mapping the positions of the two edges of RNA polymerase relative to DNA, they saw that RNA polymerase pulls in extra DNA when selecting a transcription start site further from its initial attachment site. Next, by measuring the amount of DNA unwinding, they saw that RNA polymerase unwinds extra DNA when it selects a transcription start site further from its initial attachment site. This was the case for both RNA polymerase in a test tube and RNA polymerase in living bacterial cells. The results showed that DNA scrunching accounts for known patterns of selection of transcription start sites. The findings hint at a common theory for the selection of transcription start sites across all life by DNA scrunching. Understanding these basic principles of biology reveals more about how cells work and how cells adapt to changing conditions. The experimental methods developed for mapping the positions of proteins on DNA and for measuring DNA unwinding will help scientists to learn more about other aspects of how DNA is stored, copied, read, and controlled.
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Affiliation(s)
- Libing Yu
- Department of Chemistry, Rutgers University, Piscataway, United States.,Waksman Institute, Rutgers University, Piscataway, United States
| | - Jared T Winkelman
- Department of Chemistry, Rutgers University, Piscataway, United States.,Waksman Institute, Rutgers University, Piscataway, United States.,Department of Genetics, Rutgers University, Piscataway, United States
| | - Chirangini Pukhrambam
- Waksman Institute, Rutgers University, Piscataway, United States.,Department of Genetics, Rutgers University, Piscataway, United States
| | - Terence R Strick
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France.,Programme Equipe Labellisées, Ligue Contre le Cancer, Paris, France.,Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Paris, France
| | - Bryce E Nickels
- Waksman Institute, Rutgers University, Piscataway, United States.,Department of Genetics, Rutgers University, Piscataway, United States
| | - Richard H Ebright
- Department of Chemistry, Rutgers University, Piscataway, United States.,Waksman Institute, Rutgers University, Piscataway, United States
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4
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Chen J, Wassarman KM, Feng S, Leon K, Feklistov A, Winkelman JT, Li Z, Walz T, Campbell EA, Darst SA. 6S RNA Mimics B-Form DNA to Regulate Escherichia coli RNA Polymerase. Mol Cell 2017; 68:388-397.e6. [PMID: 28988932 DOI: 10.1016/j.molcel.2017.09.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/11/2017] [Accepted: 09/05/2017] [Indexed: 01/25/2023]
Abstract
Noncoding RNAs (ncRNAs) regulate gene expression in all organisms. Bacterial 6S RNAs globally regulate transcription by binding RNA polymerase (RNAP) holoenzyme and competing with promoter DNA. Escherichia coli (Eco) 6S RNA interacts specifically with the housekeeping σ70-holoenzyme (Eσ70) and plays a key role in the transcriptional reprogramming upon shifts between exponential and stationary phase. Inhibition is relieved upon 6S RNA-templated RNA synthesis. We report here the 3.8 Å resolution structure of a complex between 6S RNA and Eσ70 determined by single-particle cryo-electron microscopy and validation of the structure using footprinting and crosslinking approaches. Duplex RNA segments have A-form C3' endo sugar puckers but widened major groove widths, giving the RNA an overall architecture that mimics B-form promoter DNA. Our results help explain the specificity of Eco 6S RNA for Eσ70 and show how an ncRNA can mimic B-form DNA to directly regulate transcription by the DNA-dependent RNAP.
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Affiliation(s)
- James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Karen M Wassarman
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Shili Feng
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Katherine Leon
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Andrey Feklistov
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Jared T Winkelman
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zongli Li
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA.
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA.
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5
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Abstract
Bacterial RNA polymerase-promoter open complexes can exist in a range of states in which the leading edge of the enzyme moves but the trailing edge does not, a phenomenon we refer to as "open complex scrunching." Here we describe how open complex scrunching can determine the position of the transcription start site for some promoters, modulate the level of expression, and potentially could be targeted by factors to regulate transcription. We suggest that open complex scrunching at the extraordinarily active ribosomal RNA promoters might have evolved to initiate transcription at an unusual position relative to the core promoter elements in order to maximize the rate of promoter escape.
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Affiliation(s)
- Jared T. Winkelman
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Genetics and Waksman Institute, Rutgers University, NJ, USA
| | - Richard L. Gourse
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
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Winkelman JT, Vvedenskaya IO, Zhang Y, Zhang Y, Bird JG, Taylor DM, Gourse RL, Ebright RH, Nickels BE. Multiplexed protein-DNA cross-linking: Scrunching in transcription start site selection. Science 2016; 351:1090-3. [PMID: 26941320 DOI: 10.1126/science.aad6881] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In bacterial transcription initiation, RNA polymerase (RNAP) selects a transcription start site (TSS) at variable distances downstream of core promoter elements. Using next-generation sequencing and unnatural amino acid-mediated protein-DNA cross-linking, we have determined, for a library of 4(10) promoter sequences, the TSS, the RNAP leading-edge position, and the RNAP trailing-edge position. We find that a promoter element upstream of the TSS, the "discriminator," participates in TSS selection, and that, as the TSS changes, the RNAP leading-edge position changes, but the RNAP trailing-edge position does not change. Changes in the RNAP leading-edge position, but not the RNAP trailing-edge position, are a defining hallmark of the "DNA scrunching" that occurs concurrent with RNA synthesis in initial transcription. We propose that TSS selection involves DNA scrunching prior to RNA synthesis.
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Affiliation(s)
- Jared T Winkelman
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA. Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Irina O Vvedenskaya
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Yuanchao Zhang
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yu Zhang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Jeremy G Bird
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Deanne M Taylor
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA. Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Richard L Gourse
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Richard H Ebright
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA.
| | - Bryce E Nickels
- Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA.
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Yang Y, Darbari VC, Zhang N, Lu D, Glyde R, Wang YP, Winkelman JT, Gourse RL, Murakami KS, Buck M, Zhang X. TRANSCRIPTION. Structures of the RNA polymerase-σ54 reveal new and conserved regulatory strategies. Science 2015; 349:882-5. [PMID: 26293966 DOI: 10.1126/science.aab1478] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transcription by RNA polymerase (RNAP) in bacteria requires specific promoter recognition by σ factors. The major variant σ factor (σ(54)) initially forms a transcriptionally silent complex requiring specialized adenosine triphosphate-dependent activators for initiation. Our crystal structure of the 450-kilodalton RNAP-σ(54) holoenzyme at 3.8 angstroms reveals molecular details of σ(54) and its interactions with RNAP. The structure explains how σ(54) targets different regions in RNAP to exert its inhibitory function. Although σ(54) and the major σ factor, σ(70), have similar functional domains and contact similar regions of RNAP, unanticipated differences are observed in their domain arrangement and interactions with RNAP, explaining their distinct properties. Furthermore, we observe evolutionarily conserved regulatory hotspots in RNAPs that can be targeted by a diverse range of mechanisms to fine tune transcription.
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Affiliation(s)
- Yun Yang
- Centre for Structural Biology, Imperial College London, South Kensington SW7 2AZ, UK. State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, China
| | - Vidya C Darbari
- Centre for Structural Biology, Imperial College London, South Kensington SW7 2AZ, UK. Department of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| | - Nan Zhang
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Duo Lu
- Centre for Structural Biology, Imperial College London, South Kensington SW7 2AZ, UK
| | - Robert Glyde
- Centre for Structural Biology, Imperial College London, South Kensington SW7 2AZ, UK. Department of Medicine, Imperial College London, South Kensington SW7 2AZ, UK
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, China
| | - Jared T Winkelman
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | - Richard L Gourse
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Martin Buck
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Xiaodong Zhang
- Centre for Structural Biology, Imperial College London, South Kensington SW7 2AZ, UK. Department of Medicine, Imperial College London, South Kensington SW7 2AZ, UK.
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Winkelman JT, Winkelman BT, Boyce J, Maloney MF, Chen AY, Ross W, Gourse RL. Crosslink Mapping at Amino Acid-Base Resolution Reveals the Path of Scrunched DNA in Initial Transcribing Complexes. Mol Cell 2015; 59:768-80. [PMID: 26257284 DOI: 10.1016/j.molcel.2015.06.037] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 06/25/2015] [Accepted: 06/30/2015] [Indexed: 12/21/2022]
Abstract
RNA polymerase binds tightly to DNA to recognize promoters with high specificity but then releases these contacts during the initial stage of transcription. We report a site-specific crosslinking approach to map the DNA path in bacterial transcription intermediates at amino acid and nucleotide resolution. After validating the approach by showing that the DNA path in open complexes (RPO) is the same as in high-resolution X-ray structures, we define the path following substrate addition in "scrunched" complexes (RPITC). The DNA bulges that form within the transcription bubble in RPITC are positioned differently on the two strands. Our data suggest that the non-template strand bulge is extruded into solvent in complexes containing a 5-mer RNA, whereas the template strand bulge remains within the template strand tunnel, exerting stress on interactions between the β flap, β' clamp, and σ3.2. We propose that this stress contributes to σ3.2 displacement from the RNA exit channel, facilitating promoter escape.
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Affiliation(s)
- Jared T Winkelman
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Bradford T Winkelman
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Julian Boyce
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Michael F Maloney
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Albert Y Chen
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Wilma Ross
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Richard L Gourse
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA.
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9
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Winkelman JT, Bree AC, Bate AR, Eichenberger P, Gourse RL, Kearns DB. RemA is a DNA-binding protein that activates biofilm matrix gene expression in Bacillus subtilis. Mol Microbiol 2013; 88:984-97. [PMID: 23646920 DOI: 10.1111/mmi.12235] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2013] [Indexed: 11/29/2022]
Abstract
Biofilm formation in Bacillus subtilis requires expression of the eps and tapA-sipW-tasA operons to synthesize the extracellular matrix components, extracellular polysaccharide and TasA amyloid proteins, respectively. Expression of both operons is inhibited by the DNA-binding protein master regulator of biofilm formation SinR and activated by the protein RemA. Here we show that RemA is a DNA-binding protein that binds to multiple sites upstream of the promoters of both operons and is both necessary and sufficient for transcriptional activation in vivo and in vitro. We further show that SinR negatively regulates eps operon expression by occluding RemA binding and thus for the P(eps) promoter SinR functions as an anti-activator. Finally, transcriptional profiling indicated that RemA was primarily a regulator of the extracellular matrix genes, but it also activated genes involved in osmoprotection, leading to the identification of another direct target, the opuA operon.
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Affiliation(s)
- Jared T Winkelman
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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10
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Abstract
Biofilms are multicellular aggregates of sessile bacteria encased by an extracellular matrix and are important medically as a source of drug-resistant microbes. In Bacillus subtilis, we found that an operon required for biofilm matrix biosynthesis also encoded an inhibitor of motility, EpsE. EpsE arrested flagellar rotation in a manner similar to that of a clutch, by disengaging motor force-generating elements in cells embedded in the biofilm matrix. The clutch is a simple, rapid, and potentially reversible form of motility control.
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Affiliation(s)
- Kris M Blair
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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