1
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Wollman AJM, Syeda AH, Howard JAL, Payne-Dwyer A, Leech A, Warecka D, Guy C, McGlynn P, Hawkins M, Leake MC. Tetrameric UvrD Helicase Is Located at the E. Coli Replisome due to Frequent Replication Blocks. J Mol Biol 2024; 436:168369. [PMID: 37977299 DOI: 10.1016/j.jmb.2023.168369] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/19/2023]
Abstract
DNA replication in all organisms must overcome nucleoprotein blocks to complete genome duplication. Accessory replicative helicases in Escherichia coli, Rep and UvrD, help remove these blocks and aid the re-initiation of replication. Mechanistic details of Rep function have emerged from recent live cell studies; however, the division of UvrD functions between its activities in DNA repair and role as an accessory helicase remain unclear in live cells. By integrating super-resolved single-molecule fluorescence microscopy with biochemical analysis, we find that UvrD self-associates into tetrameric assemblies and, unlike Rep, is not recruited to a specific replisome protein despite being found at approximately 80% of replication forks. Instead, its colocation with forks is likely due to the very high frequency of replication blocks composed of DNA-bound proteins, including RNA polymerase and factors involved in repairing DNA damage. Deleting rep and DNA repair factor genes mutS and uvrA, and inhibiting transcription through RNA polymerase mutation and antibiotic inhibition, indicates that the level of UvrD at the fork is dependent on UvrD's function. Our findings show that UvrD is recruited to sites of nucleoprotein blocks via different mechanisms to Rep and plays a multi-faceted role in ensuring successful DNA replication.
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Affiliation(s)
- Adam J M Wollman
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Aisha H Syeda
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Jamieson A L Howard
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alex Payne-Dwyer
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Andrew Leech
- Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Dominika Warecka
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Colin Guy
- Covance Laboratories Ltd., Otley Road, Harrogate HG3 1PY, United Kingdom
| | - Peter McGlynn
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Michelle Hawkins
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom.
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2
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Garcia-Seyda N, Song S, Seveau de Noray V, David-Broglio L, Matti C, Artinger M, Dupuy F, Biarnes-Pelicot M, Valignat MP, Legler DF, Bajénoff M, Theodoly O. Naive T lymphocytes chemotax long distance to CCL21 but not to a source of bioactive S1P. iScience 2023; 26:107695. [PMID: 37822497 PMCID: PMC10562802 DOI: 10.1016/j.isci.2023.107695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/12/2023] [Accepted: 08/16/2023] [Indexed: 10/13/2023] Open
Abstract
Naive T lymphocytes traffic through the organism in search for antigen, alternating between blood and secondary lymphoid organs. Lymphocyte homing to lymph nodes relies on CCL21 chemokine sensing by CCR7 receptors, while exit into efferent lymphatics relies on sphingolipid S1P sensing by S1PR1 receptors. While both molecules are claimed chemotactic, a quantitative analysis of naive T lymphocyte migration along defined gradients is missing. Here, we used a reductionist approach to study the real-time single-cell response of naive T lymphocytes to CCL21 and serum rich in bioactive S1P. Using microfluidic and micropatterning ad hoc tools, we show that CCL21 triggers stable polarization and long-range chemotaxis of cells, whereas S1P-rich serum triggers a transient polarization only and no significant displacement, potentially representing a brief transmigration step through exit portals. Our in vitro data thus suggest that naive T lymphocyte chemotax long distances to CCL21 but not toward a source of bioactive S1P.
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Affiliation(s)
- Nicolas Garcia-Seyda
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
- Aix Marseille University, Inserm, CNRS, CIML, Marseille, France
| | - Solene Song
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
- Aix Marseille University, Inserm, CNRS, CIML, Marseille, France
| | | | - Luc David-Broglio
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
| | - Christoph Matti
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, 8280 Kreuzlingen, Switzerland
| | - Marc Artinger
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, 8280 Kreuzlingen, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Florian Dupuy
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
| | - Martine Biarnes-Pelicot
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
| | - Marie-Pierre Valignat
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
| | - Daniel F. Legler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Unterseestrasse 47, 8280 Kreuzlingen, Switzerland
- Faculty of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
- Theodor Kocher Institute, University of Bern, Freiestrasse 1, 3012 Bern, Switzerland
| | - Marc Bajénoff
- Aix Marseille University, Inserm, CNRS, CIML, Marseille, France
| | - Olivier Theodoly
- Aix Marseille University, Inserm, CNRS, Turing Center for Living Systems, LAI, Marseille, France
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3
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Montorsi L, Siu JHY, Spencer J. B cells in human lymphoid structures. Clin Exp Immunol 2022; 210:240-252. [PMID: 36370126 PMCID: PMC9985168 DOI: 10.1093/cei/uxac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/30/2022] [Accepted: 11/11/2022] [Indexed: 11/13/2022] Open
Abstract
Most B cells in the human body are present in tissues where they support immune responses to pathogens, vaccines, autoantigens, and tumours. Despite their clear importance, they are very difficult to study and there are many areas of uncertainty that are difficult to resolve because of limited tissue access. In this review, we consider the zonal structure of lymphoid tissues, the B cell subsets they contain, and how these are regulated. We also discuss the impact that methods of deep interrogation have made on our current knowledge base, especially with respect to studies of cells from dissociated tissues. We discuss in some detail the controversial B cells with marginal zone distribution that some consider being archived memory B cells. We anticipate that more we understand of B cells in tissues and the niches they create, the more opportunities will be identified to harness their potential for therapeutic benefit.
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Affiliation(s)
- Lucia Montorsi
- Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College London, London, UK
| | - Jacqueline H Y Siu
- Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College London, London, UK
| | - Jo Spencer
- Correspondence: Jo Spencer, Peter Gorer Department of Immunobiology, King’s College London, Second Floor Borough Wing, Guy’s Hospital Campus, St Thomas’ St, London SE1 9RT, UK.
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4
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Schwarzenberg FL, Schütz P, Hammel JU, Riedel M, Bartl J, Bordbari S, Frank SC, Walkenfort B, Busse M, Herzen J, Lohr C, Wülfing C, Henne S. Three-dimensional analyses of vascular network morphology in a murine lymph node by X-ray phase-contrast tomography with a 2D Talbot array. Front Immunol 2022; 13:947961. [PMID: 36524111 PMCID: PMC9745095 DOI: 10.3389/fimmu.2022.947961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
With growing molecular evidence for correlations between spatial arrangement of blood vasculature and fundamental immunological functions, carried out in distinct compartments of the subdivided lymph node, there is an urgent need for three-dimensional models that can link these aspects. We reconstructed such models at a 1.84 µm resolution by the means of X-ray phase-contrast imaging with a 2D Talbot array in a short time without any staining. In addition reconstructions are verified in immunohistochemistry staining as well as in ultrastructural analyses. While conventional illustrations of mammalian lymph nodes depict the hilus as a definite point of blood and lymphatic vessel entry and exit, our method revealed that multiple branches enter and emerge from an area that extends up to one third of the organ's surface. This could be a prerequisite for the drastic and location-dependent remodeling of vascularization, which is necessary for lymph node expansion during inflammation. Contrary to corrosion cast studies we identified B-cell follicles exhibiting a two times denser capillary network than the deep cortical units of the T-cell zone. In addition to our observation of high endothelial venules spatially surrounding the follicles, this suggests a direct connection between morphology and B-cell homing. Our findings will deepen the understanding of functional lymph node composition and lymphocyte migration on a fundamental basis.
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Affiliation(s)
- Florian L. Schwarzenberg
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Paul Schütz
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Jörg U. Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - Mirko Riedel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany,Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany,Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Jasmin Bartl
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Sharareh Bordbari
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Svea-Celina Frank
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Bernd Walkenfort
- Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Madleen Busse
- Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany,Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Julia Herzen
- Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany,Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Clemens Wülfing
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany
| | - Stephan Henne
- INI-Research, Group for Interdisciplinary Neurobiology and Immunology, University of Hamburg, Hamburg, Germany,*Correspondence: Stephan Henne,
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5
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Wang ZJ, Thomson M. Localization of signaling receptors maximizes cellular information acquisition in spatially structured natural environments. Cell Syst 2022; 13:530-546.e12. [PMID: 35679857 DOI: 10.1016/j.cels.2022.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/08/2022] [Accepted: 05/12/2022] [Indexed: 01/25/2023]
Abstract
Cells in natural environments, such as tissue or soil, sense and respond to extracellular ligands with intricately structured and non-monotonic spatial distributions, sculpted by processes such as fluid flow and substrate adhesion. In this work, we show that spatial sensing and navigation can be optimized by adapting the spatial organization of signaling pathways to the spatial structure of the environment. We develop an information-theoretic framework for computing the optimal spatial organization of a sensing system for a given signaling environment. We find that receptor localization previously observed in cells maximizes information acquisition in simulated natural contexts, including tissue and soil. Specifically, information acquisition is maximized when receptors form localized patches at regions of maximal ligand concentration. Receptor localization extends naturally to produce a dynamic protocol for continuously redistributing signaling receptors, which when implemented using simple feedback, boosts cell navigation efficiency by 30-fold.
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Affiliation(s)
- Zitong Jerry Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Matt Thomson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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6
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Payne-Dwyer AL, Leake MC. Single-Molecular Quantification of Flowering Control Proteins Within Nuclear Condensates in Live Whole Arabidopsis Root. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2476:311-328. [PMID: 35635712 DOI: 10.1007/978-1-0716-2221-6_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Here we describe the coupled standardization of two complementary fluorescence imaging techniques and apply it to liquid-liquid phase-separated condensates formed from an EGFP fluorescent reporter of flowering control locus A (FCA), a protein that associates with chromosomal DNA in plants during epigenetic regulation of the flowering process. First, we use home-built single-molecule Slimfield microscopy to establish a fluorescent protein standard. This sample comprises live yeast cells expressing Mig1 protein, a metabolic regulator which localizes to the nucleus under conditions of high glucose, fused to the same type of EGFP label as for the FCA fusion construct. Then we employ commercial confocal AiryScan microscopy to study the same standard. Finally, we demonstrate how to quantify FCA-EGFP nuclear condensates in intact root tips at rapid timescales and apply this calibration. This method is a valuable approach to obtaining single-molecule precise stoichiometry and copy number estimates of protein condensates that are integrated into the chromosome architecture of plants, using confocal instrumentation that lacks de facto single-molecule detection sensitivity.
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Affiliation(s)
- Alex L Payne-Dwyer
- Department of Physics, University of York, York, UK.
- Departments of Physics and Biology, University of York, York, UK.
| | - Mark C Leake
- Departments of Physics and Biology, University of York, York, UK
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7
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Wollman AJM, Fournier C, Llorente-Garcia I, Harriman O, Payne-Dwyer AL, Shashkova S, Zhou P, Liu TC, Ouaret D, Wilding J, Kusumi A, Bodmer W, Leake MC. Critical roles for EGFR and EGFR-HER2 clusters in EGF binding of SW620 human carcinoma cells. J R Soc Interface 2022; 19:20220088. [PMID: 35612280 PMCID: PMC9131850 DOI: 10.1098/rsif.2022.0088] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Epidermal growth factor (EGF) signalling regulates normal epithelial and other cell growth, with EGF receptor (EGFR) overexpression reported in many cancers. However, the role of EGFR clusters in cancer and their dependence on EGF binding is unclear. We present novel single-molecule total internal reflection fluorescence microscopy of (i) EGF and EGFR in living cancer cells, (ii) the action of anti-cancer drugs that separately target EGFR and human EGFR2 (HER2) on these cells and (iii) EGFR–HER2 interactions. We selected human epithelial SW620 carcinoma cells for their low level of native EGFR expression, for stable transfection with fluorescent protein labelled EGFR, and imaged these using single-molecule localization microscopy to quantify receptor architectures and dynamics upon EGF binding. Prior to EGF binding, we observe pre-formed EGFR clusters. Unexpectedly, clusters likely contain both EGFR and HER2, consistent with co-diffusion of EGFR and HER2 observed in a different model CHO-K1 cell line, whose stoichiometry increases following EGF binding. We observe a mean EGFR : EGF stoichiometry of approximately 4 : 1 for plasma membrane-colocalized EGFR–EGF that we can explain using novel time-dependent kinetics modelling, indicating preferential ligand binding to monomers. Our results may inform future cancer drug developments.
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Affiliation(s)
- Adam J M Wollman
- Department of Physics, University of York, York, UK.,Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Charlotte Fournier
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK.,Science and Technology Group, Okinawa Institute of Science and Technology Graduate University (OIST), 1919 Tancha, Onna-son, Okinawa 904-0495, Japan
| | | | - Oliver Harriman
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK
| | | | | | - Peng Zhou
- Membrane Cooperativity Unit, OIST, 1919 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Ta-Chun Liu
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Djamila Ouaret
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Jenny Wilding
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Akihiro Kusumi
- Membrane Cooperativity Unit, OIST, 1919 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Walter Bodmer
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Mark C Leake
- Department of Physics, University of York, York, UK.,Department of Biology, University of York, York, UK.,Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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8
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Schnitzer B, Welkenhuysen N, Leake MC, Shashkova S, Cvijovic M. The effect of stress on biophysical characteristics of misfolded protein aggregates in living Saccharomyces cerevisiae cells. Exp Gerontol 2022; 162:111755. [PMID: 35240259 DOI: 10.1016/j.exger.2022.111755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/11/2022] [Accepted: 02/24/2022] [Indexed: 11/28/2022]
Abstract
Aggregation of misfolded or damaged proteins is often attributed to numerous metabolic and neurodegenerative disorders. To reveal underlying mechanisms and cellular responses, it is crucial to investigate protein aggregate dynamics in cells. Here, we used super-resolution single-molecule microscopy to obtain biophysical characteristics of individual aggregates of a model misfolded protein ∆ssCPY* labelled with GFP. We demonstrated that oxidative and hyperosmotic stress lead to increased aggregate stoichiometries but not necessarily the total number of aggregates. Moreover, our data suggest the importance of the thioredoxin peroxidase Tsa1 for the controlled sequestering and clearance of aggregates upon both conditions. Our work provides novel insights into the understanding of the cellular response to stress via revealing the dynamical properties of stress-induced protein aggregates.
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Affiliation(s)
- Barbara Schnitzer
- Department of Mathematical Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Mathematical Sciences, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Niek Welkenhuysen
- Department of Mathematical Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Mathematical Sciences, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Mark C Leake
- Department of Physics, University of York, YO10 5DD York, UK; Department of Biology, University of York, YO10 5DD York, UK
| | - Sviatlana Shashkova
- Department of Mathematical Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Mathematical Sciences, University of Gothenburg, 412 96 Gothenburg, Sweden; Department of Physics, University of York, YO10 5DD York, UK.
| | - Marija Cvijovic
- Department of Mathematical Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden; Department of Mathematical Sciences, University of Gothenburg, 412 96 Gothenburg, Sweden.
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9
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Abstract
The bacterial cytoplasm is a very crowded environment, and changes in crowding are thought to have an impact on cellular processes including protein folding, molecular diffusion and complex formation. Previous studies on the effects of crowding have generally compared cellular activity after imposition of stress. In response to different light intensities, in unstressed conditions, Rhodobacter sphaeroides changes the number of 50-nm intracytoplasmic membrane (ICM) vesicles, with the number varying from a few to over a thousand per cell. In this work, the effects of crowding induced by ICM vesicles in photoheterotrophic R. sphaeroides were investigated using a fluorescence resonance energy transfer (FRET) sensor and photoactivated localization microscopy (PALM). In low light grown cells where the cytoplasm has large numbers of ICM vesicles, the FRET probe adopts a more condensed conformation, resulting in higher FRET ratio readouts compared to high light cells with fewer ICM vesicles. The apparent diffusion coefficients of different sized proteins, PAmCherry, PAmCherry-CheY6, and L1-PAmCherry, measured via PALM showed that diffusion of protein molecules >27 kDa decreased as the number of ICM vesicles increased. In low light R. sphaeroides where the crowding level is high, protein molecules were found to diffuse more slowly than in aerobic and high light cells. This suggests that some physiological activities might show different kinetics in bacterial species whose intracellular membrane organization can change with growth conditions. IMPORTANCE The bacterial cytoplasm is known to be crowded, with that crowding suggested to change with growth, with chromosome replication, and under stress conditions. Many physiological activities depend on proteins and substrates diffusing through the cytoplasm; in some cases, large complexes need to diffuse from pole to pole. It is unclear how increases in crowding might affect cellular functions. We investigated whether we could naturally change the crowded state of the Rhodobacter sphaeroides cytoplasm by growing under different growth conditions. We show that increasing the number of intracytoplasmic vesicles by growing photosynthetically does change the crowded state of the cytoplasm and also alters the diffusion rates of different sized proteins measured. As many other cellular processes require protein movement, these findings could have broader implications for bacterial growth and responses under changing conditions that could alter cytoplasmic crowding.
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10
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Mohale M, Gundampati RK, Thallapuranam S, Heyes CD. Site-specific labeling and functional efficiencies of human fibroblast growth Factor-1 with a range of fluorescent dyes in the flexible N-Terminal region and a rigid β-turn region. Anal Biochem 2021; 640:114524. [PMID: 34933004 DOI: 10.1016/j.ab.2021.114524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/08/2021] [Indexed: 11/01/2022]
Abstract
Human fibroblast growth factor 1 (hFGF1) binding to its receptor and heparin play critical roles in cell proliferation, angiogenesis and wound healing but is also implicated in cancer. Fluorescence imaging is a powerful approach to study such protein interactions, but it is not always obvious if the site chosen will be efficiently labeled, often relying on trial-and-error. To provide a more systematic approach towards an efficient site-specific labeling strategy, we labeled two structurally distinct regions of the protein - the flexible N-terminus and a rigid loop. Several dyes were chosen to cover the visible region and to investigate how the structure of the dye affects the labeling efficiency. Flexibility in either the protein labeling site or the dye structure was found to result in high labeling efficiency, but flexibility in both resulted in a significant decrease in labeling efficiency. Conversely, too much rigidity in both can result in dye-protein interactions that can aggregate the protein. Importantly, site-specifically labeling hFGF1 in these regions maintained biological activity. These results could be applicable to other proteins by considering the flexibility of both the protein labeling site and the dye structure.
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Affiliation(s)
- Mamello Mohale
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA
| | - Ravi Kumar Gundampati
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA
| | - Suresh Thallapuranam
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA
| | - Colin D Heyes
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA.
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11
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Johanson TM, Keenan CR, Allan RS. Shedding Structured Light on Molecular Immunity: The Past, Present and Future of Immune Cell Super Resolution Microscopy. Front Immunol 2021; 12:754200. [PMID: 34975842 PMCID: PMC8715013 DOI: 10.3389/fimmu.2021.754200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
In the two decades since the invention of laser-based super resolution microscopy this family of technologies has revolutionised the way life is viewed and understood. Its unparalleled resolution, speed, and accessibility makes super resolution imaging particularly useful in examining the highly complex and dynamic immune system. Here we introduce the super resolution technologies and studies that have already fundamentally changed our understanding of a number of central immunological processes and highlight other immunological puzzles only addressable in super resolution.
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Affiliation(s)
- Timothy M. Johanson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Christine R. Keenan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Rhys S. Allan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
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12
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Moreno-Cañadas R, Luque-Martín L, Arroyo AG. Intravascular Crawling of Patrolling Monocytes: A Lèvy-Like Motility for Unique Search Functions? Front Immunol 2021; 12:730835. [PMID: 34603307 PMCID: PMC8485030 DOI: 10.3389/fimmu.2021.730835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/30/2021] [Indexed: 12/12/2022] Open
Abstract
Patrolling monocytes (PMo) are the organism’s preeminent intravascular guardians by their continuous search of damaged endothelial cells and harmful microparticles for their removal and to restore homeostasis. This surveillance is accomplished by PMo crawling on the apical side of the endothelium through regulated interactions of integrins and chemokine receptors with their endothelial ligands. We propose that the search mode governs the intravascular motility of PMo in vivo in a similar way to T cells looking for antigen in tissues. Signs of damage to the luminal side of the endothelium (local death, oxidized LDL, amyloid deposits, tumor cells, pathogens, abnormal red cells, etc.) will change the diffusive random towards a Lèvy-like crawling enhancing their recognition and clearance by PMo damage receptors as the integrin αMβ2 and CD36. This new perspective can help identify new actors to promote unique PMo intravascular actions aimed at maintaining endothelial fitness and combating harmful microparticles involved in diseases as lung metastasis, Alzheimer’s angiopathy, vaso-occlusive disorders, and sepsis.
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Affiliation(s)
- Rocío Moreno-Cañadas
- Molecular Biomedicine Department, Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
| | - Laura Luque-Martín
- Molecular Biomedicine Department, Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
| | - Alicia G Arroyo
- Molecular Biomedicine Department, Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
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13
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Shepherd JW, Payne-Dwyer AL, Lee JE, Syeda A, Leake MC. Combining single-molecule super-resolved localization microscopy with fluorescence polarization imaging to study cellular processes. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/ac015d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Super-resolution microscopy has catalyzed valuable insights into the sub-cellular, mechanistic details of many different biological processes across a wide range of cell types. Fluorescence polarization spectroscopy tools have also enabled important insights into cellular processes through identifying orientational changes of biological molecules typically at an ensemble level. Here, we combine these two biophysical methodologies in a single home-made instrument to enable the simultaneous detection of orthogonal fluorescence polarization signals from single fluorescent protein molecules used as common reporters on the localization of proteins in cellular processes. These enable measurement of spatial location to a super-resolved precision better than the diffraction-limited optical resolution, as well as estimation of molecular stoichiometry based on the brightness of individual fluorophores. In this innovation we have adapted a millisecond timescale microscope used for single-molecule detection to enable splitting of fluorescence polarization emissions into two separate imaging channels for s- and p-polarization signals, which are imaged onto separate halves of the same high sensitivity back-illuminated CMOS camera detector. We applied this fluorescence polarization super-resolved imaging modality to a range of test fluorescent samples relevant to the study of biological processes, including purified monomeric green fluorescent protein, single combed DNA molecules, and protein assemblies and complexes from live Escherichia coli and Saccharomyces cerevisiae cells. Our findings are qualitative but demonstrate promise in showing how fluorescence polarization and super-resolved localization microscopy can be combined on the same sample to enable simultaneous measurements of polarization and stoichiometry of tracked molecular complexes, as well as the translational diffusion coefficient.
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14
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Cosgrove J, Novkovic M, Albrecht S, Pikor NB, Zhou Z, Onder L, Mörbe U, Cupovic J, Miller H, Alden K, Thuery A, O'Toole P, Pinter R, Jarrett S, Taylor E, Venetz D, Heller M, Uguccioni M, Legler DF, Lacey CJ, Coatesworth A, Polak WG, Cupedo T, Manoury B, Thelen M, Stein JV, Wolf M, Leake MC, Timmis J, Ludewig B, Coles MC. B cell zone reticular cell microenvironments shape CXCL13 gradient formation. Nat Commun 2020; 11:3677. [PMID: 32699279 PMCID: PMC7376062 DOI: 10.1038/s41467-020-17135-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 03/12/2020] [Indexed: 02/07/2023] Open
Abstract
Through the formation of concentration gradients, morphogens drive graded responses to extracellular signals, thereby fine-tuning cell behaviors in complex tissues. Here we show that the chemokine CXCL13 forms both soluble and immobilized gradients. Specifically, CXCL13+ follicular reticular cells form a small-world network of guidance structures, with computer simulations and optimization analysis predicting that immobilized gradients created by this network promote B cell trafficking. Consistent with this prediction, imaging analysis show that CXCL13 binds to extracellular matrix components in situ, constraining its diffusion. CXCL13 solubilization requires the protease cathepsin B that cleaves CXCL13 into a stable product. Mice lacking cathepsin B display aberrant follicular architecture, a phenotype associated with effective B cell homing to but not within lymph nodes. Our data thus suggest that reticular cells of the B cell zone generate microenvironments that shape both immobilized and soluble CXCL13 gradients.
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Affiliation(s)
- Jason Cosgrove
- York Computational Immunology Lab, University of York, York, UK
- Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, UK
- Department of Electronic Engineering, University of York, York, UK
| | - Mario Novkovic
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Stefan Albrecht
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Natalia B Pikor
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Zhaoukun Zhou
- Department of Biology, University of York, York, UK
- Biological Physical Sciences Institute (BPSI), University of York, York, UK
- Department of Physics, University of York, York, UK
| | - Lucas Onder
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Urs Mörbe
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Jovana Cupovic
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Helen Miller
- Department of Biology, University of York, York, UK
- Biological Physical Sciences Institute (BPSI), University of York, York, UK
- Department of Physics, University of York, York, UK
| | - Kieran Alden
- York Computational Immunology Lab, University of York, York, UK
- Department of Electronic Engineering, University of York, York, UK
| | - Anne Thuery
- Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, UK
| | | | - Rita Pinter
- Kennedy Institute of Rheumatology at the University of Oxford, Oxford, UK
| | - Simon Jarrett
- Kennedy Institute of Rheumatology at the University of Oxford, Oxford, UK
| | - Emily Taylor
- Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, UK
| | - Daniel Venetz
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Manfred Heller
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Mariagrazia Uguccioni
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Charles J Lacey
- York Computational Immunology Lab, University of York, York, UK
| | | | - Wojciech G Polak
- Department of Surgery, Erasmus University Medical Centre, Rotterdam, Netherlands
| | - Tom Cupedo
- Department of Hematology, Erasmus University Medical Centre, Rotterdam, Netherlands
| | - Bénedicte Manoury
- Institut Necker Enfants Malades, INSERM U1151- CNRS UMR 8253, 149 rue de Sèvres 75015 Paris, France Université René Descartes, 75005, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marcus Thelen
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Jens V Stein
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
| | - Marlene Wolf
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Mark C Leake
- Department of Biology, University of York, York, UK.
- Biological Physical Sciences Institute (BPSI), University of York, York, UK.
- Department of Physics, University of York, York, UK.
| | - Jon Timmis
- York Computational Immunology Lab, University of York, York, UK.
- Department of Electronic Engineering, University of York, York, UK.
| | - Burkhard Ludewig
- Institute of Immunobiology, Kantonsspital St. Gallen, St. Gallen, Switzerland.
| | - Mark C Coles
- York Computational Immunology Lab, University of York, York, UK.
- Kennedy Institute of Rheumatology at the University of Oxford, Oxford, UK.
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15
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Jagarapu A, Piovoso MJ, Zurakowski R. An Integrated Spatial Dynamics-Pharmacokinetic Model Explaining Poor Penetration of Anti-retroviral Drugs in Lymph Nodes. Front Bioeng Biotechnol 2020; 8:667. [PMID: 32676500 PMCID: PMC7333380 DOI: 10.3389/fbioe.2020.00667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Although combined anti-retroviral therapy (cART) suppresses plasma HIV viremia below the limit of detection in a majority of HIV patients, evidence is emerging that the distribution of the anti-retroviral drugs is heterogeneous in tissue. Clinical studies measuring antiretroviral drug concentrations in lymph nodes (LNs) revealed lower concentrations compared to peripheral blood levels suggesting poor drug penetration properties. Our current study is an attempt to understand this poor anti-retroviral drug penetration inside lymph node lobules through integrating known pharmacokinetic and pharmacodynamic (PK/PD) parameters of the anti-retroviral drugs into a spatial model of reaction and transport dynamics within a solid lymph node lobule. Simulated drug penetration values were compared against experimental results whenever available or matched with data that is available for other drugs in a similar class. Our integrated spatial dynamics pharmacokinetic model reproduced the experimentally observed exclusion of antivirals from lymphoid sites. The strongest predictor of drug exclusion from the lymphoid lobule, independent of drug class, was lobule size; large lobules (high inflammation) exhibited high levels of drug exclusion. PK/PD characteristics associated with poor lymphoid penetration include high cellular uptake rates and low intracellular half-lives. To determine whether this exclusion might lead to ongoing replication, target CD4+ T cell, infected CD4+ T cell, free virus, and intracellular IC50 values of anti-retroviral drugs were incorporated into the model. Notably, for median estimates of PK/PD parameters and lobule diameters consistent with low to moderate inflammation, the model predicts no ongoing viral replication, despite substantial exclusion of the drugs from the lymphoid site. Monte-Carlo studies drawn from the prior distributions of the PK/PD parameters predicts increases in site-specific HIV replication in a small fraction of the patient population for lobule diameters greater than 0.2 mm; this fraction increases as the site diameter/ inflammation level increases. The model shows that cART consisting of two nRTIs and one PI is the most likely treatment combination to support formation of a sanctuary site, a finding that is consistent with clinical observations.
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Affiliation(s)
- Aditya Jagarapu
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Michael J Piovoso
- Department of Electrical and Computer Engineering, University of Delaware, Newark, DE, United States
| | - Ryan Zurakowski
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
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16
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Miller HL, Contera S, Wollman AJM, Hirst A, Dunn KE, Schröter S, O'Connell D, Leake MC. Biophysical characterisation of DNA origami nanostructures reveals inaccessibility to intercalation binding sites. NANOTECHNOLOGY 2020; 31:235605. [PMID: 32125281 DOI: 10.1088/1361-6528/ab7a2b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Intercalation of drug molecules into synthetic DNA nanostructures formed through self-assembled origami has been postulated as a valuable future method for targeted drug delivery. This is due to the excellent biocompatibility of synthetic DNA nanostructures, and high potential for flexible programmability including facile drug release into or near to target cells. Such favourable properties may enable high initial loading and efficient release for a predictable number of drug molecules per nanostructure carrier, important for efficient delivery of safe and effective drug doses to minimise non-specific release away from target cells. However, basic questions remain as to how intercalation-mediated loading depends on the DNA carrier structure. Here we use the interaction of dyes YOYO-1 and acridine orange with a tightly-packed 2D DNA origami tile as a simple model system to investigate intercalation-mediated loading. We employed multiple biophysical techniques including single-molecule fluorescence microscopy, atomic force microscopy, gel electrophoresis and controllable damage using low temperature plasma on synthetic DNA origami samples. Our results indicate that not all potential DNA binding sites are accessible for dye intercalation, which has implications for future DNA nanostructures designed for targeted drug delivery.
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Affiliation(s)
- Helen L Miller
- Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom
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17
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Syeda AH, Wollman AJM, Hargreaves AL, Howard JAL, Brüning JG, McGlynn P, Leake MC. Single-molecule live cell imaging of Rep reveals the dynamic interplay between an accessory replicative helicase and the replisome. Nucleic Acids Res 2020; 47:6287-6298. [PMID: 31028385 PMCID: PMC6614839 DOI: 10.1093/nar/gkz298] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 04/01/2019] [Accepted: 04/24/2019] [Indexed: 12/21/2022] Open
Abstract
DNA replication must cope with nucleoprotein barriers that impair efficient replisome translocation. Biochemical and genetic studies indicate accessory helicases play essential roles in replication in the presence of nucleoprotein barriers, but how they operate inside the cell is unclear. With high-speed single-molecule microscopy we observed genomically-encoded fluorescent constructs of the accessory helicase Rep and core replisome protein DnaQ in live Escherichia coli cells. We demonstrate that Rep colocalizes with 70% of replication forks, with a hexameric stoichiometry, indicating maximal occupancy of the single DnaB hexamer. Rep associates dynamically with the replisome with an average dwell time of 6.5 ms dependent on ATP hydrolysis, indicating rapid binding then translocation away from the fork. We also imaged PriC replication restart factor and observe Rep-replisome association is also dependent on PriC. Our findings suggest two Rep-replisome populations in vivo: one continually associating with DnaB then translocating away to aid nucleoprotein barrier removal ahead of the fork, another assisting PriC-dependent reloading of DnaB if replisome progression fails. These findings reveal how a single helicase at the replisome provides two independent ways of underpinning replication of protein-bound DNA, a problem all organisms face as they replicate their genomes.
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Affiliation(s)
- Aisha H Syeda
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Adam J M Wollman
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Alex L Hargreaves
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | - Jamieson A L Howard
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
| | | | - Peter McGlynn
- Department of Biology, University of York, York YO10 5DD, UK
| | - Mark C Leake
- Department of Physics, University of York, York YO10 5DD, UK.,Department of Biology, University of York, York YO10 5DD, UK
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18
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Lu E, Cyster JG. G-protein coupled receptors and ligands that organize humoral immune responses. Immunol Rev 2020; 289:158-172. [PMID: 30977196 DOI: 10.1111/imr.12743] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 01/22/2019] [Indexed: 12/26/2022]
Abstract
B-cell responses are dynamic processes that depend on multiple types of interactions. Rare antigen-specific B cells must encounter antigen and specialized systems are needed-unique to each lymphoid tissue type-to ensure this happens efficiently. Lymphoid tissue barrier cells act to ensure that pathogens, while being permitted entry for B-cell recognition, are blocked from replication or dissemination. T follicular helper (Tfh) cells often need to be primed by dendritic cells before supporting B-cell responses. For most responses, antigen-specific helper T cells and B cells need to interact, first to initiate clonal expansion and the plasmablast response, and later to support the germinal center (GC) response. Newly formed plasma cells need to travel to supportive niches. GC B cells must become confined to the follicle center, organize into dark and light zones, and interact with Tfh cells. Memory B cells need to be positioned for rapid responses following reinfection. Each of these events requires the actions of multiple G-protein coupled receptors (GPCRs) and their ligands, including chemokines and lipid mediators. This review will focus on the guidance cue code underlying B-cell immunity, with an emphasis on findings from our laboratory and on newer advances in related areas. We will discuss our recent identification of geranylgeranyl-glutathione as a ligand for P2RY8. Our goal is to provide the reader with a focused knowledge about the GPCRs guiding B-cell responses and how they might be therapeutic targets, while also providing examples of how multiple types of GPCRs can cooperate or act iteratively to control cell behavior.
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Affiliation(s)
- Erick Lu
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California
| | - Jason G Cyster
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California
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19
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Stracy M, Wollman AJM, Kaja E, Gapinski J, Lee JE, Leek VA, McKie SJ, Mitchenall LA, Maxwell A, Sherratt DJ, Leake MC, Zawadzki P. Single-molecule imaging of DNA gyrase activity in living Escherichia coli. Nucleic Acids Res 2019; 47:210-220. [PMID: 30445553 PMCID: PMC6326794 DOI: 10.1093/nar/gky1143] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/07/2018] [Indexed: 11/18/2022] Open
Abstract
Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by replication and transiently by transcription. Removal of these positive supercoils is essential for replication fork progression and for the overall unlinking of the two duplex DNA strands, as well as for ongoing transcription. To address how gyrase copes with these topological challenges, we used high-speed single-molecule fluorescence imaging in live Escherichia coli cells. We demonstrate that at least 300 gyrase molecules are stably bound to the chromosome at any time, with ∼12 enzymes enriched near each replication fork. Trapping of reaction intermediates with ciprofloxacin revealed complexes undergoing catalysis. Dwell times of ∼2 s were observed for the dispersed gyrase molecules, which we propose maintain steady-state levels of negative supercoiling of the chromosome. In contrast, the dwell time of replisome-proximal molecules was ∼8 s, consistent with these catalyzing processive positive supercoil relaxation in front of the progressing replisome.
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Affiliation(s)
- Mathew Stracy
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Adam J M Wollman
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of York, York YO10 5DD, UK
| | - Elzbieta Kaja
- NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - Jacek Gapinski
- Molecular Biophysics Division, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
| | - Ji-Eun Lee
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of York, York YO10 5DD, UK
| | - Victoria A Leek
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Shannon J McKie
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Lesley A Mitchenall
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Anthony Maxwell
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - David J Sherratt
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark C Leake
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of York, York YO10 5DD, UK
| | - Pawel Zawadzki
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.,Molecular Biophysics Division, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
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20
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Sun Y, Wollman AJM, Huang F, Leake MC, Liu LN. Single-Organelle Quantification Reveals Stoichiometric and Structural Variability of Carboxysomes Dependent on the Environment. THE PLANT CELL 2019; 31:1648-1664. [PMID: 31048338 PMCID: PMC6635877 DOI: 10.1105/tpc.18.00787] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/02/2019] [Indexed: 05/25/2023]
Abstract
The carboxysome is a complex, proteinaceous organelle that plays essential roles in carbon assimilation in cyanobacteria and chemoautotrophs. It comprises hundreds of protein homologs that self-assemble in space to form an icosahedral structure. Despite its significance in enhancing CO2 fixation and potentials in bioengineering applications, the formation of carboxysomes and their structural composition, stoichiometry, and adaptation to cope with environmental changes remain unclear. Here we use live-cell single-molecule fluorescence microscopy, coupled with confocal and electron microscopy, to decipher the absolute protein stoichiometry and organizational variability of single β-carboxysomes in the model cyanobacterium Synechococcus elongatus PCC7942. We determine the physiological abundance of individual building blocks within the icosahedral carboxysome. We further find that the protein stoichiometry, diameter, localization, and mobility patterns of carboxysomes in cells depend sensitively on the microenvironmental levels of CO2 and light intensity during cell growth, revealing cellular strategies of dynamic regulation. These findings, also applicable to other bacterial microcompartments and macromolecular self-assembling systems, advance our knowledge of the principles that mediate carboxysome formation and structural modulation. It will empower rational design and construction of entire functional metabolic factories in heterologous organisms, for example crop plants, to boost photosynthesis and agricultural productivity.
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Affiliation(s)
- Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Adam J M Wollman
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Mark C Leake
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
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21
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Wollman AJM, Hedlund EG, Shashkova S, Leake MC. Towards mapping the 3D genome through high speed single-molecule tracking of functional transcription factors in single living cells. Methods 2019; 170:82-89. [PMID: 31252059 PMCID: PMC6971689 DOI: 10.1016/j.ymeth.2019.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022] Open
Abstract
How genomic DNA is organized in the nucleus is a long-standing question. We describe a single-molecule bioimaging method utilizing super-localization precision coupled to fully quantitative image analysis tools, towards determining snapshots of parts of the 3D genome architecture of model eukaryote budding yeast Saccharomyces cerevisiae with exceptional millisecond time resolution. We employ astigmatism imaging to enable robust extraction of 3D position data on genomically encoded fluorescent protein reporters that bind to DNA. Our relatively straightforward method enables snippets of 3D architectures of likely single genome conformations to be resolved captured via DNA-sequence specific binding proteins in single functional living cells.
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Affiliation(s)
- Adam J M Wollman
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Erik G Hedlund
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Sviatlana Shashkova
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Mark C Leake
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
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22
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Leake MC. Transcription factors in eukaryotic cells can functionally regulate gene expression by acting in oligomeric assemblies formed from an intrinsically disordered protein phase transition enabled by molecular crowding. Transcription 2018; 9:298-306. [PMID: 29895219 PMCID: PMC6150617 DOI: 10.1080/21541264.2018.1475806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
High-speed single-molecule fluorescence microscopy in vivo shows that transcription factors in eukaryotes can act in oligomeric clusters mediated by molecular crowding and intrinsically disordered protein. This finding impacts on the longstanding puzzle of how transcription factors find their gene targets so efficiently in the complex, heterogeneous environment of the cell. Abbreviations CDF - cumulative distribution function; FRAP - fluorescence recovery after photobleaching; GFP - Green fluorescent protein; STORM - stochastic optical reconstruction microscopy; TF - Transcription factor; YFP - Yellow fluorescent protein
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Affiliation(s)
- Mark C Leake
- a Departments of Physics and Biology , Biological Physical Sciences Institute, University of York , York , UK
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