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Vauclare P, Wulffelé J, Lacroix F, Servant P, Confalonieri F, Kleman JP, Bourgeois D, Timmins J. Stress-induced nucleoid remodeling in Deinococcus radiodurans is associated with major changes in Heat Unstable (HU) protein dynamics. Nucleic Acids Res 2024; 52:6406-6423. [PMID: 38742631 PMCID: PMC11194088 DOI: 10.1093/nar/gkae379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/23/2024] [Accepted: 04/26/2024] [Indexed: 05/16/2024] Open
Abstract
Bacteria have developed a wide range of strategies to respond to stress, one of which is the rapid large-scale reorganization of their nucleoid. Nucleoid associated proteins (NAPs) are believed to be major actors in nucleoid remodeling, but the details of this process remain poorly understood. Here, using the radiation resistant bacterium D. radiodurans as a model, and advanced fluorescence microscopy, we examined the changes in nucleoid morphology and volume induced by either entry into stationary phase or exposure to UV-C light, and characterized the associated changes in mobility of the major NAP in D. radiodurans, the heat-unstable (HU) protein. While both types of stress induced nucleoid compaction, HU diffusion was reduced in stationary phase cells, but was instead increased following exposure to UV-C, suggesting distinct underlying mechanisms. Furthermore, we show that UV-C-induced nucleoid remodeling involves a rapid nucleoid condensation step associated with increased HU diffusion, followed by a slower decompaction phase to restore normal nucleoid morphology and HU dynamics, before cell division can resume. These findings shed light on the diversity of nucleoid remodeling processes in bacteria and underline the key role of HU in regulating this process through changes in its mode of assembly on DNA.
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Affiliation(s)
- Pierre Vauclare
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | - Jip Wulffelé
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | | | - Pascale Servant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Fabrice Confalonieri
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | | | | | - Joanna Timmins
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
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2
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Li W, He Z, Di W, Xu W, Li Y, Sun B. Transposition mechanism of IS Apl1-the determinant of colistin resistance dissemination. Antimicrob Agents Chemother 2024; 68:e0123123. [PMID: 38289082 PMCID: PMC10916398 DOI: 10.1128/aac.01231-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/18/2023] [Indexed: 03/07/2024] Open
Abstract
Multidrug-resistant Enterobacteriaceae, a prominent family of gram-negative pathogenic bacteria, causes a wide range of severe diseases. Strains carrying the mobile colistin resistance (mcr-1) gene show resistance to polymyxin, the last line of defense against multidrug-resistant gram-negative bacteria. However, the transmission of mcr-1 is not well understood. In this study, genomes of mcr-1-positive strains were obtained from the NCBI database, revealing their widespread distribution in China. We also showed that ISApl1, a crucial factor in mcr-1 transmission, is capable of self-transposition. Moreover, the self-cyclization of ISApl1 is mediated by its own encoded transposase. The electrophoretic mobility shift assay experiment validated that the transposase can bind to the inverted repeats (IRs) on both ends, facilitating the cyclization of ISApl1. Through knockout or shortening of IRs at both ends of ISApl1, we demonstrated that the cyclization of ISApl1 is dependent on the sequences of the IRs at both ends. Simultaneously, altering the ATCG content of the bases at both ends of ISApl1 can impact the excision rate by modifying the binding ability between IRs and ISAPL1. Finally, we showed that heat-unstable nucleoid protein (HU) can inhibit ISApl1 transposition by binding to the IRs and preventing ISAPL1 binding and expression. In conclusion, the regulation of ISApl1-self-circling is predominantly controlled by the inverted repeat (IR) sequence and the HU protein. This molecular mechanism deepens our comprehension of mcr-1 dissemination.
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Affiliation(s)
- Wei Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Zhien He
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Wei Di
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Weifeng Xu
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Yujie Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Baolin Sun
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
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3
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Norris V, Kayser C, Muskhelishvili G, Konto-Ghiorghi Y. The roles of nucleoid-associated proteins and topoisomerases in chromosome structure, strand segregation, and the generation of phenotypic heterogeneity in bacteria. FEMS Microbiol Rev 2023; 47:fuac049. [PMID: 36549664 DOI: 10.1093/femsre/fuac049] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
How to adapt to a changing environment is a fundamental, recurrent problem confronting cells. One solution is for cells to organize their constituents into a limited number of spatially extended, functionally relevant, macromolecular assemblies or hyperstructures, and then to segregate these hyperstructures asymmetrically into daughter cells. This asymmetric segregation becomes a particularly powerful way of generating a coherent phenotypic diversity when the segregation of certain hyperstructures is with only one of the parental DNA strands and when this pattern of segregation continues over successive generations. Candidate hyperstructures for such asymmetric segregation in prokaryotes include those containing the nucleoid-associated proteins (NAPs) and the topoisomerases. Another solution to the problem of creating a coherent phenotypic diversity is by creating a growth-environment-dependent gradient of supercoiling generated along the replication origin-to-terminus axis of the bacterial chromosome. This gradient is modulated by transcription, NAPs, and topoisomerases. Here, we focus primarily on two topoisomerases, TopoIV and DNA gyrase in Escherichia coli, on three of its NAPs (H-NS, HU, and IHF), and on the single-stranded binding protein, SSB. We propose that the combination of supercoiling-gradient-dependent and strand-segregation-dependent topoisomerase activities result in significant differences in the supercoiling of daughter chromosomes, and hence in the phenotypes of daughter cells.
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Affiliation(s)
- Vic Norris
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Clara Kayser
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Georgi Muskhelishvili
- Agricultural University of Georgia, School of Natural Sciences, 0159 Tbilisi, Georgia
| | - Yoan Konto-Ghiorghi
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
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4
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Dadinova LA, Petoukhov MV, Gordienko AM, Manuvera VA, Lazarev VN, Rakitina TV, Mozhaev AA, Peters GS, Shtykova EV. Nucleoid-Associated Proteins HU and IHF: Oligomerization in Solution and Hydrodynamic Properties. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:640-654. [PMID: 37331710 DOI: 10.1134/s0006297923050073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/10/2023] [Accepted: 03/23/2023] [Indexed: 06/20/2023]
Abstract
Structure and function of bacterial nucleoid is controlled by the nucleoid-associated proteins (NAP). In any phase of growth, various NAPs, acting sequentially, condense nucleoid and facilitate formation of its transcriptionally active structure. However, in the late stationary phase, only one of the NAPs, Dps protein, is strongly expressed, and DNA-protein crystals are formed that transform nucleoid into a static, transcriptionally inactive structure, effectively protected from the external influences. Discovery of crystal structures in living cells and association of this phenomenon with the bacterial resistance to antibiotics has aroused great interest in studying this phenomenon. The aim of this work is to obtain and compare structures of two related NAPs (HU and IHF), since they are the ones that accumulate in the cell at the late stationary stage of growth, which precedes formation of the protective DNA-Dps crystalline complex. For structural studies, two complementary methods were used in the work: small-angle X-ray scattering (SAXS) as the main method for studying structure of proteins in solution, and dynamic light scattering as a complementary one. To interpret the SAXS data, various approaches and computer programs were used (in particular, the evaluation of structural invariants, rigid body modeling and equilibrium mixture analysis in terms of the volume fractions of its components were applied), which made it possible to determine macromolecular characteristics and obtain reliable 3D structural models of various oligomeric forms of HU and IHF proteins with ~2 nm resolution typical for SAXS. It was shown that these proteins oligomerize in solution to varying degrees, and IHF is characterized by the presence of large oligomers consisting of initial dimers arranged in a chain. An analysis of the experimental and published data made it possible to hypothesize that just before the Dps expression, it is IHF that forms toroidal structures previously observed in vivo and prepares the platform for formation of DNA-Dps crystals. The results obtained are necessary for further investigation of the phenomenon of biocrystal formation in bacterial cells and finding ways to overcome resistance of various pathogens to external conditions.
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Affiliation(s)
- Liubov A Dadinova
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Maxim V Petoukhov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Alexander M Gordienko
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Valentin A Manuvera
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, 141701, Russia
| | - Vassili N Lazarev
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, 141701, Russia
| | - Tatiana V Rakitina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
- National Research Centre "Kurchatov Institute", Moscow, 123182, Russia
| | - Andrey A Mozhaev
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Georgy S Peters
- National Research Centre "Kurchatov Institute", Moscow, 123182, Russia
| | - Eleonora V Shtykova
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia.
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5
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Loconte V, Chen J, Vanslembrouck B, Ekman AA, McDermott G, Le Gros MA, Larabell CA. Soft X-ray tomograms provide a structural basis for whole-cell modeling. FASEB J 2023; 37:e22681. [PMID: 36519968 PMCID: PMC10107707 DOI: 10.1096/fj.202200253r] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 11/13/2022] [Accepted: 11/21/2022] [Indexed: 12/23/2022]
Abstract
Developing in silico models that accurately reflect a whole, functional cell is an ongoing challenge in biology. Current efforts bring together mathematical models, probabilistic models, visual representations, and data to create a multi-scale description of cellular processes. A realistic whole-cell model requires imaging data since it provides spatial constraints and other critical cellular characteristics that are still impossible to obtain by calculation alone. This review introduces Soft X-ray Tomography (SXT) as a powerful imaging technique to visualize and quantify the mesoscopic (~25 nm spatial scale) organelle landscape in whole cells. SXT generates three-dimensional reconstructions of cellular ultrastructure and provides a measured structural framework for whole-cell modeling. Combining SXT with data from disparate technologies at varying spatial resolutions provides further biochemical details and constraints for modeling cellular mechanisms. We conclude, based on the results discussed here, that SXT provides a foundational dataset for a broad spectrum of whole-cell modeling experiments.
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Affiliation(s)
- Valentina Loconte
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Jian‐Hua Chen
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Bieke Vanslembrouck
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Axel A. Ekman
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Gerry McDermott
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Mark A. Le Gros
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
| | - Carolyn A. Larabell
- Department of AnatomyUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
- National Center for X‐ray TomographyAdvanced Light SourceBerkeleyCaliforniaUSA
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6
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Cossa A, Trépout S, Wien F, Groen J, Le Brun E, Turbant F, Besse L, Pereiro E, Arluison V. Cryo soft X-ray tomography to explore Escherichia coli nucleoid remodeling by Hfq master regulator. J Struct Biol 2022; 214:107912. [PMID: 36283630 DOI: 10.1016/j.jsb.2022.107912] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 09/28/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022]
Abstract
The bacterial chromosomic DNA is packed within a membrane-less structure, the nucleoid, due to the association of DNA with proteins called Nucleoid Associated Proteins (NAPs). Among these NAPs, Hfq is one of the most intriguing as it plays both direct and indirect roles on DNA structure. Indeed, Hfq is best known to mediate post-transcriptional regulation by using small noncoding RNA (sRNA). Although Hfq presence in the nucleoid has been demonstrated for years, its precise role is still unclear. Recently, it has been shown in vitro that Hfq forms amyloid-like structures through its C-terminal region, hence belonging to the bridging family of NAPs. Here, using cryo soft X-ray tomography imaging of native unlabeled cells and using a semi-automatic analysis and segmentation procedure, we show that Hfq significantly remodels the Escherichia coli nucleoid. More specifically, Hfq influences nucleoid density especially during the stationary growth phase when it is more abundant. Our results indicate that Hfq could regulate nucleoid compaction directly via its interaction with DNA, but also at the post-transcriptional level via its interaction with RNAs. Taken together, our findings reveal a new role for this protein in nucleoid remodeling in vivo, that may serve in response to stress conditions and in adapting to changing environments.
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Affiliation(s)
- Antoine Cossa
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France; Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Sylvain Trépout
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France; Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria 3800, Australia.
| | - Frank Wien
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France
| | - Johannes Groen
- Mistral Beamline, Alba Light Source, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Etienne Le Brun
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; Department of Molecular Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Laetitia Besse
- Institut Curie, Université PSL, CNRS UAR2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France
| | - Eva Pereiro
- Mistral Beamline, Alba Light Source, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; Université Paris Cité, UFR Sciences du vivant, 75006 Paris cedex, France.
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7
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Chen JH, Vanslembrouck B, Ekman A, Aho V, Larabell CA, Le Gros MA, Vihinen-Ranta M, Weinhardt V. Soft X-ray Tomography Reveals HSV-1-Induced Remodeling of Human B Cells. Viruses 2022; 14:2651. [PMID: 36560654 PMCID: PMC9781670 DOI: 10.3390/v14122651] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Upon infection, viruses hijack the cell machinery and remodel host cell structures to utilize them for viral proliferation. Since viruses are about a thousand times smaller than their host cells, imaging virus-host interactions at high spatial resolution is like looking for a needle in a haystack. Scouting gross cellular changes with fluorescent microscopy is only possible for well-established viruses, where fluorescent tagging is developed. Soft X-ray tomography (SXT) offers 3D imaging of entire cells without the need for chemical fixation or labeling. Here, we use full-rotation SXT to visualize entire human B cells infected by the herpes simplex virus 1 (HSV-1). We have mapped the temporospatial remodeling of cells during the infection and observed changes in cellular structures, such as the presence of cytoplasmic stress granules and multivesicular structures, formation of nuclear virus-induced dense bodies, and aggregates of capsids. Our results demonstrate the power of SXT imaging for scouting virus-induced changes in infected cells and understanding the orchestration of virus-host remodeling quantitatively.
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Affiliation(s)
- Jian-Hua Chen
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Bieke Vanslembrouck
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Axel Ekman
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Vesa Aho
- Department of Biological and Environmental Science, Nanoscience Center, University of Jyvaskyla, 40014 Jyvaskyla, Finland
| | - Carolyn A. Larabell
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Mark A. Le Gros
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Maija Vihinen-Ranta
- Department of Biological and Environmental Science, Nanoscience Center, University of Jyvaskyla, 40014 Jyvaskyla, Finland
| | - Venera Weinhardt
- Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
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8
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Strzałka A, Kois-Ostrowska A, Kędra M, Łebkowski T, Bieniarz G, Szafran MJ, Jakimowicz D. Enhanced binding of an HU homologue under increased DNA supercoiling preserves chromosome organisation and sustains Streptomyces hyphal growth. Nucleic Acids Res 2022; 50:12202-12216. [PMID: 36420903 PMCID: PMC9756944 DOI: 10.1093/nar/gkac1093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 10/25/2022] [Accepted: 11/08/2022] [Indexed: 11/27/2022] Open
Abstract
Bacterial chromosome topology is controlled by topoisomerases and nucleoid-associated proteins (NAPs). While topoisomerases regulate DNA supercoiling, NAPs introduce bends or coat DNA upon its binding, affecting DNA loop formation. Streptomyces, hyphal, multigenomic bacteria known for producing numerous clinically important compounds, use the highly processive topoisomerase I (TopA) to remove excessive negative DNA supercoils. Elongated vegetative Streptomyces cells contain multiple copies of their linear chromosome, which remain relaxed and relatively evenly distributed. Here, we explored how TopA cooperates with HupA, an HU homologue that is the most abundant Streptomyces NAP. We verified that HupA has an increased affinity for supercoiled DNA in vivo and in vitro. Analysis of mutant strains demonstrated that HupA elimination is detrimental under high DNA supercoiling conditions. The absence of HupA, combined with decreased TopA levels, disrupted chromosome distribution in hyphal cells, eventually inhibiting hyphal growth. We concluded that increased HupA binding to DNA under elevated chromosome supercoiling conditions is critical for the preservation of chromosome organisation.
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Affiliation(s)
| | - Agnieszka Kois-Ostrowska
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Magda Kędra
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Tomasz Łebkowski
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Grażyna Bieniarz
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Marcin J Szafran
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Dagmara Jakimowicz
- Molecular Microbiology Department, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
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9
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Domb K, Wang N, Hummel G, Liu C. Spatial Features and Functional Implications of Plant 3D Genome Organization. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:173-200. [PMID: 35130445 DOI: 10.1146/annurev-arplant-102720-022810] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The advent of high-throughput sequencing-based methods for chromatin conformation, accessibility, and immunoprecipitation assays has been a turning point in 3D genomics. Altogether, these new tools have been pushing upward the interpretation of pioneer cytogenetic evidence for a higher order in chromatin packing. Here, we review the latest development in our understanding of plant spatial genome structures and different levels of organization and discuss their functional implications. Then, we spotlight the complexity of organellar (i.e., mitochondria and plastids) genomes and discuss their 3D packing into nucleoids. Finally, we propose unaddressed research axes to investigate functional links between chromatin-like dynamics and transcriptional regulation within organellar nucleoids.
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Affiliation(s)
- Katherine Domb
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Nan Wang
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Guillaume Hummel
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Chang Liu
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
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10
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Agarwal N, Nagar N, Raj R, Kumar D, Poluri KM. Conserved Apical Proline Regulating the Structure and DNA Binding Properties of Helicobacter pylori Histone-like DNA Binding Protein (Hup). ACS OMEGA 2022; 7:15231-15246. [PMID: 35572751 PMCID: PMC9089689 DOI: 10.1021/acsomega.2c01754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Prokaryotic cells lack a proper dedicated nuclear arrangement machinery. A set of proteins known as nucleoid associated proteins (NAPs) perform opening and closure of nucleic acids, behest cellular requirement. Among these, a special class of proteins analogous to eukaryotic histones popularly known as histone-like (HU) DNA binding proteins facilitate the nucleic acid folding/compaction thereby regulating gene architecture and gene regulation. DNA compaction and DNA protection in Helicobacter pylori is performed by HU protein (Hup). To dissect and galvanize the role of proline residue in the binding of Hup with DNA, the structure-dynamics-functional relationship of Hup-P64A variant was analyzed. NMR and biophysical studies evidenced that Hup-P64A protein attenuated DNA-binding and induced structural/stability changes in the DNA binding domain (DBD). Moreover, molecular dynamics simulations and 15N relaxation studies established the reduced conformational dynamics of P64A protein. This comprehensive study dissected the exclusive role of evolutionarily conserved apical proline residue in regulating the structure and DNA binding of Hup protein as P64 is presumed to be involved in the external leverage mechanism responsible for DNA bending and packaging, as proline rings wedge into the DNA backbone through intercalation besides their significant role in DNA binding.
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Affiliation(s)
- Nipanshu Agarwal
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Nupur Nagar
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Ritu Raj
- Centre
of Biomedical Research, SGPGIMS Campus, Lucknow-226014, India
| | - Dinesh Kumar
- Centre
of Biomedical Research, SGPGIMS Campus, Lucknow-226014, India
| | - Krishna Mohan Poluri
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
- Centre
for Nanotechnology, Indian Institute of
Technology Roorkee, Roorkee-247667, Uttarakhand, India
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11
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Krupinska K, Desel C, Frank S, Hensel G. WHIRLIES Are Multifunctional DNA-Binding Proteins With Impact on Plant Development and Stress Resistance. FRONTIERS IN PLANT SCIENCE 2022; 13:880423. [PMID: 35528945 PMCID: PMC9070903 DOI: 10.3389/fpls.2022.880423] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 03/24/2022] [Indexed: 06/01/2023]
Abstract
WHIRLIES are plant-specific proteins binding to DNA in plastids, mitochondria, and nucleus. They have been identified as significant components of nucleoids in the organelles where they regulate the structure of the nucleoids and diverse DNA-associated processes. WHIRLIES also fulfil roles in the nucleus by interacting with telomers and various transcription factors, among them members of the WRKY family. While most plants have two WHIRLY proteins, additional WHIRLY proteins evolved by gene duplication in some dicot families. All WHIRLY proteins share a conserved WHIRLY domain responsible for ssDNA binding. Structural analyses revealed that WHIRLY proteins form tetramers and higher-order complexes upon binding to DNA. An outstanding feature is the parallel localization of WHIRLY proteins in two or three cell compartments. Because they translocate from organelles to the nucleus, WHIRLY proteins are excellent candidates for transducing signals between organelles and nucleus to allow for coordinated activities of the different genomes. Developmental cues and environmental factors control the expression of WHIRLY genes. Mutants and plants with a reduced abundance of WHIRLY proteins gave insight into their multiple functionalities. In chloroplasts, a reduction of the WHIRLY level leads to changes in replication, transcription, RNA processing, and DNA repair. Furthermore, chloroplast development, ribosome formation, and photosynthesis are impaired in monocots. In mitochondria, a low level of WHIRLIES coincides with a reduced number of cristae and a low rate of respiration. The WHIRLY proteins are involved in the plants' resistance toward abiotic and biotic stress. Plants with low levels of WHIRLIES show reduced responsiveness toward diverse environmental factors, such as light and drought. Consequently, because such plants are impaired in acclimation, they accumulate reactive oxygen species under stress conditions. In contrast, several plant species overexpressing WHIRLIES were shown to have a higher resistance toward stress and pathogen attacks. By their multiple interactions with organelle proteins and nuclear transcription factors maybe a comma can be inserted here? and their participation in organelle-nucleus communication, WHIRLY proteins are proposed to serve plant development and stress resistance by coordinating processes at different levels. It is proposed that the multifunctionality of WHIRLY proteins is linked to the plasticity of land plants that develop and function in a continuously changing environment.
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Affiliation(s)
- Karin Krupinska
- Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Christine Desel
- Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Susann Frank
- Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Götz Hensel
- Centre for Plant Genome Engineering, Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- Centre of Region Haná for Biotechnological and Agricultural Research, Czech Advanced Technology and Research Institute, Palacký University Olomouc, Olomouc, Czechia
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12
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Relationship between the Chromosome Structural Dynamics and Gene Expression—A Chicken and Egg Dilemma? Microorganisms 2022; 10:microorganisms10050846. [PMID: 35630292 PMCID: PMC9144111 DOI: 10.3390/microorganisms10050846] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 04/14/2022] [Indexed: 02/06/2023] Open
Abstract
Prokaryotic transcription was extensively studied over the last half-century. A great deal of data has been accumulated regarding the control of gene expression by transcription factors regulating their target genes by binding at specific DNA sites. However, there is a significant gap between the mechanistic description of transcriptional control obtained from in vitro biochemical studies and the complexity of transcriptional regulation in the context of the living cell. Indeed, recent studies provide ample evidence for additional levels of complexity pertaining to the regulation of transcription in vivo, such as, for example, the role of the subcellular localization and spatial organization of different molecular components involved in the transcriptional control and, especially, the role of chromosome configurational dynamics. The question as to how the chromosome is dynamically reorganized under the changing environmental conditions and how this reorganization is related to gene expression is still far from being clear. In this article, we focus on the relationships between the chromosome structural dynamics and modulation of gene expression during bacterial adaptation. We argue that spatial organization of the bacterial chromosome is of central importance in the adaptation of gene expression to changing environmental conditions and vice versa, that gene expression affects chromosome dynamics.
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13
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Facilitated Dissociation of Nucleoid Associated Proteins from DNA in the Bacterial Confinement. Biophys J 2022; 121:1119-1133. [PMID: 35257784 PMCID: PMC9034294 DOI: 10.1016/j.bpj.2022.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/04/2021] [Accepted: 03/01/2022] [Indexed: 11/20/2022] Open
Abstract
Transcription machinery depends on the temporal formation of protein-DNA complexes. Recent experiments demonstrated that not only the formation but also the lifetime of such complexes can affect the transcriptional machinery. In parallel, in vitro single-molecule studies showed that nucleoid-associated proteins (NAPs) leave the DNA rapidly as the bulk concentration of the protein increases via facilitated dissociation (FD). Nevertheless, whether such a concentration-dependent mechanism is functional in a bacterial cell, in which NAP levels and the 3d chromosomal structure are often coupled, is not clear a priori. Here, by using extensive coarse-grained molecular simulations, we model the unbinding of specific and nonspecific dimeric NAPs from a high-molecular-weight circular DNA molecule in a cylindrical structure mimicking the cellular confinement of a bacterial chromosome. Our simulations confirm that physiologically relevant peak protein levels (tens of micromolar) lead to highly compact chromosomal structures. This compaction results in rapid off rates (shorter DNA residence times) for specifically DNA-binding NAPs, such as the factor for inversion stimulation, which mostly dissociate via a segmental jump mechanism. Contrarily, for nonspecific NAPs, which are more prone to leave their binding sites via 1d sliding, the off rates decrease as the protein levels increase. The simulations with restrained chromosome models reveal that chromosome compaction is in favor of faster dissociation but only for specific proteins, and nonspecific proteins are not affected by the chromosome compaction. Overall, our results suggest that the cellular concentration level of a structural DNA-binding protein can be highly intermingled with its DNA residence time.
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14
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Amemiya HM, Goss TJ, Nye TM, Hurto RL, Simmons LA, Freddolino PL. Distinct heterochromatin-like domains promote transcriptional memory and silence parasitic genetic elements in bacteria. EMBO J 2022; 41:e108708. [PMID: 34961960 PMCID: PMC8804932 DOI: 10.15252/embj.2021108708] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 02/03/2023] Open
Abstract
There is increasing evidence that prokaryotes maintain chromosome structure, which in turn impacts gene expression. We recently characterized densely occupied, multi-kilobase regions in the E. coli genome that are transcriptionally silent, similar to eukaryotic heterochromatin. These extended protein occupancy domains (EPODs) span genomic regions containing genes encoding metabolic pathways as well as parasitic elements such as prophages. Here, we investigate the contributions of nucleoid-associated proteins (NAPs) to the structuring of these domains, by examining the impacts of deleting NAPs on EPODs genome-wide in E. coli and B. subtilis. We identify key NAPs contributing to the silencing of specific EPODs, whose deletion opens a chromosomal region for RNA polymerase binding at genes contained within that region. We show that changes in E. coli EPODs facilitate an extra layer of transcriptional regulation, which prepares cells for exposure to exotic carbon sources. Furthermore, we distinguish novel xenogeneic silencing roles for the NAPs Fis and Hfq, with the presence of at least one being essential for cell viability in the presence of domesticated prophages. Our findings reveal previously unrecognized mechanisms through which genomic architecture primes bacteria for changing metabolic environments and silences harmful genomic elements.
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Affiliation(s)
- Haley M Amemiya
- Cellular and Molecular Biology ProgramUniversity of Michigan Medical SchoolAnn ArborMIUSA,Department of Computational Medicine and BioinformaticsUniversity of Michigan Medical SchoolAnn ArborMIUSA,Present address:
Broad Institute of MIT and HarvardCambridgeMAUSA
| | - Thomas J Goss
- Department of Biological ChemistryUniversity of Michigan Medical SchoolAnn ArborMIUSA
| | - Taylor M Nye
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA,Present address:
Department of Molecular MicrobiologyWashington University in St. Louis School of MedicineSt. LouisMOUSA
| | - Rebecca L Hurto
- Department of Biological ChemistryUniversity of Michigan Medical SchoolAnn ArborMIUSA
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA
| | - Peter L Freddolino
- Cellular and Molecular Biology ProgramUniversity of Michigan Medical SchoolAnn ArborMIUSA,Department of Computational Medicine and BioinformaticsUniversity of Michigan Medical SchoolAnn ArborMIUSA,Department of Biological ChemistryUniversity of Michigan Medical SchoolAnn ArborMIUSA
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15
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Fisunov GY, Zubov AI, Pobeguts OV, Varizhuk AM, Galyamina MA, Evsyutina DV, Semashko TA, Manuvera VA, Kovalchuk SI, Ziganshin RK, Barinov NA, Klinov DV, Govorun VM. The Dynamics of Mycoplasma gallisepticum Nucleoid Structure at the Exponential and Stationary Growth Phases. Front Microbiol 2021; 12:753760. [PMID: 34867875 PMCID: PMC8637272 DOI: 10.3389/fmicb.2021.753760] [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: 08/13/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
The structure and dynamics of bacterial nucleoids play important roles in regulating gene expression. Bacteria of class Mollicutes and, in particular, mycoplasmas feature extremely reduced genomes. They lack multiple structural proteins of the nucleoid, as well as regulators of gene expression. We studied the organization of Mycoplasma gallisepticum nucleoids in the stationary and exponential growth phases at the structural and protein levels. The growth phase transition results in the structural reorganization of M. gallisepticum nucleoid. In particular, it undergoes condensation and changes in the protein content. The observed changes corroborate with the previously identified global rearrangement of the transcriptional landscape in this bacterium during the growth phase transition. In addition, we identified that the glycolytic enzyme enolase functions as a nucleoid structural protein in this bacterium. It is capable of non-specific DNA binding and can form fibril-like complexes with DNA.
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Affiliation(s)
- Gleb Y Fisunov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Alexander I Zubov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Olga V Pobeguts
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Anna M Varizhuk
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Mariya A Galyamina
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Daria V Evsyutina
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Tatiana A Semashko
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Valentin A Manuvera
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Sergey I Kovalchuk
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Rustam K Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nicolay A Barinov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Dmitry V Klinov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Vadim M Govorun
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
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16
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Su Q, Wang X, Leng M, Qi Y, Pang F, Tang J, Lu G. A HU-like protein is required for full virulence in Xanthomonas campestris pv. campestris. MOLECULAR PLANT PATHOLOGY 2021; 22:1574-1586. [PMID: 34424610 PMCID: PMC8578834 DOI: 10.1111/mpp.13128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/26/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Bacteria harbour several abundant small DNA-binding proteins known as nucleoid-associated proteins (NAPs) that contribute to the structure of the bacterial nucleoid as well as to gene regulation. Although the function of NAPs as global transcriptional regulators has been comprehensively studied in the model organism Escherichia coli, their regulatory functions in other bacteria remain relatively poorly understood. Xanthomonas campestris pv. campestris (Xcc) is a gram-negative bacterium that causes black rot disease in almost all members of the crucifer family. In previous work, we demonstrated that a Fis homologue protein, which we named Fis-like protein (Flp), contributes to the regulation of virulence, type III secretion, and a series of other phenotypes in Xcc. Here we have examined the role of XC_1355, which is predicted to encode a DNA-binding protein belonging to the HU family herein named HU-like protein (Hlp). We show that mutation of XC_1355 in Xcc reduces the virulence, extracellular polysaccharide production, and cell motility, but has no effect on the production of extracellular enzymes and induction of the hypersensitive response. These data together with transcriptome analysis indicate that hlp is a previously uncharacterized gene involved in virulence that has partially overlapping and complementary functions with flp in Xcc, although the two regulators have opposite effects on the expression of genes involved in type III secretion. The findings add to our understanding of the complex regulatory pathways that act to regulate virulence in Xcc.
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Affiliation(s)
- Qian Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Xin‐Xin Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Yan‐Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Fu‐Yuan Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
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17
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Agarwal N, Jaiswal N, Gulati K, Gangele K, Nagar N, Kumar D, Poluri KM. Molecular Insights into Conformational Heterogeneity and Enhanced Structural Integrity of Helicobacter pylori DNA Binding Protein Hup at Low pH. Biochemistry 2021; 60:3236-3252. [PMID: 34665609 DOI: 10.1021/acs.biochem.1c00395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The summarized amalgam of internal relaxation modulations and external forces like pH, temperature, and solvent conditions determine the protein structure, stability, and function. In a free-energy landscape, although conformers are arranged in vertical hierarchy, there exist several adjacent parallel sets with conformers occupying equivalent energy cleft. Such conformational states are pre-requisites for the functioning of proteins that have oscillating environmental conditions. As these conformational changes have utterly small re-arrangements, nuclear magnetic resonance (NMR) spectroscopy is unique in elucidating the structure-dynamics-stability-function relationships for such conformations. Helicobacter pylori survives and causes gastric cancer at extremely low pH also. However, least is known as to how the genome of the pathogen is protected from reactive oxygen species (ROS) scavenging in the gut at low pH under acidic stress. In the current study, biophysical characteristics of H. pylori DNA binding protein (Hup) have been elucidated at pH 2 using a combination of circular dichroism, fluorescence, NMR spectroscopy, and molecular dynamics simulations. Interestingly, the protein was found to have conserved structural features, differential backbone dynamics, enhanced stability, and DNA binding ability at low pH as well. In summary, the study suggests the partaking of Hup protein even at low pH in DNA protection for maintaining the genome integrity.
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Affiliation(s)
- Nipanshu Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nancy Jaiswal
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Khushboo Gulati
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Krishnakant Gangele
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nupur Nagar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Krishna Mohan Poluri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India.,Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
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18
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Spatial rearrangement of the Streptomyces venezuelae linear chromosome during sporogenic development. Nat Commun 2021; 12:5222. [PMID: 34471115 PMCID: PMC8410768 DOI: 10.1038/s41467-021-25461-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 08/12/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria of the genus Streptomyces have a linear chromosome, with a core region and two ‘arms’. During their complex life cycle, these bacteria develop multi-genomic hyphae that differentiate into chains of exospores that carry a single copy of the genome. Sporulation-associated cell division requires chromosome segregation and compaction. Here, we show that the arms of Streptomyces venezuelae chromosomes are spatially separated at entry to sporulation, but during sporogenic cell division they are closely aligned with the core region. Arm proximity is imposed by segregation protein ParB and condensin SMC. Moreover, the chromosomal terminal regions are organized into distinct domains by the Streptomyces-specific HU-family protein HupS. Thus, as seen in eukaryotes, there is substantial chromosomal remodelling during the Streptomyces life cycle, with the chromosome undergoing rearrangements from an ‘open’ to a ‘closed’ conformation. Streptomyces bacteria have a linear chromosome and a complex life cycle, including development of multi-genomic hyphae that differentiate into mono-genomic exospores. Here, Szafran et al. show that the chromosome of Streptomyces venezuelae undergoes substantial remodelling during sporulation, from an ‘open’ to a ‘closed’ conformation.
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19
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Kamagata K, Itoh Y, Tan C, Mano E, Wu Y, Mandali S, Takada S, Johnson RC. Testing mechanisms of DNA sliding by architectural DNA-binding proteins: dynamics of single wild-type and mutant protein molecules in vitro and in vivo. Nucleic Acids Res 2021; 49:8642-8664. [PMID: 34352099 PMCID: PMC8421229 DOI: 10.1093/nar/gkab658] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/10/2021] [Accepted: 07/22/2021] [Indexed: 01/06/2023] Open
Abstract
Architectural DNA-binding proteins (ADBPs) are abundant constituents of eukaryotic or bacterial chromosomes that bind DNA promiscuously and function in diverse DNA reactions. They generate large conformational changes in DNA upon binding yet can slide along DNA when searching for functional binding sites. Here we investigate the mechanism by which ADBPs diffuse on DNA by single-molecule analyses of mutant proteins rationally chosen to distinguish between rotation-coupled diffusion and DNA surface sliding after transient unbinding from the groove(s). The properties of yeast Nhp6A mutant proteins, combined with molecular dynamics simulations, suggest Nhp6A switches between two binding modes: a static state, in which the HMGB domain is bound within the minor groove with the DNA highly bent, and a mobile state, where the protein is traveling along the DNA surface by means of its flexible N-terminal basic arm. The behaviors of Fis mutants, a bacterial nucleoid-associated helix-turn-helix dimer, are best explained by mobile proteins unbinding from the major groove and diffusing along the DNA surface. Nhp6A, Fis, and bacterial HU are all near exclusively associated with the chromosome, as packaged within the bacterial nucleoid, and can be modeled by three diffusion modes where HU exhibits the fastest and Fis the slowest diffusion.
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Affiliation(s)
- Kiyoto Kamagata
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yuji Itoh
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Cheng Tan
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Eriko Mano
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Yining Wu
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Sridhar Mandali
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Reid C Johnson
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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20
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Yoshua SB, Watson GD, Howard JAL, Velasco-Berrelleza V, Leake MC, Noy A. Integration host factor bends and bridges DNA in a multiplicity of binding modes with varying specificity. Nucleic Acids Res 2021; 49:8684-8698. [PMID: 34352078 PMCID: PMC8421141 DOI: 10.1093/nar/gkab641] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 07/02/2021] [Accepted: 07/16/2021] [Indexed: 11/29/2022] Open
Abstract
Nucleoid-associated proteins (NAPs) are crucial in organizing prokaryotic DNA and regulating genes. Vital to these activities are complex nucleoprotein structures, however, how these form remains unclear. Integration host factor (IHF) is an Escherichia coli NAP that creates very sharp bends in DNA at sequences relevant to several functions including transcription and recombination, and is also responsible for general DNA compaction when bound non-specifically. We show that IHF–DNA structural multimodality is more elaborate than previously thought, and provide insights into how this drives mechanical switching towards strongly bent DNA. Using single-molecule atomic force microscopy and atomic molecular dynamics simulations we find three binding modes in roughly equal proportions: ‘associated’ (73° of DNA bend), ‘half-wrapped’ (107°) and ‘fully-wrapped’ (147°), only the latter occurring with sequence specificity. We show IHF bridges two DNA double helices through non-specific recognition that gives IHF a stoichiometry greater than one and enables DNA mesh assembly. We observe that IHF-DNA structural multiplicity is driven through non-specific electrostatic interactions that we anticipate to be a general NAP feature for physical organization of chromosomes.
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Affiliation(s)
- Samuel B Yoshua
- Department of Physics, University of York, York YO10 5DD, UK
| | - George D Watson
- Department of Physics, 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
| | - Agnes Noy
- Department of Physics, University of York, York YO10 5DD, UK
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21
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Amemiya HM, Schroeder J, Freddolino PL. Nucleoid-associated proteins shape chromatin structure and transcriptional regulation across the bacterial kingdom. Transcription 2021; 12:182-218. [PMID: 34499567 PMCID: PMC8632127 DOI: 10.1080/21541264.2021.1973865] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/15/2021] [Accepted: 08/18/2021] [Indexed: 01/21/2023] Open
Abstract
Genome architecture has proven to be critical in determining gene regulation across almost all domains of life. While many of the key components and mechanisms of eukaryotic genome organization have been described, the interplay between bacterial DNA organization and gene regulation is only now being fully appreciated. An increasing pool of evidence has demonstrated that the bacterial chromosome can reasonably be thought of as chromatin, and that bacterial chromosomes contain transcriptionally silent and transcriptionally active regions analogous to heterochromatin and euchromatin, respectively. The roles played by histones in eukaryotic systems appear to be shared across a range of nucleoid-associated proteins (NAPs) in bacteria, which function to compact, structure, and regulate large portions of bacterial chromosomes. The broad range of extant NAPs, and the extent to which they differ from species to species, has raised additional challenges in identifying and characterizing their roles in all but a handful of model bacteria. Here we review the regulatory roles played by NAPs in several well-studied bacteria and use the resulting state of knowledge to provide a working definition for NAPs, based on their function, binding pattern, and expression levels. We present a screening procedure which can be applied to any species for which transcriptomic data are available. Finally, we note that NAPs tend to play two major regulatory roles - xenogeneic silencers and developmental regulators - and that many unrecognized potential NAPs exist in each bacterial species examined.
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Affiliation(s)
- Haley M. Amemiya
- University of Michigan Medical School, Ann Arbor, MI, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jeremy Schroeder
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L. Freddolino
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
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22
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Feric M, Misteli T. Phase separation in genome organization across evolution. Trends Cell Biol 2021; 31:671-685. [PMID: 33771451 PMCID: PMC8286288 DOI: 10.1016/j.tcb.2021.03.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/17/2021] [Accepted: 03/01/2021] [Indexed: 02/06/2023]
Abstract
Phase separation is emerging as a paradigm to explain the self-assembly and organization of membraneless bodies in the cell. Recent advances show that this principle also extends to nucleoprotein complexes, including DNA-based structures. We discuss here recent observations on the role of phase separation in genome organization across the evolutionary spectrum from bacteria to mammals. These findings suggest that molecular interactions amongst DNA-binding proteins evolved to form a variety of biomolecular condensates with distinct material properties that affect genome organization and function. We suggest that phase separation contributes to genome organization across evolution and that the resulting phase behavior of genomes may underlie regulatory mechanisms and disease.
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Affiliation(s)
- Marina Feric
- National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD, USA; National Institute of General Medical Sciences, NIH, Bethesda, MD, USA.
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD, USA.
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23
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Hammel M, Tainer JA. X-ray scattering reveals disordered linkers and dynamic interfaces in complexes and mechanisms for DNA double-strand break repair impacting cell and cancer biology. Protein Sci 2021; 30:1735-1756. [PMID: 34056803 PMCID: PMC8376411 DOI: 10.1002/pro.4133] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 12/17/2022]
Abstract
Evolutionary selection ensures specificity and efficiency in dynamic metastable macromolecular machines that repair DNA damage without releasing toxic and mutagenic intermediates. Here we examine non‐homologous end joining (NHEJ) as the primary conserved DNA double‐strand break (DSB) repair process in human cells. NHEJ has exemplary key roles in networks determining the development, outcome of cancer treatments by DSB‐inducing agents, generation of antibody and T‐cell receptor diversity, and innate immune response for RNA viruses. We determine mechanistic insights into NHEJ structural biochemistry focusing upon advanced small angle X‐ray scattering (SAXS) results combined with X‐ray crystallography (MX) and cryo‐electron microscopy (cryo‐EM). SAXS coupled to atomic structures enables integrated structural biology for objective quantitative assessment of conformational ensembles and assemblies in solution, intra‐molecular distances, structural similarity, functional disorder, conformational switching, and flexibility. Importantly, NHEJ complexes in solution undergo larger allosteric transitions than seen in their cryo‐EM or MX structures. In the long‐range synaptic complex, X‐ray repair cross‐complementing 4 (XRCC4) plus XRCC4‐like‐factor (XLF) form a flexible bridge and linchpin for DNA ends bound to KU heterodimer (Ku70/80) and DNA‐PKcs (DNA‐dependent protein kinase catalytic subunit). Upon binding two DNA ends, auto‐phosphorylation opens DNA‐PKcs dimer licensing NHEJ via concerted conformational transformations of XLF‐XRCC4, XLF–Ku80, and LigIVBRCT–Ku70 interfaces. Integrated structures reveal multifunctional roles for disordered linkers and modular dynamic interfaces promoting DSB end processing and alignment into the short‐range complex for ligation by LigIV. Integrated findings define dynamic assemblies fundamental to designing separation‐of‐function mutants and allosteric inhibitors targeting conformational transitions in multifunctional complexes.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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24
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Glinkowska M, Waldminghaus T, Riber L. Editorial: Bacterial Chromosomes Under Changing Environmental Conditions. Front Microbiol 2021; 12:633466. [PMID: 33776964 PMCID: PMC7991073 DOI: 10.3389/fmicb.2021.633466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/18/2021] [Indexed: 11/14/2022] Open
Affiliation(s)
- Monika Glinkowska
- Department of Bacterial Molecular Genetics, University of Gdansk, Gdańsk, Poland
| | - Torsten Waldminghaus
- Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany.,Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Leise Riber
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
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25
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Zhao H. Self-assembled nucleoid proteins scaffold bacterial DNA. Biophys J 2021; 120:754-755. [PMID: 33600765 PMCID: PMC8008264 DOI: 10.1016/j.bpj.2021.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 11/28/2022] Open
Affiliation(s)
- Haiqing Zhao
- Department of Systems Biology, Columbia University, New York, New York.
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26
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Feric M, Demarest TG, Tian J, Croteau DL, Bohr VA, Misteli T. Self-assembly of multi-component mitochondrial nucleoids via phase separation. EMBO J 2021; 40:e107165. [PMID: 33619770 DOI: 10.15252/embj.2020107165] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondria contain an autonomous and spatially segregated genome. The organizational unit of their genome is the nucleoid, which consists of mitochondrial DNA (mtDNA) and associated architectural proteins. Here, we show that phase separation is the primary physical mechanism for assembly and size control of the mitochondrial nucleoid (mt-nucleoid). The major mtDNA-binding protein TFAM spontaneously phase separates in vitro via weak, multivalent interactions into droplets with slow internal dynamics. TFAM and mtDNA form heterogenous, viscoelastic structures in vitro, which recapitulate the dynamics and behavior of mt-nucleoids in vivo. Mt-nucleoids coalesce into larger droplets in response to various forms of cellular stress, as evidenced by the enlarged and transcriptionally active nucleoids in mitochondria from patients with the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS). Our results point to phase separation as an evolutionarily conserved mechanism of genome organization.
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Affiliation(s)
- Marina Feric
- National Cancer Institute, NIH, Bethesda, MD, USA.,National Institute of General Medical Sciences, NIH, Bethesda, MD, USA
| | | | - Jane Tian
- National Institute on Aging, NIH, Baltimore, MD, USA
| | | | | | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
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