1
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Tang S, Huang CH, Ko TP, Lin KF, Chang YC, Lin PY, Sun L, Chen CY. Dual dimeric interactions in the nucleic acid-binding protein Sac10b lead to multiple bridging of double-stranded DNA. Heliyon 2024; 10:e31630. [PMID: 38867953 PMCID: PMC11167270 DOI: 10.1016/j.heliyon.2024.e31630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/26/2024] [Accepted: 05/20/2024] [Indexed: 06/14/2024] Open
Abstract
Nucleoid-associated proteins play a crucial role in the compaction and regulation of genetic material across organisms. The Sac10b family, also known as Alba, comprises widely distributed and highly conserved nucleoid-associated proteins found in archaea. Sac10b is identified as the first 10 kDa DNA-binding protein in the thermoacidophile Sulfolobus acidocaldarius. Here, we present the crystal structures of two homologous proteins, Sac10b1 and Sac10b2, as well as the Sac10b1 mutant F59A, determined at a resolution of 1.4-2.0 Å. Electron microscopic images reveal the DNA-bridging capabilities of both Sac10b1 and Sac10b2, albeit to varying extents. Analyses of crystal packing and electron microscopic results suggest that Sac10b1 facilitates cooperative DNA binding, forming extensive bridged filaments via the conserved R58 and F59 residues at the dimer-dimer interface. Substitutions at R58 or F59 of Sac10b1 attenuate end-to-end association, resulting in non-cooperative DNA binding, and formation of small, bridged DNA segments in a way similar to Sac10b2. Analytical ultracentrifuge and circular dichroism confirm the presence of thermostable, acid-tolerant dimers in both Sac10b1 and Sac10b2. These findings attest to the functional role of Sac10b in organizing and stabilizing chromosomal DNA through distinct bridging interactions, particularly under extreme growth conditions.
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Affiliation(s)
- Songqiang Tang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Chun-Hsiang Huang
- Protein Diffraction Group, Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Kuan-Fu Lin
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Yuan-Chih Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Po-Yen Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Liuchang Sun
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Chin-Yu Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
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2
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Hustmyer CM, Landick R. Bacterial chromatin proteins, transcription, and DNA topology: Inseparable partners in the control of gene expression. Mol Microbiol 2024. [PMID: 38847475 DOI: 10.1111/mmi.15283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 06/15/2024]
Abstract
DNA in bacterial chromosomes is organized into higher-order structures by DNA-binding proteins called nucleoid-associated proteins (NAPs) or bacterial chromatin proteins (BCPs). BCPs often bind to or near DNA loci transcribed by RNA polymerase (RNAP) and can either increase or decrease gene expression. To understand the mechanisms by which BCPs alter transcription, one must consider both steric effects and the topological forces that arise when DNA deviates from its fully relaxed double-helical structure. Transcribing RNAP creates DNA negative (-) supercoils upstream and positive (+) supercoils downstream whenever RNAP and DNA are unable to rotate freely. This (-) and (+) supercoiling generates topological forces that resist forward translocation of DNA through RNAP unless the supercoiling is constrained by BCPs or relieved by topoisomerases. BCPs also may enhance topological stress and overall can either inhibit or aid transcription. Here, we review current understanding of how RNAP, BCPs, and DNA topology interplay to control gene expression.
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Affiliation(s)
- Christine M Hustmyer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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3
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Baglivo I, Malgieri G, Roop RM, Barton IS, Wang X, Russo V, Pirone L, Pedone EM, Pedone PV. MucR protein: Three decades of studies have led to the identification of a new H-NS-like protein. Mol Microbiol 2024. [PMID: 38619026 DOI: 10.1111/mmi.15261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024]
Abstract
MucR belongs to a large protein family whose members regulate the expression of virulence and symbiosis genes in α-proteobacteria species. This protein and its homologs were initially studied as classical transcriptional regulators mostly involved in repression of target genes by binding their promoters. Very recent studies have led to the classification of MucR as a new type of Histone-like Nucleoid Structuring (H-NS) protein. Thus this review is an effort to put together a complete and unifying story demonstrating how genetic and biochemical findings on MucR suggested that this protein is not a classical transcriptional regulator, but functions as a novel type of H-NS-like protein, which binds AT-rich regions of genomic DNA and regulates gene expression.
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Affiliation(s)
- Ilaria Baglivo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Caserta, Italy
| | - Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Caserta, Italy
| | - Roy Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ian S Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | | | - Luciano Pirone
- Institute of Biostructures and Bioimaging, CNR, Naples, Italy
| | - Emilia M Pedone
- Institute of Biostructures and Bioimaging, CNR, Naples, Italy
| | - Paolo V Pedone
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Caserta, Italy
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4
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Park J, Kim JJ, Ryu JK. Mechanism of phase condensation for chromosome architecture and function. Exp Mol Med 2024; 56:809-819. [PMID: 38658703 PMCID: PMC11059216 DOI: 10.1038/s12276-024-01226-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 04/26/2024] Open
Abstract
Chromosomal phase separation is involved in a broad spectrum of chromosome organization and functional processes. Nonetheless, the intricacy of this process has left its molecular mechanism unclear. Here, we introduce the principles governing phase separation and its connections to physiological roles in this context. Our primary focus is contrasting two phase separation mechanisms: self-association-induced phase separation (SIPS) and bridging-induced phase separation (BIPS). We provide a comprehensive discussion of the distinct features characterizing these mechanisms and offer illustrative examples that suggest their broad applicability. With a detailed understanding of these mechanisms, we explore their associations with nucleosomes and chromosomal biological functions. This comprehensive review contributes to the exploration of uncharted territory in the intricate interplay between chromosome architecture and function.
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Affiliation(s)
- Jeongveen Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Jeong-Jun Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Je-Kyung Ryu
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
- Institute of Applied Physics of Seoul National University, Seoul, 08826, South Korea.
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, South Korea.
- Department of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, 08826, South Korea.
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5
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Erkelens AM, van Erp B, Meijer WJJ, Dame RT. Rok from B. subtilis: Bridging genome structure and transcription regulation. Mol Microbiol 2024. [PMID: 38511404 DOI: 10.1111/mmi.15250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/02/2024] [Accepted: 03/07/2024] [Indexed: 03/22/2024]
Abstract
Bacterial genomes are folded and organized into compact yet dynamic structures, called nucleoids. Nucleoid orchestration involves many factors at multiple length scales, such as nucleoid-associated proteins and liquid-liquid phase separation, and has to be compatible with replication and transcription. Possibly, genome organization plays an intrinsic role in transcription regulation, in addition to classical transcription factors. In this review, we provide arguments supporting this view using the Gram-positive bacterium Bacillus subtilis as a model. Proteins BsSMC, HBsu and Rok all impact the structure of the B. subtilis chromosome. Particularly for Rok, there is compelling evidence that it combines its structural function with a role as global gene regulator. Many studies describe either function of Rok, but rarely both are addressed at the same time. Here, we review both sides of the coin and integrate them into one model. Rok forms unusually stable DNA-DNA bridges and this ability likely underlies its repressive effect on transcription by either preventing RNA polymerase from binding to DNA or trapping it inside DNA loops. Partner proteins are needed to change or relieve Rok-mediated gene repression. Lastly, we investigate which features characterize H-NS-like proteins, a family that, at present, lacks a clear definition.
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Affiliation(s)
- Amanda M Erkelens
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, the Netherlands
| | - Bert van Erp
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, the Netherlands
| | - Wilfried J J Meijer
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma, Madrid, Spain
| | - Remus T Dame
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, the Netherlands
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6
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Nishiyama A, Shimizu M, Narita T, Kodera N, Ozeki Y, Yokoyama A, Mayanagi K, Yamaguchi T, Hakamata M, Shaban A, Tateishi Y, Ito K, Matsumoto S. Dynamic action of an intrinsically disordered protein in DNA compaction that induces mycobacterial dormancy. Nucleic Acids Res 2024; 52:816-830. [PMID: 38048321 PMCID: PMC10810275 DOI: 10.1093/nar/gkad1149] [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: 03/08/2023] [Revised: 10/17/2023] [Accepted: 11/23/2023] [Indexed: 12/06/2023] Open
Abstract
Mycobacteria are the major human pathogens with the capacity to become dormant persisters. Mycobacterial DNA-binding protein 1 (MDP1), an abundant histone-like protein in dormant mycobacteria, induces dormancy phenotypes, e.g. chromosome compaction and growth suppression. For these functions, the polycationic intrinsically disordered region (IDR) is essential. However, the disordered property of IDR stands in the way of clarifying the molecular mechanism. Here we clarified the molecular and structural mechanism of DNA compaction by MDP1. Using high-speed atomic force microscopy, we observed that monomeric MDP1 bundles two adjacent DNA duplexes side-by-side via IDR. Combined with coarse-grained molecular dynamics simulation, we revealed the novel dynamic DNA cross-linking model of MDP1 in which a stretched IDR cross-links two DNA duplexes like double-sided tape. IDR is able to hijack HU function, resulting in the induction of strong mycobacterial growth arrest. This IDR-mediated reversible DNA cross-linking is a reasonable model for MDP1 suppression of the genomic function in the resuscitable non-replicating dormant mycobacteria.
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Affiliation(s)
- Akihito Nishiyama
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Masahiro Shimizu
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
- Division of Quantum Beam Material Science, Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-Nishi, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Tomoyuki Narita
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
| | - Noriyuki Kodera
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuriko Ozeki
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Akira Yokoyama
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Kouta Mayanagi
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takehiro Yamaguchi
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Pharmacology, Osaka Metropolitan University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan
| | - Mariko Hakamata
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Respiratory Medicine and Infectious Disease, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Amina Kaboso Shaban
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Yoshitaka Tateishi
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Kosuke Ito
- Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Sohkichi Matsumoto
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Laboratory of Tuberculosis, Institute of Tropical Disease, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya, East Java 60115, Indonesia
- Division of Research Aids, Hokkaido University Institute for Vaccine Research & Development, Kita 20, Nishi 10, Kita-ku, Sapporo, 001-0020, Japan
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7
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van Heesch T, Bolhuis PG, Vreede J. Decoding dissociation of sequence-specific protein-DNA complexes with non-equilibrium simulations. Nucleic Acids Res 2023; 51:12150-12160. [PMID: 37953329 PMCID: PMC10711434 DOI: 10.1093/nar/gkad1014] [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: 02/27/2023] [Revised: 10/13/2023] [Accepted: 10/19/2023] [Indexed: 11/14/2023] Open
Abstract
Sequence-specific protein-DNA interactions are crucial in processes such as DNA organization, gene regulation and DNA replication. Obtaining detailed insights into the recognition mechanisms of protein-DNA complexes through experiments is hampered by a lack of resolution in both space and time. Here, we present a molecular simulation approach to quantify the sequence specificity of protein-DNA complexes, that yields results fast, and is generally applicable to any protein-DNA complex. The approach is based on molecular dynamics simulations in combination with a sophisticated steering potential and results in an estimate of the free energy difference of dissociation. We provide predictions of the nucleotide specific binding affinity of the minor groove binding Histone-like Nucleoid Structuring (H-NS) protein, that are in agreement with experimental data. Furthermore, our approach offers mechanistic insight into the process of dissociation. Applying our approach to the major groove binding ETS domain in complex with three different nucleotide sequences identified the high affinity consensus sequence, quantitatively in agreement with experiments. Our protocol facilitates quantitative prediction of protein-DNA complex stability, while also providing high resolution insights into recognition mechanisms. As such, our simulation approach has the potential to yield detailed and quantitative insights into biological processes involving sequence-specific protein-DNA interactions.
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Affiliation(s)
- Thor van Heesch
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands
| | - Peter G Bolhuis
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands
| | - Jocelyne Vreede
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands
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8
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Rashid FZM, Crémazy FGE, Hofmann A, Forrest D, Grainger DC, Heermann DW, Dame RT. The environmentally-regulated interplay between local three-dimensional chromatin organisation and transcription of proVWX in E. coli. Nat Commun 2023; 14:7478. [PMID: 37978176 PMCID: PMC10656529 DOI: 10.1038/s41467-023-43322-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/07/2023] [Indexed: 11/19/2023] Open
Abstract
Nucleoid associated proteins (NAPs) maintain the architecture of bacterial chromosomes and regulate gene expression. Thus, their role as transcription factors may involve three-dimensional chromosome re-organisation. While this model is supported by in vitro studies, direct in vivo evidence is lacking. Here, we use RT-qPCR and 3C-qPCR to study the transcriptional and architectural profiles of the H-NS (histone-like nucleoid structuring protein)-regulated, osmoresponsive proVWX operon of Escherichia coli at different osmolarities and provide in vivo evidence for transcription regulation by NAP-mediated chromosome re-modelling in bacteria. By consolidating our in vivo investigations with earlier in vitro and in silico studies that provide mechanistic details of how H-NS re-models DNA in response to osmolarity, we report that activation of proVWX in response to a hyperosmotic shock involves the destabilization of H-NS-mediated bridges anchored between the proVWX downstream and upstream regulatory elements (DRE and URE), and between the DRE and ygaY that lies immediately downstream of proVWX. The re-establishment of these bridges upon adaptation to hyperosmolarity represses the operon. Our results also reveal additional structural features associated with changes in proVWX transcript levels such as the decompaction of local chromatin upstream of the operon, highlighting that further complexity underlies the regulation of this model operon. H-NS and H-NS-like proteins are wide-spread amongst bacteria, suggesting that chromosome re-modelling may be a typical feature of transcriptional control in bacteria.
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Affiliation(s)
- Fatema-Zahra M Rashid
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden, 2333CC, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, 2333CC, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, 2333CC, The Netherlands
| | - Frédéric G E Crémazy
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden, 2333CC, The Netherlands
- Laboratoire Infection et Inflammation, INSERM, UVSQ, Université Paris-Saclay, Versailles, 78180, France
| | - Andreas Hofmann
- Statistical Physics and Theoretical Biophysics, Heidelberg University, Heidelberg, D-69120, Germany
| | - David Forrest
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - David C Grainger
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Dieter W Heermann
- Statistical Physics and Theoretical Biophysics, Heidelberg University, Heidelberg, D-69120, Germany
| | - Remus T Dame
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden, 2333CC, The Netherlands.
- Centre for Microbial Cell Biology, Leiden University, Leiden, 2333CC, The Netherlands.
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, 2333CC, The Netherlands.
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9
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Slapakova M, Sgambati D, Pirone L, Russo V, D’Abrosca G, Valletta M, Russo R, Chambery A, Malgieri G, Pedone EM, Dame RT, Pedone PV, Baglivo I. MucR from Sinorhizobium meliloti: New Insights into Its DNA Targets and Its Ability to Oligomerize. Int J Mol Sci 2023; 24:14702. [PMID: 37834166 PMCID: PMC10572780 DOI: 10.3390/ijms241914702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
Proteins of the MucR/Ros family play a crucial role in bacterial infection or symbiosis with eukaryotic hosts. MucR from Sinorhizobium meliloti plays a regulatory role in establishing symbiosis with the host plant, both dependent and independent of Quorum Sensing. Here, we report the first characterization of MucR isolated from Sinorhizobium meliloti by mass spectrometry and demonstrate that this protein forms higher-order oligomers in its native condition of expression by SEC-MALS. We show that MucR purified from Sinorhizobium meliloti can bind DNA and recognize the region upstream of the ndvA gene in EMSA, revealing that this gene is a direct target of MucR. Although MucR DNA binding activity was already described, a detailed characterization of Sinorhizobium meliloti DNA targets has never been reported. We, thus, analyze sequences recognized by MucR in the rem gene promoter, showing that this protein recognizes AT-rich sequences and does not require a consensus sequence to bind DNA. Furthermore, we investigate the dependence of MucR DNA binding on the length of DNA targets. Taken together, our studies establish MucR from Sinorhizobium meliloti as a member of a new family of Histone-like Nucleoid Structuring (H-NS) proteins, thus explaining the multifaceted role of this protein in many species of alpha-proteobacteria.
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Affiliation(s)
- Martina Slapakova
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Domenico Sgambati
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Luciano Pirone
- Institute of Biostructures and Bioimaging, CNR, Via Pietro Castellino, 80134 Naples, Italy; (L.P.); (E.M.P.)
| | - Veronica Russo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Gianluca D’Abrosca
- Department of Clinical and Experimental Medicine, University of Foggia, Viale Pinto, 1, 71122 Foggia, Italy;
| | - Mariangela Valletta
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Rosita Russo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Angela Chambery
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Emilia Maria Pedone
- Institute of Biostructures and Bioimaging, CNR, Via Pietro Castellino, 80134 Naples, Italy; (L.P.); (E.M.P.)
| | - Remus Thei Dame
- Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands;
- Centre for Microbial Cell Biology, Leiden University, 2333 CC Leiden, The Netherlands
| | - Paolo Vincenzo Pedone
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
| | - Ilaria Baglivo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi, 43, 81100 Caserta, Italy; (M.S.); (D.S.); (V.R.); (M.V.); (R.R.); (A.C.); (G.M.); (P.V.P.)
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10
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Rashid FZM, Dame RT. Three-dimensional chromosome re-modelling: The integral mechanism of transcription regulation in bacteria. Mol Microbiol 2023; 120:60-70. [PMID: 37433047 DOI: 10.1111/mmi.15062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 07/13/2023]
Abstract
Nucleoid-associated proteins (NAPs) are architectural proteins of the bacterial chromosome and transcription factors that dynamically organise the chromosome and regulate gene expression in response to physicochemical environmental signals. While the architectural and regulatory functions of NAPs have been verified independently, the coupling between these functions in vivo has not been conclusively proven. Here we describe a model NAP - histone-like nucleoid structuring protein (H-NS) - as a coupled sensor-effector that directly regulates gene expression by chromatin re-modelling in response to physicochemical environmental signals. We outline how H-NS-binding partners and post-translational modifications modulate the role of H-NS as a transcription factor by influencing its DNA structuring properties. We consolidate our ideas in models of how H-NS may regulate the expression of the proVWX and hlyCABD operons by chromatin re-modelling. The interplay between chromosome structure and gene expression may be a common - but, at present, under-appreciated - concept of transcription regulation in bacteria.
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Affiliation(s)
- Fatema-Zahra M Rashid
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
| | - Remus T Dame
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
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11
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Tarrés-Solé A, Battistini F, Gerhold JM, Piétrement O, Martínez-García B, Ruiz-López E, Lyonnais S, Bernadó P, Roca J, Orozco M, Le Cam E, Sedman J, Solà M. Structural analysis of the Candida albicans mitochondrial DNA maintenance factor Gcf1p reveals a dynamic DNA-bridging mechanism. Nucleic Acids Res 2023; 51:5864-5882. [PMID: 37207342 PMCID: PMC10287934 DOI: 10.1093/nar/gkad397] [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: 07/19/2022] [Revised: 04/01/2023] [Accepted: 05/03/2023] [Indexed: 05/21/2023] Open
Abstract
The compaction of mitochondrial DNA (mtDNA) is regulated by architectural HMG-box proteins whose limited cross-species similarity suggests diverse underlying mechanisms. Viability of Candida albicans, a human antibiotic-resistant mucosal pathogen, is compromised by altering mtDNA regulators. Among them, there is the mtDNA maintenance factor Gcf1p, which differs in sequence and structure from its human and Saccharomyces cerevisiae counterparts, TFAM and Abf2p. Our crystallographic, biophysical, biochemical and computational analysis showed that Gcf1p forms dynamic protein/DNA multimers by a combined action of an N-terminal unstructured tail and a long helix. Furthermore, an HMG-box domain canonically binds the minor groove and dramatically bends the DNA while, unprecedentedly, a second HMG-box binds the major groove without imposing distortions. This architectural protein thus uses its multiple domains to bridge co-aligned DNA segments without altering the DNA topology, revealing a new mechanism of mtDNA condensation.
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Affiliation(s)
- Aleix Tarrés-Solé
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Federica Battistini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
- Department of Biochemistry, University of Barcelona, Barcelona 08028, Spain
| | - Joachim M Gerhold
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Olivier Piétrement
- Genome Integrity and Cancer UMR 9019 CNRS, Université Paris Saclay, Gustave Roussy Campus, 114 rue Edouard Vaillant 94805VillejuifCedex, France
| | | | - Elena Ruiz-López
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Sébastien Lyonnais
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Inserm, CNRS and Université de Montpellier, France, Sébastien Lyonnais, UAR 3725 CNRS, Université de Montpellier, 34000 Montpellier, France
| | - Joaquim Roca
- Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona 08028, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
- Department of Biochemistry, University of Barcelona, Barcelona 08028, Spain
| | - Eric Le Cam
- Genome Integrity and Cancer UMR 9019 CNRS, Université Paris Saclay, Gustave Roussy Campus, 114 rue Edouard Vaillant 94805VillejuifCedex, France
| | - Juhan Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Maria Solà
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
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12
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Picker MA, Karney MMA, Gerson TM, Karabachev A, Duhart J, McKenna J, Wing H. Localized modulation of DNA supercoiling, triggered by the Shigella anti-silencer VirB, is sufficient to relieve H-NS-mediated silencing. Nucleic Acids Res 2023; 51:3679-3695. [PMID: 36794722 PMCID: PMC10164555 DOI: 10.1093/nar/gkad088] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/17/2023] Open
Abstract
In Bacteria, nucleoid structuring proteins govern nucleoid dynamics and regulate transcription. In Shigella spp., at ≤30°C, the histone-like nucleoid structuring protein (H-NS) transcriptionally silences many genes on the large virulence plasmid. Upon a switch to 37°C, VirB, a DNA binding protein and key transcriptional regulator of Shigella virulence, is produced. VirB functions to counter H-NS-mediated silencing in a process called transcriptional anti-silencing. Here, we show that VirB mediates a loss of negative DNA supercoils from our plasmid-borne, VirB-regulated PicsP-lacZ reporter in vivo. The changes are not caused by a VirB-dependent increase in transcription, nor do they require the presence of H-NS. Instead, the VirB-dependent change in DNA supercoiling requires the interaction of VirB with its DNA binding site, a critical first step in VirB-dependent gene regulation. Using two complementary approaches, we show that VirB:DNA interactions in vitro introduce positive supercoils in plasmid DNA. Subsequently, by exploiting transcription-coupled DNA supercoiling, we reveal that a localized loss of negative supercoils is sufficient to alleviate H-NS-mediated transcriptional silencing independently of VirB. Together, our findings provide novel insight into VirB, a central regulator of Shigella virulence and, more broadly, a molecular mechanism that offsets H-NS-dependent silencing of transcription in bacteria.
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Affiliation(s)
- Michael A Picker
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Monika M A Karney
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Taylor M Gerson
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | | | - Juan C Duhart
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Joy A McKenna
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Helen J Wing
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
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13
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Picker MA, Karney MMA, Gerson TM, Karabachev AD, Duhart JC, McKenna JA, Wing HJ. Localized modulation of DNA supercoiling, triggered by the Shigella anti-silencer VirB, is sufficient to relieve H-NS-mediated silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523335. [PMID: 36711906 PMCID: PMC9882051 DOI: 10.1101/2023.01.09.523335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In Bacteria, nucleoid structuring proteins govern nucleoid dynamics and regulate transcription. In Shigella spp ., at ≤ 30 °C, the histone-like nucleoid structuring protein (H-NS) transcriptionally silences many genes on the large virulence plasmid. Upon a switch to 37 °C, VirB, a DNA binding protein and key transcriptional regulator of Shigella virulence, is produced. VirB functions to counter H-NS-mediated silencing in a process called transcriptional anti-silencing. Here, we show that VirB mediates a loss of negative DNA supercoils from our plasmid-borne, VirB-regulated PicsP-lacZ reporter, in vivo . The changes are not caused by a VirB-dependent increase in transcription, nor do they require the presence of H-NS. Instead, the VirB-dependent change in DNA supercoiling requires the interaction of VirB with its DNA binding site, a critical first step in VirB-dependent gene regulation. Using two complementary approaches, we show that VirB:DNA interactions in vitro introduce positive supercoils in plasmid DNA. Subsequently, by exploiting transcription-coupled DNA supercoiling, we reveal that a localized loss of negative supercoils is sufficient to alleviate H-NS-mediated transcriptional silencing, independently of VirB. Together, our findings provide novel insight into VirB, a central regulator of Shigella virulence and more broadly, a molecular mechanism that offsets H-NS-dependent silencing of transcription in bacteria.
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14
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RfaH Counter-Silences Inhibition of Transcript Elongation by H-NS-StpA Nucleoprotein Filaments in Pathogenic Escherichia coli. mBio 2022; 13:e0266222. [PMID: 36264101 PMCID: PMC9765446 DOI: 10.1128/mbio.02662-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of virulence genes in pathogenic Escherichia coli is controlled in part by the transcription silencer H-NS and its paralogs (e.g., StpA), which sequester DNA in multi-kb nucleoprotein filaments to inhibit transcription initiation, elongation, or both. Some activators counter-silence initiation by displacing H-NS from promoters, but how H-NS inhibition of elongation is overcome is not understood. In uropathogenic E. coli (UPEC), elongation regulator RfaH aids expression of some H-NS-silenced pathogenicity operons (e.g., hlyCABD encoding hemolysin). RfaH associates with elongation complexes (ECs) via direct contacts to a transiently exposed, nontemplate DNA strand sequence called operon polarity suppressor (ops). RfaH-ops interactions establish long-lived RfaH-EC contacts that allow RfaH to recruit ribosomes to the nascent mRNA and to suppress transcriptional pausing and termination. Using ChIP-seq, we mapped the genome-scale distributions of RfaH, H-NS, StpA, RNA polymerase (RNAP), and σ70 in the UPEC strain CFT073. We identify eight RfaH-activated operons, all of which were bound by H-NS and StpA. Four are new additions to the RfaH regulon. Deletion of RfaH caused premature termination, whereas deletion of H-NS and StpA allowed elongation without RfaH. Thus, RfaH is an elongation counter-silencer of H-NS. Consistent with elongation counter-silencing, deletion of StpA alone decreased the effect of RfaH. StpA increases DNA bridging, which inhibits transcript elongation via topological constraints on RNAP. Residual RfaH effect when both H-NS and StpA were deleted was attributable to targeting of RfaH-regulated operons by a minor H-NS paralog, Hfp. These operons have evolved higher levels of H-NS-binding features, explaining minor-paralog targeting. IMPORTANCE Bacterial pathogens adapt to hosts and host defenses by reprogramming gene expression, including by H-NS counter-silencing. Counter-silencing turns on transcription initiation when regulators bind to promoters and rearrange repressive H-NS nucleoprotein filaments that ordinarily block transcription. The specialized NusG paralog RfaH also reprograms virulence genes but regulates transcription elongation. To understand how elongation regulators might affect genes silenced by H-NS, we mapped H-NS, StpA (an H-NS paralog), RfaH, σ70, and RNA polymerase (RNAP) locations on DNA in the uropathogenic E. coli strain CFT073. Although H-NS-StpA filaments bind only 18% of the CFT073 genome, all loci at which RfaH binds RNAP are also bound by H-NS-StpA and are silenced when RfaH is absent. Thus, RfaH represents a distinct class of counter-silencer that acts on elongating RNAP to enable transcription through repressive nucleoprotein filaments. Our findings define a new mechanism of elongation counter-silencing and explain how RfaH functions as a virulence regulator.
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15
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Holub M, Birnie A, Japaridze A, van der Torre J, Ridder MD, de Ram C, Pabst M, Dekker C. Extracting and characterizing protein-free megabase-pair DNA for in vitro experiments. CELL REPORTS METHODS 2022; 2:100366. [PMID: 36590691 PMCID: PMC9795359 DOI: 10.1016/j.crmeth.2022.100366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/29/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022]
Abstract
Chromosome structure and function is studied using various cell-based methods as well as with a range of in vitro single-molecule techniques on short DNA substrates. Here, we present a method to obtain megabase-pair-length deproteinated DNA for in vitro studies. We isolated chromosomes from bacterial cells and enzymatically digested the native proteins. Mass spectrometry indicated that 97%-100% of DNA-binding proteins are removed from the sample. Fluorescence microscopy analysis showed an increase in the radius of gyration of the DNA polymers, while the DNA length remained megabase-pair sized. In proof-of-concept experiments using these deproteinated long DNA molecules, we observed DNA compaction upon adding the DNA-binding protein Fis or PEG crowding agents and showed that it is possible to track the motion of a fluorescently labeled DNA locus. These results indicate the practical feasibility of a "genome-in-a-box" approach to study chromosome organization from the bottom up.
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Affiliation(s)
- Martin Holub
- Department of Bionanoscience & Kavli Institute for Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Anthony Birnie
- Department of Bionanoscience & Kavli Institute for Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Aleksandre Japaridze
- Department of Bionanoscience & Kavli Institute for Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Jaco van der Torre
- Department of Bionanoscience & Kavli Institute for Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Maxime den Ridder
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Carol de Ram
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Cees Dekker
- Department of Bionanoscience & Kavli Institute for Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands
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16
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Elpers L, Deiwick J, Hensel M. Effect of Environmental Temperatures on Proteome Composition of Salmonella enterica Serovar Typhimurium. Mol Cell Proteomics 2022; 21:100265. [PMID: 35788066 PMCID: PMC9396072 DOI: 10.1016/j.mcpro.2022.100265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 06/17/2022] [Accepted: 06/30/2022] [Indexed: 12/29/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (STM) is a major cause of gastroenteritis and transmitted by consumption of contaminated food. STM is associated to food originating from animals (pork, chicken, eggs) or plants (vegetables, fruits, nuts, and herbs). Infection of warm-blooded mammalian hosts by STM and the underlying complex regulatory network of virulence gene expression depend on various environmental conditions encountered in hosts. However, less is known about the proteome and possible regulatory networks for gene expression of STM outside the preferred host. Nutritional limitations and changes in temperature are the most obvious stresses outside the native host. Thus, we analyzed the proteome profile of STM grown in rich medium (LB medium) or minimal medium (PCN medium) at temperatures ranging from 8 °C to 37 °C. LB medium mimics the nutritional rich environment inside the host, whereas minimal PCN medium represents nutritional limitations outside the host, found during growth of fresh produce (field conditions). Further, the range of temperatures analyzed reflects conditions within natural hosts (37 °C), room temperature (20 °C), during growth under agricultural conditions (16 °C and 12 °C), and during food storage (8 °C). Implications of altered nutrient availability and growth temperature on STM proteomes were analyzed by HPLC/MS-MS and label-free quantification. Our study provides first insights into the complex adaptation of STM to various environmental temperatures, which allows STM not only to infect mammalian hosts but also to enter new infection routes that have been poorly studied so far. With the present dataset, global virulence factors, their impact on infection routes, and potential anti-infective strategies can now be investigated in detail. Especially, we were able to demonstrate functional flagella at 12 °C growth temperature for STM with an altered motility behavior.
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Affiliation(s)
- Laura Elpers
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Jörg Deiwick
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany,CellNanOs – Center of Cellular Nanoanalytics Osnabrück, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany,For correspondence: Michael Hensel
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17
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Bacterial H-NS contacts DNA at the same irregularly spaced sites in both bridged and hemi-sequestered linear filaments. iScience 2022; 25:104429. [PMID: 35669520 PMCID: PMC9162952 DOI: 10.1016/j.isci.2022.104429] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/01/2022] [Accepted: 05/13/2022] [Indexed: 11/22/2022] Open
Abstract
Gene silencing in bacteria is mediated by chromatin proteins, of which Escherichia coli H-NS is a paradigmatic example. H-NS forms nucleoprotein filaments with either one or two DNA duplexes. However, the structures, arrangements of DNA-binding domains (DBDs), and positions of DBD-DNA contacts in linear and bridged filaments are uncertain. To characterize the H-NS DBD contacts that silence transcription by RNA polymerase, we combined ·OH footprinting, molecular dynamics, statistical modeling, and DBD mapping using a chemical nuclease (Fe2+-EDTA) tethered to the DBDs (TEN-map). We find that H-NS DBDs contact DNA at indistinguishable locations in bridged or linear filaments and that the DBDs vary in orientation and position with ∼10-bp average spacing. Our results support a hemi-sequestration model of linear-to-bridged H-NS switching. Linear filaments able to inhibit only transcription initiation switch to bridged filaments able to inhibit both initiation and elongation using the same irregularly spaced DNA contacts.
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18
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DNA-Binding Properties of a Novel Crenarchaeal Chromatin-Organizing Protein in Sulfolobus acidocaldarius. Biomolecules 2022; 12:biom12040524. [PMID: 35454113 PMCID: PMC9025068 DOI: 10.3390/biom12040524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/17/2022] [Accepted: 03/24/2022] [Indexed: 02/06/2023] Open
Abstract
In archaeal microorganisms, the compaction and organization of the chromosome into a dynamic but condensed structure is mediated by diverse chromatin-organizing proteins in a lineage-specific manner. While many archaea employ eukaryotic-type histones for nucleoid organization, this is not the case for the crenarchaeal model species Sulfolobus acidocaldarius and related species in Sulfolobales, in which the organization appears to be mostly reliant on the action of small basic DNA-binding proteins. There is still a lack of a full understanding of the involved proteins and their functioning. Here, a combination of in vitro and in vivo methodologies is used to study the DNA-binding properties of Sul12a, an uncharacterized small basic protein conserved in several Sulfolobales species displaying a winged helix–turn–helix structural motif and annotated as a transcription factor. Genome-wide chromatin immunoprecipitation and target-specific electrophoretic mobility shift assays demonstrate that Sul12a of S. acidocaldarius interacts with DNA in a non-sequence specific manner, while atomic force microscopy imaging of Sul12a–DNA complexes indicate that the protein induces structural effects on the DNA template. Based on these results, and a contrario to its initial annotation, it can be concluded that Sul12a is a novel chromatin-organizing protein.
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19
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Khina AG, Krutyakov YA. Similarities and Differences in the Mechanism of Antibacterial Action of Silver Ions and Nanoparticles. APPL BIOCHEM MICRO+ 2021. [DOI: 10.1134/s0003683821060053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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20
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Bdira FB, Erkelens AM, Qin L, Volkov AN, Lippa A, Bowring N, Boyle A, Ubbink M, Dove S, Dame R. Novel anti-repression mechanism of H-NS proteins by a phage protein. Nucleic Acids Res 2021; 49:10770-10784. [PMID: 34520554 PMCID: PMC8501957 DOI: 10.1093/nar/gkab793] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/16/2021] [Accepted: 09/01/2021] [Indexed: 12/17/2022] Open
Abstract
H-NS family proteins, bacterial xenogeneic silencers, play central roles in genome organization and in the regulation of foreign genes. It is thought that gene repression is directly dependent on the DNA binding modes of H-NS family proteins. These proteins form lateral protofilaments along DNA. Under specific environmental conditions they switch to bridging two DNA duplexes. This switching is a direct effect of environmental conditions on electrostatic interactions between the oppositely charged DNA binding and N-terminal domains of H-NS proteins. The Pseudomonas lytic phage LUZ24 encodes the protein gp4, which modulates the DNA binding and function of the H-NS family protein MvaT of Pseudomonas aeruginosa. However, the mechanism by which gp4 affects MvaT activity remains elusive. In this study, we show that gp4 specifically interferes with the formation and stability of the bridged MvaT-DNA complex. Structural investigations suggest that gp4 acts as an 'electrostatic zipper' between the oppositely charged domains of MvaT protomers, and stabilizes a structure resembling their 'half-open' conformation, resulting in relief of gene silencing and adverse effects on P. aeruginosa growth. The ability to control H-NS conformation and thereby its impact on global gene regulation and growth might open new avenues to fight Pseudomonas multidrug resistance.
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Affiliation(s)
- Fredj Ben Bdira
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Amanda M Erkelens
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Liang Qin
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Alexander N Volkov
- VIB-VUB Structural Biology Research Center, Pleinlaan 2, 1050 Brussels, Belgium
- Jean Jeener NMR Centre, VUB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Andrew M Lippa
- Boston Children's Hospital, Division of Infectious Diseases, Harvard Medical School, Boston, MA 02115, USA
| | - Nicholas Bowring
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Aimee L Boyle
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Marcellus Ubbink
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Simon L Dove
- Boston Children's Hospital, Division of Infectious Diseases, Harvard Medical School, Boston, MA 02115, USA
| | - Remus T Dame
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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21
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Son B, Patterson-West J, Arroyo-Mendoza M, Ramachandran R, Iben J, Zhu J, Rao V, Dimitriadis E, Hinton D. A phage-encoded nucleoid associated protein compacts both host and phage DNA and derepresses H-NS silencing. Nucleic Acids Res 2021; 49:9229-9245. [PMID: 34365505 PMCID: PMC8450097 DOI: 10.1093/nar/gkab678] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 07/20/2021] [Accepted: 08/06/2021] [Indexed: 12/23/2022] Open
Abstract
Nucleoid Associated Proteins (NAPs) organize the bacterial chromosome within the nucleoid. The interaction of the NAP H-NS with DNA also represses specific host and xenogeneic genes. Previously, we showed that the bacteriophage T4 early protein MotB binds to DNA, co-purifies with H-NS/DNA, and improves phage fitness. Here we demonstrate using atomic force microscopy that MotB compacts the DNA with multiple MotB proteins at the center of the complex. These complexes differ from those observed with H-NS and other NAPs, but resemble those formed by the NAP-like proteins CbpA/Dps and yeast condensin. Fluorescent microscopy indicates that expression of motB in vivo, at levels like that during T4 infection, yields a significantly compacted nucleoid containing MotB and H-NS. motB overexpression dysregulates hundreds of host genes; ∼70% are within the hns regulon. In infected cells overexpressing motB, 33 T4 late genes are expressed early, and the T4 early gene repEB, involved in replication initiation, is up ∼5-fold. We postulate that MotB represents a phage-encoded NAP that aids infection in a previously unrecognized way. We speculate that MotB-induced compaction may generate more room for T4 replication/assembly and/or leads to beneficial global changes in host gene expression, including derepression of much of the hns regulon.
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Affiliation(s)
- Bokyung Son
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer Patterson-West
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Melissa Arroyo-Mendoza
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Revathy Ramachandran
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James R Iben
- Molecular Genomics Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jingen Zhu
- Department of Biology, The Catholic University of America, Washington, DC, USA
| | - Venigalla Rao
- Department of Biology, The Catholic University of America, Washington, DC, USA
| | - Emilios K Dimitriadis
- Trans-NIH Shared Resource on Biomedical Engineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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22
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Zhao X, Remington JM, Schneebeli ST, Arold ST, Li J. Molecular Basis for Environment Sensing by a Nucleoid-Structuring Bacterial Protein Filament. J Phys Chem Lett 2021; 12:7878-7884. [PMID: 34382809 PMCID: PMC9346976 DOI: 10.1021/acs.jpclett.1c01710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The histone-like nucleoid structuring (H-NS) protein controls the expression of hundreds of genes in Gram-positive bacteria through its capability to coat and condense DNA. This mechanism requires the formation of superhelical H-NS protein filaments that are sensitive to temperature and salinity, allowing H-NS to act as an environment sensor. We use multiscale modeling and simulations to obtain detailed insights into the mechanism of H-NS filament's sensitivity to environmental changes. Through the simulations of the superhelical H-NS filament, we reveal how different environments induce heterogeneity of H-NS monomers. Further, we observe that transient self-association within the H-NS filament creates temperature-inducible strain and might mildly oppose DNA binding. We also probe different H-NS-DNA complex architectures and show that complexation enhances the stability of both DNA and H-NS superhelices. Overall, our results provide unprecedented molecular insights into the environmental sensing and DNA interactions of a prototypical nucleoid-structuring bacterial protein filament.
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Affiliation(s)
- Xiaochuan Zhao
- Departments of Chemistry and Materials Science, University of Vermont, Burlington VT 05405
| | - Jacob M. Remington
- Departments of Chemistry and Materials Science, University of Vermont, Burlington VT 05405
| | - Severin T. Schneebeli
- Departments of Chemistry and Materials Science, University of Vermont, Burlington VT 05405
| | - Stefan T. Arold
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia
- Centre de Biologie Structurale, CNRS, INSERM, Université de Montpellier, 34090 Montpellier, France
| | - Jianing Li
- Departments of Chemistry and Materials Science, University of Vermont, Burlington VT 05405
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23
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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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24
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Anand C, Santoshi M, Singh PR, Nagaraja V. Rv0802c is an acyltransferase that succinylates and acetylates Mycobacterium tuberculosis nucleoid-associated protein HU. MICROBIOLOGY-SGM 2021; 167. [PMID: 34224344 DOI: 10.1099/mic.0.001058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Among the nucleoid-associated proteins (NAPs), HU is the most conserved in eubacteria, engaged in overall chromosome organization and regulation of gene expression. Unlike other bacteria, HU from Mycobacterium tuberculosis (MtHU), has a long carboxyl terminal domain enriched in basic amino acids, resembling eukaryotic histone N-terminal tails. As with histones, MtHU undergoes post-translational modifications and we have previously identified interacting kinases, methyltransferases, an acetyltransferase and a deacetylase. Here we show that Rv0802c interacts and succinylates MtHU. Although categorized as a succinyltransferase, we show that this GNAT superfamily member can catalyse both succinylation and acetylation of MtHU with comparable kinetic parameters. Like acetylation of MtHU, succinylation of MtHU caused reduced interaction of the NAP with DNA, determined by electrophoretic mobility shift assay and surface plasmon resonance. However, in vivo expression of Rv0802c did not significantly alter the nucleoid architecture. Although such succinylation of NAPs is rare, these modifications of the archetypal NAP may provide avenues to the organism to compensate for the underrepresentation of NAPs in its genome to control the dynamics of nucleoid architecture and cellular functions.
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Affiliation(s)
- Chinmay Anand
- Department of Microbiology and Cell biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Meghna Santoshi
- Department of Microbiology and Cell biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Prakruti R Singh
- Department of Microbiology and Cell biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, Karnataka 560064, India
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25
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Duan B, Ding P, Navarre WW, Liu J, Xia B. Xenogeneic Silencing and Bacterial Genome Evolution: Mechanisms for DNA Recognition Imply Multifaceted Roles of Xenogeneic Silencers. Mol Biol Evol 2021; 38:4135-4148. [PMID: 34003286 PMCID: PMC8476142 DOI: 10.1093/molbev/msab136] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/08/2021] [Indexed: 12/14/2022] Open
Abstract
Horizontal gene transfer (HGT) is a major driving force for bacterial evolution. To avoid the deleterious effects due to the unregulated expression of newly acquired foreign genes, bacteria have evolved specific proteins named xenogeneic silencers to recognize foreign DNA sequences and suppress their transcription. As there is considerable diversity in genomic base compositions among bacteria, how xenogeneic silencers distinguish self- from nonself DNA in different bacteria remains poorly understood. This review summarizes the progress in studying the DNA binding preferences and the underlying molecular mechanisms of known xenogeneic silencer families, represented by H-NS of Escherichia coli, Lsr2 of Mycobacterium, MvaT of Pseudomonas, and Rok of Bacillus. Comparative analyses of the published data indicate that the differences in DNA recognition mechanisms enable these xenogeneic silencers to have clear characteristics in DNA sequence preferences, which are further correlated with different host genomic features. These correlations provide insights into the mechanisms of how these xenogeneic silencers selectively target foreign DNA in different genomic backgrounds. Furthermore, it is revealed that the genomic AT contents of bacterial species with the same xenogeneic silencer family proteins are distributed in a limited range and are generally lower than those species without any known xenogeneic silencers in the same phylum/class/genus, indicating that xenogeneic silencers have multifaceted roles on bacterial genome evolution. In addition to regulating horizontal gene transfer, xenogeneic silencers also act as a selective force against the GC to AT mutational bias found in bacterial genomes and help the host genomic AT contents maintained at relatively low levels.
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Affiliation(s)
- Bo Duan
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, and School of Life Sciences, Peking University, Beijing, 100871, China
| | - Pengfei Ding
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, and School of Life Sciences, Peking University, Beijing, 100871, China
| | - William Wiley Navarre
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 1M1, Canada
| | - Bin Xia
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, and School of Life Sciences, Peking University, Beijing, 100871, China
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26
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Visser EWA, Miladinovic J, Milstein JN. An Ultrastable and Dense Single-Molecule Click Platform for Sensing Protein-Deoxyribonucleic Acid Interactions. SMALL METHODS 2021; 5:e2001180. [PMID: 34928085 DOI: 10.1002/smtd.202001180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/29/2021] [Indexed: 06/14/2023]
Abstract
An ultrastable, highly dense single-molecule assay ideal for observing protein-DNA interactions is demonstrated. Stable click tethered particle motion leverages next generation click-chemistry to achieve an ultrahigh density of surface tethered reporter particles, and has low non-specific interactions, is stable at elevated temperatures to at least 45 °C, and is compatible with Mg2+ , an important ionic component of many regulatory protein-DNA interactions. Prepared samples remain stable, with little degradation, for >6 months in physiological buffers. These improvements enable the authors to study previously inaccessible sequence and temperature-dependent effects on DNA binding by the bacterial protein, histone-like nucleoid-structuring protein, a global transcriptional regulator found in Escherichia coli. This greatly improved assay can directly be translated to accelerate existing tethered particle-based, single-molecule biosensing applications.
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Affiliation(s)
- Emiel W A Visser
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
- Eindhoven University of Technology, Eindhoven, 5612 AZ, The Netherlands
| | - Jovana Miladinovic
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Joshua N Milstein
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
- Department of Physics, University of Toronto, Toronto, ON M5S 1A1, Canada
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27
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Japaridze A, Yang W, Dekker C, Nasser W, Muskhelishvili G. DNA sequence-directed cooperation between nucleoid-associated proteins. iScience 2021; 24:102408. [PMID: 33997690 PMCID: PMC8099737 DOI: 10.1016/j.isci.2021.102408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/05/2021] [Accepted: 04/06/2021] [Indexed: 02/01/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) are a class of highly abundant DNA-binding proteins in bacteria and archaea. While both the composition and relative abundance of the NAPs change during the bacterial growth cycle, surprisingly little is known about their crosstalk in mutually binding and stabilizing higher-order nucleoprotein complexes in the bacterial chromosome. Here, we use atomic force microscopy and solid-state nanopores to investigate long-range nucleoprotein structures formed by the binding of two major NAPs, FIS and H-NS, to DNA molecules with distinct binding site arrangements. We find that spatial organization of the protein binding sites can govern the higher-order architecture of the nucleoprotein complexes. Based on sequence arrangement the complexes differed in their global shape and compaction as well as the extent of FIS and H-NS binding. Our observations highlight the important role the DNA sequence plays in driving structural differentiation within the bacterial chromosome. The location of protein binding sites along DNA is important for 3D organization FIS protein forms DNA loops while H-NS forms compact DNA plectonemes FIS DNA loops inhibit H-NS from spreading over the DNA FIS and H-NS competition creates regions of ‘open’ and ‘closed’ DNA
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Affiliation(s)
- Aleksandre Japaridze
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Wayne Yang
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - William Nasser
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
| | - Georgi Muskhelishvili
- School of Natural Sciences, Agricultural University of Georgia, Davit Aghmashenebeli Alley 240, 0159 Tbilisi, Georgia
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28
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Birnie A, Dekker C. Genome-in-a-Box: Building a Chromosome from the Bottom Up. ACS NANO 2021; 15:111-124. [PMID: 33347266 PMCID: PMC7844827 DOI: 10.1021/acsnano.0c07397] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/16/2020] [Indexed: 05/24/2023]
Abstract
Chromosome structure and dynamics are essential for life, as the way that our genomes are spatially organized within cells is crucial for gene expression, differentiation, and genome transfer to daughter cells. There is a wide variety of methods available to study chromosomes, ranging from live-cell studies to single-molecule biophysics, which we briefly review. While these technologies have yielded a wealth of data, such studies still leave a significant gap between top-down experiments on live cells and bottom-up in vitro single-molecule studies of DNA-protein interactions. Here, we introduce "genome-in-a-box" (GenBox) as an alternative in vitro approach to build and study chromosomes, which bridges this gap. The concept is to assemble a chromosome from the bottom up by taking deproteinated genome-sized DNA isolated from live cells and subsequently add purified DNA-organizing elements, followed by encapsulation in cell-sized containers using microfluidics. Grounded in the rationale of synthetic cell research, the approach would enable to experimentally study emergent effects at the global genome level that arise from the collective action of local DNA-structuring elements. We review the various DNA-structuring elements present in nature, from nucleoid-associated proteins and SMC complexes to phase separation and macromolecular crowders. Finally, we discuss how GenBox can contribute to several open questions on chromosome structure and dynamics.
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Affiliation(s)
- Anthony Birnie
- Department of Bionanoscience, Kavli
Institute of Nanoscience Delft, Delft University
of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli
Institute of Nanoscience Delft, Delft University
of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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29
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Purkait D, Bandyopadhyay D, Mishra PP. Vital insights into prokaryotic genome compaction by nucleoid-associated protein (NAP) and illustration of DNA flexure angles at single-molecule resolution. Int J Biol Macromol 2021; 171:100-111. [PMID: 33418050 DOI: 10.1016/j.ijbiomac.2020.12.194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/24/2020] [Accepted: 12/25/2020] [Indexed: 11/20/2022]
Abstract
Integration Host Factor (IHF) is a heterodimeric site-specific nucleoid-associated protein (NAP), well known for its DNA bending ability. Although the IHF induced bending states of DNA have been captured by both X-ray Crystallography and Atomic Force Microscopy (AFM), the range of flexibility and degree of heterogeneity in terms of quantitative analysis of the nucleoprotein complex has largely remained unexplored. Binding of IHF leads to introduction of two kinks in the dsDNA that allowed us to come up with a quadrilateral model. The findings have further been extended by calculating the angles of flexibility, that gives the idea of the degree of dynamicity of the nucleoprotein complex. We have monitored and compared the trajectories of the conformational dynamics of a dsDNA upon binding of wild-type (wt) and single-chain (sc) IHF at millisecond resolution through single-molecule FRET (smFRET). Our findings reveal that the nucleoprotein complex exists in a 'Slacked-Dynamic' state throughout the observation window where many of them have switched between multiple 'Wobbling States' in the course of attainment of packaged form. This study opens up an opportunity to improve the understanding of the functions of other nucleoid-associated proteins (NAPs) by complementing the previous detailed atomic-level structural analysis, which eventually will allow accessibility towards a better hypothesis.
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Affiliation(s)
- Debayan Purkait
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India
| | - Debolina Bandyopadhyay
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India
| | - Padmaja P Mishra
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India.
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30
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Saran R, Wang Y, Li ITS. Mechanical Flexibility of DNA: A Quintessential Tool for DNA Nanotechnology. SENSORS (BASEL, SWITZERLAND) 2020; 20:E7019. [PMID: 33302459 PMCID: PMC7764255 DOI: 10.3390/s20247019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/04/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
The mechanical properties of DNA have enabled it to be a structural and sensory element in many nanotechnology applications. While specific base-pairing interactions and secondary structure formation have been the most widely utilized mechanism in designing DNA nanodevices and biosensors, the intrinsic mechanical rigidity and flexibility are often overlooked. In this article, we will discuss the biochemical and biophysical origin of double-stranded DNA rigidity and how environmental and intrinsic factors such as salt, temperature, sequence, and small molecules influence it. We will then take a critical look at three areas of applications of DNA bending rigidity. First, we will discuss how DNA's bending rigidity has been utilized to create molecular springs that regulate the activities of biomolecules and cellular processes. Second, we will discuss how the nanomechanical response induced by DNA rigidity has been used to create conformational changes as sensors for molecular force, pH, metal ions, small molecules, and protein interactions. Lastly, we will discuss how DNA's rigidity enabled its application in creating DNA-based nanostructures from DNA origami to nanomachines.
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Affiliation(s)
- Runjhun Saran
- Department of Chemistry, Biochemistry and Molecular Biology, Irving K. Barber Faculty of Science, The University of British Columbia, Kelowna, BC V1V1V7, Canada;
| | - Yong Wang
- Department of Physics, Materials Science and Engineering Program, Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA;
| | - Isaac T. S. Li
- Department of Chemistry, Biochemistry and Molecular Biology, Irving K. Barber Faculty of Science, The University of British Columbia, Kelowna, BC V1V1V7, Canada;
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31
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32
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Jiao J, Tian CF. Ancestral zinc-finger bearing protein MucR in alpha-proteobacteria: A novel xenogeneic silencer? Comput Struct Biotechnol J 2020; 18:3623-3631. [PMID: 33304460 PMCID: PMC7710501 DOI: 10.1016/j.csbj.2020.11.028] [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: 08/30/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/26/2022] Open
Abstract
The MucR/Ros family protein is conserved in alpha-proteobacteria and characterized by its zinc-finger motif that has been proposed as the ancestral domain from which the eukaryotic C2H2 zinc-finger structure evolved. In the past decades, accumulated evidences have revealed MucR as a pleiotropic transcriptional regulator that integrating multiple functions such as virulence, symbiosis, cell cycle and various physiological processes. Scattered reports indicate that MucR mainly acts as a repressor, through oligomerization and binding to multiple sites of AT-rich target promoters. The N-terminal region and zinc-finger bearing C-terminal region of MucR mediate oligomerization and DNA-binding, respectively. These features are convergent to those of xenogeneic silencers such as H-NS, MvaT, Lsr2 and Rok, which are mainly found in other lineages. Phylogenetic analysis of MucR homologs suggests an ancestral origin of MucR in alpha- and delta-proteobacteria. Multiple independent duplication and lateral gene transfer events contribute to the diversity and phyletic distribution of MucR. Finally, we posed questions which remain unexplored regarding the putative roles of MucR as a xenogeneic silencer and a general manager in balancing adaptation and regulatory integration in the pangenome context.
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Affiliation(s)
- Jian Jiao
- State Key Laboratory of Agrobiotechnology, and College of Biological Sciences, China Agricultural University, Beijing, China.,MOA Key Laboratory of Soil Microbiology, and Rhizobium Research Center, China Agricultural University, Beijing, China
| | - Chang-Fu Tian
- State Key Laboratory of Agrobiotechnology, and College of Biological Sciences, China Agricultural University, Beijing, China.,MOA Key Laboratory of Soil Microbiology, and Rhizobium Research Center, China Agricultural University, Beijing, China
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33
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Cristofalo M, Marrano CA, Salerno D, Corti R, Cassina V, Mammola A, Gherardi M, Sclavi B, Cosentino Lagomarsino M, Mantegazza F. Cooperative effects on the compaction of DNA fragments by the nucleoid protein H-NS and the crowding agent PEG probed by Magnetic Tweezers. Biochim Biophys Acta Gen Subj 2020; 1864:129725. [PMID: 32891648 DOI: 10.1016/j.bbagen.2020.129725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/22/2020] [Accepted: 08/30/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND DNA bridging promoted by the H-NS protein, combined with the compaction induced by cellular crowding, plays a major role in the structuring of the E. coli genome. However, only few studies consider the effects of the physical interplay of these two factors in a controlled environment. METHODS We apply a single molecule technique (Magnetic Tweezers) to study the nanomechanics of compaction and folding kinetics of a 6 kb DNA fragment, induced by H-NS bridging and/or PEG crowding. RESULTS In the presence of H-NS alone, the DNA shows a step-wise collapse driven by the formation of multiple bridges, and little variations in the H-NS concentration-dependent unfolding force. Conversely, the DNA collapse force observed with PEG was highly dependent on the volume fraction of the crowding agent. The two limit cases were interpreted considering the models of loop formation in a pulled chain and pulling of an equilibrium globule respectively. CONCLUSIONS We observed an evident cooperative effect between H-NS activity and the depletion of forces induced by PEG. GENERAL SIGNIFICANCE Our data suggest a double role for H-NS in enhancing compaction while forming specific loops, which could be crucial in vivo for defining specific mesoscale domains in chromosomal regions in response to environmental changes.
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Affiliation(s)
- M Cristofalo
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy
| | - C A Marrano
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy
| | - D Salerno
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy
| | - R Corti
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy
| | - V Cassina
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy
| | - A Mammola
- Università degli Studi di Milano, Via Celoria 16, 20133 Milano (MI), Italy
| | - M Gherardi
- Università degli Studi di Milano, Via Celoria 16, 20133 Milano (MI), Italy; IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milano (MI), Italy; I.N.F.N. Sezione di Milano, Via Celoria 16, 20133 Milano (MI), Italy
| | - B Sclavi
- Université Pierre et Marie Curie, Institut de Biologie Paris Seine, 7-9 Quai Saint Bernard, 75005 Paris, France
| | - M Cosentino Lagomarsino
- Università degli Studi di Milano, Via Celoria 16, 20133 Milano (MI), Italy; IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milano (MI), Italy; I.N.F.N. Sezione di Milano, Via Celoria 16, 20133 Milano (MI), Italy
| | - F Mantegazza
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, via Raoul Follereau 3, 20854, Vedano al Lambro (MB), Italy.
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34
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Zamora M, Ziegler CA, Freddolino PL, Wolfe AJ. A Thermosensitive, Phase-Variable Epigenetic Switch: pap Revisited. Microbiol Mol Biol Rev 2020; 84:e00030-17. [PMID: 32727743 PMCID: PMC7392537 DOI: 10.1128/mmbr.00030-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It has been more than a decade since the last comprehensive review of the phase-variable uropathogen-associated pyelonephritis-associated pilus (pap) genetic switch. Since then, important data have come to light, including additional factors that regulate pap expression, better characterization of H-NS regulation, the structure of the Lrp octamer in complex with pap regulatory DNA, the temperature-insensitive phenotype of a mutant lacking the acetyltransferase RimJ, evidence that key components of the regulatory machinery are acetylated, and new insights into the role of DNA binding by key regulators in shaping both the physical structure and regulatory state of the papI and papBA promoters. This review revisits pap, integrating these newer observations with older ones to produce a new model for the concerted behavior of this virulence-regulatory region.
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Affiliation(s)
- Mario Zamora
- Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alan J Wolfe
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
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35
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Joyeux M, Junier I. Requirements for DNA-Bridging Proteins to Act as Topological Barriers of the Bacterial Genome. Biophys J 2020; 119:1215-1225. [PMID: 32822585 PMCID: PMC7420610 DOI: 10.1016/j.bpj.2020.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/16/2020] [Accepted: 08/06/2020] [Indexed: 11/29/2022] Open
Abstract
Bacterial genomes have been shown to be partitioned into several-kilobase-long chromosomal domains that are topologically independent from each other, meaning that change of DNA superhelicity in one domain does not propagate to neighbors. Both in vivo and in vitro experiments have been performed to question the nature of the topological barriers at play, leading to several predictions on possible molecular actors. Here, we address the question of topological barriers using polymer models of supercoiled DNA chains that are constrained such as to mimic the action of predicted molecular actors. More specifically, we determine under which conditions DNA-bridging proteins may act as topological barriers. To this end, we developed a coarse-grained bead-and-spring model and investigated its properties through Brownian dynamics simulations. As a result, we find that DNA-bridging proteins must exert rather strong constraints on their binding sites; they must block the diffusion of the excess of twist through the two binding sites on the DNA molecule and, simultaneously, prevent the rotation of one DNA segment relative to the other one. Importantly, not all DNA-bridging proteins satisfy this second condition. For example, single bridges formed by proteins that bind DNA nonspecifically, like H-NS dimers, are expected to fail with this respect. Our findings might also explain, in the case of specific DNA-bridging proteins like LacI, why multiple bridges are required to create stable independent topological domains. Strikingly, when the relative rotation of the DNA segments is not prevented, relaxation results in complex intrication of the two domains. Moreover, although the value of the torsional stress in each domain may vary, their differential is preserved. Our work also predicts that nucleoid-associated proteins known to wrap DNA must form higher protein-DNA complexes to efficiently work as topological barriers.
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Affiliation(s)
- Marc Joyeux
- Laboratoire Interdisciplinaire de Physique, CNRS, Université Grenoble Alpes, Grenoble, France.
| | - Ivan Junier
- TIMC-IMAG, CNRS, Université Grenoble Alpes, Grenoble, France
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36
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Joyeux M. Bacterial Nucleoid: Interplay of DNA Demixing and Supercoiling. Biophys J 2020; 118:2141-2150. [PMID: 31629479 PMCID: PMC7202931 DOI: 10.1016/j.bpj.2019.09.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/03/2019] [Accepted: 09/23/2019] [Indexed: 01/17/2023] Open
Abstract
This work addresses the question of the interplay of DNA demixing and supercoiling in bacterial cells. Demixing of DNA from other globular macromolecules results from the overall repulsion between all components of the system and leads to the formation of the nucleoid, which is the region of the cell that contains the genomic DNA in a rather compact form. Supercoiling describes the coiling of the axis of the DNA double helix to accommodate the torsional stress injected in the molecule by topoisomerases. Supercoiling is able to induce some compaction of the bacterial DNA, although to a lesser extent than demixing. In this work, we investigate the interplay of these two mechanisms with the goal of determining whether the total compaction ratio of the DNA is the mere sum or some more complex function of the compaction ratios due to each mechanism. To this end, we developed a coarse-grained bead-and-spring model and investigated its properties through Brownian dynamics simulations. This work reveals that there actually exist different regimes, depending on the crowder volume ratio and the DNA superhelical density. In particular, a regime in which the effects of DNA demixing and supercoiling on the compaction of the DNA coil simply add up is shown to exist up to moderate values of the superhelical density. In contrast, the mean radius of the DNA coil no longer decreases above this threshold and may even increase again for sufficiently large crowder concentrations. Finally, the model predicts that the DNA coil may depart from the spherical geometry very close to the jamming threshold as a trade-off between the need to minimize both the bending energy of the stiff plectonemes and the volume of the DNA coil to accommodate demixing.
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Affiliation(s)
- Marc Joyeux
- Laboratoire Interdisciplinaire de Physique, CNRS and Université Grenoble Alpes, Grenoble, France.
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37
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Qin L, Bdira FB, Sterckx YGJ, Volkov AN, Vreede J, Giachin G, van Schaik P, Ubbink M, Dame RT. Structural basis for osmotic regulation of the DNA binding properties of H-NS proteins. Nucleic Acids Res 2020; 48:2156-2172. [PMID: 31925429 PMCID: PMC7039000 DOI: 10.1093/nar/gkz1226] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/29/2019] [Accepted: 12/19/2019] [Indexed: 01/07/2023] Open
Abstract
H-NS proteins act as osmotic sensors translating changes in osmolarity into altered DNA binding properties, thus, regulating enterobacterial genome organization and genes transcription. The molecular mechanism underlying the switching process and its conservation among H-NS family members remains elusive. Here, we focus on the H-NS family protein MvaT from Pseudomonas aeruginosa and demonstrate experimentally that its protomer exists in two different conformations, corresponding to two different functional states. In the half-opened state (dominant at low salt) the protein forms filaments along DNA, in the fully opened state (dominant at high salt) the protein bridges DNA. This switching is a direct effect of ionic strength on electrostatic interactions between the oppositely charged DNA binding and N-terminal domains of MvaT. The asymmetric charge distribution and intramolecular interactions are conserved among the H-NS family of proteins. Therefore, our study establishes a general paradigm for the molecular mechanistic basis of the osmosensitivity of H-NS proteins.
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Affiliation(s)
- Liang Qin
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, the Netherlands.,Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
| | - Fredj Ben Bdira
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, the Netherlands.,Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
| | - Yann G J Sterckx
- Laboratory of Medical Biochemistry, University of Antwerp, Campus Drie Eiken, University Square 1, 2610 Wilrijk, Belgium
| | - Alexander N Volkov
- VIB-VUB Structural Biology Research Center, Pleinlaan 2, 1050 Brussels, Belgium.,Jean Jeener NMR Centre, VUB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jocelyne Vreede
- Department of Computational Chemistry, Van't Hoff Institute for Molecular Sciences, University of Amsterdam Science Park 904, 1098 XH Amsterdam, the Netherlands
| | - Gabriele Giachin
- Structural Biology Group, European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - Peter van Schaik
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, the Netherlands.,Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
| | - Marcellus Ubbink
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, the Netherlands
| | - Remus T Dame
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden, the Netherlands.,Centre for Microbial Cell Biology, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
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38
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Sadoon AA, Khadka P, Freeland J, Gundampati RK, Manso RH, Ruiz M, Krishnamurthi VR, Thallapuranam SK, Chen J, Wang Y. Silver Ions Caused Faster Diffusive Dynamics of Histone-Like Nucleoid-Structuring Proteins in Live Bacteria. Appl Environ Microbiol 2020; 86:e02479-19. [PMID: 31953329 PMCID: PMC7054089 DOI: 10.1128/aem.02479-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/10/2020] [Indexed: 12/13/2022] Open
Abstract
The antimicrobial activity and mechanism of silver ions (Ag+) have gained broad attention in recent years. However, dynamic studies are rare in this field. Here, we report our measurement of the effects of Ag+ ions on the dynamics of histone-like nucleoid-structuring (H-NS) proteins in live bacteria using single-particle-tracking photoactivated localization microscopy (sptPALM). It was found that treating the bacteria with Ag+ ions led to faster diffusive dynamics of H-NS proteins. Several techniques were used to understand the mechanism of the observed faster dynamics. Electrophoretic mobility shift assay on purified H-NS proteins indicated that Ag+ ions weaken the binding between H-NS proteins and DNA. Isothermal titration calorimetry confirmed that DNA and Ag+ ions interact directly. Our recently developed sensing method based on bent DNA suggested that Ag+ ions caused dehybridization of double-stranded DNA (i.e., dissociation into single strands). These evidences led us to a plausible mechanism for the observed faster dynamics of H-NS proteins in live bacteria when subjected to Ag+ ions: Ag+-induced DNA dehybridization weakens the binding between H-NS proteins and DNA. This work highlighted the importance of dynamic study of single proteins in live cells for understanding the functions of antimicrobial agents in bacteria.IMPORTANCE As so-called "superbug" bacteria resistant to commonly prescribed antibiotics have become a global threat to public health in recent years, noble metals, such as silver, in various forms have been attracting broad attention due to their antimicrobial activities. However, most of the studies in the existing literature have relied on the traditional bioassays for studying the antimicrobial mechanism of silver; in addition, temporal resolution is largely missing for understanding the effects of silver on the molecular dynamics inside bacteria. Here, we report our study of the antimicrobial effect of silver ions at the nanoscale on the diffusive dynamics of histone-like nucleoid-structuring (H-NS) proteins in live bacteria using single-particle-tracking photoactivated localization microscopy. This work highlights the importance of dynamic study of single proteins in live cells for understanding the functions of antimicrobial agents in bacteria.
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Affiliation(s)
- Asmaa A Sadoon
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, USA
- Microelectronics-Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Physics, University of Thi Qar, Thi Qar, Iraq
| | - Prabhat Khadka
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, USA
| | - Jack Freeland
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas, USA
| | - Ravi Kumar Gundampati
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas, USA
| | - Ryan H Manso
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas, USA
| | - Mason Ruiz
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | | | | | - Jingyi Chen
- Microelectronics-Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas, USA
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas, USA
| | - Yong Wang
- Department of Physics, University of Arkansas, Fayetteville, Arkansas, USA
- Microelectronics-Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas, USA
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, Arkansas, USA
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Abstract
How genomes are organized within cells and how the 3D architecture of a genome influences cellular functions are significant questions in biology. A bacterial genomic DNA resides inside cells in a highly condensed and functionally organized form called nucleoid (nucleus-like structure without a nuclear membrane). The Escherichia coli chromosome or nucleoid is composed of the genomic DNA, RNA, and protein. The nucleoid forms by condensation and functional arrangement of a single chromosomal DNA with the help of chromosomal architectural proteins and RNA molecules as well as DNA supercoiling. Although a high-resolution structure of a bacterial nucleoid is yet to come, five decades of research has established the following salient features of the E. coli nucleoid elaborated below: 1) The chromosomal DNA is on the average a negatively supercoiled molecule that is folded as plectonemic loops, which are confined into many independent topological domains due to supercoiling diffusion barriers; 2) The loops spatially organize into megabase size regions called macrodomains, which are defined by more frequent physical interactions among DNA sites within the same macrodomain than between different macrodomains; 3) The condensed and spatially organized DNA takes the form of a helical ellipsoid radially confined in the cell; and 4) The DNA in the chromosome appears to have a condition-dependent 3-D structure that is linked to gene expression so that the nucleoid architecture and gene transcription are tightly interdependent, influencing each other reciprocally. Current advents of high-resolution microscopy, single-molecule analysis and molecular structure determination of the components are expected to reveal the total structure and function of the bacterial nucleoid.
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Affiliation(s)
- Subhash C. Verma
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (SCV); (SLA)
| | - Zhong Qian
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sankar L. Adhya
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (SCV); (SLA)
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40
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Qin L, Erkelens AM, Ben Bdira F, Dame RT. The architects of bacterial DNA bridges: a structurally and functionally conserved family of proteins. Open Biol 2019; 9:190223. [PMID: 31795918 PMCID: PMC6936261 DOI: 10.1098/rsob.190223] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 11/08/2019] [Indexed: 12/15/2022] Open
Abstract
Every organism across the tree of life compacts and organizes its genome with architectural chromatin proteins. While eukaryotes and archaea express histone proteins, the organization of bacterial chromosomes is dependent on nucleoid-associated proteins. In Escherichia coli and other proteobacteria, the histone-like nucleoid structuring protein (H-NS) acts as a global genome organizer and gene regulator. Functional analogues of H-NS have been found in other bacterial species: MvaT in Pseudomonas species, Lsr2 in actinomycetes and Rok in Bacillus species. These proteins complement hns- phenotypes and have similar DNA-binding properties, despite their lack of sequence homology. In this review, we focus on the structural and functional characteristics of these four architectural proteins. They are able to bridge DNA duplexes, which is key to genome compaction, gene regulation and their response to changing conditions in the environment. Structurally the domain organization and charge distribution of these proteins are conserved, which we suggest is at the basis of their conserved environment responsive behaviour. These observations could be used to find and validate new members of this protein family and to predict their response to environmental changes.
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Affiliation(s)
- L. Qin
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - A. M. Erkelens
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - F. Ben Bdira
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - R. T. Dame
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
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41
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Chromosome organization in bacteria: mechanistic insights into genome structure and function. Nat Rev Genet 2019; 21:227-242. [DOI: 10.1038/s41576-019-0185-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2019] [Indexed: 12/28/2022]
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42
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Shen BA, Landick R. Transcription of Bacterial Chromatin. J Mol Biol 2019; 431:4040-4066. [PMID: 31153903 PMCID: PMC7248592 DOI: 10.1016/j.jmb.2019.05.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
Abstract
Decades of research have probed the interplay between chromatin (genomic DNA associated with proteins and RNAs) and transcription by RNA polymerase (RNAP) in all domains of life. In bacteria, chromatin is compacted into a membrane-free region known as the nucleoid that changes shape and composition depending on the bacterial state. Transcription plays a key role in both shaping the nucleoid and organizing it into domains. At the same time, chromatin impacts transcription by at least five distinct mechanisms: (i) occlusion of RNAP binding; (ii) roadblocking RNAP progression; (iii) constraining DNA topology; (iv) RNA-mediated interactions; and (v) macromolecular demixing and heterogeneity, which may generate phase-separated condensates. These mechanisms are not mutually exclusive and, in combination, mediate gene regulation. Here, we review the current understanding of these mechanisms with a focus on gene silencing by H-NS, transcription coordination by HU, and potential phase separation by Dps. The myriad questions about transcription of bacterial chromatin are increasingly answerable due to methodological advances, enabling a needed paradigm shift in the field of bacterial transcription to focus on regulation of genes in their native state. We can anticipate answers that will define how bacterial chromatin helps coordinate and dynamically regulate gene expression in changing environments.
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Affiliation(s)
- Beth A Shen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, United States.
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43
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Alqahtany M, Khadka P, Niyonshuti I, Krishnamurthi VR, Sadoon AA, Challapalli SD, Chen J, Wang Y. Nanoscale reorganizations of histone-like nucleoid structuring proteins in Escherichia coli are caused by silver nanoparticles. NANOTECHNOLOGY 2019; 30:385101. [PMID: 31212266 DOI: 10.1088/1361-6528/ab2a9f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Silver nanoparticles (AgNPs) and ions (Ag+) have recently gained broad attention due to their antimicrobial effects against bacteria and other microbes. In this work, we demonstrate the use of super-resolution fluorescence microscopy for investigating and quantifying the antimicrobial effect of AgNPs at the molecular level. We found that subjecting Escherichia coli (E. coli) bacteria to AgNPs led to nanoscale reorganization of histone-like nucleoid structuring (H-NS) proteins, an essential nucleoid associated protein in bacteria. We observed that H-NS proteins formed denser and larger clusters at the center of the bacteria after exposure to AgNPs. We quantified the spatial reorganizations of H-NS proteins by examining the changes of various spatial parameters, including the inter-molecular distances and molecular densities. Clustering analysis based on Voronoi-tessellation were also performed to characterize the change of H-NS proteins' clustering behavior. We found that AgNP-treatment led to an increase in the fraction of H-NS proteins forming clusters. Similar effects were observed for bacteria exposed to Ag+ ions, suggesting that the release of Ag+ ions plays an important role in the toxicity of AgNPs. On the other hand, we observed that AgNPs with two surface coatings showed difference in the nanoscale reorganization of H-NS proteins, indicating that particle-specific effects also contribute to the antimicrobial activities of AgNPs. Our results suggested that H-NS proteins were significantly affected by AgNPs and Ag+ ions, which has been overlooked previously. In addition, we examined the dynamic motion of AgNPs that were attached to the surface of bacteria. We expect that the current methodology can be readily applied to broadly and quantitatively study the spatial reorganization of biological macromolecules at the scale of nanometers caused by metal nanoparticles, which are expected to shed new light on the antimicrobial mechanism of metal nanoparticles.
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Affiliation(s)
- Meaad Alqahtany
- Department of Physics, University of Arkansas, Fayetteville, AR 72701, United States of America. Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, United States of America
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44
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Yaghini N. Population balance modeling of assembly formation; accounting for the H-NS protein oligomerization and DNA binding mechanisms. Int J Biol Macromol 2019; 142:33-51. [PMID: 31491518 DOI: 10.1016/j.ijbiomac.2019.08.229] [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: 06/18/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 10/26/2022]
Abstract
The results obtained in this study demonstrate H-NS oligomerization in solution is not sufficient in forming large structures of H-NS-DNA assemblies indicating oligomerization along bacterial DNA is crucial. We present a comprehensive and novel multi-scale modeling scheme to study protein-protein and protein-DNA interactions, with the focus on population balance modeling of assemblies formed by the H-NS protein and bacterial DNA. The model helps understanding how the concentration of H-NS influences the formation of H-NS-DNA assemblies. The presented model covers the two underlying molecular mechanisms involved in assembly formation, H-NS oligomerization in solution and H-NS-DNA binding. Within protein oligomerization interactions, protein molecules are entitled to dimerize, propagate, recombine and deform (break). In addition, DNA binding and unbinding interactions are included to account for formation of filaments along DNA. All mechanisms have been modeled with their associated forward (formation) and backward (deformation) interactions. The results obtained agree well with former experimental studies.
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Affiliation(s)
- Nazila Yaghini
- Department of Mechanical Engineering, Materials Technology Group, Eindhoven University of Technology, P.O. Box 513, Eindhoven, MB 5600, the Netherlands
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45
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Yildirim A, Feig M. High-resolution 3D models of Caulobacter crescentus chromosome reveal genome structural variability and organization. Nucleic Acids Res 2019. [PMID: 29529244 PMCID: PMC5934669 DOI: 10.1093/nar/gky141] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
High-resolution three-dimensional models of Caulobacter crescentus nucleoid structures were generated via a multi-scale modeling protocol. Models were built as a plectonemically supercoiled circular DNA and by incorporating chromosome conformation capture based data to generate an ensemble of base pair resolution models consistent with the experimental data. Significant structural variability was found with different degrees of bending and twisting but with overall similar topologies and shapes that are consistent with C. crescentus cell dimensions. The models allowed a direct mapping of the genomic sequence onto the three-dimensional nucleoid structures. Distinct spatial distributions were found for several genomic elements such as AT-rich sequence elements where nucleoid associated proteins (NAPs) are likely to bind, promoter sites, and some genes with common cellular functions. These findings shed light on the correlation between the spatial organization of the genome and biological functions.
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Affiliation(s)
- Asli Yildirim
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Michael Feig
- Department of Biochemistry & Molecular Biology, Michigan State University, MI 48824, USA
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46
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Will WR, Whitham PJ, Reid PJ, Fang FC. Modulation of H-NS transcriptional silencing by magnesium. Nucleic Acids Res 2019; 46:5717-5725. [PMID: 29757411 PMCID: PMC6009595 DOI: 10.1093/nar/gky387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 04/30/2018] [Indexed: 11/15/2022] Open
Abstract
The bacterial histone-like protein H-NS silences AT-rich DNA, binding DNA as 'stiffened' filaments or 'bridged' intrastrand loops. The switch between these modes has been suggested to depend on the concentration of divalent cations, in particular Mg2+, with elevated Mg2+ concentrations associated with a transition to bridging. Here we demonstrate that the observed binding mode is a function of the local concentration of H-NS and its cognate binding sites, as well as the affinity of the interactions between them. Mg2+ does not control a binary switch between these two modes but rather modulates the affinity of this interaction, inhibiting the DNA-binding and silencing activity of H-NS in a continuous linear fashion. The direct relationship between conditions that favor stiffening and transcriptional silencing activity suggests that although both modes can occur in the cell, stiffening is the predominant mode of binding at silenced genes.
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Affiliation(s)
- W Ryan Will
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Patrick J Whitham
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Philip J Reid
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Ferric C Fang
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA.,Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195, USA
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47
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Dias RS. Role of Protein Self-Association on DNA Condensation and Nucleoid Stability in a Bacterial Cell Model. Polymers (Basel) 2019; 11:E1102. [PMID: 31261873 PMCID: PMC6680993 DOI: 10.3390/polym11071102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 01/15/2023] Open
Abstract
Bacterial cells do not have a nuclear membrane that encompasses and isolates the genetic material. In addition, they do not possess histone proteins, which are responsible for the first levels of genome condensation in eukaryotes. Instead, there is a number of more or less specific nucleoid-associated proteins that induce DNA bridging, wrapping and bending. Many of these proteins self-assemble into oligomers. The crowded environment of cells is also believed to contribute to DNA condensation due to excluded volume effects. Ribosomes are protein-RNA complexes found in large concentrations in the cytosol of cells. They are overall negatively charged and some DNA-binding proteins have been reported to also bind to ribosomes. Here the effect of protein self-association on DNA condensation and stability of DNA-protein complexes is explored using Monte Carlo simulations and a simple coarse-grained model. The DNA-binding proteins are described as positively charged dimers with the same linear charge density as the DNA, described using a bead and spring model. The crowding molecules are simply described as hard-spheres with varying charge density. It was found that applying a weak attractive potential between protein dimers leads to their association in the vicinity of the DNA (but not in its absence), which greatly enhances the condensation of the model DNA. The presence of neutral crowding agents does not affect the DNA conformation in the presence or absence of protein dimers. For weakly self-associating proteins, the presence of negatively charged crowding particles induces the dissociation of the DNA-protein complex due to the partition of the proteins between the DNA and the crowders. Protein dimers with stronger association potentials, on the other hand, stabilize the nucleoid, even in the presence of highly charged crowders. The interactions between protein dimers and crowding agents are not completely prevented and a few crowding molecules typically bind to the nucleoid.
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Affiliation(s)
- Rita S Dias
- Department of Physics, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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48
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H-NS Family Members MvaT and MvaU Regulate the Pseudomonas aeruginosa Type III Secretion System. J Bacteriol 2019; 201:JB.00054-19. [PMID: 30782629 DOI: 10.1128/jb.00054-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 02/07/2019] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen capable of causing severe disease in immunocompromised individuals. A major P. aeruginosa virulence factor is the type III secretion system (T3SS). The T3SS is used to translocate effector proteins into host cells, causing cytotoxicity. The T3SS is under the transcriptional control of the master regulator ExsA. ExsA is encoded in the exsCEBA operon and autoregulates transcription via the P exsC promoter. There is also a Vfr-dependent promoter (P exsA ) located in the intergenic region between exsB and exsA A previous chromatin immunoprecipitation (ChIP)-on-chip experiment identified strong binding signatures for MvaT and MvaU in the intergenic region containing the P exsA promoter. MvaT and MvaU are DNA-binding histone-like nucleoid-structuring proteins that can repress gene expression. As predicted from the previous ChIP data, purified MvaT specifically bound to the P exsA promoter region in electrophoretic mobility shift assays. Whereas disruption of mvaT or mvaU by either transposon insertion or clustered regularly interspaced short palindromic repeat interference (CRISPRi) derepressed P exsA promoter activity and T3SS gene expression, overexpression of MvaT or MvaU inhibited P exsA promoter activity. Disruption of mvaT, however, did not suppress the Vfr requirement for P exsA promoter activity. Mutated MvaT/MvaU defective in transcriptional silencing exhibited dominant negative activity, resulting in a significant increase in P exsA promoter activity. Because no effect of MvaT or MvaU on Vfr expression was detected, we propose a model in which the primary effect of MvaT/MvaU on T3SS gene expression is through direct silencing of the P exsA promoter.IMPORTANCE Global regulatory systems play a prominent role in controlling the P. aeruginosa T3SS and include the Gac/RsmA, c-di-GMP, and Vfr-cAMP signaling pathways. Many of these pathways appear to directly or indirectly influence exsA transcription or translation. In this study, the histone-like proteins MvaT and MvaU are added to the growing list of global regulators that control the T3SS. MvaT and MvaU bind AT-rich regions in the genome and silence xenogeneic genes, including pathogenicity islands. The T3SS gene cluster has been horizontally transmitted among many Gram-negative pathogens. Control by MvaT/MvaU may reflect a residual effect that has persisted since the initial acquisition of the gene cluster, subsequently imposing a requirement for active regulatory mechanisms to override MvaT/MvaU-mediated silencing.
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Gehrke EJ, Zhang X, Pimentel-Elardo SM, Johnson AR, Rees CA, Jones SE, Hindra, Gehrke SS, Turvey S, Boursalie S, Hill JE, Carlson EE, Nodwell JR, Elliot MA. Silencing cryptic specialized metabolism in Streptomyces by the nucleoid-associated protein Lsr2. eLife 2019; 8:47691. [PMID: 31215866 PMCID: PMC6584129 DOI: 10.7554/elife.47691] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022] Open
Abstract
Lsr2 is a nucleoid-associated protein conserved throughout the actinobacteria, including the antibiotic-producing Streptomyces. Streptomyces species encode paralogous Lsr2 proteins (Lsr2 and Lsr2-like, or LsrL), and we show here that of the two, Lsr2 has greater functional significance. We found that Lsr2 binds AT-rich sequences throughout the chromosome, and broadly represses gene expression. Strikingly, specialized metabolic clusters were over-represented amongst its targets, and the cryptic nature of many of these clusters appears to stem from Lsr2-mediated repression. Manipulating Lsr2 activity in model species and uncharacterized isolates resulted in the production of new metabolites not seen in wild type strains. Our results suggest that the transcriptional silencing of biosynthetic clusters by Lsr2 may protect Streptomyces from the inappropriate expression of specialized metabolites, and provide global control over Streptomyces’ arsenal of signaling and antagonistic compounds.
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Affiliation(s)
- Emma J Gehrke
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Xiafei Zhang
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | | | - Andrew R Johnson
- Department of Chemistry, Indiana University, Bloomington, United States
| | - Christiaan A Rees
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Stephanie E Jones
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Hindra
- Department of Biology, McMaster University, Hamilton, Canada
| | - Sebastian S Gehrke
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Sonya Turvey
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Suzanne Boursalie
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Jane E Hill
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Erin E Carlson
- Department of Chemistry, Indiana University, Bloomington, United States.,Department of Chemistry, University of Minnesota, Minneapolis, United States
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Marie A Elliot
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
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Organization of DNA in Mammalian Mitochondria. Int J Mol Sci 2019; 20:ijms20112770. [PMID: 31195723 PMCID: PMC6600607 DOI: 10.3390/ijms20112770] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 12/22/2022] Open
Abstract
As with all organisms that must organize and condense their DNA to fit within the limited volume of a cell or a nucleus, mammalian mitochondrial DNA (mtDNA) is packaged into nucleoprotein structures called nucleoids. In this study, we first introduce the general modes of DNA compaction, especially the role of the nucleoid-associated proteins (NAPs) that structure the bacterial chromosome. We then present the mitochondrial nucleoid and the main factors responsible for packaging of mtDNA: ARS- (autonomously replicating sequence-) binding factor 2 protein (Abf2p) in yeast and mitochondrial transcription factor A (TFAM) in mammals. We summarize the single-molecule manipulation experiments on mtDNA compaction and visualization of mitochondrial nucleoids that have led to our current knowledge on mtDNA compaction. Lastly, we discuss the possible regulatory role of DNA packaging by TFAM in DNA transactions such as mtDNA replication and transcription.
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