1
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Islam F, Mishra PP. Molecular Insight into the Structural Dynamics of Holliday Junctions Modulated by Integration Host Factor. J Phys Chem B 2024; 128:5642-5657. [PMID: 38812070 DOI: 10.1021/acs.jpcb.4c02997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The integration host factor (IHF) in Escherichia coli is a nucleoid-associated protein with multifaceted roles that encompass DNA packaging, viral DNA integration, and recombination. IHF binds to double-stranded DNA featuring a 13-base pair (bp) consensus sequence with high affinity, causing a substantial bend of approximately 160° upon binding. Although wild-type IHF (WtIHF) is principally involved in DNA bending to facilitate foreign DNA integration into the host genome, its engineered counterpart, single-chain IHF (ScIHF), was specifically designed for genetic engineering and biotechnological applications. Our study delves into the interactions of both IHF variants with Holliday junctions (HJs), pivotal intermediates in DNA repair, and homologous recombination. HJs are dynamic structures capable of adopting open or stacked conformations, with the open conformation facilitating processes such as branch migration and strand exchange. Using microscale thermophoresis, we quantitatively assessed the binding of IHF to four-way DNA junctions that harbor specific binding sequences H' and H1. Our findings demonstrate that both IHF variants exhibit a strong affinity for HJs, signifying a structure-based recognition mechanism. Circular dichroism (CD) experiments unveiled the impact of the protein on the junction's conformation. Furthermore, single-molecule Förster resonance energy transfer (smFRET) confirmed the influence of IHF on the junction's dynamicity. Intriguingly, our results revealed that WtIHF and ScIHF binding shifts the population toward the open conformation of the junction and stabilizes it in that state. In summary, our findings underscore the robust affinity of the IHF for HJs and its capacity to stabilize the open conformation of these junctions.
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Affiliation(s)
- Farhana Islam
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
- Homi Bhabha National Institute, Mumbai 400094, India
| | - Padmaja Prasad Mishra
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
- Homi Bhabha National Institute, Mumbai 400094, India
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2
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Schumacher MA, Singh RR, Salinas R. Structure of the E. coli nucleoid-associated protein YejK reveals a novel DNA binding clamp. Nucleic Acids Res 2024:gkae459. [PMID: 38832628 DOI: 10.1093/nar/gkae459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/02/2024] [Accepted: 05/15/2024] [Indexed: 06/05/2024] Open
Abstract
Nucleoid-associated proteins (NAPs) play central roles in bacterial chromosome organization and DNA processes. The Escherichia coli YejK protein is a highly abundant, yet poorly understood NAP. YejK proteins are conserved among Gram-negative bacteria but show no homology to any previously characterized DNA-binding protein. Hence, how YejK binds DNA is unknown. To gain insight into YejK structure and its DNA binding mechanism we performed biochemical and structural analyses on the E. coli YejK protein. Biochemical assays demonstrate that, unlike many NAPs, YejK does not show a preference for AT-rich DNA and binds non-sequence specifically. A crystal structure revealed YejK adopts a novel fold comprised of two domains. Strikingly, each of the domains harbors an extended arm that mediates dimerization, creating an asymmetric clamp with a 30 Å diameter pore. The lining of the pore is electropositive and mutagenesis combined with fluorescence polarization assays support DNA binding within the pore. Finally, our biochemical analyses on truncated YejK proteins suggest a mechanism for YejK clamp loading. Thus, these data reveal YejK contains a newly described DNA-binding motif that functions as a novel clamp.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
| | - Rajiv R Singh
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
| | - Raul Salinas
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
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3
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Zhang H, Shao C, Wang J, Chu Y, Xiao J, Kang Y, Zhang Z. Combined Study of Gene Expression and Chromosome Three-Dimensional Structure in Escherichia coli During Growth Process. Curr Microbiol 2024; 81:122. [PMID: 38530471 DOI: 10.1007/s00284-024-03640-w] [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: 08/11/2023] [Accepted: 02/13/2024] [Indexed: 03/28/2024]
Abstract
The chromosome structure of different bacteria has its unique organization pattern, which plays an important role in maintaining the spatial location relationship between genes and regulating gene expression. Conversely, transcription also plays a global role in regulating the three-dimensional structure of bacterial chromosomes. Therefore, we combine RNA-Seq and Hi-C technology to explore the relationship between chromosome structure changes and transcriptional regulation in E. coli at different growth stages. Transcriptome analysis indicates that E. coli synthesizes many ribosomes and peptidoglycan in the exponential phase. In contrast, E. coli undergoes more transcriptional regulation and catabolism during the stationary phase, reflecting its adaptability to changes in environmental conditions during growth. Analyzing the Hi-C data shows that E. coli has a higher frequency of global chromosomal interaction in the exponential phase and more defined chromosomal interaction domains (CIDs). Still, the long-distance interactions at the replication termination region are lower than in the stationary phase. Combining transcriptome and Hi-C data analysis, we conclude that highly expressed genes are more likely to be distributed in CID boundary regions during the exponential phase. At the same time, most high-expression genes distributed in the CID boundary regions are ribosomal gene clusters, forming clearer CID boundaries during the exponential phase. The three-dimensional structure of chromosome and expression pattern is altered during the growth of E. coli from the exponential phase to the stationary phase, clarifying the synergy between the two regulatory aspects.
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Affiliation(s)
- Hao Zhang
- National Genomics Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changjun Shao
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
| | - Jian Wang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
| | - Yanan Chu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
| | - Jingfa Xiao
- National Genomics Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu Kang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China.
| | - Zhewen Zhang
- National Genomics Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China.
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing, 100101, China.
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4
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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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5
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Beard S, Moya-Beltrán A, Silva-García D, Valenzuela C, Pérez-Acle T, Loyola A, Quatrini R. Pangenome-level analysis of nucleoid-associated proteins in the Acidithiobacillia class: insights into their functional roles in mobile genetic elements biology. Front Microbiol 2023; 14:1271138. [PMID: 37817747 PMCID: PMC10561277 DOI: 10.3389/fmicb.2023.1271138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/01/2023] [Indexed: 10/12/2023] Open
Abstract
Mobile genetic elements (MGEs) are relevant agents in bacterial adaptation and evolutionary diversification. Stable appropriation of these DNA elements depends on host factors, among which are the nucleoid-associated proteins (NAPs). NAPs are highly abundant proteins that bind and bend DNA, altering its topology and folding, thus affecting all known cellular DNA processes from replication to expression. Even though NAP coding genes are found in most prokaryotic genomes, their functions in host chromosome biology and xenogeneic silencing are only known for a few NAP families. Less is known about the occurrence, abundance, and roles of MGE-encoded NAPs in foreign elements establishment and mobility. In this study, we used a combination of comparative genomics and phylogenetic strategies to gain insights into the diversity, distribution, and functional roles of NAPs within the class Acidithiobacillia with a special focus on their role in MGE biology. Acidithiobacillia class members are aerobic, chemolithoautotrophic, acidophilic sulfur-oxidizers, encompassing substantial genotypic diversity attributable to MGEs. Our search for NAP protein families (PFs) in more than 90 genomes of the different species that conform the class, revealed the presence of 1,197 proteins pertaining to 12 different NAP families, with differential occurrence and conservation across species. Pangenome-level analysis revealed 6 core NAP PFs that were highly conserved across the class, some of which also existed as variant forms of scattered occurrence, in addition to NAPs of taxa-restricted distribution. Core NAPs identified are reckoned as essential based on the conservation of genomic context and phylogenetic signals. In turn, various highly diversified NAPs pertaining to the flexible gene complement of the class, were found to be encoded in known plasmids or, larger integrated MGEs or, present in genomic loci associated with MGE-hallmark genes, pointing to their role in the stabilization/maintenance of these elements in strains and species with larger genomes. Both core and flexible NAPs identified proved valuable as markers, the former accurately recapitulating the phylogeny of the class, and the later, as seed in the bioinformatic identification of novel episomal and integrated mobile elements.
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Affiliation(s)
- Simón Beard
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Ana Moya-Beltrán
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Santiago, Chile
| | - Danitza Silva-García
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
| | - Cesar Valenzuela
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
| | - Tomás Pérez-Acle
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Santiago, Chile
| | - Alejandra Loyola
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Raquel Quatrini
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
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6
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de Vasconcelos Junior AA, Tirado-Vélez JM, Martín-Galiano AJ, Megias D, Ferrándiz MJ, Hernández P, Amblar M, de la Campa AG. StaR Is a Positive Regulator of Topoisomerase I Activity Involved in Supercoiling Maintenance in Streptococcus pneumoniae. Int J Mol Sci 2023; 24:ijms24065973. [PMID: 36983048 PMCID: PMC10053502 DOI: 10.3390/ijms24065973] [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: 02/20/2023] [Revised: 03/16/2023] [Accepted: 03/18/2023] [Indexed: 03/30/2023] Open
Abstract
The DNA topoisomerases gyrase and topoisomerase I as well as the nucleoid-associated protein HU maintain supercoiling levels in Streptococcus pneumoniae, a main human pathogen. Here, we characterized, for the first time, a topoisomerase I regulator protein (StaR). In the presence of sub-inhibitory novobiocin concentrations, which inhibit gyrase activity, higher doubling times were observed in a strain lacking staR, and in two strains in which StaR was over-expressed either under the control of the ZnSO4-inducible PZn promoter (strain ΔstaRPZnstaR) or of the maltose-inducible PMal promoter (strain ΔstaRpLS1ROMstaR). These results suggest that StaR has a direct role in novobiocin susceptibility and that the StaR level needs to be maintained within a narrow range. Treatment of ΔstaRPZnstaR with inhibitory novobiocin concentrations resulted in a change of the negative DNA supercoiling density (σ) in vivo, which was higher in the absence of StaR (σ = -0.049) than when StaR was overproduced (σ = -0.045). We have located this protein in the nucleoid by using super-resolution confocal microscopy. Through in vitro activity assays, we demonstrated that StaR stimulates TopoI relaxation activity, while it has no effect on gyrase activity. Interaction between TopoI and StaR was detected both in vitro and in vivo by co-immunoprecipitation. No alteration of the transcriptome was associated with StaR amount variation. The results suggest that StaR is a new streptococcal nucleoid-associated protein that activates topoisomerase I activity by direct protein-protein interaction.
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Affiliation(s)
| | - Jose M Tirado-Vélez
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Antonio J Martín-Galiano
- Unidades Centrales Científico-Técnicas, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Diego Megias
- Unidad de Microscopía Confocal, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - María-José Ferrándiz
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Pablo Hernández
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Mónica Amblar
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Adela G de la Campa
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
- Presidencia, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
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7
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Gupta A, Joshi A, Arora K, Mukhopadhyay S, Guptasarma P. The bacterial nucleoid-associated proteins, HU, and Dps, condense DNA into context-dependent biphasic or multiphasic complex coacervates. J Biol Chem 2023; 299:104637. [PMID: 36963493 PMCID: PMC10141540 DOI: 10.1016/j.jbc.2023.104637] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/27/2023] [Accepted: 03/08/2023] [Indexed: 03/26/2023] Open
Abstract
The bacterial chromosome, known as its nucleoid, is an amorphous assemblage of globular nucleoprotein domains. It exists in a state of phase separation from the cell's cytoplasm, as an irregularly-shaped, membrane-less, intracellular compartment. This state (the nature of which remains largely unknown) is maintained through bacterial generations ad infinitum. Here, we show that HU, and Dps, two of the most abundant nucleoid-associated proteins (NAPs) of Escherichia coli, undergo spontaneous complex coacervation with different forms of DNA/RNA, both individually and in each other's presence, to cause accretion and compaction of DNA/RNA into liquid-liquid phase separated (LLPS) condensates in vitro. Upon mixing with nucleic acids, HU-A and HU-B form (a) bi-phasic heterotypic mixed condensates in which HU-B helps to lower the Csat of HU-A; and also (b) multi-phasic heterotypic condensates, with Dps, in which de-mixed domains display different contents of HU and Dps. We believe that these modes of complex coacervation that are seen in vitro can serve as models for the in vivo relationships amongst NAPs in nucleoids, involving local and global variations in the relative abundances of the different NAPs, especially in de-mixed sub-domains that are characterized by differing grades of phase separation. Our results clearly demonstrate some quantitative, and some qualitative, differences in the coacervating abilities of different NAPs with DNA, potentially explaining (i) why E. coli has two isoforms of HU, and (ii) why changes in the abundances of HU and Dps facilitate the lag, logarithmic and stationary phases of E. coli growth.
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Affiliation(s)
- Archit Gupta
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India.
| | - Ashish Joshi
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Kanika Arora
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Chemical Sciences; Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Purnananda Guptasarma
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India.
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Chromosomal Position of Ribosomal Protein Genes Affects Long-Term Evolution of Vibrio cholerae. mBio 2023; 14:e0343222. [PMID: 36861972 PMCID: PMC10127744 DOI: 10.1128/mbio.03432-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
It is unclear how gene order within the chromosome influences genome evolution. Bacteria cluster transcription and translation genes close to the replication origin (oriC). In Vibrio cholerae, relocation of s10-spc-α locus (S10), the major locus of ribosomal protein genes, to ectopic genomic positions shows that its relative distance to the oriC correlates to a reduction in growth rate, fitness, and infectivity. To test the long-term impact of this trait, we evolved 12 populations of V. cholerae strains bearing S10 at an oriC-proximal or an oriC-distal location for 1,000 generations. During the first 250 generations, positive selection was the main force driving mutation. After 1,000 generations, we observed more nonadaptative mutations and hypermutator genotypes. Populations fixed inactivating mutations at many genes linked to virulence: flagellum, chemotaxis, biofilm, and quorum sensing. Throughout the experiment, all populations increased their growth rates. However, those bearing S10 close to oriC remained the fittest, indicating that suppressor mutations cannot compensate for the genomic position of the main ribosomal protein locus. Selection and sequencing of the fastest-growing clones allowed us to characterize mutations inactivating, among other sites, flagellum master regulators. Reintroduction of these mutations into the wild-type context led to a ≈10% growth improvement. In conclusion, the genomic location of ribosomal protein genes conditions the evolutionary trajectory of V. cholerae. While genomic content is highly plastic in prokaryotes, gene order is an underestimated factor that conditions cellular physiology and evolution. A lack of suppression enables artificial gene relocation as a tool for genetic circuit reprogramming. IMPORTANCE The bacterial chromosome harbors several entangled processes such as replication, transcription, DNA repair, and segregation. Replication begins bidirectionally at the replication origin (oriC) until the terminal region (ter) organizing the genome along the ori-ter axis gene order along this axis could link genome structure to cell physiology. Fast-growing bacteria cluster translation genes near oriC. In Vibrio cholerae, moving them away was feasible but at the cost of losing fitness and infectivity. Here, we evolved strains harboring ribosomal genes close or far from oriC. Growth rate differences persisted after 1,000 generations. No mutation was able to compensate for the growth defect, showing that ribosomal gene location conditions their evolutionary trajectory. Despite the high plasticity of bacterial genomes, evolution has sculpted gene order to optimize the ecological strategy of the microorganism. We observed growth rate improvement throughout the evolution experiment that occurred at expense of energetically costly processes such the flagellum biosynthesis and virulence-related functions. From the biotechnological point of view, manipulation of gene order enables altering bacterial growth with no escape events.
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9
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Waszkiewicz R, Ranasinghe M, Fogg JM, Catanese DJ, Ekiel-Jeżewska ML, Lisicki M, Demeler B, Zechiedrich L, Szymczak P. DNA supercoiling-induced shapes alter minicircle hydrodynamic properties. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522747. [PMID: 36711572 PMCID: PMC9881935 DOI: 10.1101/2023.01.04.522747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
DNA in cells is organized in negatively supercoiled loops. The resulting torsional and bending strain allows DNA to adopt a surprisingly wide variety of 3-D shapes. This interplay between negative supercoiling, looping, and shape influences how DNA is stored, replicated, transcribed, repaired, and likely every other aspect of DNA activity. To understand the consequences of negative supercoiling and curvature on the hydrodynamic properties of DNA, we submitted 336 bp and 672 bp DNA minicircles to analytical ultracentrifugation (AUC). We found that the diffusion coefficient, sedimentation coefficient, and the DNA hydrodynamic radius strongly depended on circularity, loop length, and degree of negative supercoiling. Because AUC cannot ascertain shape beyond degree of non-globularity, we applied linear elasticity theory to predict DNA shapes, and combined these with hydrodynamic calculations to interpret the AUC data, with reasonable agreement between theory and experiment. These complementary approaches, together with earlier electron cryotomography data, provide a framework for understanding and predicting the effects of supercoiling on the shape and hydrodynamic properties of DNA.
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Affiliation(s)
- Radost Waszkiewicz
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Maduni Ranasinghe
- University of Lethbridge, Dept. of Chemistry and Biochemistry, Alberta, T1K3M4, Canada
| | - Jonathan M. Fogg
- Department of Molecular Virology and Microbiology, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Pharmacology and Chemical Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Daniel J. Catanese
- Department of Biosciences, Rice University, 6100 Main St., Houston, TX 77005-1827, USA
| | - Maria L. Ekiel-Jeżewska
- Institute of Fundamental Technological Research, Polish Academy of Sciences, A. Pawińskiego 5B, 02-106 Warsaw, Poland,Co-contributing authors: MLE-J: , ML: , BD: , LZ: , PS:
| | - Maciej Lisicki
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland,Co-contributing authors: MLE-J: , ML: , BD: , LZ: , PS:
| | - Borries Demeler
- University of Lethbridge, Dept. of Chemistry and Biochemistry, Alberta, T1K3M4, Canada,University of Montana, Dept. of Chemistry and Biochemistry, Missoula, MT 59812, USA,Co-contributing authors: MLE-J: , ML: , BD: , LZ: , PS:
| | - Lynn Zechiedrich
- Department of Molecular Virology and Microbiology, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Pharmacology and Chemical Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA,Co-contributing authors: MLE-J: , ML: , BD: , LZ: , PS:
| | - Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland,Co-contributing authors: MLE-J: , ML: , BD: , LZ: , PS:
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10
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Integration Host Factor Binds DNA Holliday Junctions. Int J Mol Sci 2022; 24:ijms24010580. [PMID: 36614023 PMCID: PMC9820253 DOI: 10.3390/ijms24010580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/21/2022] [Accepted: 12/24/2022] [Indexed: 12/31/2022] Open
Abstract
Integration host factor (IHF) is a nucleoid-associated protein involved in DNA packaging, integration of viral DNA and recombination. IHF binds with nanomolar affinity to duplex DNA containing a 13 bp consensus sequence, inducing a bend of ~160° upon binding. We determined that IHF binds to DNA Four-way or Holliday junctions (HJ) with high affinity regardless of the presence of the consensus sequence, signifying a structure-based mechanism of recognition. Junctions, important intermediates in DNA repair and homologous recombination, are dynamic and can adopt either an open or stacked conformation, where the open conformation facilitates branch migration and strand exchange. Using ensemble and single molecule Förster resonance energy transfer (FRET) methods, we investigated IHF-induced changes in the population distribution of junction conformations and determined that IHF binding shifts the population to the open conformation. Further analysis of smFRET dynamics revealed that even in the presence of protein, the junctions remain dynamic as fast transitions are observed for the protein-bound open state. Protein binding alters junction conformational dynamics, as cross correlation analyses reveal the protein slows the transition rate at 1 mM Mg2+ but accelerates the transition rate at 10 mM Mg2+. Stopped flow kinetic experiments provide evidence for two binding steps, a rapid, initial binding step followed by a slower step potentially associated with a conformational change. These measurements also confirm that the protein remains bound to the junction during the conformer transitions and further suggest that the protein forms a partially dissociated state that allows junction arms to be dynamic. These findings, which demonstrate that IHF binds HJs with high affinity and stabilizes junctions in the open conformation, suggest that IHF may play multiple roles in the processes of integration and recombination in addition to stabilizing bacterial biofilms.
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11
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The Spatial Organization of Bacterial Transcriptional Regulatory Networks. Microorganisms 2022; 10:microorganisms10122366. [PMID: 36557619 PMCID: PMC9787925 DOI: 10.3390/microorganisms10122366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/18/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022] Open
Abstract
The transcriptional regulatory network (TRN) is the central pivot of a prokaryotic organism to receive, process and respond to internal and external environmental information. However, little is known about its spatial organization so far. In recent years, chromatin interaction data of bacteria such as Escherichia coli and Bacillus subtilis have been published, making it possible to study the spatial organization of bacterial transcriptional regulatory networks. By combining TRNs and chromatin interaction data of E. coli and B. subtilis, we explored the spatial organization characteristics of bacterial TRNs in many aspects such as regulation directions (positive and negative), central nodes (hubs, bottlenecks), hierarchical levels (top, middle, bottom) and network motifs (feed-forward loops and single input modules) of the TRNs and found that the bacterial TRNs have a variety of stable spatial organization features under different physiological conditions that may be closely related with biological functions. Our findings provided new insights into the connection between transcriptional regulation and the spatial organization of chromosome in bacteria and might serve as a factual foundation for trying spatial-distance-based gene circuit design in synthetic biology.
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12
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Martin CS, Jubelin G, Darsonval M, Leroy S, Leneveu-Jenvrin C, Hmidene G, Omhover L, Stahl V, Guillier L, Briandet R, Desvaux M, Dubois-Brissonnet F. Genetic, physiological, and cellular heterogeneities of bacterial pathogens in food matrices: Consequences for food safety. Compr Rev Food Sci Food Saf 2022; 21:4294-4326. [PMID: 36018457 DOI: 10.1111/1541-4337.13020] [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: 03/22/2022] [Revised: 07/12/2022] [Accepted: 07/14/2022] [Indexed: 01/28/2023]
Abstract
In complex food systems, bacteria live in heterogeneous microstructures, and the population displays phenotypic heterogeneities at the single-cell level. This review provides an overview of spatiotemporal drivers of phenotypic heterogeneity of bacterial pathogens in food matrices at three levels. The first level is the genotypic heterogeneity due to the possibility for various strains of a given species to contaminate food, each of them having specific genetic features. Then, physiological heterogeneities are induced within the same strain, due to specific microenvironments and heterogeneous adaptative responses to the food microstructure. The third level of phenotypic heterogeneity is related to cellular heterogeneity of the same strain in a specific microenvironment. Finally, we consider how these phenotypic heterogeneities at the single-cell level could be implemented in mathematical models to predict bacterial behavior and help ensure microbiological food safety.
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Affiliation(s)
- Cédric Saint Martin
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France.,Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Grégory Jubelin
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Maud Darsonval
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Charlène Leneveu-Jenvrin
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France.,Association pour le Développement de l'Industrie de la Viande (ADIV), Clermont-Ferrand, France
| | - Ghaya Hmidene
- Risk Assessment Department, ANSES, Maisons-Alfort, France
| | - Lysiane Omhover
- Aerial, Technical Institute of Agro-Industry, Illkirch, France
| | - Valérie Stahl
- Aerial, Technical Institute of Agro-Industry, Illkirch, France
| | | | - Romain Briandet
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
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13
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Facilitated Dissociation of Nucleoid Associated Proteins from DNA in the Bacterial Confinement. Biophys J 2022; 121:1119-1133. [PMID: 35257784 PMCID: PMC9034294 DOI: 10.1016/j.bpj.2022.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/04/2021] [Accepted: 03/01/2022] [Indexed: 11/20/2022] Open
Abstract
Transcription machinery depends on the temporal formation of protein-DNA complexes. Recent experiments demonstrated that not only the formation but also the lifetime of such complexes can affect the transcriptional machinery. In parallel, in vitro single-molecule studies showed that nucleoid-associated proteins (NAPs) leave the DNA rapidly as the bulk concentration of the protein increases via facilitated dissociation (FD). Nevertheless, whether such a concentration-dependent mechanism is functional in a bacterial cell, in which NAP levels and the 3d chromosomal structure are often coupled, is not clear a priori. Here, by using extensive coarse-grained molecular simulations, we model the unbinding of specific and nonspecific dimeric NAPs from a high-molecular-weight circular DNA molecule in a cylindrical structure mimicking the cellular confinement of a bacterial chromosome. Our simulations confirm that physiologically relevant peak protein levels (tens of micromolar) lead to highly compact chromosomal structures. This compaction results in rapid off rates (shorter DNA residence times) for specifically DNA-binding NAPs, such as the factor for inversion stimulation, which mostly dissociate via a segmental jump mechanism. Contrarily, for nonspecific NAPs, which are more prone to leave their binding sites via 1d sliding, the off rates decrease as the protein levels increase. The simulations with restrained chromosome models reveal that chromosome compaction is in favor of faster dissociation but only for specific proteins, and nonspecific proteins are not affected by the chromosome compaction. Overall, our results suggest that the cellular concentration level of a structural DNA-binding protein can be highly intermingled with its DNA residence time.
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14
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The economy of chromosomal distances in bacterial gene regulation. NPJ Syst Biol Appl 2021; 7:49. [PMID: 34911953 PMCID: PMC8674286 DOI: 10.1038/s41540-021-00209-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 11/12/2021] [Indexed: 12/04/2022] Open
Abstract
In the transcriptional regulatory network (TRN) of a bacterium, the nodes are genes and a directed edge represents the action of a transcription factor (TF), encoded by the source gene, on the target gene. It is a condensed representation of a large number of biological observations and facts. Nonrandom features of the network are structural evidence of requirements for a reliable systemic function. For the bacterium Escherichia coli we here investigate the (Euclidean) distances covered by the edges in the TRN when its nodes are embedded in the real space of the circular chromosome. Our work is motivated by 'wiring economy' research in Computational Neuroscience and starts from two contradictory hypotheses: (1) TFs are predominantly employed for long-distance regulation, while local regulation is exerted by chromosomal structure, locally coordinated by the action of structural proteins. Hence long distances should often occur. (2) A large distance between the regulator gene and its target requires a higher expression level of the regulator gene due to longer reaching times and ensuing increased degradation (proteolysis) of the TF and hence will be evolutionarily reduced. Our analysis supports the latter hypothesis.
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15
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Dame RT. Special Issue: Role of Bacterial Chromatin in Environmental Sensing, Adaptation and Evolution. Microorganisms 2021; 9:microorganisms9112406. [PMID: 34835530 PMCID: PMC8619304 DOI: 10.3390/microorganisms9112406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
A typical bacterial cell is micron-sized and contains a genome several million base pairs in length [...].
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Affiliation(s)
- Remus T. Dame
- Department of Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands;
- Centre for Microbial Cell Biology, Leiden University, 2333 CC Leiden, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, 2333 CC Leiden, The Netherlands
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16
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Huang L, Zhang Z, McMacken R. Interaction of the Escherichia coli HU Protein with Various Topological Forms of DNA. Biomolecules 2021; 11:1724. [PMID: 34827722 PMCID: PMC8616027 DOI: 10.3390/biom11111724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/06/2021] [Accepted: 11/15/2021] [Indexed: 01/24/2023] Open
Abstract
E. coli histone-like protein HU has been shown to interact with different topological forms of DNA. Using radiolabeled HU, we examine the effects of DNA supercoiling on HU-DNA interactions. We show that HU binds preferentially to negatively supercoiled DNA and that the affinity of HU for DNA increases with increases in the negative superhelical density of DNA. Binding of HU to DNA is most sensitively influenced by DNA supercoiling within a narrow but physiologically relevant range of superhelicity (σ = -0.06-0). Under stoichiometric binding conditions, the affinity of HU for negatively supercoiled DNA (σ = -0.06) is more than 10 times higher than that for relaxed DNA at physiologically relevant HU/DNA mass ratios (e.g., 1:10). This binding preference, however, becomes negligible at HU/DNA mass ratios higher than 1:2. At saturation, HU binds both negatively supercoiled and relaxed DNA with similar stoichiometries, i.e., 5-6 base pairs per HU dimer. In our chemical crosslinking studies, we demonstrate that HU molecules bound to negatively supercoiled DNA are more readily crosslinked than those bound to linear DNA. At in vivo HU/DNA ratios, HU appears to exist predominantly in a tetrameric form on negatively supercoiled DNA and in a dimeric form on linear DNA. Using a DNA ligase-mediated nick closure assay, we show that approximately 20 HU dimers are required to constrain one negative supercoil on relaxed DNA. Although fewer HU dimers may be needed to constrain one negative supercoil on negatively supercoiled DNA, our results and estimates of the cellular level of HU argue against a major role for HU in constraining supercoils in vivo. We discuss our data within the context of the dynamic distribution of the HU protein in cells, where temporal and local changes of DNA supercoiling are known to take place.
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Affiliation(s)
- Li Huang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA;
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhenfeng Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Roger McMacken
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA;
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17
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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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18
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Fogg JM, Judge AK, Stricker E, Chan HL, Zechiedrich L. Supercoiling and looping promote DNA base accessibility and coordination among distant sites. Nat Commun 2021; 12:5683. [PMID: 34584096 PMCID: PMC8478907 DOI: 10.1038/s41467-021-25936-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 08/30/2021] [Indexed: 11/29/2022] Open
Abstract
DNA in cells is supercoiled and constrained into loops and this supercoiling and looping influence every aspect of DNA activity. We show here that negative supercoiling transmits mechanical stress along the DNA backbone to disrupt base pairing at specific distant sites. Cooperativity among distant sites localizes certain sequences to superhelical apices. Base pair disruption allows sharp bending at superhelical apices, which facilitates DNA writhing to relieve torsional strain. The coupling of these processes may help prevent extensive denaturation associated with genomic instability. Our results provide a model for how DNA can form short loops, which are required for many essential processes, and how cells may use DNA loops to position nicks to facilitate repair. Furthermore, our results reveal a complex interplay between site-specific disruptions to base pairing and the 3-D conformation of DNA, which influences how genomes are stored, replicated, transcribed, repaired, and many other aspects of DNA activity.
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Affiliation(s)
- Jonathan M Fogg
- Department of Molecular Virology and Microbiology, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, TX, USA
- Department of Pharmacology and Chemical Biology, Houston, TX, USA
| | - Allison K Judge
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, TX, USA
| | - Erik Stricker
- Department of Molecular Virology and Microbiology, Houston, TX, USA
| | - Hilda L Chan
- Graduate Program in Immunology and Microbiology, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
| | - Lynn Zechiedrich
- Department of Molecular Virology and Microbiology, Houston, TX, USA.
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Houston, TX, USA.
- Department of Pharmacology and Chemical Biology, Houston, TX, USA.
- Graduate Program in Immunology and Microbiology, Houston, TX, USA.
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19
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Direct Interaction of Polar Scaffolding Protein Wag31 with Nucleoid-Associated Protein Rv3852 Regulates Its Polar Localization. Cells 2021; 10:cells10061558. [PMID: 34203111 PMCID: PMC8233713 DOI: 10.3390/cells10061558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 11/25/2022] Open
Abstract
Rv3852 is a unique nucleoid-associated protein (NAP) found exclusively in Mycobacterium tuberculosis (Mtb) and closely related species. Although annotated as H-NS, we showed previously that it is very different from H-NS in its properties and is distinct from other NAPs, anchoring to cell membrane by virtue of possessing a C-terminal transmembrane helix. Here, we investigated the role of Rv3852 in Mtb in organizing architecture or synthesis machinery of cell wall by protein–protein interaction approach. We demonstrated a direct physical interaction of Rv3852 with Wag31, an important cell shape and cell wall integrity determinant essential in Mtb. Wag31 localizes to the cell poles and possibly acts as a scaffold for cell wall synthesis proteins, resulting in polar cell growth in Mtb. Ectopic expression of Rv3852 in M. smegmatis resulted in its interaction with Wag31 orthologue DivIVAMsm. Binding of the NAP to Wag31 appears to be necessary for fine-tuning Wag31 localization to the cell poles, enabling complex cell wall synthesis in Mtb. In Rv3852 knockout background, Wag31 is mislocalized resulting in disturbed nascent peptidoglycan synthesis, suggesting that the NAP acts as a driver for localization of Wag31 to the cell poles. While this novel association between these two proteins presents one of the mechanisms to structure the elaborate multi-layered cell envelope of Mtb, it also exemplifies a new function for a NAP in mycobacteria.
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20
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Dienstbier A, Amman F, Petráčková D, Štipl D, Čapek J, Zavadilová J, Fabiánová K, Držmíšek J, Kumar D, Wildung M, Pouchnik D, Večerek B. Comparative Omics Analysis of Historic and Recent Isolates of Bordetella pertussis and Effects of Genome Rearrangements on Evolution. Emerg Infect Dis 2021; 27:57-68. [PMID: 33350934 PMCID: PMC7774529 DOI: 10.3201/eid2701.191541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Despite high vaccination coverage, pertussis is increasing in many industrialized countries, including the Czech Republic. To better understand Bordetella pertussis resurgence, we analyzed historic strains and recent clinical isolates by using a comparative omics approach. Whole-genome sequencing showed that historic and recent isolates of B. pertussis have substantial variation in genome organization and form separate phylogenetic clusters. Subsequent RNA sequence analysis and liquid chromatography with mass tandem spectrometry analyses showed that these variations translated into discretely separated transcriptomic and proteomic profiles. When compared with historic strains, recent isolates showed increased expression of flagellar genes and genes involved in lipopolysaccharide biosynthesis and decreased expression of polysaccharide capsule genes. Compared with reference strain Tohama I, all strains had increased expression and production of the type III secretion system apparatus. We detected the potential link between observed effects and insertion sequence element–induced changes in gene context only for a few genes.
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21
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Thakur B, Arora K, Gupta A, Guptasarma P. The DNA-binding protein HU is a molecular glue that attaches bacteria to extracellular DNA in biofilms. J Biol Chem 2021; 296:100532. [PMID: 33713701 PMCID: PMC8063757 DOI: 10.1016/j.jbc.2021.100532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023] Open
Abstract
In biofilms, bacteria that possess a negatively charged surface are embedded within a matrix of polymers consisting mainly of negatively charged extracellular DNA (e-DNA). In all likelihood, a multivalent positively charged substance, for example, a basic protein, exists within biofilms to neutralize charge–charge repulsions and act as a ‘glue’ attaching negatively charged bacteria to negatively charged e-DNA; however, no protein capable of doing so has yet been identified. We decided to investigate whether a highly abundant nucleoid-associated histone-like protein (HU) happens to be the glue in question. In recent years, HU has been shown to possess qualities that could be considered desirable in the proposed glue, for example, (a) availability in association with e-DNA; (b) multivalent DNA binding; (c) non–sequence-specific DNA-binding; (d) enhancement of biofilm formation upon exogenous addition, and (e) disruption of biofilms, upon removal by HU–cognate antibodies. Geometric considerations suggest that basic residues in HU's canonical and noncanonical DNA-binding sites can interact with sugar-linked terminal phosphates in lipopolysaccharide (LPS) molecules in bacterial outer membranes. Here, using genetic, spectroscopic, biophysical–chemical, microscopy-based, and cytometry-based experiments, we demonstrate that HU's DNA-binding sites also bind to LPS, that this facilitates DNA–DNA, DNA–LPS, and LPS–LPS interactions, and that this facilitates bacterial clumping and attachment of bacteria to DNA. Exogenous addition of HU to bacteria in (nonshaken) cultures is shown to cause cells to become engulfed in a matrix of DNA, potentially arising from the lysis of bacteria with vulnerable cell walls (as they strain to grow, divide, and move away from each other, in opposition to the accreting influence of HUs).
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Affiliation(s)
- Bhishem Thakur
- Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Punjab, India
| | - Kanika Arora
- Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Punjab, India
| | - Archit Gupta
- Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Punjab, India
| | - Purnananda Guptasarma
- Centre for Protein Science, Design and Engineering (CPSDE), Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Punjab, India.
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22
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Szafran MJ, Jakimowicz D, Elliot MA. Compaction and control-the role of chromosome-organizing proteins in Streptomyces. FEMS Microbiol Rev 2021; 44:725-739. [PMID: 32658291 DOI: 10.1093/femsre/fuaa028] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022] Open
Abstract
Chromosomes are dynamic entities, whose organization and structure depend on the concerted activity of DNA-binding proteins and DNA-processing enzymes. In bacteria, chromosome replication, segregation, compaction and transcription are all occurring simultaneously, and to ensure that these processes are appropriately coordinated, all bacteria employ a mix of well-conserved and species-specific proteins. Unusually, Streptomyces bacteria have large, linear chromosomes and life cycle stages that include multigenomic filamentous hyphae and unigenomic spores. Moreover, their prolific secondary metabolism yields a wealth of bioactive natural products. These different life cycle stages are associated with profound changes in nucleoid structure and chromosome compaction, and require distinct repertoires of architectural-and regulatory-proteins. To date, chromosome organization is best understood during Streptomyces sporulation, when chromosome segregation and condensation are most evident, and these processes are coordinated with synchronous rounds of cell division. Advances are, however, now being made in understanding how chromosome organization is achieved in multigenomic hyphal compartments, in defining the functional and regulatory interplay between different architectural elements, and in appreciating the transcriptional control exerted by these 'structural' proteins.
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Affiliation(s)
- Marcin J Szafran
- Laboratory of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Dagmara Jakimowicz
- Laboratory of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Marie A Elliot
- Department of Biology, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, L8S 4K1, Canada
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23
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Romero-González LE, Pérez-Morales D, Cortés-Avalos D, Vázquez-Guerrero E, Paredes-Hernández DA, Estrada-de los Santos P, Villa-Tanaca L, De la Cruz MA, Bustamante VH, Ibarra JA. The Salmonella Typhimurium InvF-SicA complex is necessary for the transcription of sopB in the absence of the repressor H-NS. PLoS One 2020; 15:e0240617. [PMID: 33119619 PMCID: PMC7595419 DOI: 10.1371/journal.pone.0240617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/21/2020] [Indexed: 12/25/2022] Open
Abstract
Expression of virulence factors in non-typhoidal Salmonella enterica depends on a wide variety of general and specific transcriptional factors that act in response to multiple environmental signals. Expression of genes for cellular invasion located in the Salmonella pathogenicity island 1 (SPI-1) is tightly regulated by several transcriptional regulators arrayed in a cascade, while repression of this system is exerted mainly by H-NS. In SPI-1, H-NS represses the expression mainly by binding to the regulatory region of hilA and derepression is exercised mainly by HilD. However, the possible regulatory role of H-NS in genes downstream from HilD and HilA, such as those regulated by InvF, has not been fully explored. Here the role of H-NS on the expression of sopB, an InvF dependent gene encoded in SPI-5, was evaluated. Our data show that InvF is required for the expression of sopB even in the absence of H-NS. Furthermore, in agreement with previous results on other InvF-regulated genes, we found that the expression of sopB requires the InvF/SicA complex. Our results support that SicA is not required for DNA binding nor for increasing affinity of InvF to DNA in vitro. Moreover, by using a bacterial two-hybrid system we were able to identify interactions between SicA and InvF. Lastly, protein-protein interaction assays suggest that InvF functions as a monomer. Derived from these results we postulate that the InvF/SicA complex does not act on sopB as an anti-H-NS factor; instead, it seems to induce the expression of sopB by acting as a classical transcriptional regulator.
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Affiliation(s)
- Luis E. Romero-González
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Deyanira Pérez-Morales
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Daniel Cortés-Avalos
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Edwin Vázquez-Guerrero
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Denisse A. Paredes-Hernández
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Paulina Estrada-de los Santos
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Lourdes Villa-Tanaca
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Miguel A. De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarías, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Víctor H. Bustamante
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - J. Antonio Ibarra
- Laboratorio de Genética Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
- * E-mail: ,
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Manolov A, Konanov D, Fedorov D, Osmolovsky I, Vereshchagin R, Ilina E. Genome Complexity Browser: Visualization and quantification of genome variability. PLoS Comput Biol 2020; 16:e1008222. [PMID: 33035207 PMCID: PMC7577506 DOI: 10.1371/journal.pcbi.1008222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 10/21/2020] [Accepted: 08/05/2020] [Indexed: 12/30/2022] Open
Abstract
Comparative genomics studies may be used to acquire new knowledge regarding genome architecture, which defines the rules for combining sets of genes in the genome of living organisms. Hundreds of thousands of prokaryotic genomes have been sequenced and assembled. However, computational tools capable of simultaneously comparing large numbers of genomes are lacking. We developed the Genome Complexity Browser, a tool that allows the visualization of gene contexts, in a graph-based format, and the quantification of variability for different segments of a genome. The graph-based visualization allows the inspection of changes in gene contents and neighborhoods across hundreds of genomes, simultaneously, which may facilitate the identification of conserved and variable segments of operons or the estimation of the overall variability associated with a particular genome locus. We introduced a measure called complexity, to quantify genome variability. Intraspecies and interspecies comparisons revealed that regions with high complexity values tended to be located in areas that are conserved across different strains and species. The comparison of genomes among different bacteria and archaea species has revealed that many species frequently exchange genes. Occasionally, such horizontal gene transfer events result in the acquisition of pathogenic properties or antibiotic resistance in the recipient organism. Previously, the probabilities of gene insertions were found to vary, with unequal distributions along a chromosome. At some loci, referred to as hotspots, changes occur with much higher frequencies compared with other regions of the chromosome. We developed a computational method and a software tool, called Genome Complexity Browser, that allows the identification of genome variability hotspots and the visualization of changes. We compared the localization of various hotspots and revealed that some demonstrate conserved localizations, even across species, whereas others are transient. Our tool allows users to visually inspect the patterns of gene changes in graph-based format, which presents the visualization in a format that is both compact and informative.
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Affiliation(s)
- Alexander Manolov
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
- * E-mail:
| | - Dmitry Konanov
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
| | - Dmitry Fedorov
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
| | - Ivan Osmolovsky
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
| | - Rinat Vereshchagin
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
| | - Elena Ilina
- Federal Research and Clinical Center of Physical and Chemical Medicine, Federal Medical and Biological Agency of Russia, Moscow, Russian Federation
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25
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Correlated chromosomal periodicities according to the growth rate and gene expression. Sci Rep 2020; 10:15531. [PMID: 32968121 PMCID: PMC7511328 DOI: 10.1038/s41598-020-72389-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/10/2020] [Indexed: 12/02/2022] Open
Abstract
Linking genetic information to population fitness is crucial to understanding living organisms. Despite the abundant knowledge of the genetic contribution to growth, the overall patterns/features connecting genes, their expression, and growth remain unclear. To reveal the quantitative and direct connections, systematic growth assays of single-gene knockout Escherichia coli strains under both rich and poor nutritional conditions were performed; subsequently, the resultant growth rates were associated with the original expression levels of the knockout genes in the parental genome. Comparative analysis of growth and the transcriptome identified not only the nutritionally differentiated fitness cost genes but also a significant correlation between the growth rates of the single-gene knockout strains and the original expression levels of these knockout genes in the parental strain, regardless of the nutritional variation. In addition, the coordinated chromosomal periodicities of the wild-type transcriptome and the growth rates of the strains lacking the corresponding genes were observed. The common six-period periodicity was somehow attributed to the essential genes, although the underlying mechanism remains to be addressed. The correlated chromosomal periodicities associated with the gene expression-growth dataset were highly valuable for bacterial growth prediction and discovering the working principles governing minimal genetic information.
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26
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Irastortza-Olaziregi M, Amster-Choder O. RNA localization in prokaryotes: Where, when, how, and why. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1615. [PMID: 32851805 DOI: 10.1002/wrna.1615] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/27/2020] [Accepted: 06/02/2020] [Indexed: 12/27/2022]
Abstract
Only recently has it been recognized that the transcriptome of bacteria and archaea can be spatiotemporally regulated. All types of prokaryotic transcripts-rRNAs, tRNAs, mRNAs, and regulatory RNAs-may acquire specific localization and these patterns can be temporally regulated. In some cases bacterial RNAs reside in the vicinity of the transcription site, but in many others, transcripts show distinct localizations to the cytoplasm, the inner membrane, or the pole of rod-shaped species. This localization, which often overlaps with that of the encoded proteins, can be achieved either in a translation-dependent or translation-independent fashion. The latter implies that RNAs carry sequence-level features that determine their final localization with the aid of RNA-targeting factors. Localization of transcripts regulates their posttranscriptional fate by affecting their degradation and processing, translation efficiency, sRNA-mediated regulation, and/or propensity to undergo RNA modifications. By facilitating complex assembly and liquid-liquid phase separation, RNA localization is not only a consequence but also a driver of subcellular spatiotemporal complexity. We foresee that in the coming years the study of RNA localization in prokaryotes will produce important novel insights regarding the fundamental understanding of membrane-less subcellular organization and lead to practical outputs with biotechnological and therapeutic implications. This article is categorized under: RNA Export and Localization > RNA Localization Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Mikel Irastortza-Olaziregi
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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27
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Liu Z, Feng J, Yu B, Ma Q, Liu B. The functional determinants in the organization of bacterial genomes. Brief Bioinform 2020; 22:5892344. [PMID: 32793986 DOI: 10.1093/bib/bbaa172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial genomes are now recognized as interacting intimately with cellular processes. Uncovering organizational mechanisms of bacterial genomes has been a primary focus of researchers to reveal the potential cellular activities. The advances in both experimental techniques and computational models provide a tremendous opportunity for understanding these mechanisms, and various studies have been proposed to explore the organization rules of bacterial genomes associated with functions recently. This review focuses mainly on the principles that shape the organization of bacterial genomes, both locally and globally. We first illustrate local structures as operons/transcription units for facilitating co-transcription and horizontal transfer of genes. We then clarify the constraints that globally shape bacterial genomes, such as metabolism, transcription and replication. Finally, we highlight challenges and opportunities to advance bacterial genomic studies and provide application perspectives of genome organization, including pathway hole assignment and genome assembly and understanding disease mechanisms.
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Affiliation(s)
| | | | - Bin Yu
- College of Mathematics and Physics, Qingdao University of Science and Technology
| | - Qin Ma
- Department of Biomedical Informatics, the Ohio State University
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28
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Remesh SG, Verma SC, Chen JH, Ekman AA, Larabell CA, Adhya S, Hammel M. Nucleoid remodeling during environmental adaptation is regulated by HU-dependent DNA bundling. Nat Commun 2020; 11:2905. [PMID: 32518228 PMCID: PMC7283360 DOI: 10.1038/s41467-020-16724-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/19/2020] [Indexed: 01/26/2023] Open
Abstract
Bacterial nucleoid remodeling dependent on conserved histone-like protein, HU is one of the determining factors in global gene regulation. By imaging of near-native, unlabeled E. coli cells by soft X-ray tomography, we show that HU remodels nucleoids by promoting the formation of a dense condensed core surrounded by less condensed isolated domains. Nucleoid remodeling during cell growth and environmental adaptation correlate with pH and ionic strength controlled molecular switch that regulated HUαα dependent intermolecular DNA bundling. Through crystallographic and solution-based studies we show that these effects mechanistically rely on HUαα promiscuity in forming multiple electrostatically driven multimerization interfaces. Changes in DNA bundling consequently affects gene expression globally, likely by constrained DNA supercoiling. Taken together our findings unveil a critical function of HU–DNA interaction in nucleoid remodeling that may serve as a general microbial mechanism for transcriptional regulation to synchronize genetic responses during the cell cycle and adapt to changing environments. HU is among the most conserved and abundant nucleoid-associated proteins in eubacteria. Here the authors investigate the role of histone-like proteins (HU) in the 3D organization of the bacteria DNA and show via soft X-ray tomography the process of nucleoid remodeling.
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Affiliation(s)
- Soumya G Remesh
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Subhash C Verma
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA
| | - Jian-Hua Chen
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Axel A Ekman
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Carolyn A Larabell
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Sankar Adhya
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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29
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Nagai M, Kurokawa M, Ying BW. The highly conserved chromosomal periodicity of transcriptomes and the correlation of its amplitude with the growth rate in Escherichia coli. DNA Res 2020; 27:5899727. [PMID: 32866232 PMCID: PMC7508348 DOI: 10.1093/dnares/dsaa018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/24/2020] [Indexed: 11/12/2022] Open
Abstract
The growth rate, representing the fitness of a bacterial population, is determined by the transcriptome. Chromosomal periodicity, which is known as the periodic spatial pattern of a preferred chromosomal distance in microbial genomes, is a representative overall feature of the transcriptome; however, whether and how it is associated with the bacterial growth rate are unknown. To address these questions, we analysed a total of 213 transcriptomes of multiple Escherichia coli strains growing in an assortment of culture conditions varying in terms of temperature, nutrition level and osmotic pressure. Intriguingly, Fourier transform analyses of the transcriptome identified a common chromosomal periodicity of transcriptomes, which was independent of the variation in genomes and environments. In addition, fitting of the data to a theoretical model, we found that the amplitudes of the periodic transcriptomes were significantly correlated with the growth rates. These results indicated that the amplitude of periodic transcriptomes is a parameter representing the global pattern of gene expression in correlation with the bacterial growth rate. Thus, our study provides a novel parameter for evaluating the adaptiveness of a growing bacterial population and quantitatively predicting the growth dynamics according to the global expression pattern.
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Affiliation(s)
- Motoki Nagai
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Masaomi Kurokawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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30
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Yousuf M, Iuliani I, Veetil RT, Seshasayee A, Sclavi B, Cosentino Lagomarsino M. Early fate of exogenous promoters in E. coli. Nucleic Acids Res 2020; 48:2348-2356. [PMID: 31960057 PMCID: PMC7049719 DOI: 10.1093/nar/gkz1196] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/05/2019] [Accepted: 12/20/2019] [Indexed: 01/12/2023] Open
Abstract
Gene gain by horizontal gene transfer is a major pathway of genome innovation in bacteria. The current view posits that acquired genes initially need to be silenced and that a bacterial chromatin protein, H-NS, plays a role in this silencing. However, we lack direct observation of the early fate of a horizontally transferred gene to prove this theory. We combine sequencing, flow cytometry and sorting, followed by microscopy to monitor gene expression and its variability after large-scale random insertions of a reporter gene in a population of Escherichia coli bacteria. We find that inserted promoters have a wide range of gene-expression variability related to their location. We find that high-expression clones carry insertions that are not correlated with H-NS binding. Conversely, binding of H-NS correlates with silencing. Finally, while most promoters show a common level of extrinsic noise, some insertions show higher noise levels. Analysis of these high-noise clones supports a scenario of switching due to transcriptional interference from divergent ribosomal promoters. Altogether, our findings point to evolutionary pathways where newly-acquired genes are not necessarily silenced, but may immediately explore a wide range of expression levels to probe the optimal ones.
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Affiliation(s)
- Malikmohamed Yousuf
- LBPA, UMR 8113, CNRS, ENS Paris-Saclay, 61 Avenue du President Wilson, 94235 Cachan, France
- Current Affiliation: Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ilaria Iuliani
- LBPA, UMR 8113, CNRS, ENS Paris-Saclay, 61 Avenue du President Wilson, 94235 Cachan, France
- Current Affiliation: LCQB, UMR 7238, Sorbonne Université, 4 Place Jussieu, 75005 Paris, France
| | - Reshma T Veetil
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
- School of Life science, The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru 560064, Karnataka, India
| | - Aswin Sai Narain Seshasayee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
| | - Bianca Sclavi
- LBPA, UMR 8113, CNRS, ENS Paris-Saclay, 61 Avenue du President Wilson, 94235 Cachan, France
- Current Affiliation: LCQB, UMR 7238, Sorbonne Université, 4 Place Jussieu, 75005 Paris, France
| | - Marco Cosentino Lagomarsino
- Sorbonne Université, Campus Pierre and Marie Curie, 4 Place Jussieu, 75005 Paris, France
- CNRS, UMR7238, 4 Place Jussieu, 75005 Paris, France
- Current Affiliation: IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20143 Milan, Italy
- Current Affiliation: Physics Department, University of Milan, and I.N.F.N., Via Celoria 16, 20133 Milan, Italy
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31
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Pradhan S, Bipinachandran SV, Kumari P, Suguna M, Prasad MD, Kumar R. MksB, an alternate condensin from Mycobacterium smegmatis is involved in DNA binding and condensation. Biochimie 2020; 171-172:136-146. [PMID: 32145349 DOI: 10.1016/j.biochi.2020.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/02/2020] [Indexed: 01/28/2023]
Abstract
The structural maintenance of chromosomes (SMC) proteins play a vital role in genome stability and chromosome organization in all domains of life. Previous reports show that smc deletion causes decondensation of chromosome and an increased frequency of anucleated cells in bacteria. However, smc deletion in both Mycobacterium smegmatis and Mycobacterium tuberculosis did not affect chromosome condensation or the frequency of anucleated cells. In an attempt to understand this difference in M. smegmatis, we investigated the function of MksB (MsMksB), an alternate SMC-like protein. Like other bacterial SMCs, MsMksB is also an elongated homodimer, in which a central hinge domain connects two globular ATPase head domains via two coiled-coil arms. We show that full-length MsMksB binds to different topological forms of DNA without any preferences. However, the hinge and headless domains prefer binding to single-stranded DNA (ssDNA) and linear double-stranded DNA (dsDNA), respectively. The binding of MsMksB to DNA was independent of ATP as its ATP hydrolysis deficient mutant was also proficient in DNA binding. Further, the cytological profiling studies revealed that only the full-length MsMksB and none of its structural domains could condense the bacterial chromosome. This observation indicates the plausibility of the concerted action of different structural domains of SMC to bind and condense the chromosome. Moreover, MsMksB exhibited DNA stimulated ATPase activity, in addition to its intrinsic ATPase activity. Taken together, we have elucidated the function of an alternate bacterial condensin protein MksB and its structural domains in DNA binding and condensation.
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Affiliation(s)
- Suchitra Pradhan
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, Karnataka, 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | | | - Pratibha Kumari
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, Karnataka, 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - M Suguna
- Prosetta Bioconformatics Private Limited, #67B, Hootagalli, Karnataka, 570018, India
| | - M Dharma Prasad
- Prosetta Bioconformatics Private Limited, #67B, Hootagalli, Karnataka, 570018, India
| | - Ravi Kumar
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, Karnataka, 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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32
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Kawalek A, Wawrzyniak P, Bartosik AA, Jagura-Burdzy G. Rules and Exceptions: The Role of Chromosomal ParB in DNA Segregation and Other Cellular Processes. Microorganisms 2020; 8:E105. [PMID: 31940850 PMCID: PMC7022226 DOI: 10.3390/microorganisms8010105] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 12/11/2022] Open
Abstract
The segregation of newly replicated chromosomes in bacterial cells is a highly coordinated spatiotemporal process. In the majority of bacterial species, a tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target(s) parS sequence(s), facilitates the initial steps of chromosome partitioning. ParB nucleates around parS(s) located in the vicinity of newly replicated oriCs to form large nucleoprotein complexes, which are subsequently relocated by ParA to distal cellular compartments. In this review, we describe the role of ParB in various processes within bacterial cells, pointing out interspecies differences. We outline recent progress in understanding the ParB nucleoprotein complex formation and its role in DNA segregation, including ori positioning and anchoring, DNA condensation, and loading of the structural maintenance of chromosome (SMC) proteins. The auxiliary roles of ParBs in the control of chromosome replication initiation and cell division, as well as the regulation of gene expression, are discussed. Moreover, we catalog ParB interacting proteins. Overall, this work highlights how different bacterial species adapt the DNA partitioning ParAB-parS system to meet their specific requirements.
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Affiliation(s)
| | | | | | - Grazyna Jagura-Burdzy
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (A.K.); (P.W.); (A.A.B.)
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33
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Thairu MW, Hansen AK. It's a small, small world: unravelling the role and evolution of small RNAs in organelle and endosymbiont genomes. FEMS Microbiol Lett 2019; 366:5371121. [PMID: 30844054 DOI: 10.1093/femsle/fnz049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 03/05/2019] [Indexed: 12/19/2022] Open
Abstract
Organelles and host-restricted bacterial symbionts are characterized by having highly reduced genomes that lack many key regulatory genes and elements. Thus, it has been hypothesized that the eukaryotic nuclear genome is primarily responsible for regulating these symbioses. However, with the discovery of organelle- and symbiont-expressed small RNAs (sRNAs) there is emerging evidence that these sRNAs may play a role in gene regulation as well. Here, we compare the diversity of organelle and bacterial symbiont sRNAs recently identified using genome-enabled '-omic' technologies and discuss their potential role in gene regulation. We also discuss how the genome architecture of small genomes may influence the evolution of these sRNAs and their potential function. Additionally, these new studies suggest that some sRNAs are conserved within organelle and symbiont taxa and respond to changes in the environment and/or their hosts. In summary, these results suggest that organelle and symbiont sRNAs may play a role in gene regulation in addition to nuclear-encoded host mechanisms.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
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34
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Lazarini-Martínez A, Pérez-Valdespino A, Martínez FH, Ordaz NR, Galíndez-Mayer J, Juárez-Ramírez C, Curiel-Quesada E. Assembly of an atrazine catabolic operon and its introduction to Gram-negative hosts for robust and stable degradation of triazine herbicides. FEMS Microbiol Lett 2019; 366:5634263. [DOI: 10.1093/femsle/fnz233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/19/2019] [Indexed: 01/24/2023] Open
Abstract
ABSTRACTIn 1995, Pseudomonas sp. ADP, capable of metabolizing atrazine, was isolated from contaminated soil. Genes responsible for atrazine mineralization were found scattered in the 108.8 kb pADP-1 plasmid carried by this strain, some of them flanked by insertion sequences rendering them unstable. The goal of this work was to construct a transcriptional unit containing the atz operon in an easy to transfer manner, to be introduced and inherited stably by Gram-negative bacteria. atz genes were PCR amplified, joined into an operon and inserted onto the mobilizable plasmid pBAMD1–2. Primers were designed to add efficient transcription and translation signals. Plasmid bearing the atz operon was transferred to different Gram-negative strains by conjugation, which resulted in Tn5 transposase-mediated chromosomal insertion of the atz operon. To test the operon activity, atrazine degradation by transposants was assessed both colorimetrically and by high-performance liquid chromatography (HPLC). Transposants mineralized atrazine more efficiently than wild-type Pseudomonas sp. ADP and did not accumulate cyanuric acid. Atrazine degradation was not repressed by simple nitrogen sources. Genes conferring atrazine-mineralizing capacities were stable and had little or null effect on the fitness of different transposants. Introduction of catabolic operons in a stable fashion could be used to develop bacteria with better degrading capabilities useful in bioremediation.
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Affiliation(s)
- Alfredo Lazarini-Martínez
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás. CP11340 Mexico City, Mexico
| | - Abigail Pérez-Valdespino
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás. CP11340 Mexico City, Mexico
| | - Fernando Hernández Martínez
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás. CP11340 Mexico City, Mexico
| | - Nora Ruiz Ordaz
- Department of Biochemical Engineering, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional. Av. Wilfrido Massieu 399, Unidad Adolfo López Mateos, CP07738 Mexico City, Mexico
| | - Juvencio Galíndez-Mayer
- Department of Biochemical Engineering, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional. Av. Wilfrido Massieu 399, Unidad Adolfo López Mateos, CP07738 Mexico City, Mexico
| | - Cleotilde Juárez-Ramírez
- Department of Biochemical Engineering, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional. Av. Wilfrido Massieu 399, Unidad Adolfo López Mateos, CP07738 Mexico City, Mexico
| | - Everardo Curiel-Quesada
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás. CP11340 Mexico City, Mexico
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Hua KJ, Ma BG. EVR: reconstruction of bacterial chromosome 3D structure models using error-vector resultant algorithm. BMC Genomics 2019; 20:738. [PMID: 31615397 PMCID: PMC6794827 DOI: 10.1186/s12864-019-6096-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/11/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND More and more 3C/Hi-C experiments on prokaryotes have been published. However, most of the published modeling tools for chromosome 3D structures are targeting at eukaryotes. How to transform prokaryotic experimental chromosome interaction data into spatial structure models is an important task and in great need. RESULTS We have developed a new reconstruction program for bacterial chromosome 3D structure models called EVR that exploits a simple Error-Vector Resultant (EVR) algorithm. This software tool is particularly optimized for the closed-loop structural features of prokaryotic chromosomes. The parallel implementation of the program can utilize the computing power of both multi-core CPUs and GPUs. CONCLUSIONS EVR can be used to reconstruct the bacterial 3D chromosome structure based on the contact frequency matrix derived from 3C/Hi-C experimental data quickly and precisely.
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Affiliation(s)
- Kang-Jian Hua
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Bin-Guang Ma
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
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36
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Stoof R, Wood A, Goñi-Moreno Á. A Model for the Spatiotemporal Design of Gene Regulatory Circuits †. ACS Synth Biol 2019; 8:2007-2016. [PMID: 31429541 DOI: 10.1021/acssynbio.9b00022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mathematical modeling assists the design of synthetic regulatory networks by providing a detailed mechanistic understanding of biological systems. Models that can predict the performance of a design are fundamental for synthetic biology since they minimize iterations along the design-build-test lifecycle. Such predictability depends crucially on what assumptions (i.e., biological simplifications) the model considers. Here, we challenge a common assumption when it comes to the modeling of bacterial-based gene regulation: considering negligible the effects of intracellular physical space. It is commonly assumed that molecules, such as transcription factors (TF), are homogeneously distributed inside a cell, so there is no need to model their diffusion. We describe a mathematical model that accounts for molecular diffusion and show how simulations of network performance are decisively affected by the distance between its components. Specifically, the model focuses on the search by a TF for its target promoter. The combination of local searches, via one-dimensional sliding along the chromosome, and global searches, via three-dimensional diffusion through the cytoplasm, determine TF-promoter interplay. Previous experimental results with engineered bacteria in which the distance between TF source and target was minimized or enlarged were successfully reproduced by the spatially resolved model we introduce here. This suggests that the spatial specification of the circuit alone can be exploited as a design parameter in synthetic biology to select programmable output levels.
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Affiliation(s)
- Ruud Stoof
- School of Computing, Newcastle University, Newcastle upon Tyne NE4 5TG, U.K
| | - Alexander Wood
- School of Computing, Newcastle University, Newcastle upon Tyne NE4 5TG, U.K
| | - Ángel Goñi-Moreno
- School of Computing, Newcastle University, Newcastle upon Tyne NE4 5TG, U.K
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37
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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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Xu M, Lawrence JG, Durand D. Selection, periodicity and potential function for Highly Iterative Palindrome-1 (HIP1) in cyanobacterial genomes. Nucleic Acids Res 2019; 46:2265-2278. [PMID: 29432573 PMCID: PMC5861425 DOI: 10.1093/nar/gky075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 01/25/2018] [Indexed: 02/05/2023] Open
Abstract
Highly Iterated Palindrome 1 (HIP1, GCGATCGC) is hyper-abundant in most cyanobacterial genomes. In some cyanobacteria, average HIP1 abundance exceeds one motif per gene. Such high abundance suggests a significant role in cyanobacterial biology. However, 20 years of study have not revealed whether HIP1 has a function, much less what that function might be. We show that HIP1 is 15- to 300-fold over-represented in genomes analyzed. More importantly, HIP1 sites are conserved both within and between open reading frames, suggesting that their overabundance is maintained by selection rather than by continual replenishment by neutral processes, such as biased DNA repair. This evidence for selection suggests a functional role for HIP1. No evidence was found to support a functional role as a peptide or RNA motif or a role in the regulation of gene expression. Rather, we demonstrate that the distribution of HIP1 along cyanobacterial chromosomes is significantly periodic, with periods ranging from 10 to 90 kb, consistent in scale with periodicities reported for co-regulated, co-expressed and evolutionarily correlated genes. The periodicity we observe is also comparable in scale to chromosomal interaction domains previously described in other bacteria. In this context, our findings imply HIP1 functions associated with chromosome and nucleoid structure.
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Affiliation(s)
- Minli Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jeffrey G Lawrence
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Dannie Durand
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Department of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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39
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Flores-Ríos R, Quatrini R, Loyola A. Endogenous and Foreign Nucleoid-Associated Proteins of Bacteria: Occurrence, Interactions and Effects on Mobile Genetic Elements and Host's Biology. Comput Struct Biotechnol J 2019; 17:746-756. [PMID: 31303979 PMCID: PMC6606824 DOI: 10.1016/j.csbj.2019.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 02/08/2023] Open
Abstract
Mobile Genetic Elements (MGEs) are mosaics of functional gene modules of diverse evolutionary origin and are generally divergent from the hosts´ genetic background. Existing biases in base composition and codon usage of these elements` genes impose transcription and translation limitations that may affect the physical and regulatory integration of MGEs in new hosts. Stable appropriation of the foreign DNA depends on a number of host factors among which are the Nucleoid-Associated Proteins (NAPs). These small, basic, highly abundant proteins bind and bend DNA, altering its topology and folding, thereby affecting all known essential DNA metabolism related processes. Both chromosomally- (endogenous) and MGE- (foreign) encoded NAPs have been shown to exist in bacteria. While the role of host-encoded NAPs in xenogeneic silencing of both episomal (plasmids) and integrative MGEs (pathogenicity islands and prophages) is well acknowledged, less is known about the role of MGE-encoded NAPs in the foreign elements biology or their influence on the host's chromosome expression dynamics. Here we review existing literature on the topic, present examples on the positive and negative effects that endogenous and foreign NAPs exert on global transcriptional gene expression, MGE integrative and excisive recombination dynamics, persistence and transfer to suitable hosts and discuss the nature and relevance of synergistic and antagonizing higher order interactions between diverse types of NAPs.
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Affiliation(s)
| | - Raquel Quatrini
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile.,Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile
| | - Alejandra Loyola
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile
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40
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Abstract
In bacteria, chromosomes are highly organized within the limited volume of the cell to form a nucleoid. Recent application of microscopy and chromosome conformation capture techniques have together provided a comprehensive understanding of the nature of this organization and the role of factors such as the structural maintenance of chromosomes (SMC) proteins in the establishment and maintenance of the same. In this chapter, we outline a microfluidics-based approach for live cell imaging of Escherichia coli chromosome dynamics in wild-type cells. This assay can be used to track the activity of the SMC complex, MukBEF, on DNA and assess the impact of perturbations such as DNA damage on chromosome organization and segregation.
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41
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Ultee E, Ramijan K, Dame RT, Briegel A, Claessen D. Stress-induced adaptive morphogenesis in bacteria. Adv Microb Physiol 2019; 74:97-141. [PMID: 31126537 DOI: 10.1016/bs.ampbs.2019.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria thrive in virtually all environments. Like all other living organisms, bacteria may encounter various types of stresses, to which cells need to adapt. In this chapter, we describe how cells cope with stressful conditions and how this may lead to dramatic morphological changes. These changes may not only allow harmless cells to withstand environmental insults but can also benefit pathogenic bacteria by enabling them to escape from the immune system and the activity of antibiotics. A better understanding of stress-induced morphogenesis will help us to develop new approaches to combat such harmful pathogens.
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Affiliation(s)
- Eveline Ultee
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Karina Ramijan
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Remus T Dame
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands; Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CE Leiden, the Netherlands
| | - Ariane Briegel
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Dennis Claessen
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
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42
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Ambrosino L, Ruggieri V, Bostan H, Miralto M, Vitulo N, Zouine M, Barone A, Bouzayen M, Frusciante L, Pezzotti M, Valle G, Chiusano ML. Multilevel comparative bioinformatics to investigate evolutionary relationships and specificities in gene annotations: an example for tomato and grapevine. BMC Bioinformatics 2018; 19:435. [PMID: 30497367 PMCID: PMC6266932 DOI: 10.1186/s12859-018-2420-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background “Omics” approaches may provide useful information for a deeper understanding of speciation events, diversification and function innovation. This can be achieved by investigating the molecular similarities at sequence level between species, allowing the definition of ortholog and paralog genes. However, the spreading of sequenced genome, often endowed with still preliminary annotations, requires suitable bioinformatics to be appropriately exploited in this framework. Results We presented here a multilevel comparative approach to investigate on genome evolutionary relationships and peculiarities of two fleshy fruit species of relevant agronomic interest, Solanum lycopersicum (tomato) and Vitis vinifera (grapevine). We defined 17,823 orthology relationships between tomato and grapevine reference gene annotations. The resulting orthologs are associated with the detected paralogs in each species, permitting the definition of gene networks, useful to investigate the different relationships. The reconciliation of the compared collections in terms of an updating of the functional descriptions was also exploited. All the results were made accessible in ComParaLogs, a dedicated bioinformatics platform available at http://biosrv.cab.unina.it/comparalogs/gene/search. Conclusions The aim of the work was to suggest a reliable approach to detect all similarities of gene loci between two species based on the integration of results from different levels of information, such as the gene, the transcript and the protein sequences, overcoming possible limits due to exclusive protein versus protein comparisons. This to define reliable ortholog and paralog genes, as well as species specific gene loci in the two species, overcoming limits due to the possible draft nature of preliminary gene annotations. Moreover, reconciled functional descriptions, as well as common or peculiar enzymatic classes and protein domains from tomato and grapevine, together with the definition of species-specific gene sets after the pairwise comparisons, contributed a comprehensive set of information useful to comparatively exploit the two species gene annotations and investigate on differences between species with climacteric and non-climacteric fruits. In addition, the definition of networks of ortholog genes and of associated paralogs, and the organization of web-based interfaces for the exploration of the results, defined a friendly computational bench-work in support of comparative analyses between two species. Electronic supplementary material The online version of this article (10.1186/s12859-018-2420-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Luca Ambrosino
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy.,Current address: Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Valentino Ruggieri
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy.,Current address: Center for Research in Agricultural Genomics, Cerdanyola, Barcelona, Spain
| | - Hamed Bostan
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy.,Current address: Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
| | - Marco Miralto
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy.,Current address: Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Nicola Vitulo
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Mohamed Zouine
- Génomique et Biotechnologie des Fruits, UMR990 INRA / INP-Toulouse, Université de Toulouse, Castanet-Tolosan, France
| | - Amalia Barone
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy
| | - Mondher Bouzayen
- Génomique et Biotechnologie des Fruits, UMR990 INRA / INP-Toulouse, Université de Toulouse, Castanet-Tolosan, France
| | - Luigi Frusciante
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy
| | - Mario Pezzotti
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Giorgio Valle
- CRIBI Biotechnology Centre, University of Padova, Padova, Italy
| | - Maria Luisa Chiusano
- Department of Agriculture, University of Naples "Federico II,", Portici, Naples, Italy. .,Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Naples, Italy.
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43
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Spahn CK, Glaesmann M, Grimm JB, Ayala AX, Lavis LD, Heilemann M. A toolbox for multiplexed super-resolution imaging of the E. coli nucleoid and membrane using novel PAINT labels. Sci Rep 2018; 8:14768. [PMID: 30282984 PMCID: PMC6170473 DOI: 10.1038/s41598-018-33052-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/21/2018] [Indexed: 11/09/2022] Open
Abstract
Maintenance of the bacterial homeostasis initially emanates from interactions between proteins and the bacterial nucleoid. Investigating their spatial correlation requires high spatial resolution, especially in tiny, highly confined and crowded bacterial cells. Here, we present super-resolution microscopy using a palette of fluorescent labels that bind transiently to either the membrane or the nucleoid of fixed E. coli cells. The presented labels are easily applicable, versatile and allow long-term single-molecule super-resolution imaging independent of photobleaching. The different spectral properties allow for multiplexed imaging in combination with other localisation-based super-resolution imaging techniques. As examples for applications, we demonstrate correlated super-resolution imaging of the bacterial nucleoid with the position of genetic loci, of nascent DNA in correlation to the entire nucleoid, and of the nucleoid of metabolically arrested cells. We furthermore show that DNA- and membrane-targeting labels can be combined with photoactivatable fluorescent proteins and visualise the nano-scale distribution of RNA polymerase relative to the nucleoid in drug-treated E. coli cells.
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Affiliation(s)
- Christoph K Spahn
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Mathilda Glaesmann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Anthony X Ayala
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA.
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
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44
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Abstract
The genomes of all organisms throughout the tree of life are compacted and organized in chromatin by association of chromatin proteins. Eukaryotic genomes encode histones, which are assembled on the genome into octamers, yielding nucleosomes. Post-translational modifications of the histones, which occur mostly on their N-terminal tails, define the functional state of chromatin. Like eukaryotes, most archaeal genomes encode histones, which are believed to be involved in the compaction and organization of their genomes. Instead of discrete multimers, in vivo data suggest assembly of “nucleosomes” of variable size, consisting of multiples of dimers, which are able to induce repression of transcription. Based on these data and a model derived from X-ray crystallography, it was recently proposed that archaeal histones assemble on DNA into “endless” hypernucleosomes. In this review, we discuss the amino acid determinants of hypernucleosome formation and highlight differences with the canonical eukaryotic octamer. We identify archaeal histones differing from the consensus, which are expected to be unable to assemble into hypernucleosomes. Finally, we identify atypical archaeal histones with short N- or C-terminal extensions and C-terminal tails similar to the tails of eukaryotic histones, which are subject to post-translational modification. Based on the expected characteristics of these archaeal histones, we discuss possibilities of involvement of histones in archaeal transcription regulation. Both Archaea and eukaryotes express histones, but whereas the tertiary structure of histones is conserved, the quaternary structure of histone–DNA complexes is very different. In a recent study, the crystal structure of the archaeal hypernucleosome was revealed to be an “endless” core of interacting histones that wraps the DNA around it in a left-handed manner. The ability to form a hypernucleosome is likely determined by dimer–dimer interactions as well as stacking interactions between individual layers of the hypernucleosome. We analyzed a wide variety of archaeal histones and found that most but not all histones possess residues able to facilitate hypernucleosome formation. Among these are histones with truncated termini or extended histone tails. Based on our analysis, we propose several possibilities of archaeal histone involvement in transcription regulation.
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Affiliation(s)
- Bram Henneman
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
| | - Clara van Emmerik
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
| | - Hugo van Ingen
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
| | - Remus T. Dame
- Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
- * E-mail:
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45
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Krogh TJ, Møller-Jensen J, Kaleta C. Impact of Chromosomal Architecture on the Function and Evolution of Bacterial Genomes. Front Microbiol 2018; 9:2019. [PMID: 30210483 PMCID: PMC6119826 DOI: 10.3389/fmicb.2018.02019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/09/2018] [Indexed: 12/14/2022] Open
Abstract
The bacterial nucleoid is highly condensed and forms compartment-like structures within the cell. Much attention has been devoted to investigating the dynamic topology and organization of the nucleoid. In contrast, the specific nucleoid organization, and the relationship between nucleoid structure and function is often neglected with regard to importance for adaption to changing environments and horizontal gene acquisition. In this review, we focus on the structure-function relationship in the bacterial nucleoid. We provide an overview of the fundamental properties that shape the chromosome as a structured yet dynamic macromolecule. These fundamental properties are then considered in the context of the living cell, with focus on how the informational flow affects the nucleoid structure, which in turn impacts on the genetic output. Subsequently, the dynamic living nucleoid will be discussed in the context of evolution. We will address how the acquisition of foreign DNA impacts nucleoid structure, and conversely, how nucleoid structure constrains the successful and sustainable chromosomal integration of novel DNA. Finally, we will discuss current challenges and directions of research in understanding the role of chromosomal architecture in bacterial survival and adaptation.
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Affiliation(s)
- Thøger J Krogh
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Christoph Kaleta
- Institute of Experimental Medicine, Christian-Albrechts-University Kiel, Kiel, Germany
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46
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Abstract
The causes and consequences of spatiotemporal variation in mutation rates remain to be explored in nearly all organisms. Here we examine relationships between local mutation rates and replication timing in three bacterial species whose genomes have multiple chromosomes: Vibrio fischeri, Vibrio cholerae, and Burkholderia cenocepacia. Following five mutation accumulation experiments with these bacteria conducted in the near absence of natural selection, the genomes of clones from each lineage were sequenced and analyzed to identify variation in mutation rates and spectra. In lineages lacking mismatch repair, base substitution mutation rates vary in a mirrored wave-like pattern on opposing replichores of the large chromosomes of V. fischeri and V. cholerae, where concurrently replicated regions experience similar base substitution mutation rates. The base substitution mutation rates on the small chromosome are less variable in both species but occur at similar rates to those in the concurrently replicated regions of the large chromosome. Neither nucleotide composition nor frequency of nucleotide motifs differed among regions experiencing high and low base substitution rates, which along with the inferred ~800-kb wave period suggests that the source of the periodicity is not sequence specific but rather a systematic process related to the cell cycle. These results support the notion that base substitution mutation rates are likely to vary systematically across many bacterial genomes, which exposes certain genes to elevated deleterious mutational load. That mutation rates vary within bacterial genomes is well known, but the detailed study of these biases has been made possible only recently with contemporary sequencing methods. We applied these methods to understand how bacterial genomes with multiple chromosomes, like those of Vibrio and Burkholderia, might experience heterogeneous mutation rates because of their unusual replication and the greater genetic diversity found on smaller chromosomes. This study captured thousands of mutations and revealed wave-like rate variation that is synchronized with replication timing and not explained by sequence context. The scale of this rate variation over hundreds of kilobases of DNA strongly suggests that a temporally regulated cellular process may generate wave-like variation in mutation risk. These findings add to our understanding of how mutation risk is distributed across bacterial and likely also eukaryotic genomes, owing to their highly conserved replication and repair machinery.
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47
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Janissen R, Arens MMA, Vtyurina NN, Rivai Z, Sunday ND, Eslami-Mossallam B, Gritsenko AA, Laan L, de Ridder D, Artsimovitch I, Dekker NH, Abbondanzieri EA, Meyer AS. Global DNA Compaction in Stationary-Phase Bacteria Does Not Affect Transcription. Cell 2018; 174:1188-1199.e14. [PMID: 30057118 DOI: 10.1016/j.cell.2018.06.049] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 03/14/2018] [Accepted: 06/26/2018] [Indexed: 11/18/2022]
Abstract
In stationary-phase Escherichia coli, Dps (DNA-binding protein from starved cells) is the most abundant protein component of the nucleoid. Dps compacts DNA into a dense complex and protects it from damage. Dps has also been proposed to act as a global regulator of transcription. Here, we directly examine the impact of Dps-induced compaction of DNA on the activity of RNA polymerase (RNAP). Strikingly, deleting the dps gene decompacted the nucleoid but did not significantly alter the transcriptome and only mildly altered the proteome during stationary phase. Complementary in vitro assays demonstrated that Dps blocks restriction endonucleases but not RNAP from binding DNA. Single-molecule assays demonstrated that Dps dynamically condenses DNA around elongating RNAP without impeding its progress. We conclude that Dps forms a dynamic structure that excludes some DNA-binding proteins yet allows RNAP free access to the buried genes, a behavior characteristic of phase-separated organelles.
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Affiliation(s)
- Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Mathia M A Arens
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Natalia N Vtyurina
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Zaïda Rivai
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Nicholas D Sunday
- Department of Microbiology and the Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Behrouz Eslami-Mossallam
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Alexey A Gritsenko
- Department of Intelligent Systems, Delft University of Technology, Delft, South-Holland 2628CD, the Netherlands
| | - Liedewij Laan
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands
| | - Dick de Ridder
- Department of Intelligent Systems, Delft University of Technology, Delft, South-Holland 2628CD, the Netherlands; Bioinformatics Group, Wageningen University, Wageningen, Gelderland 6700AP, the Netherlands
| | - Irina Artsimovitch
- Department of Microbiology and the Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands.
| | - Elio A Abbondanzieri
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands.
| | - Anne S Meyer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland 2629HZ, the Netherlands.
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48
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Garnier F, Debat H, Nadal M. Type IA DNA Topoisomerases: A Universal Core and Multiple Activities. Methods Mol Biol 2018; 1703:1-20. [PMID: 29177730 DOI: 10.1007/978-1-4939-7459-7_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
All the type IA topoisomerases display universal characteristics relying on a core region basically responsible for the transesterification and the strand passage reaction. First limited to the bacterial domain for a long time, these enzymes were further retrieved in Archaea and Eukarya as well. This is representative of an extremely ancient origin, probably due to an inheritance from the RNA world. As remaining evidence, some current topoisomerases IA have retained a RNA topoisomerase activity. Despite the presence of this core region in all of these TopoIAs, some differences exist and are originated from variable regions, located essentially within both extremities, conferring on them their specificities. During the last 2 decades the evidence of multiple activities and dedicated roles highlighted the importance of the topoisomerases IA. It is now obvious that topoisomerases IA are key enzymes involved in the maintenance of the genome stability. The discovery of these new activities was done thanks to the use of more accurate assays, based on new sophisticated DNA substrates.
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Affiliation(s)
- Florence Garnier
- Université Versailles St-Quentin, Institut Jacques Monod, UMR 7592 CNRS-Univ. Paris Diderot, 15, rue Hélène Brion, Paris, 75013, France
| | - Hélène Debat
- Université Versailles St-Quentin, Institut Jacques Monod, UMR 7592 CNRS-Univ. Paris Diderot, 15, rue Hélène Brion, Paris, 75013, France
| | - Marc Nadal
- Institut Jacques Monod, UMR 7592 CNRS-Université Paris Diderot, 15, rue Hélène Brion, Paris, 75013, France.
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49
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Regulation of Global Transcription in Escherichia coli by Rsd and 6S RNA. G3-GENES GENOMES GENETICS 2018; 8:2079-2089. [PMID: 29686109 PMCID: PMC5982834 DOI: 10.1534/g3.118.200265] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In Escherichia coli, the sigma factor σ70 directs RNA polymerase to transcribe growth-related genes, while σ38 directs transcription of stress response genes during stationary phase. Two molecules hypothesized to regulate RNA polymerase are the protein Rsd, which binds to σ70, and the non-coding 6S RNA which binds to the RNA polymerase-σ70 holoenzyme. Despite multiple studies, the functions of Rsd and 6S RNA remain controversial. Here we use RNA-Seq in five phases of growth to elucidate their function on a genome-wide scale. We show that Rsd and 6S RNA facilitate σ38 activity throughout bacterial growth, while 6S RNA also regulates widely different genes depending upon growth phase. We discover novel interactions between 6S RNA and Rsd and show widespread expression changes in a strain lacking both regulators. Finally, we present a mathematical model of transcription which highlights the crosstalk between Rsd and 6S RNA as a crucial factor in controlling sigma factor competition and global gene expression.
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50
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González-Tortuero E, Rodríguez-Beltrán J, Radek R, Blázquez J, Rodríguez-Rojas A. Clay-induced DNA breaks as a path for genetic diversity, antibiotic resistance, and asbestos carcinogenesis. Sci Rep 2018; 8:8504. [PMID: 29855603 PMCID: PMC5981458 DOI: 10.1038/s41598-018-26958-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/23/2018] [Indexed: 11/09/2022] Open
Abstract
Natural clays and synthetic nanofibres can have a severe impact on human health. After several decades of research, the molecular mechanism of how asbestos induces cancer is not well understood. Different fibres, including asbestos, can penetrate cell membranes and introduce foreign DNA in bacterial and eukaryotic cells. Incubating Escherichia coli under friction forces with sepiolite, a clayey material, or with asbestos, causes double-strand DNA breaks. Antibiotics and clays are used together in animal husbandry, the mutagenic effect of these fibres could be a pathway to antibiotic resistance due to the friction provided by peristalsis of the gut from farm animals in addition to horizontal gene transfer. Moreover, we raise the possibility that the same mechanism could generate bacteria diversity in natural scenarios, playing a role in the evolution of species. Finally, we provide a new model on how asbestos may promote mutagenesis and cancer based on the observed mechanical genotoxicity.
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Affiliation(s)
- Enrique González-Tortuero
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany.,Berlin Centre for Genomics in Biodiversity Research (BeGenDiv), Königin-Luise-Straße 6-8, 14195, Berlin, Germany.,Institute for Genome Sciences, University of Maryland Baltimore School of Medicine, 670 West Baltimore Street, 21201, Baltimore, MD, USA
| | - Jerónimo Rodríguez-Beltrán
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology, Calle Darwin 3, 28049, Madrid, Spain
| | - Renate Radek
- Evolutionary Biology, Institut für Biologie, Freie Universität Berlin, Berlin, Germany
| | - Jesús Blázquez
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology, Calle Darwin 3, 28049, Madrid, Spain
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