1
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Vigoda MB, Argaman L, Kournos M, Margalit H. Unraveling the interplay between a small RNA and RNase E in bacteria. Nucleic Acids Res 2024; 52:8947-8966. [PMID: 39036964 PMCID: PMC11347164 DOI: 10.1093/nar/gkae621] [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: 09/21/2023] [Revised: 06/28/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
Small RNAs (sRNAs) are major regulators of gene expression in bacteria, exerting their regulation primarily via base pairing with their target transcripts and modulating translation. Accumulating evidence suggest that sRNAs can also affect the stability of their target transcripts by altering their accessibility to endoribonucleases. Yet, the effects of sRNAs on transcript stability and the mechanisms underlying them have not been studied in wide scale. Here we employ large-scale RNA-seq-based methodologies in the model bacterium Escherichia coli to quantitatively study the functional interaction between a sRNA and an endoribonuclease in regulating gene expression, using the well-established sRNA, GcvB, and the major endoribonuclease, RNase E. Studying single and double mutants of gcvB and rne and analysing their RNA-seq results by the Double Mutant Cycle approach, we infer distinct modes of the interplay between GcvB and RNase E. Transcriptome-wide mapping of RNase E cleavage sites provides further support to the results of the RNA-seq analysis, identifying cleavage sites in targets in which the functional interaction between GcvB and RNase E is evident. Together, our results indicate that the most dominant mode of GcvB-RNase E functional interaction is GcvB enhancement of RNase E cleavage, which varies in its magnitude between different targets.
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Affiliation(s)
- Meshi Barsheshet Vigoda
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Liron Argaman
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Mark Kournos
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hanah Margalit
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
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2
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Dubois Q, Brual T, Oriol C, Mandin P, Condemine G, Gueguen E. Function and mechanism of action of the small regulatory RNA ArcZ in Enterobacterales. RNA (NEW YORK, N.Y.) 2024; 30:1107-1121. [PMID: 38839110 PMCID: PMC11331407 DOI: 10.1261/rna.080010.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/15/2024] [Indexed: 06/07/2024]
Abstract
ArcZ is a small regulatory RNA conserved in Enterobacterales It is an Hfq-dependent RNA that is cleaved by RNase E in a processed form of 55-60 nucleotides. This processed form is highly conserved for controlling the expression of target mRNAs. ArcZ expression is induced by abundant oxygen levels and reaches its peak during the stationary growth phase. This control is mediated by the oxygen-responsive two-component system ArcAB, leading to the repression of arcZ transcription under low-oxygen conditions in most bacteria in which it has been studied. ArcZ displays multiple targets, and it can control up to 10% of a genome and interact directly with more than 300 mRNAs in Escherichia coli and Salmonella enterica ArcZ displays a multifaceted ability to regulate its targets through diverse mechanisms such as RNase recruitment, modulation of ribosome accessibility on the mRNA, and interaction with translational enhancing regions. By influencing stress response, motility, and virulence through the regulation of master regulators such as FlhDC or RpoS, ArcZ emerges as a major orchestrator of cell physiology within Enterobacterales.
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Affiliation(s)
- Quentin Dubois
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, UMR5240 MAP Lyon, France
| | - Typhaine Brual
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, UMR5240 MAP Lyon, France
| | - Charlotte Oriol
- CNRS, Aix-Marseille Université, Laboratoire de Chimie Bactérienne, UMR7283, IMM, IM2B, F-13009 Marseille, France
| | - Pierre Mandin
- CNRS, Aix-Marseille Université, Laboratoire de Chimie Bactérienne, UMR7283, IMM, IM2B, F-13009 Marseille, France
| | - Guy Condemine
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, UMR5240 MAP Lyon, France
| | - Erwan Gueguen
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INSA Lyon, UMR5240 MAP Lyon, France
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3
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Lara P, Gama-Castro S, Salgado H, Rioualen C, Tierrafría VH, Muñiz-Rascado LJ, Bonavides-Martínez C, Collado-Vides J. Flexible gold standards for transcription factor regulatory interactions in Escherichia coli K-12: architecture of evidence types. Front Genet 2024; 15:1353553. [PMID: 38505828 PMCID: PMC10949920 DOI: 10.3389/fgene.2024.1353553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 02/09/2024] [Indexed: 03/21/2024] Open
Abstract
Post-genomic implementations have expanded the experimental strategies to identify elements involved in the regulation of transcription initiation. Here, we present for the first time a detailed analysis of the sources of knowledge supporting the collection of transcriptional regulatory interactions (RIs) of Escherichia coli K-12. An RI groups the transcription factor, its effect (positive or negative) and the regulated target, a promoter, a gene or transcription unit. We improved the evidence codes so that specific methods are incorporated and classified into independent groups. On this basis we updated the computation of confidence levels, weak, strong, or confirmed, for the collection of RIs. These updates enabled us to map the RI set to the current collection of HT TF-binding datasets from ChIP-seq, ChIP-exo, gSELEX and DAP-seq in RegulonDB, enriching in this way the evidence of close to one-quarter (1329) of RIs from the current total 5446 RIs. Based on the new computational capabilities of our improved annotation of evidence sources, we can now analyze the internal architecture of evidence, their categories (experimental, classical, HT, computational), and confidence levels. This is how we know that the joint contribution of HT and computational methods increase the overall fraction of reliable RIs (the sum of confirmed and strong evidence) from 49% to 71%. Thus, the current collection has 3912 reliable RIs, with 2718 or 70% of them with classical evidence which can be used to benchmark novel HT methods. Users can selectively exclude the method they want to benchmark, or keep for instance only the confirmed interactions. The recovery of regulatory sites in RegulonDB by the different HT methods ranges between 33% by ChIP-exo to 76% by ChIP-seq although as discussed, many potential confounding factors limit their interpretation. The collection of improvements reported here provides a solid foundation to incorporate new methods and data, and to further integrate the diverse sources of knowledge of the different components of the transcriptional regulatory network. There is no other genomic database that offers this comprehensive high-quality architecture of knowledge supporting a corpus of transcriptional regulatory interactions.
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Affiliation(s)
- Paloma Lara
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - Socorro Gama-Castro
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - Heladia Salgado
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - Claire Rioualen
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - Víctor H. Tierrafría
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Luis J. Muñiz-Rascado
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - César Bonavides-Martínez
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
| | - Julio Collado-Vides
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad S/N, Cuernavaca, Mexico
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
- Center for Genomic Regulation, The Barcelona Institute of Science and Technology, Universitat Pompeu Fabra, Barcelona, Spain
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4
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Frendorf PO, Heyde SAH, Nørholm MHH. Mutations upstream from sdaC and malT in Escherichia coli uncover a complex interplay between the cAMP receptor protein and different sigma factors. J Bacteriol 2024; 206:e0035523. [PMID: 38197669 PMCID: PMC10882989 DOI: 10.1128/jb.00355-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/12/2023] [Indexed: 01/11/2024] Open
Abstract
In Escherichia coli, one of the best understood microorganisms, much can still be learned about the basic interactions between transcription factors and promoters. When a cAMP-deficient cya mutant is supplied with maltose as the main carbon source, mutations develop upstream from the two genes malT and sdaC. Here, we explore the regulation of the two promoters, using fluorescence-based genetic reporters in combination with both spontaneously evolved and systematically engineered cis-acting mutations. We show that in the cya mutant, regulation of malT and sdaC evolves toward cAMP-independence and increased expression in the stationary phase. Furthermore, we show that the location of the cAMP receptor protein (Crp) binding site upstream of malT is important for alternative sigma factor usage. This provides new insights into the architecture of bacterial promoters and the global interplay between Crp and sigma factors in different growth phases.IMPORTANCEThis work provides new general insights into (1) the architecture of bacterial promoters, (2) the importance of the location of Class I Crp-dependent promoters, and (3) the global interplay between Crp and sigma factors in different growth phases.
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Affiliation(s)
- Pernille Ott Frendorf
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Sophia A. H. Heyde
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Morten H. H. Nørholm
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
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5
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Miyakoshi M. Multilayered regulation of amino acid metabolism in Escherichia coli. Curr Opin Microbiol 2024; 77:102406. [PMID: 38061078 DOI: 10.1016/j.mib.2023.102406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 02/12/2024]
Abstract
Amino acid metabolism in Escherichia coli has long been studied and has established the basis for regulatory mechanisms at the transcriptional, posttranscriptional, and posttranslational levels. In addition to the classical signal transduction cascade involving posttranslational modifications (PTMs), novel PTMs in the two primary nitrogen assimilation pathways have recently been uncovered. The regulon of the master transcriptional regulator NtrC is further expanded by a small RNA derived from the 3´UTR of glutamine synthetase mRNA, which coordinates central carbon and nitrogen metabolism. Furthermore, recent advances in sequencing technologies have revealed the global regulatory networks of transcriptional and posttranscriptional regulators, Lrp and GcvB. This review provides an update of the multilayered and interconnected regulatory networks governing amino acid metabolism in E. coli.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Infection Biology, Institute of Medicine, University of Tsukuba, 305-8575 Ibaraki, Japan.
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6
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Lara P, Gama-Castro S, Salgado H, Rioualen C, Tierrafría VH, Muñiz-Rascado LJ, Bonavides-Martínez C, Collado-Vides J. A Gold Standard for Transcription Factor Regulatory Interactions in Escherichia coli K-12: Architecture of Evidence Types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.25.530038. [PMID: 37163020 PMCID: PMC10168212 DOI: 10.1101/2023.02.25.530038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Post-genomic implementations have expanded the experimental strategies to identify elements involved in the regulation of transcription initiation. As new methodologies emerge, a natural step is to compare their results with those from established methodologies, such as the classic methods of molecular biology used to characterize transcription factor binding sites, promoters, or transcription units. In the case of Escherichia coli K-12, the best-studied microorganism, for the last 30 years we have continuously gathered such knowledge from original scientific publications, and have organized it in two databases, RegulonDB and EcoCyc. Furthermore, since RegulonDB version 11.0 (1), we offer comprehensive datasets of binding sites from chromatin immunoprecipitation combined with sequencing (ChIP-seq), ChIP combined with exonuclease digestion and next-generation sequencing (ChIP-exo), genomic SELEX screening (gSELEX), and DNA affinity purification sequencing (DAP-seq) HT technologies, as well as additional datasets for transcription start sites, transcription units and RNA sequencing (RNA-seq) expression profiles. Here, we present for the first time an analysis of the sources of knowledge supporting the collection of transcriptional regulatory interactions (RIs) of E. coli K-12. An RI is formed by the transcription factor, its positive or negative effect on a promoter, a gene or transcription unit. We improved the evidence codes so that the specific methods are described, and we classified them into seven independent groups. This is the basis for our updated computation of confidence levels, weak, strong, or confirmed, for the collection of RIs. We compare the confidence levels of the RI collection before and after adding HT evidence illustrating how knowledge will change as more HT data and methods appear in the future. Users can generate subsets filtering out the method they want to benchmark and avoid circularity, or keep for instance only the confirmed interactions. The comparison of different HT methods with the available datasets indicate that ChIP-seq recovers the highest fraction (>70%) of binding sites present in RegulonDB followed by gSELEX, DAP-seq and ChIP-exo. There is no other genomic database that offers this comprehensive high-quality anatomy of evidence supporting a corpus of transcriptional regulatory interactions.
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7
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Dubey S, Maurya RK, Shree S, Kumar S, Jahan F, Krishnan MY, Ramachandran R. Mycobacterium tuberculosis Rv2324 is a multifunctional feast/famine regulatory protein involved in growth, DNA replication and damage control. Int J Biol Macromol 2023; 252:126459. [PMID: 37634786 DOI: 10.1016/j.ijbiomac.2023.126459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/20/2023] [Accepted: 08/20/2023] [Indexed: 08/29/2023]
Abstract
Feast/famine regulatory proteins (FFRPs) are multifunctional regulators. We show that Mtb Rv2324 is important for growth, survival, and countering DNA damage in Mycobacterium tuberculosis (Mtb). DNA-relaxation activity against linear and supercoiled substrates suggest its involvement in transcription activation, while its high affinity for recombination, replication and repair substrates suggest a role there too. Small-Angle-X-ray scattering supports the adoption of an 'open' quaternary association in response to amino-acid binding. Size-exclusion-chromatography and glutaraldehyde cross-linking identify the adoption of diverse oligomers modulated by amino-acid binding, and DNA interactions. We tested G52A, G101T and D104A mutants which correspond to highly conserved residues, distal to the DNA-binding site, and are important for amino acids binding. G101T exhibits increased DNA affinity, while G52A and D104A exhibit weak DNA-binding thereby suggesting that they mediate effector-binding, and DNA binding activities. Gain and loss-of-function studies show that Rv2324 overexpression promotes growth-rate, while its knock-down leads to retarded growth. Rv2324 down-regulation lowers Mtb survival inside resting and IFN-ϒ-activated macrophages. Rv2324 protects the pathogen from DNA damage, as evidenced by the reduction in the knockdown strain's survival following treatment with H2O2 and UV light. Overall, we show that Rv2324 plays a crucial role in regulating survival and growth of Mtb.
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Affiliation(s)
- Shikha Dubey
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rahul Kumar Maurya
- Molecular Microbiology and Immunology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India
| | - Sonal Shree
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India; Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
| | - Sanjay Kumar
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Farheen Jahan
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India
| | - Manju Yasoda Krishnan
- Molecular Microbiology and Immunology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India
| | - Ravishankar Ramachandran
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Uttar Pradesh 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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8
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Simpson BW, Gilmore MC, McLean AB, Cava F, Trent MS. Escherichia coli utilizes multiple peptidoglycan recycling permeases with distinct strategies of recycling. Proc Natl Acad Sci U S A 2023; 120:e2308940120. [PMID: 37871219 PMCID: PMC10622912 DOI: 10.1073/pnas.2308940120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/27/2023] [Indexed: 10/25/2023] Open
Abstract
Bacteria produce a structural layer of peptidoglycan (PG) that enforces cell shape, resists turgor pressure, and protects the cell. As bacteria grow and divide, the existing layer of PG is remodeled and PG fragments are released. Enterics such as Escherichia coli go to great lengths to internalize and reutilize PG fragments. E. coli is estimated to break down one-third of its cell wall, yet only loses ~0 to 5% of meso-diaminopimelic acid, a PG-specific amino acid, per generation. Two transporters were identified early on to possibly be the primary permease that facilitates PG fragment recycling, i) AmpG and ii) the Opp ATP binding cassette transporter in conjunction with a PG-specific periplasmic binding protein, MppA. The contribution of each transporter to PG recycling has been debated. Here, we have found that AmpG and MppA/Opp are differentially regulated by carbon source and growth phase. In addition, MppA/Opp is uniquely capable of high-affinity scavenging of muropeptides from growth media, demonstrating that AmpG and MppA/Opp allow for different strategies of recycling PG fragments. Altogether, this work clarifies environmental contexts under which E. coli utilizes distinct permeases for PG recycling and explores how scavenging by MppA/Opp could be beneficial in mixed communities.
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Affiliation(s)
- Brent W. Simpson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
| | - Michael C. Gilmore
- Laboratory for Molecular Infection Medicine Sweden, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, Umeå90187, Sweden
| | - Amanda Briann McLean
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, Umeå90187, Sweden
| | - M. Stephen Trent
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
- Department of Microbiology, College of Art and Sciences, University of Georgia, Athens, GA30602
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9
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Trouillon J, Doubleday PF, Sauer U. Genomic footprinting uncovers global transcription factor responses to amino acids in Escherichia coli. Cell Syst 2023; 14:860-871.e4. [PMID: 37820729 DOI: 10.1016/j.cels.2023.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/01/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023]
Abstract
Our knowledge of transcriptional responses to changes in nutrient availability comes primarily from few well-studied transcription factors (TFs), often lacking an unbiased genome-wide perspective. Leveraging recent advances allowing bacterial genomic footprinting, we comprehensively mapped the genome-wide regulatory responses of Escherichia coli to exogenous leucine, methionine, alanine, and lysine. The global TF Lrp was found to individually sense three amino acids and mount three different target gene responses. Overall, 531 genes had altered RNA polymerase occupancy, and 32 TFs responded directly or indirectly to the presence of amino acids, including regulators of membrane and osmotic pressure homeostasis. About 70% of the detected TF-DNA interactions had not been reported before. We thus identified 682 previously unknown TF-binding locations, for a subset of which the involved TFs were identified by affinity purification. This comprehensive map of amino acid regulation illustrates the incompleteness of the known transcriptional regulation network, even in E. coli.
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Affiliation(s)
- Julian Trouillon
- Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Peter F Doubleday
- Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Uwe Sauer
- Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland.
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10
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Hou C, Liu L, Ju X, Xiao Y, Li B, You C. Revisiting Fur Regulon Leads to a Comprehensive Understanding of Iron and Fur Regulation. Int J Mol Sci 2023; 24:ijms24109078. [PMID: 37240425 DOI: 10.3390/ijms24109078] [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: 03/20/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Iron is an essential element because it functions as a cofactor of many enzymes, but excess iron causes cell damage. Iron hemostasis in Escherichia coli was transcriptionally maintained by the ferric uptake regulator (Fur). Despite having been studied extensively, the comprehensive physiological roles and mechanisms of Fur-coordinated iron metabolism still remain obscure. In this work, by integrating a high-resolution transcriptomic study of the Fur wild-type and knockout Escherichia coli K-12 strains in the presence or absence of iron with high-throughput ChIP-seq assay and physiological studies, we revisited the regulatory roles of iron and Fur systematically and discovered several intriguing features of Fur regulation. The size of the Fur regulon was expanded greatly, and significant discrepancies were observed to exist between the regulations of Fur on the genes under its direct repression and activation. Fur showed stronger binding strength to the genes under its repression, and genes that were repressed by Fur were more sensitive to Fur and iron regulation as compared to the genes that were activated by Fur. Finally, we found that Fur linked iron metabolism to many essential processes, and the systemic regulations of Fur on carbon metabolism, respiration, and motility were further validated or discussed. These results highlight how Fur and Fur-controlled iron metabolism affect many cellular processes in a systematic way.
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Affiliation(s)
- Chaofan Hou
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Lin Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Xian Ju
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Yunzhu Xiao
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Bingyu Li
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Conghui You
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
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11
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Ziegler CA, Freddolino PL. Escherichia coli Leucine-Responsive Regulatory Protein Bridges DNA In Vivo and Tunably Dissociates in the Presence of Exogenous Leucine. mBio 2023; 14:e0269022. [PMID: 36786566 PMCID: PMC10127797 DOI: 10.1128/mbio.02690-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
Feast-famine response proteins are a widely conserved class of global regulators in prokaryotes, the most highly studied of which is the Escherichia coli leucine-responsive regulatory protein (Lrp). Lrp senses the environmental nutrition status and subsequently regulates up to one-third of the genes in E. coli, either directly or indirectly. Lrp exists predominantly as octamers and hexadecamers (16mers), where leucine is believed to shift the equilibrium toward the octameric state. In this study, we analyzed the effects of three oligomerization state mutants of Lrp in terms of their ability to bind to DNA and regulate gene expression in response to exogenous leucine. We find that oligomerization beyond dimers is required for Lrp's regulatory activity and that, contrary to previous speculation, exogenous leucine modulates Lrp activity at its target promoters exclusively by inhibiting Lrp binding to DNA. We also show evidence that Lrp binding bridges DNA over length scales of multiple kilobases, revealing a new range of mechanisms for Lrp-mediated transcriptional regulation. IMPORTANCE Leucine-responsive regulatory protein (Lrp) is one of the most impactful regulators in E. coli and other bacteria. Lrp senses nutrient conditions and responds by controlling strategies for virulence, cellular motility, and nutrient acquisition. Despite its importance and being evolutionarily highly conserved across bacteria and archaea, several mysteries remain regarding Lrp, including how it actually responds to leucine to change its regulation of targets. Previous studies have led to the hypothesis that Lrp switches between two states, an octamer (8 Lrp molecules together) and a hexadecamer (16 Lrp molecules together), upon exposure to leucine; these are referred to as different oligomerization states. Here, we show that contrary to previous expectations, it is Lrp's propensity to bind DNA, rather than its oligomerization state, that is directly affected by leucine in the cell's environment. Our new understanding of Lrp activity will aid in identifying and disrupting pathways used by bacteria to cause disease.
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Affiliation(s)
- Christine A. Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter L. Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
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12
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The Hypersaline Archaeal Histones HpyA and HstA Are DNA Binding Proteins That Defy Categorization According to Commonly Used Functional Criteria. mBio 2023; 14:e0344922. [PMID: 36779711 PMCID: PMC10128011 DOI: 10.1128/mbio.03449-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Histone proteins are found across diverse lineages of Archaea, many of which package DNA and form chromatin. However, previous research has led to the hypothesis that the histone-like proteins of high-salt-adapted archaea, or halophiles, function differently. The sole histone protein encoded by the model halophilic species Halobacterium salinarum, HpyA, is nonessential and expressed at levels too low to enable genome-wide DNA packaging. Instead, HpyA mediates the transcriptional response to salt stress. Here we compare the features of genome-wide binding of HpyA to those of HstA, the sole histone of another model halophile, Haloferax volcanii. hstA, like hpyA, is a nonessential gene. To better understand HpyA and HstA functions, protein-DNA binding data (chromatin immunoprecipitation sequencing [ChIP-seq]) of these halophilic histones are compared to publicly available ChIP-seq data from DNA binding proteins across all domains of life, including transcription factors (TFs), nucleoid-associated proteins (NAPs), and histones. These analyses demonstrate that HpyA and HstA bind the genome infrequently in discrete regions, which is similar to TFs but unlike NAPs, which bind a much larger genomic fraction. However, unlike TFs that typically bind in intergenic regions, HpyA and HstA binding sites are located in both coding and intergenic regions. The genome-wide dinucleotide periodicity known to facilitate histone binding was undetectable in the genomes of both species. Instead, TF-like and histone-like binding sequence preferences were detected for HstA and HpyA, respectively. Taken together, these data suggest that halophilic archaeal histones are unlikely to facilitate genome-wide chromatin formation and that their function defies categorization as a TF, NAP, or histone. IMPORTANCE Most cells in eukaryotic species-from yeast to humans-possess histone proteins that pack and unpack DNA in response to environmental cues. These essential proteins regulate genes necessary for important cellular processes, including development and stress protection. Although the histone fold domain originated in the domain of life Archaea, the function of archaeal histone-like proteins is not well understood relative to those of eukaryotes. We recently discovered that, unlike histones of eukaryotes, histones in hypersaline-adapted archaeal species do not package DNA and can act as transcription factors (TFs) to regulate stress response gene expression. However, the function of histones across species of hypersaline-adapted archaea still remains unclear. Here, we compare hypersaline histone function to a variety of DNA binding proteins across the tree of life, revealing histone-like behavior in some respects and specific transcriptional regulatory function in others.
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Conway C, Beckett MC, Dorman CJ. The DNA relaxation-dependent OFF-to-ON biasing of the type 1 fimbrial genetic switch requires the Fis nucleoid-associated protein. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001283. [PMID: 36748578 PMCID: PMC9993118 DOI: 10.1099/mic.0.001283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The structural genes expressing type 1 fimbriae in Escherichia coli alternate between expressed (phase ON) and non-expressed (phase OFF) states due to inversion of the 314 bp fimS genetic switch. The FimB tyrosine integrase inverts fimS by site-specific recombination, alternately connecting and disconnecting the fim operon, encoding the fimbrial subunit protein and its associated secretion and adhesin factors, to and from its transcriptional promoter within fimS. Site-specific recombination by the FimB recombinase becomes biased towards phase ON as DNA supercoiling is relaxed, a condition that occurs when bacteria approach the stationary phase of the growth cycle. This effect can be mimicked in exponential phase cultures by inhibiting the negative DNA supercoiling activity of DNA gyrase. We report that this bias towards phase ON depends on the presence of the Fis nucleoid-associated protein. We mapped the Fis binding to a site within the invertible fimS switch by DNase I footprinting. Disruption of this binding site by base substitution mutagenesis abolishes both Fis binding and the ability of the mutated switch to sustain its phase ON bias when DNA is relaxed, even in bacteria that produce the Fis protein. In addition, the Fis binding site overlaps one of the sites used by the Lrp protein, a known directionality determinant of fimS inversion that also contributes to phase ON bias. The Fis–Lrp relationship at fimS is reminiscent of that between Fis and Xis when promoting DNA relaxation-dependent excision of bacteriophage λ from the E. coli chromosome. However, unlike the co-binding mechanism used by Fis and Xis at λ attR, the Fis–Lrp relationship at fimS involves competitive binding. We discuss these findings in the context of the link between fimS inversion biasing and the physiological state of the bacterium.
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Affiliation(s)
- Colin Conway
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland.,Present address: Technical University of the Atlantic, Galway, Ireland
| | - Michael C Beckett
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Charles J Dorman
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
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RfaH Counter-Silences Inhibition of Transcript Elongation by H-NS-StpA Nucleoprotein Filaments in Pathogenic Escherichia coli. mBio 2022; 13:e0266222. [PMID: 36264101 PMCID: PMC9765446 DOI: 10.1128/mbio.02662-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of virulence genes in pathogenic Escherichia coli is controlled in part by the transcription silencer H-NS and its paralogs (e.g., StpA), which sequester DNA in multi-kb nucleoprotein filaments to inhibit transcription initiation, elongation, or both. Some activators counter-silence initiation by displacing H-NS from promoters, but how H-NS inhibition of elongation is overcome is not understood. In uropathogenic E. coli (UPEC), elongation regulator RfaH aids expression of some H-NS-silenced pathogenicity operons (e.g., hlyCABD encoding hemolysin). RfaH associates with elongation complexes (ECs) via direct contacts to a transiently exposed, nontemplate DNA strand sequence called operon polarity suppressor (ops). RfaH-ops interactions establish long-lived RfaH-EC contacts that allow RfaH to recruit ribosomes to the nascent mRNA and to suppress transcriptional pausing and termination. Using ChIP-seq, we mapped the genome-scale distributions of RfaH, H-NS, StpA, RNA polymerase (RNAP), and σ70 in the UPEC strain CFT073. We identify eight RfaH-activated operons, all of which were bound by H-NS and StpA. Four are new additions to the RfaH regulon. Deletion of RfaH caused premature termination, whereas deletion of H-NS and StpA allowed elongation without RfaH. Thus, RfaH is an elongation counter-silencer of H-NS. Consistent with elongation counter-silencing, deletion of StpA alone decreased the effect of RfaH. StpA increases DNA bridging, which inhibits transcript elongation via topological constraints on RNAP. Residual RfaH effect when both H-NS and StpA were deleted was attributable to targeting of RfaH-regulated operons by a minor H-NS paralog, Hfp. These operons have evolved higher levels of H-NS-binding features, explaining minor-paralog targeting. IMPORTANCE Bacterial pathogens adapt to hosts and host defenses by reprogramming gene expression, including by H-NS counter-silencing. Counter-silencing turns on transcription initiation when regulators bind to promoters and rearrange repressive H-NS nucleoprotein filaments that ordinarily block transcription. The specialized NusG paralog RfaH also reprograms virulence genes but regulates transcription elongation. To understand how elongation regulators might affect genes silenced by H-NS, we mapped H-NS, StpA (an H-NS paralog), RfaH, σ70, and RNA polymerase (RNAP) locations on DNA in the uropathogenic E. coli strain CFT073. Although H-NS-StpA filaments bind only 18% of the CFT073 genome, all loci at which RfaH binds RNAP are also bound by H-NS-StpA and are silenced when RfaH is absent. Thus, RfaH represents a distinct class of counter-silencer that acts on elongating RNAP to enable transcription through repressive nucleoprotein filaments. Our findings define a new mechanism of elongation counter-silencing and explain how RfaH functions as a virulence regulator.
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15
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Yang P, Liu W, Chen Y, Gong AD. Engineering the glyoxylate cycle for chemical bioproduction. Front Bioeng Biotechnol 2022; 10:1066651. [PMID: 36532595 PMCID: PMC9755347 DOI: 10.3389/fbioe.2022.1066651] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/17/2022] [Indexed: 07/24/2023] Open
Abstract
With growing concerns about environmental issues and sustainable economy, bioproduction of chemicals utilizing microbial cell factories provides an eco-friendly alternative to current petro-based processes. Creating high-performance strains (with high titer, yield, and productivity) through metabolic engineering strategies is critical for cost-competitive production. Commonly, it is inevitable to fine-tuning or rewire the endogenous or heterologous pathways in such processes. As an important pathway involved in the synthesis of many kinds of chemicals, the potential of the glyoxylate cycle in metabolic engineering has been studied extensively these years. Here, we review the metabolic regulation of the glyoxylate cycle and summarize recent achievements in microbial production of chemicals through tuning of the glyoxylate cycle, with a focus on studies implemented in model microorganisms. Also, future prospects for bioproduction of glyoxylate cycle-related chemicals are discussed.
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Wisniewska A, Wons E, Potrykus K, Hinrichs R, Gucwa K, Graumann PL, Mruk I. Molecular basis for lethal cross-talk between two unrelated bacterial transcription factors - the regulatory protein of a restriction-modification system and the repressor of a defective prophage. Nucleic Acids Res 2022; 50:10964-10980. [PMID: 36271797 DOI: 10.1093/nar/gkac914] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/29/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial gene expression depends on the efficient functioning of global transcriptional networks, however their interconnectivity and orchestration rely mainly on the action of individual DNA binding proteins called transcription factors (TFs). TFs interact not only with their specific target sites, but also with secondary (off-target) sites, and vary in their promiscuity. It is not clear yet what mechanisms govern the interactions with secondary sites, and how such rewiring affects the overall regulatory network, but this could clearly constrain horizontal gene transfer. Here, we show the molecular mechanism of one such off-target interaction between two unrelated TFs in Escherichia coli: the C regulatory protein of a Type II restriction-modification system, and the RacR repressor of a defective prophage. We reveal that the C protein interferes with RacR repressor expression, resulting in derepression of the toxic YdaT protein. These results also provide novel insights into regulation of the racR-ydaST operon. We mapped the C regulator interaction to a specific off-target site, and also visualized C protein dynamics, revealing intriguing differences in single molecule dynamics in different genetic contexts. Our results demonstrate an apparent example of horizontal gene transfer leading to adventitious TF cross-talk with negative effects on the recipient's viability. More broadly, this study represents an experimentally-accessible model of a regulatory constraint on horizontal gene transfer.
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Affiliation(s)
- Aleksandra Wisniewska
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Ewa Wons
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Katarzyna Potrykus
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Rebecca Hinrichs
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Germany.,Department of Chemistry, Philipps Universität Marburg, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Katarzyna Gucwa
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Peter L Graumann
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Philipps Universität Marburg, Germany.,Department of Chemistry, Philipps Universität Marburg, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Iwona Mruk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
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17
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Scholz SA, Lindeboom CD, Freddolino PL. Genetic context effects can override canonical cis regulatory elements in Escherichia coli. Nucleic Acids Res 2022; 50:10360-10375. [PMID: 36134716 PMCID: PMC9561378 DOI: 10.1093/nar/gkac787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 11/12/2022] Open
Abstract
Recent experiments have shown that in addition to control by cis regulatory elements, the local chromosomal context of a gene also has a profound impact on its transcription. Although this chromosome-position dependent expression variation has been empirically mapped at high-resolution, the underlying causes of the variation have not been elucidated. Here, we demonstrate that 1 kb of flanking, non-coding synthetic sequences with a low frequency of guanosine and cytosine (GC) can dramatically reduce reporter expression compared to neutral and high GC-content flanks in Escherichia coli. Natural and artificial genetic context can have a similarly strong effect on reporter expression, regardless of cell growth phase or medium. Despite the strong reduction in the maximal expression level from the fully-induced reporter, low GC synthetic flanks do not affect the time required to reach the maximal expression level after induction. Overall, we demonstrate key determinants of transcriptional propensity that appear to act as tunable modulators of transcription, independent of regulatory sequences such as the promoter. These findings provide insight into the regulation of naturally occurring genes and an independent control for optimizing expression of synthetic biology constructs.
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Affiliation(s)
- Scott A Scholz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Chase D Lindeboom
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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18
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Ahn-Horst TA, Mille LS, Sun G, Morrison JH, Covert MW. An expanded whole-cell model of E. coli links cellular physiology with mechanisms of growth rate control. NPJ Syst Biol Appl 2022; 8:30. [PMID: 35986058 PMCID: PMC9391491 DOI: 10.1038/s41540-022-00242-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/28/2022] [Indexed: 11/09/2022] Open
Abstract
Growth and environmental responses are essential for living organisms to survive and adapt to constantly changing environments. In order to simulate new conditions and capture dynamic responses to environmental shifts in a developing whole-cell model of E. coli, we incorporated additional regulation, including dynamics of the global regulator guanosine tetraphosphate (ppGpp), along with dynamics of amino acid biosynthesis and translation. With the model, we show that under perturbed ppGpp conditions, small molecule feedback inhibition pathways, in addition to regulation of expression, play a role in ppGpp regulation of growth. We also found that simulations with dysregulated amino acid synthesis pathways provide average amino acid concentration predictions that are comparable to experimental results but on the single-cell level, concentrations unexpectedly show regular fluctuations. Additionally, during both an upshift and downshift in nutrient availability, the simulated cell responds similarly with a transient increase in the mRNA:rRNA ratio. This additional simulation functionality should support a variety of new applications and expansions of the E. coli Whole-Cell Modeling Project.
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Affiliation(s)
- Travis A Ahn-Horst
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | | | - Gwanggyu Sun
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Jerry H Morrison
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Markus W Covert
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
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19
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Bacteria reduce flagellin synthesis to evade microglia-astrocyte-driven immunity in the brain. Cell Rep 2022; 40:111033. [PMID: 35793624 DOI: 10.1016/j.celrep.2022.111033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 05/09/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022] Open
Abstract
The immune response of brain cells to invading bacteria in vivo and the mechanism used by pathogenic bacteria to escape brain immune surveillance remain largely unknown. It is believed that microglia eliminate bacteria by phagocytosis based on in vitro data. Here we find that a small percentage of microglia in the brain engulf neonatal meningitis-causing Escherichia coli (NMEC), but more microglia are activated to produce tumor necrosis factor alpha (TNFα), which activates astrocytes to secrete complement component 3 (C3) involved in anti-bacterial activity. To evade anti-bacterial activity of the immune system, NMEC senses low concentration of threonine in cerebrospinal fluid (CSF) to down-modulate the expression of flagellin and reduce microglial TNFα and astrocyte C3 production. Our findings may help develop strategies for bacterial meningitis treatment.
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20
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Parisutham V, Chhabra S, Ali MZ, Brewster RC. Tunable transcription factor library for robust quantification of regulatory properties in Escherichia coli. Mol Syst Biol 2022; 18:e10843. [PMID: 35694815 PMCID: PMC9189660 DOI: 10.15252/msb.202110843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 11/12/2022] Open
Abstract
Predicting the quantitative regulatory function of transcription factors (TFs) based on factors such as binding sequence, binding location, and promoter type is not possible. The interconnected nature of gene networks and the difficulty in tuning individual TF concentrations make the isolated study of TF function challenging. Here, we present a library of Escherichia coli strains designed to allow for precise control of the concentration of individual TFs enabling the study of the role of TF concentration on physiology and regulation. We demonstrate the usefulness of this resource by measuring the regulatory function of the zinc-responsive TF, ZntR, and the paralogous TF pair, GalR/GalS. For ZntR, we find that zinc alters ZntR regulatory function in a way that enables activation of the regulated gene to be robust with respect to ZntR concentration. For GalR and GalS, we are able to demonstrate that these paralogous TFs have fundamentally distinct regulatory roles beyond differences in binding affinity.
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Affiliation(s)
- Vinuselvi Parisutham
- Department of Systems BiologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Shivani Chhabra
- Department of Pharmacological SciencesIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - Md Zulfikar Ali
- Department of Systems BiologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Robert C Brewster
- Department of Systems BiologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
- Department of Microbiology and Physiological SystemsUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
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21
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Liu R, Wei X, Song W, Wang L, Cao J, Wu J, Thomas T, Jin T, Wang Z, Wei W, Wei Y, Zhai H, Yao C, Shen Z, Du J, Fang J. Novel Chloroflexi genomes from the deepest ocean reveal metabolic strategies for the adaptation to deep-sea habitats. MICROBIOME 2022; 10:75. [PMID: 35538590 PMCID: PMC9088039 DOI: 10.1186/s40168-022-01263-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 03/24/2022] [Indexed: 05/04/2023]
Abstract
BACKGROUND The deep sea harbors the majority of the microbial biomass in the ocean and is a key site for organic matter (OM) remineralization and storage in the biosphere. Microbial metabolism in the deep ocean is greatly controlled by the generally depleted but periodically fluctuating supply of OM. Currently, little is known about metabolic potentials of dominant deep-sea microbes to cope with the variable OM inputs, especially for those living in the hadal trenches-the deepest part of the ocean. RESULTS In this study, we report the first extensive examination of the metabolic potentials of hadal sediment Chloroflexi, a dominant phylum in hadal trenches and the global deep ocean. In total, 62 metagenome-assembled-genomes (MAGs) were reconstructed from nine metagenomic datasets derived from sediments of the Mariana Trench. These MAGs represent six novel species, four novel genera, one novel family, and one novel order within the classes Anaerolineae and Dehalococcoidia. Fragment recruitment showed that these MAGs are globally distributed in deep-sea waters and surface sediments, and transcriptomic analysis indicated their in situ activities. Metabolic reconstruction showed that hadal Chloroflexi mainly had a heterotrophic lifestyle, with the potential to degrade a wide range of organic carbon, sulfur, and halogenated compounds. Our results revealed for the first time that hadal Chloroflexi harbor pathways for the complete hydrolytic or oxidative degradation of various recalcitrant OM, including aromatic compounds (e.g., benzoate), polyaromatic hydrocarbons (e.g., fluorene), polychlorobiphenyl (e.g., 4-chlorobiphenyl), and organochlorine compounds (e.g., chloroalkanes, chlorocyclohexane). Moreover, these organisms showed the potential to synthesize energy storage compounds (e.g., trehalose) and had regulatory modules to respond to changes in nutrient conditions. These metabolic traits suggest that Chloroflexi may follow a "feast-or-famine" metabolic strategy, i.e., preferentially consume labile OM and store the energy intracellularly under OM-rich conditions, and utilize the stored energy or degrade recalcitrant OM for survival under OM-limited condition. CONCLUSION This study expands the current knowledge on metabolic strategies in deep-ocean Chlorolfexi and highlights their significance in deep-sea carbon, sulfur, and halogen cycles. The metabolic plasticity likely provides Chloroflexi with advantages for survival under variable and heterogenic OM inputs in the deep ocean. Video Abstract.
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Affiliation(s)
- Rulong Liu
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China.
| | - Xing Wei
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Weizhi Song
- Centre for Marine Science & Innovation and School of Biological Earth and Environmental Science, University of New South Wales, Kensington, Australia
| | - Li Wang
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Junwei Cao
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Jiaxin Wu
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Torsten Thomas
- Centre for Marine Science & Innovation and School of Biological Earth and Environmental Science, University of New South Wales, Kensington, Australia
| | - Tao Jin
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Zixuan Wang
- Tidal Flat Research Center of Jiangsu Province, Nanjing, Jiangsu, China
| | - Wenxia Wei
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Yuli Wei
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Haofeng Zhai
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Cheng Yao
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Ziyi Shen
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Jiangtao Du
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China
- National Engineering Research Center for Oceanic Fisheries, Shanghai Ocean University, Shanghai, China
| | - Jiasong Fang
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
- Department of Natural Sciences, Hawaii Pacific University, Honolulu, HI, USA.
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Relationship between the Chromosome Structural Dynamics and Gene Expression—A Chicken and Egg Dilemma? Microorganisms 2022; 10:microorganisms10050846. [PMID: 35630292 PMCID: PMC9144111 DOI: 10.3390/microorganisms10050846] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 04/14/2022] [Indexed: 02/06/2023] Open
Abstract
Prokaryotic transcription was extensively studied over the last half-century. A great deal of data has been accumulated regarding the control of gene expression by transcription factors regulating their target genes by binding at specific DNA sites. However, there is a significant gap between the mechanistic description of transcriptional control obtained from in vitro biochemical studies and the complexity of transcriptional regulation in the context of the living cell. Indeed, recent studies provide ample evidence for additional levels of complexity pertaining to the regulation of transcription in vivo, such as, for example, the role of the subcellular localization and spatial organization of different molecular components involved in the transcriptional control and, especially, the role of chromosome configurational dynamics. The question as to how the chromosome is dynamically reorganized under the changing environmental conditions and how this reorganization is related to gene expression is still far from being clear. In this article, we focus on the relationships between the chromosome structural dynamics and modulation of gene expression during bacterial adaptation. We argue that spatial organization of the bacterial chromosome is of central importance in the adaptation of gene expression to changing environmental conditions and vice versa, that gene expression affects chromosome dynamics.
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Schubert C, Unden G. C 4-Dicarboxylates as Growth Substrates and Signaling Molecules for Commensal and Pathogenic Enteric Bacteria in Mammalian Intestine. J Bacteriol 2022; 204:e0054521. [PMID: 34978458 PMCID: PMC9017328 DOI: 10.1128/jb.00545-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The C4-dicarboxylates (C4-DC) l-aspartate and l-malate have been identified as playing an important role in the colonization of mammalian intestine by enteric bacteria, such as Escherichia coli and Salmonella enterica serovar Typhimurium, and succinate as a signaling molecule for host-enteric bacterium interaction. Thus, endogenous and exogenous fumarate respiration and related functions are required for efficient initial growth of the bacteria. l-Aspartate represents a major substrate for fumarate respiration in the intestine and a high-quality substrate for nitrogen assimilation. During nitrogen assimilation, DcuA catalyzes an l-aspartate/fumarate antiport and serves as a nitrogen shuttle for the net uptake of ammonium only, whereas DcuB acts as a redox shuttle that catalyzes the l-malate/succinate antiport during fumarate respiration. The C4-DC two-component system DcuS-DcuR is active in the intestine and responds to intestinal C4-DC levels. Moreover, in macrophages and in mice, succinate is a signal that promotes virulence and survival of S. Typhimurium and pathogenic E. coli. On the other hand, intestinal succinate is an important signaling molecule for the host and activates response and protective programs. Therefore, C4-DCs play a major role in supporting colonization of enteric bacteria and as signaling molecules for the adaptation of host physiology.
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Affiliation(s)
- Christopher Schubert
- Institute for Molecular Physiology (IMP), Microbiology and Wine Research, Johannes Gutenberg University, Mainz, Germany
| | - Gottfried Unden
- Institute for Molecular Physiology (IMP), Microbiology and Wine Research, Johannes Gutenberg University, Mainz, Germany
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The Escherichia coli Amino Acid Uptake Protein CycA: Regulation of Its Synthesis and Practical Application in l-Isoleucine Production. Microorganisms 2022; 10:microorganisms10030647. [PMID: 35336222 PMCID: PMC8948829 DOI: 10.3390/microorganisms10030647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 02/04/2023] Open
Abstract
Amino acid transport systems perform important physiological functions; their role should certainly be considered in microbial production of amino acids. Typically, in the context of metabolic engineering, efforts are focused on the search for and application of specific amino acid efflux pumps. However, in addition, importers can also be used to improve the industrial process as a whole. In this study, the protein CycA, which is known for uptake of nonpolar amino acids, was characterized from the viewpoint of regulating its expression and range of substrates. We prepared a cycA-overexpressing strain and found that it exhibited high sensitivity to branched-chain amino acids and their structural analogues, with relatively increased consumption of these amino acids, suggesting that they are imported by CycA. The expression of cycA was found to be dependent on the extracellular concentrations of substrate amino acids. The role of some transcription factors in cycA expression, including of Lrp and Crp, was studied using a reporter gene construct. Evidence for the direct binding of Crp to the cycA regulatory region was obtained using a gel-retardation assay. The enhanced import of named amino acids due to cycA overexpression in the l-isoleucine-producing strain resulted in a significant reduction in the generation of undesirable impurities. This work demonstrates the importance of uptake systems with respect to their application in metabolic engineering.
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Abstract
Persisters represent a small subpopulation of cells that are tolerant of killing by antibiotics and are implicated in the recalcitrance of chronic infections to antibiotic therapy. One general theme has emerged regarding persisters formed by different bacterial species, namely, a state of relative dormancy characterized by diminished activity of antibiotic targets. Within this framework, a number of studies have linked persister formation to stochastic decreases in energy-generating components, leading to low ATP and target activity. In this study, we screen knockouts in the main global regulators of Escherichia coli for their effect on persisters. A knockout in integration host factor (IHF) had elevated ATP and a diminished level of persisters. This was accompanied by an overexpression of isocitrate dehydrogenase (Icd) and a downregulation of isocitrate lyase (AceA), two genes located at the bifurcation between the tricarboxylic acid (TCA) cycle and the glyoxylate bypass. Using a translational ihfA-mVenus fusion, we sort out rare bright cells, and this subpopulation is enriched in persisters. Our results suggest that noise in the expression of ihf produces rare cells with low Icd/high AceA, diverting substrates into the glyoxylate bypass, which decreases ATP, leading to antibiotic-tolerant persisters. We further examine noise in a simple model, the lac operon, and show that a knockout of the lacI repressor increases expression of the operon and decreases persister formation. Our results suggest that noise quenching by overexpression serves as a general approach to determine the nature of persister genes in a variety of bacterial species and conditions. IMPORTANCE Persisters are phenotypic variants that survive exposure to antibiotics through temporary dormancy. Mutants with increased levels of persisters have been identified in clinical isolates, and evidence suggests these cells contribute to chronic infections and antibiotic treatment failure. Understanding the underlying mechanism of persister formation and tolerance is important for developing therapeutic approaches to treat chronic infections. In this study, we examine a global regulator, IHF, that plays a role in persister formation. We find that noise in expression of IHF contributes to persister formation, likely by regulating the switch between the TCA cycle that efficiently produces energy and the glyoxylate bypass. We extend this study to a simple model lac operon and show that when grown on lactose as the sole carbon source, noise in its expression influences ATP levels and determines persister formation. This noise is quenched by overexpression of the lac operon, providing a simple approach to test the involvement of a gene in persister formation.
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Femerling G, Gama-Castro S, Lara P, Ledezma-Tejeida D, Tierrafría VH, Muñiz-Rascado L, Bonavides-Martínez C, Collado-Vides J. Sensory Systems and Transcriptional Regulation in Escherichia coli. Front Bioeng Biotechnol 2022; 10:823240. [PMID: 35237580 PMCID: PMC8882922 DOI: 10.3389/fbioe.2022.823240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
In free-living bacteria, the ability to regulate gene expression is at the core of adapting and interacting with the environment. For these systems to have a logic, a signal must trigger a genetic change that helps the cell to deal with what implies its presence in the environment; briefly, the response is expected to include a feedback to the signal. Thus, it makes sense to think of genetic sensory mechanisms of gene regulation. Escherichia coli K-12 is the bacterium model for which the largest number of regulatory systems and its sensing capabilities have been studied in detail at the molecular level. In this special issue focused on biomolecular sensing systems, we offer an overview of the transcriptional regulatory corpus of knowledge for E. coli that has been gathered in our database, RegulonDB, from the perspective of sensing regulatory systems. Thus, we start with the beginning of the information flux, which is the signal's chemical or physical elements detected by the cell as changes in the environment; these signals are internally transduced to transcription factors and alter their conformation. Signals transduced to effectors bind allosterically to transcription factors, and this defines the dominant sensing mechanism in E. coli. We offer an updated list of the repertoire of known allosteric effectors, as well as a list of the currently known different mechanisms of this sensing capability. Our previous definition of elementary genetic sensory-response units, GENSOR units for short, that integrate signals, transport, gene regulation, and the biochemical response of the regulated gene products of a given transcriptional factor fit perfectly with the purpose of this overview. We summarize the functional heterogeneity of their response, based on our updated collection of GENSORs, and we use them to identify the expected feedback as part of their response. Finally, we address the question of multiple sensing in the regulatory network of E. coli. This overview introduces the architecture of sensing and regulation of native components in E.coli K-12, which might be a source of inspiration to bioengineering applications.
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Affiliation(s)
- Georgette Femerling
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Socorro Gama-Castro
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Paloma Lara
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Víctor H. Tierrafría
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Luis Muñiz-Rascado
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Julio Collado-Vides
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
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Bartholomew HP, Reynoso G, Thomas BJ, Mullins CM, Smith C, Gentzel IN, Giese LA, Mackey D, Stevens AM. The Transcription Factor Lrp of Pantoea stewartii subsp. stewartii Controls Capsule Production, Motility, and Virulence Important for in planta Growth. Front Microbiol 2022; 12:806504. [PMID: 35237242 PMCID: PMC8882988 DOI: 10.3389/fmicb.2021.806504] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
The bacterial phytopathogen Pantoea stewartii subsp. stewartii causes leaf blight and Stewart's wilt disease in susceptible corn varieties. A previous RNA-Seq study examined P. stewartii gene expression patterns during late-stage infection in the xylem, and a Tn-Seq study using a P. stewartii mutant library revealed genes essential for colonization of the xylem. Based on these findings, strains with in-frame chromosomal deletions in the genes encoding seven transcription factors (NsrR, IscR, Nac, Lrp, DSJ_00125, DSJ_03645, and DSJ_18135) and one hypothetical protein (DSJ_21690) were constructed to further evaluate the role of the encoded gene products during in vitro and in planta growth. Assays for capsule production and motility indicate that Lrp plays a role in regulating these two key physiological outputs in vitro. Single infections of each deletion strain into the xylem of corn seedlings determined that Lrp plays a significant role in P. stewartii virulence. In planta xylem competition assays between co-inoculated deletion and the corresponding complementation or wild-type strains as well as in vitro growth curves determined that Lrp controls functions important for P. stewartii colonization and growth in corn plants, whereas IscR may have a more generalized impact on growth. Defining the role of essential transcription factors, such as Lrp, during in planta growth will enable modeling of key components of the P. stewartii regulatory network utilized during growth in corn plants.
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Affiliation(s)
| | - Guadalupe Reynoso
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Brandi J. Thomas
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Chase M. Mullins
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Chastyn Smith
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Irene N. Gentzel
- Department of Horticulture & Crop Science, The Ohio State University, Columbus, OH, United States
| | - Laura A. Giese
- Department of Horticulture & Crop Science, The Ohio State University, Columbus, OH, United States
| | - David Mackey
- Department of Horticulture & Crop Science, The Ohio State University, Columbus, OH, United States
- Department of Molecular Genetics and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
| | - Ann M. Stevens
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Center for Emerging, Zoonotic and Arthropod-Borne Pathogens, Virginia Tech, Blacksburg, VA, United States
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Miyakoshi M, Okayama H, Lejars M, Kanda T, Tanaka Y, Itaya K, Okuno M, Itoh T, Iwai N, Wachi M. Mining RNA-seq data reveals the massive regulon of GcvB small RNA and its physiological significance in maintaining amino acid homeostasis in Escherichia coli. Mol Microbiol 2022; 117:160-178. [PMID: 34543491 PMCID: PMC9299463 DOI: 10.1111/mmi.14814] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 11/30/2022]
Abstract
Bacterial small RNAs regulate the expression of multiple genes through imperfect base-pairing with target mRNAs mediated by RNA chaperone proteins such as Hfq. GcvB is the master sRNA regulator of amino acid metabolism and transport in a wide range of Gram-negative bacteria. Recently, independent RNA-seq approaches identified a plethora of transcripts interacting with GcvB in Escherichia coli. In this study, the compilation of RIL-seq, CLASH, and MAPS data sets allowed us to identify GcvB targets with high accuracy. We validated 21 new GcvB targets repressed at the posttranscriptional level, raising the number of direct targets to >50 genes in E. coli. Among its multiple seed sequences, GcvB utilizes either R1 or R3 to regulate most of these targets. Furthermore, we demonstrated that both R1 and R3 seed sequences are required to fully repress the expression of gdhA, cstA, and sucC genes. In contrast, the ilvLXGMEDA polycistronic mRNA is targeted by GcvB through at least four individual binding sites in the mRNA. Finally, we revealed that GcvB is involved in the susceptibility of peptidase-deficient E. coli strain (Δpeps) to Ala-Gln dipeptide by regulating both Dpp dipeptide importer and YdeE dipeptide exporter via R1 and R3 seed sequences, respectively.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Biomedical ScienceFaculty of MedicineUniversity of TsukubaTsukubaJapan
| | - Haruna Okayama
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Maxence Lejars
- Department of Biomedical ScienceFaculty of MedicineUniversity of TsukubaTsukubaJapan
| | - Takeshi Kanda
- Department of Biomedical ScienceFaculty of MedicineUniversity of TsukubaTsukubaJapan
| | - Yuki Tanaka
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Kaori Itaya
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Miki Okuno
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
- Present address:
School of MedicineKurume UniversityKurumeJapan
| | - Takehiko Itoh
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Noritaka Iwai
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Masaaki Wachi
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
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Bessaiah H, Anamalé C, Sung J, Dozois CM. What Flips the Switch? Signals and Stress Regulating Extraintestinal Pathogenic Escherichia coli Type 1 Fimbriae (Pili). Microorganisms 2021; 10:5. [PMID: 35056454 PMCID: PMC8777976 DOI: 10.3390/microorganisms10010005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/18/2022] Open
Abstract
Pathogens are exposed to a multitude of harmful conditions imposed by the environment of the host. Bacterial responses against these stresses are pivotal for successful host colonization and pathogenesis. In the case of many E. coli strains, type 1 fimbriae (pili) are an important colonization factor that can contribute to diseases such as urinary tract infections and neonatal meningitis. Production of type 1 fimbriae in E. coli is dependent on an invertible promoter element, fimS, which serves as a phase variation switch determining whether or not a bacterial cell will produce type 1 fimbriae. In this review, we present aspects of signaling and stress involved in mediating regulation of type 1 fimbriae in extraintestinal E. coli; in particular, how certain regulatory mechanisms, some of which are linked to stress response, can influence production of fimbriae and influence bacterial colonization and infection. We suggest that regulation of type 1 fimbriae is potentially linked to environmental stress responses, providing a perspective for how environmental cues in the host and bacterial stress response during infection both play an important role in regulating extraintestinal pathogenic E. coli colonization and virulence.
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Affiliation(s)
- Hicham Bessaiah
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Carole Anamalé
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
| | - Jacqueline Sung
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Charles M. Dozois
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
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30
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Shimizu K, Matsuoka Y. Feedback regulation and coordination of the main metabolism for bacterial growth and metabolic engineering for amino acid fermentation. Biotechnol Adv 2021; 55:107887. [PMID: 34921951 DOI: 10.1016/j.biotechadv.2021.107887] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/05/2021] [Accepted: 12/09/2021] [Indexed: 12/28/2022]
Abstract
Living organisms such as bacteria are often exposed to continuous changes in the nutrient availability in nature. Therefore, bacteria must constantly monitor the environmental condition, and adjust the metabolism quickly adapting to the change in the growth condition. For this, bacteria must orchestrate (coordinate and integrate) the complex and dynamically changing information on the environmental condition. In particular, the central carbon metabolism (CCM), monomer synthesis, and macromolecular synthesis must be coordinately regulated for the efficient growth. It is a grand challenge in bioscience, biotechnology, and synthetic biology to understand how living organisms coordinate the metabolic regulation systems. Here, we consider the integrated sensing of carbon sources by the phosphotransferase system (PTS), and the feed-forward/feedback regulation systems incorporated in the CCM in relation to the pool sizes of flux-sensing metabolites and αketoacids. We also consider the metabolic regulation of amino acid biosynthesis (as well as purine and pyrimidine biosyntheses) paying attention to the feedback control systems consisting of (fast) enzyme level regulation with (slow) transcriptional regulation. The metabolic engineering for the efficient amino acid production by bacteria such as Escherichia coli and Corynebacterium glutamicum is also discussed (in relation to the regulation mechanisms). The amino acid synthesis is important for determining the rate of ribosome biosynthesis. Thus, the growth rate control (growth law) is further discussed on the relationship between (p)ppGpp level and the ribosomal protein synthesis.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Department of Fisheries Distribution and Management, National Fisheries University, Shimonoseki, Yamaguchi 759-6595, Japan
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31
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Modrzejewska M, Kawalek A, Bartosik AA. The Lrp/AsnC-Type Regulator PA2577 Controls the EamA-like Transporter Gene PA2576 in Pseudomonas aeruginosa. Int J Mol Sci 2021; 22:13340. [PMID: 34948137 PMCID: PMC8707732 DOI: 10.3390/ijms222413340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/04/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
The regulatory network of gene expression in Pseudomonas aeruginosa, an opportunistic human pathogen, is very complex. In the PAO1 reference strain, about 10% of genes encode transcriptional regulators, many of which have undefined regulons and unknown functions. The aim of this study is the characterization of PA2577 protein, a representative of the Lrp/AsnC family of transcriptional regulators. This family encompasses proteins involved in the amino acid metabolism, regulation of transport processes or cell morphogenesis. The transcriptome profiling of P. aeruginosa cells with mild PA2577 overproduction revealed a decreased expression of the PA2576 gene oriented divergently to PA2577 and encoding an EamA-like transporter. A gene expression analysis showed a higher mRNA level of PA2576 in P. aeruginosa ΔPA2577, indicating that PA2577 acts as a repressor. Concomitantly, ChIP-seq and EMSA assays confirmed strong interactions of PA2577 with the PA2577/PA2576 intergenic region. Additionally, phenotype microarray analyses indicated an impaired metabolism of ΔPA2576 and ΔPA2577 mutants in the presence of polymyxin B, which suggests disturbances of membrane functions in these mutants. We show that PA2576 interacts with two proteins, PA5006 and PA3694, with a predicted role in lipopolysaccharide (LPS) and membrane biogenesis. Overall, our results indicate that PA2577 acts as a repressor of the PA2576 gene coding for the EamA-like transporter and may play a role in the modulation of the cellular response to stress conditions, including antimicrobial peptides, e.g., polymyxin B.
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Affiliation(s)
| | | | - Aneta Agnieszka Bartosik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.M.); (A.K.)
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32
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Holden ER, Yasir M, Turner AK, Wain J, Charles IG, Webber MA. Massively parallel transposon mutagenesis identifies temporally essential genes for biofilm formation in Escherichia coli. Microb Genom 2021; 7. [PMID: 34783647 PMCID: PMC8743551 DOI: 10.1099/mgen.0.000673] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Biofilms complete a life cycle where cells aggregate, grow and produce a structured community before dispersing to colonize new environments. Progression through this life cycle requires temporally controlled gene expression to maximize fitness at each stage. Previous studies have largely focused on identifying genes essential for the formation of a mature biofilm; here, we present an insight into the genes involved at different stages of biofilm formation. We used TraDIS-Xpress, a massively parallel transposon mutagenesis approach using transposon-located promoters to assay the impact of disruption or altered expression of all genes in the genome on biofilm formation. We identified 48 genes that affected the fitness of cells growing in a biofilm, including genes with known roles and those not previously implicated in biofilm formation. Regulation of type 1 fimbriae and motility were important at all time points, adhesion and motility were important for the early biofilm, whereas matrix production and purine biosynthesis were only important as the biofilm matured. We found strong temporal contributions to biofilm fitness for some genes, including some where expression changed between being beneficial or detrimental depending on the stage at which they are expressed, including dksA and dsbA. Novel genes implicated in biofilm formation included zapE and truA involved in cell division, maoP in chromosome organization, and yigZ and ykgJ of unknown function. This work provides new insights into the requirements for successful biofilm formation through the biofilm life cycle and demonstrates the importance of understanding expression and fitness through time.
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Affiliation(s)
- Emma R Holden
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - Muhammad Yasir
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - A Keith Turner
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK
| | - John Wain
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Ian G Charles
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ, UK.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
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33
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Leucine-Responsive Regulatory Protein in Acetic Acid Bacteria Is Stable and Functions at a Wide Range of Intracellular pH Levels. J Bacteriol 2021; 203:e0016221. [PMID: 34228496 DOI: 10.1128/jb.00162-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetic acid bacteria grow while producing acetic acid, resulting in acidification of the culture. Limited reports elucidate the effect of changes in intracellular pH on transcriptional factors. In the present study, the intracellular pH of Komagataeibacter europaeus was monitored with a pH-sensitive green fluorescent protein, showing that the intracellular pH decreased from 6.3 to 4.7 accompanied by acetic acid production during cell growth. The leucine-responsive regulatory protein of K. europaeus (KeLrp) was used as a model to examine pH-dependent effects, and its properties were compared with those of the Escherichia coli ortholog (EcLrp) at different pH levels. The DNA-binding activities of EcLrp and KeLrp with the target DNA (Ec-ilvI and Ke-ilvI) were examined by gel mobility shift assays under various pH conditions. EcLrp showed the highest affinity with the target at pH 8.0 (Kd [dissociation constant], 0.7 μM), decreasing to a minimum of 3.4 μM at pH 4.0. Conversely, KeLrp did not show significant differences in binding affinity between pH 4 and 7 (Kd, 1.0 to 1.5 μM), and the highest affinity was at pH 5.0 (Kd, 1.0 μM). Circular dichroism spectroscopy revealed that the α-helical content of KeLrp was the highest at pH 5.0 (49%) and was almost unchanged while being maintained at >45% over a range of pH levels examined, while that of EcLrp decreased from its maximum (49% at pH 7.0) to its minimum (36% at pH 4.0). These data indicate that KeLrp is stable and functions over a wide range of intracellular pH levels. IMPORTANCE Lrp is a highly conserved transcriptional regulator found in bacteria and archaea and regulates transcriptions of various genes. The intracellular pH of acetic acid bacteria (AAB) changes accompanied by acetic acid production during cell growth. The Lrp of AAB K. europaeus (KeLrp) was structurally stable over a wide range of pH and maintained DNA-binding activity even at low pH compared with Lrp from E. coli living in a neutral environment. An in vitro experiment showed DNA-binding activity of KeLrp to the target varied with changes in pH. In AAB, change of the intracellular pH during a cell growth would be an important trigger in controlling the activity of Lrp in vivo.
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34
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Keseler IM, Gama-Castro S, Mackie A, Billington R, Bonavides-Martínez C, Caspi R, Kothari A, Krummenacker M, Midford PE, Muñiz-Rascado L, Ong WK, Paley S, Santos-Zavaleta A, Subhraveti P, Tierrafría VH, Wolfe AJ, Collado-Vides J, Paulsen IT, Karp PD. The EcoCyc Database in 2021. Front Microbiol 2021; 12:711077. [PMID: 34394059 PMCID: PMC8357350 DOI: 10.3389/fmicb.2021.711077] [Citation(s) in RCA: 128] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
The EcoCyc model-organism database collects and summarizes experimental data for Escherichia coli K-12. EcoCyc is regularly updated by the manual curation of individual database entries, such as genes, proteins, and metabolic pathways, and by the programmatic addition of results from select high-throughput analyses. Updates to the Pathway Tools software that supports EcoCyc and to the web interface that enables user access have continuously improved its usability and expanded its functionality. This article highlights recent improvements to the curated data in the areas of metabolism, transport, DNA repair, and regulation of gene expression. New and revised data analysis and visualization tools include an interactive metabolic network explorer, a circular genome viewer, and various improvements to the speed and usability of existing tools.
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Affiliation(s)
- Ingrid M. Keseler
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Socorro Gama-Castro
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Amanda Mackie
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Richard Billington
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | | | - Ron Caspi
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Anamika Kothari
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Markus Krummenacker
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Peter E. Midford
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Luis Muñiz-Rascado
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Wai Kit Ong
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Suzanne Paley
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Alberto Santos-Zavaleta
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Temixco, México
| | - Pallavi Subhraveti
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
| | - Víctor H. Tierrafría
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Alan J. Wolfe
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
| | - Julio Collado-Vides
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Ian T. Paulsen
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Peter D. Karp
- Bioinformatics Research Group, Artificial Intelligence Center, SRI International, Menlo Park, CA, United States
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35
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Freddolino PL, Amemiya HM, Goss TJ, Tavazoie S. Dynamic landscape of protein occupancy across the Escherichia coli chromosome. PLoS Biol 2021; 19:e3001306. [PMID: 34170902 PMCID: PMC8282354 DOI: 10.1371/journal.pbio.3001306] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 07/15/2021] [Accepted: 06/02/2021] [Indexed: 12/18/2022] Open
Abstract
Free-living bacteria adapt to environmental change by reprogramming gene expression through precise interactions of hundreds of DNA-binding proteins. A predictive understanding of bacterial physiology requires us to globally monitor all such protein-DNA interactions across a range of environmental and genetic perturbations. Here, we show that such global observations are possible using an optimized version of in vivo protein occupancy display technology (in vivo protein occupancy display-high resolution, IPOD-HR) and present a pilot application to Escherichia coli. We observe that the E. coli protein-DNA interactome organizes into 2 distinct prototypic features: (1) highly dynamic condition-dependent transcription factor (TF) occupancy; and (2) robust kilobase scale occupancy by nucleoid factors, forming silencing domains analogous to eukaryotic heterochromatin. We show that occupancy dynamics across a range of conditions can rapidly reveal the global transcriptional regulatory organization of a bacterium. Beyond discovery of previously hidden regulatory logic, we show that these observations can be utilized to computationally determine sequence specificity models for the majority of active TFs. Our study demonstrates that global observations of protein occupancy combined with statistical inference can rapidly and systematically reveal the transcriptional regulatory and structural features of a bacterial genome. This capacity is particularly crucial for non-model bacteria that are not amenable to routine genetic manipulation.
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Affiliation(s)
- Peter L. Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Haley M. Amemiya
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Thomas J. Goss
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Saeed Tavazoie
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
- Department of Systems Biology, Columbia University, New York, New York, United States of America
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
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36
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Schubert C, Winter M, Ebert‐Jung A, Kierszniowska S, Nagel‐Wolfrum K, Schramm T, Link H, Winter S, Unden G. C4
‐dicarboxylates and
l
‐aspartate utilization by
Escherichia coli
K‐12 in the mouse intestine:
l
‐aspartate as a major substrate for fumarate respiration and as a nitrogen source. Environ Microbiol 2021; 23:2564-2577. [DOI: 10.1111/1462-2920.15478] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher Schubert
- Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Mainz 55099 Germany
| | - Maria Winter
- Department of Microbiology UT Southwestern Medical Center Dallas TX 75287 USA
| | - Andrea Ebert‐Jung
- Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Mainz 55099 Germany
| | | | - Kerstin Nagel‐Wolfrum
- Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Mainz 55099 Germany
| | - Thorben Schramm
- Max Planck Institute for Terrestrial Microbiology Karl‐von‐Frisch‐Straße 10 Marburg 35043 Germany
| | - Hannes Link
- Max Planck Institute for Terrestrial Microbiology Karl‐von‐Frisch‐Straße 10 Marburg 35043 Germany
| | - Sebastian Winter
- Department of Microbiology UT Southwestern Medical Center Dallas TX 75287 USA
| | - Gottfried Unden
- Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Mainz 55099 Germany
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37
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Faucher C, Mazana V, Kardacz M, Parthuisot N, Ferdy JB, Duneau D. Step-Specific Adaptation and Trade-Off over the Course of an Infection by GASP Mutation Small Colony Variants. mBio 2021; 12:e01399-20. [PMID: 33436427 PMCID: PMC7845629 DOI: 10.1128/mbio.01399-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/17/2020] [Indexed: 11/20/2022] Open
Abstract
During an infection, parasites face a succession of challenges, each decisive for disease outcome. The diversity of challenges requires a series of parasite adaptations to successfully multiply and transmit from host to host. Thus, the pathogen genotypes that succeed during one step might be counterselected in later stages of the infection. Using the bacterium Xenorhabdus nematophila and adult Drosophila melanogaster flies as hosts, we showed that such step-specific adaptations, here linked to GASP (i.e., growth advantage in stationary phase) mutations in the X. nematophila master gene regulator lrp, exist and can trade off with each other. We found that nonsense lrp mutations had lowered the ability to resist the host immune response, while all classes of mutations in lrp were associated with a decrease in the ability to proliferate during early infection. We demonstrate that reduced proliferation of X. nematophila best explains diminished virulence in this infection model. Finally, decreased proliferation during the first step of infection is accompanied by improved proliferation during late infection, suggesting a trade-off between the adaptations to each step. Step-specific adaptations could play a crucial role in the chronic phase of infections in any disease organisms that show similar small colony variants (SCVs) to X. nematophilaIMPORTANCE Within-host evolution has been described in many bacterial diseases, and the genetic basis behind the adaptations has stimulated a lot of interest. Yet, the studied adaptations are generally focused on antibiotic resistance and rarely on the adaptation to the environment given by the host, and the potential trade-offs hindering adaptations to each step of the infection are rarely considered. Those trade-offs are key to understanding intrahost evolution and thus the dynamics of the infection. However, understanding these trade-offs supposes a detailed study of host-pathogen interactions at each step of the infection process, with an adapted methodology for each step. Using Drosophila melanogaster as the host and the bacterium Xenorhabdus nematophila, we investigated the bacterial adaptations resulting from GASP mutations known to induce the small colony variant (SCV) phenotype positively selected within the host over the course of an infection, as well as the trade-off between step-specific adaptations.
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Affiliation(s)
- Christian Faucher
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Vincent Mazana
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Marion Kardacz
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Nathalie Parthuisot
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Jean-Baptiste Ferdy
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - David Duneau
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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38
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Mejía-Almonte C, Busby SJW, Wade JT, van Helden J, Arkin AP, Stormo GD, Eilbeck K, Palsson BO, Galagan JE, Collado-Vides J. Redefining fundamental concepts of transcription initiation in bacteria. Nat Rev Genet 2020; 21:699-714. [PMID: 32665585 PMCID: PMC7990032 DOI: 10.1038/s41576-020-0254-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2020] [Indexed: 12/15/2022]
Abstract
Despite enormous progress in understanding the fundamentals of bacterial gene regulation, our knowledge remains limited when compared with the number of bacterial genomes and regulatory systems to be discovered. Derived from a small number of initial studies, classic definitions for concepts of gene regulation have evolved as the number of characterized promoters has increased. Together with discoveries made using new technologies, this knowledge has led to revised generalizations and principles. In this Expert Recommendation, we suggest precise, updated definitions that support a logical, consistent conceptual framework of bacterial gene regulation, focusing on transcription initiation. The resulting concepts can be formalized by ontologies for computational modelling, laying the foundation for improved bioinformatics tools, knowledge-based resources and scientific communication. Thus, this work will help researchers construct better predictive models, with different formalisms, that will be useful in engineering, synthetic biology, microbiology and genetics.
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Affiliation(s)
- Citlalli Mejía-Almonte
- Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Morelos, Cuernavaca, México
| | | | - Joseph T Wade
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Jacques van Helden
- Aix-Marseille University, INSERM UMR S 1090, Theory and Approaches of Genome Complexity (TAGC), Marseille, France
- CNRS, Institut Français de Bioinformatique, IFB-core, UMS 3601, Evry, France
| | - Adam P Arkin
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Gary D Stormo
- Department of Genetics, Washington University School of Medicine, St Louis, MO, USA
| | - Karen Eilbeck
- Department of Biomedical Informatics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - James E Galagan
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Julio Collado-Vides
- Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Morelos, Cuernavaca, México.
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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39
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Zamora M, Ziegler CA, Freddolino PL, Wolfe AJ. A Thermosensitive, Phase-Variable Epigenetic Switch: pap Revisited. Microbiol Mol Biol Rev 2020; 84:e00030-17. [PMID: 32727743 PMCID: PMC7392537 DOI: 10.1128/mmbr.00030-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It has been more than a decade since the last comprehensive review of the phase-variable uropathogen-associated pyelonephritis-associated pilus (pap) genetic switch. Since then, important data have come to light, including additional factors that regulate pap expression, better characterization of H-NS regulation, the structure of the Lrp octamer in complex with pap regulatory DNA, the temperature-insensitive phenotype of a mutant lacking the acetyltransferase RimJ, evidence that key components of the regulatory machinery are acetylated, and new insights into the role of DNA binding by key regulators in shaping both the physical structure and regulatory state of the papI and papBA promoters. This review revisits pap, integrating these newer observations with older ones to produce a new model for the concerted behavior of this virulence-regulatory region.
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Affiliation(s)
- Mario Zamora
- Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alan J Wolfe
- Department of Microbiology and Immunology, Stritch School of Medicine, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
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40
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Zulkower V, Rosser S. DNA Features Viewer: a sequence annotation formatting and plotting library for Python. BIOINFORMATICS (OXFORD, ENGLAND) 2020; 36:4350-4352. [PMID: 32637988 DOI: 10.1101/2020.01.09.900589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/15/2020] [Accepted: 07/01/2020] [Indexed: 05/19/2023]
Abstract
MOTIVATION Although the Python programming language counts many Bioinformatics and Computational Biology libraries; none offers customizable sequence annotation visualizations with layout optimization. RESULTS DNA Features Viewer is a sequence annotation plotting library which optimizes plot readability while letting users tailor other visual aspects (colors, labels, highlights etc.) to their particular use case. AVAILABILITY AND IMPLEMENTATION Open-source code and documentation are available on Github under the MIT license (https://github.com/Edinburgh-Genome-Foundry/DnaFeaturesViewer). SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Valentin Zulkower
- Edinburgh Genome Foundry, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Susan Rosser
- Edinburgh Genome Foundry, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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41
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Zulkower V, Rosser S. DNA Features Viewer: a sequence annotation formatting and plotting library for Python. Bioinformatics 2020; 36:4350-4352. [PMID: 32637988 DOI: 10.1093/bioinformatics/btaa213] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/15/2020] [Accepted: 07/01/2020] [Indexed: 01/09/2023] Open
Abstract
MOTIVATION Although the Python programming language counts many Bioinformatics and Computational Biology libraries; none offers customizable sequence annotation visualizations with layout optimization. RESULTS DNA Features Viewer is a sequence annotation plotting library which optimizes plot readability while letting users tailor other visual aspects (colors, labels, highlights etc.) to their particular use case. AVAILABILITY AND IMPLEMENTATION Open-source code and documentation are available on Github under the MIT license (https://github.com/Edinburgh-Genome-Foundry/DnaFeaturesViewer). SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Valentin Zulkower
- Edinburgh Genome Foundry, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Susan Rosser
- Edinburgh Genome Foundry, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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42
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Specific Eco-evolutionary Contexts in the Mouse Gut Reveal Escherichia coli Metabolic Versatility. Curr Biol 2020; 30:1049-1062.e7. [PMID: 32142697 DOI: 10.1016/j.cub.2020.01.050] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/21/2019] [Accepted: 01/15/2020] [Indexed: 02/08/2023]
Abstract
Members of the gut microbiota are thought to experience strong competition for nutrients. However, how such competition shapes their evolutionary dynamics and depends on intra- and interspecies interactions is poorly understood. Here, we test the hypothesis that Escherichia coli evolution in the mouse gut is more predictable across hosts in the absence of interspecies competition than in the presence of other microbial species. In support, we observed that lrp, a gene encoding a global regulator of amino acid metabolism, was repeatedly selected in germ-free mice 2 weeks after mono-colonization by this bacterium. We established that this specific genetic adaptation increased E. coli's ability to compete for amino acids, and analysis of gut metabolites identified serine and threonine as the metabolites preferentially consumed by E. coli in the mono-colonized mouse gut. Preference for serine consumption was further supported by testing a set of mutants that showed loss of advantage of an lrp mutant impaired in serine metabolism in vitro and in vivo. Remarkably, the presence of a single additional member of the microbiota, Blautia coccoides, was sufficient to alter the gut metabolome and, consequently, the evolutionary path of E. coli. In this environment, the fitness advantage of the lrp mutant bacteria is lost, and mutations in genes involved in anaerobic respiration were selected instead, recapitulating the eco-evolutionary context from mice with a complex microbiota. Together, these results highlight the metabolic plasticity and evolutionary versatility of E. coli, tailored to the specific ecology it experiences in the gut.
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43
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Effect of restricted dissolved oxygen on expression of Clostridium difficile toxin A subunit from E. coli. Sci Rep 2020; 10:3059. [PMID: 32080292 PMCID: PMC7033237 DOI: 10.1038/s41598-020-59978-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/06/2020] [Indexed: 12/11/2022] Open
Abstract
The repeating unit of the C. difficile Toxin A (rARU, also known as CROPS [combined repetitive oligopeptides]) C-terminal region, was shown to elicit protective immunity against C. difficile and is under consideration as a possible vaccine against this pathogen. However, expression of recombinant rARU in E. coli using the standard vaccine production process was very low. Transcriptome and proteome analyses showed that at restricted dissolved oxygen (DO) the numbers of differentially expressed genes (DEGs) was 2.5-times lower than those expressed at unrestricted oxygen. Additionally, a 7.4-times smaller number of ribosome formation genes (needed for translation) were down-regulated as compared with unrestricted DO. Higher rARU expression at restricted DO was associated with up-regulation of 24 heat shock chaperones involved in protein folding and with the up-regulation of the global regulator RNA chaperone hfq. Cellular stress response leading to down-regulation of transcription, translation, and energy generating pathways at unrestricted DO were associated with lower rARU expression. Investigation of the C. difficile DNA sequence revealed the presence of cell wall binding profiles, which based on structural similarity prediction by BLASTp, can possibly interact with cellular proteins of E. coli such as the transcriptional repressor ulaR, and the ankyrins repeat proteins. At restricted DO, rARU mRNA was 5-fold higher and the protein expression 27-fold higher compared with unrestricted DO. The report shows a strategy for improved production of C. difficile vaccine candidate in E. coli by using restricted DO growth. This strategy could improve the expression of recombinant proteins from anaerobic origin or those with cell wall binding profiles.
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44
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Chen KY, Rathod J, Chiu YC, Chen JW, Tsai PJ, Huang IH. The Transcriptional Regulator Lrp Contributes to Toxin Expression, Sporulation, and Swimming Motility in Clostridium difficile. Front Cell Infect Microbiol 2019; 9:356. [PMID: 31681632 PMCID: PMC6811523 DOI: 10.3389/fcimb.2019.00356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/02/2019] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile is a Gram-positive, spore-forming bacterium, and major cause of nosocomial diarrhea. Related studies have identified numerous factors that influence virulence traits such as the production of the two primary toxins, toxin A (TcdA) and toxin B (TcdB), as well as sporulation, motility, and biofilm formation. However, multiple putative transcriptional regulators are reportedly encoded in the genome, and additional factors are likely involved in virulence regulation. Although the leucine-responsive regulatory protein (Lrp) has been studied extensively in Gram-negative bacteria, little is known about its function in Gram-positive bacteria, although homologs have been identified in the genome. This study revealed that disruption of the lone lrp homolog in C. difficile decelerated growth under nutrient-limiting conditions, increased TcdA and TcdB production. Lrp was also found to negatively regulate sporulation while positively regulate swimming motility in strain R20291, but not in strain 630. The C. difficile Lrp appeared to function through transcriptional repression or activation. In addition, the lrp mutant was relatively virulent in a mouse model of infection. The results of this study collectively demonstrated that Lrp has broad regulatory function in C. difficile toxin expression, sporulation, motility, and pathogenesis.
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Affiliation(s)
- Kuan-Yu Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jagat Rathod
- Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ching Chiu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Jane Tsai
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.,Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - I-Hsiu Huang
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
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45
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Shen BA, Landick R. Transcription of Bacterial Chromatin. J Mol Biol 2019; 431:4040-4066. [PMID: 31153903 PMCID: PMC7248592 DOI: 10.1016/j.jmb.2019.05.041] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
Abstract
Decades of research have probed the interplay between chromatin (genomic DNA associated with proteins and RNAs) and transcription by RNA polymerase (RNAP) in all domains of life. In bacteria, chromatin is compacted into a membrane-free region known as the nucleoid that changes shape and composition depending on the bacterial state. Transcription plays a key role in both shaping the nucleoid and organizing it into domains. At the same time, chromatin impacts transcription by at least five distinct mechanisms: (i) occlusion of RNAP binding; (ii) roadblocking RNAP progression; (iii) constraining DNA topology; (iv) RNA-mediated interactions; and (v) macromolecular demixing and heterogeneity, which may generate phase-separated condensates. These mechanisms are not mutually exclusive and, in combination, mediate gene regulation. Here, we review the current understanding of these mechanisms with a focus on gene silencing by H-NS, transcription coordination by HU, and potential phase separation by Dps. The myriad questions about transcription of bacterial chromatin are increasingly answerable due to methodological advances, enabling a needed paradigm shift in the field of bacterial transcription to focus on regulation of genes in their native state. We can anticipate answers that will define how bacterial chromatin helps coordinate and dynamically regulate gene expression in changing environments.
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Affiliation(s)
- Beth A Shen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, United States.
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46
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The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora. mBio 2019; 10:mBio.00757-19. [PMID: 31138749 PMCID: PMC6538786 DOI: 10.1128/mbio.00757-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Fire blight disease continues to plague the commercial production of apples and pears despite more than a century of research into disease epidemiology and disease control. The causative agent of fire blight, Erwinia amylovora coordinates turning on or off specific virulence-associated traits at the appropriate time during disease development. The development of novel control strategies requires an in-depth understanding of E. amylovora regulatory mechanisms, including regulatory control of virulence-associated traits. This study investigates how the small RNA ArcZ regulates motility at the transcriptional level and identifies the transcription factor Lrp as a novel participant in the regulation of several virulence-associated traits. We report that ArcZ and Lrp together affect key virulence-associated traits through integration of transcriptional and posttranscriptional mechanisms. Further understanding of the topology of virulence regulatory networks can uncover weak points that can subsequently be exploited to control E. amylovora. Erwinia amylovora causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Growing evidence indicates that small RNAs (sRNAs) play an important role in disease progression as posttranscriptional regulators. The sRNA ArcZ positively regulates the motility phenotype and transcription of flagellar genes in E. amylovora Ea1189 yet is a direct repressor of translation of the flagellar master regulator, FlhD. We utilized transposon mutagenesis to conduct a forward genetic screen and identified suppressor mutations that increase motility in the Ea1189ΔarcZ mutant background. This enabled us to determine that the mechanism of transcriptional activation of the flhDC mRNA by ArcZ is mediated by the leucine-responsive regulatory protein, Lrp. We show that Lrp contributes to expression of virulence and several virulence-associated traits, including production of the exopolysaccharide amylovoran, levansucrase activity, and biofilm formation. We further show that Lrp is regulated posttranscriptionally by ArcZ through destabilization of lrp mRNA. Thus, ArcZ regulation of FlhDC directly and indirectly through Lrp forms an incoherent feed-forward loop that regulates levansucrase activity and motility as outputs. This work identifies Lrp as a novel participant in virulence regulation in E. amylovora and places it in the context of a virulence-associated regulatory network.
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47
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Scholz SA, Diao R, Wolfe MB, Fivenson EM, Lin XN, Freddolino PL. High-Resolution Mapping of the Escherichia coli Chromosome Reveals Positions of High and Low Transcription. Cell Syst 2019; 8:212-225.e9. [PMID: 30904377 DOI: 10.1016/j.cels.2019.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/19/2018] [Accepted: 02/11/2019] [Indexed: 01/28/2023]
Abstract
Recent studies on targeted gene integrations in bacteria have demonstrated that chromosomal location can substantially affect a gene's expression level. However, these studies have only provided information on a small number of sites. To measure position effects on transcriptional propensity at high resolution across the genome, we built and analyzed a library of over 144,000 genome-integrated, standardized reporters in a single mixed population of Escherichia coli. We observed more than 20-fold variations in transcriptional propensity across the genome when the length of the chromosome was binned into broad 4 kbp regions; greater variability was observed over smaller regions. Our data reveal peaks of high transcriptional propensity centered on ribosomal RNA operons and core metabolic genes, while prophages and mobile genetic elements were enriched in less transcribable regions. In total, our work supports the hypothesis that E. coli has evolved gene-independent mechanisms for regulating expression from specific regions of its genome.
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Affiliation(s)
- Scott A Scholz
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48103, USA
| | - Rucheng Diao
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA
| | - Michael B Wolfe
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48103, USA
| | - Elayne M Fivenson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48103, USA
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48103, USA.
| | - Peter L Freddolino
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48103, USA.
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