1
|
Li Z, Zhu Y, Zhang W, Mu W. Rcs signal transduction system in Escherichia coli: Composition, related functions, regulatory mechanism, and applications. Microbiol Res 2024; 285:127783. [PMID: 38795407 DOI: 10.1016/j.micres.2024.127783] [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: 03/19/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
The regulator of capsule synthesis (Rcs) system, an atypical two-component system prevalent in numerous gram-negative bacteria, serves as a sophisticated regulatory phosphorylation cascade mechanism. It plays a pivotal role in perceiving environmental stress and regulating the expression of downstream genes to ensure host survival. During the signaling transduction process, various proteins participate in phosphorylation to further modulate signal inputs and outputs. Although the structure of core proteins related to the Rcs system has been partially well-defined, and two models have been proposed to elucidate the intricate molecular mechanisms underlying signal sensing, a systematic characterization of the signal transduction process of the Rcs system remains challenging. Furthermore, exploring its corresponding regulator outputs is also unremitting. This review aimed to shed light on the regulation of bacterial virulence by the Rcs system. Moreover, with the assistance of the Rcs system, biosynthesis technology has developed high-value target production. Additionally, via this review, we propose designing chimeric Rcs biosensor systems to expand their application as synthesis tools. Finally, unsolved challenges are highlighted to provide the basic direction for future development of the Rcs system.
Collapse
Affiliation(s)
- Zeyu Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China.
| |
Collapse
|
2
|
Wan Y, Wai Chi Chan E, Chen S. Maintenance and generation of proton motive force are both essential for expression of phenotypic antibiotic tolerance in bacteria. Microbiol Spectr 2023; 11:e0083223. [PMID: 37623371 PMCID: PMC10580908 DOI: 10.1128/spectrum.00832-23] [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: 02/25/2023] [Accepted: 07/11/2023] [Indexed: 08/26/2023] Open
Abstract
Bacterial antibiotic tolerance, a phenomenon first observed in 1944, is known to be responsible for both onset and exacerbation of recurrent and chronic bacterial infections. The development of antibiotic tolerance was previously thought to be due to a switch to physiological dormancy when bacteria encounter adverse growth conditions. Our recent laboratory findings, however, showed that a set of genes related to the maintenance of proton motive force (PMF) are up-regulated under starvation, indicating that the tolerant sub-population, which are commonly known as persisters, can actively maintain their tolerance phenotypes. In this study, we investigated the relative functional roles of proteins involved in the maintenance and active generation of PMF in mediating tolerance formation in bacteria and found that the PspA and RcsB proteins play a key role in PMF maintenance in persisters, as deletion of genes encoding these two proteins resulted in significantly lower tolerance levels. Consistently, expression of the OsmC and Bdm proteins, which is under regulation by RcsB, is required to maintain PMF and the antibiotic tolerance phenotypes. On the other hand, the NuoL, Ndh, AppC, CyoB, and NuoF proteins, which are electron transport chain (ETC) components, were also found to be actively expressed in persisters in order to generate PMF to support functioning of various tolerance mechanisms such as efflux activities. Our data show that active generation of PMF is even more important than the PMF maintenance functions of PspA and RcsB in the expression of antibiotic tolerance phenotypes in persisters. Assessment of double- and triple-gene knockout strains, in which the PMF maintenance genes and those encoding ETC components were simultaneously deleted, confirms that these two groups of genes are both required for the expression of antibiotic tolerance phenotypes and that a lack of these functions would result in complete PMF dissipation and accumulation of antibiotics in the intracellular compartment of persisters and eventually cell death. Products of these genes are, therefore, ideal targets for future development of anti-tolerance agents. IMPORTANCE In this work, bacteria were found to undergo active generation and maintenance of proton motive force (PMF) under adverse conditions, such as starvation so as to support a range of physiological functions in order to survive under such conditions for a prolonged period. The ability to maintain a substantial level of PMF was found to be directly linked to that exhibiting phenotypic antibiotic tolerance under nutrient starvation or other adverse conditions. These findings infer that bacteria do not simply become physiologically dormant when they become antibiotic tolerant, instead they need to produce a wide range of proteins including those which help prevent PMF dissipation, such as PspA and RcsB, and the electron transport chain components, such as NuoL and Ndh, that actively generate PMF even during long-term starvation. As antibiotic tolerant sub-population is known to play a role in eliciting recurrent and chronic infections, especially among patients with a weakened immune system, the PMF maintenance mechanisms identified in this work are potential targets for the development of new strategies to control recurrent and chronic infections.
Collapse
Affiliation(s)
- Yingkun Wan
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Edward Wai Chi Chan
- Department of Applied Biology and Chemical Technology, State Key Lab of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Sheng Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
- Department of Applied Biology and Chemical Technology, State Key Lab of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- City University of Hong Kong Chendu Research Institute, Chengdu, China
- Shenzhen Key Lab for Food Biological Safety Control, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, China
| |
Collapse
|
3
|
Bäumler W, Eckl D, Holzmann T, Schneider-Brachert W. Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene. Crit Rev Microbiol 2021; 48:531-564. [PMID: 34699296 DOI: 10.1080/1040841x.2021.1991271] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements.
Collapse
Affiliation(s)
- Wolfgang Bäumler
- Department of Dermatology, University Hospital, Regensburg, Germany
| | - Daniel Eckl
- Department of Microbiology, University of Regensburg, Regensburg, Germany
| | - Thomas Holzmann
- Department of Infection Control and Infectious Diseases, University Hospital, Regensburg, Germany
| | - Wulf Schneider-Brachert
- Department of Infection Control and Infectious Diseases, University Hospital, Regensburg, Germany
| |
Collapse
|
4
|
Differential Cellular Response to Translocated Toxic Effectors and Physical Penetration by the Type VI Secretion System. Cell Rep 2021; 31:107766. [PMID: 32553162 DOI: 10.1016/j.celrep.2020.107766] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 04/28/2020] [Accepted: 05/21/2020] [Indexed: 01/06/2023] Open
Abstract
The type VI secretion system (T6SS) is a lethal microbial weapon that injects a large needle-like structure carrying toxic effectors into recipient cells through physical penetration. How recipients respond to physical force and effectors remains elusive. Here, we use a series of effector mutants of Vibrio cholerae to determine how T6SS elicits response in Pseudomonas aeruginosa and Escherichia coli. We show that TseL, but no other effectors or physical puncture, triggers the tit-for-tat response of P. aeruginosa H1-T6SS. Although E. coli is sensitive to all periplasmically expressed effectors, P. aeruginosa is most sensitive to TseL alone. We identify a number of stress response pathways that confer protection against TseL. Physical puncture of T6SS has a moderate inhibitory effect only on envelope-impaired tolB and rseA mutants. Our data reveal that recipient cells primarily respond to effector toxicity but not to physical contact, and they rely on the stress response for immunity-independent protection.
Collapse
|
5
|
Identification of Z nucleotides as an ancient signal for two-component system activation in bacteria. Proc Natl Acad Sci U S A 2020; 117:33530-33539. [PMID: 33318202 DOI: 10.1073/pnas.2006209117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two-component systems (TCSs) in bacteria are molecular circuits that allow the perception of and response to diverse stimuli. These signaling circuits rely on phosphoryl-group transfers between transmitter and receiver domains of sensor kinase and response regulator proteins, and regulate several cellular processes in response to internal or external cues. Phosphorylation, and thereby activation, of response regulators has been demonstrated to occur by their cognate histidine kinases but also by low molecular weight phosphodonors such as acetyl phosphate and carbamoyl phosphate. Here, we present data indicating that the intermediates of the de novo syntheses of purines and histidine, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranosyl 5'-monophosphate (ZMP) and/or 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranosyl 5'-triphosphate (ZTP), activate the response regulator UvrY, by promoting its autophosphorylation at the conserved aspartate at position 54. Moreover, these Z nucleotides are shown to also activate the nonrelated response regulators ArcA, CpxR, RcsB, and PhoQ. We propose that ZMP and/or ZTP act as alarmones for a wide range of response regulators in vivo, providing a novel mechanism by which they could impact gene expression in response to metabolic cues.
Collapse
|
6
|
Kimkes TEP, Heinemann M. How bacteria recognise and respond to surface contact. FEMS Microbiol Rev 2020; 44:106-122. [PMID: 31769807 PMCID: PMC7053574 DOI: 10.1093/femsre/fuz029] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/23/2019] [Indexed: 12/27/2022] Open
Abstract
Bacterial biofilms can cause medical problems and issues in technical systems. While a large body of knowledge exists on the phenotypes of planktonic and of sessile cells in mature biofilms, our understanding of what happens when bacteria change from the planktonic to the sessile state is still very incomplete. Fundamental questions are unanswered: for instance, how do bacteria sense that they are in contact with a surface, and what are the very initial cellular responses to surface contact. Here, we review the current knowledge on the signals that bacteria could perceive once they attach to a surface, the signal transduction systems that could be involved in sensing the surface contact and the cellular responses that are triggered as a consequence to surface contact ultimately leading to biofilm formation. Finally, as the main obstacle in investigating the initial responses to surface contact has been the difficulty to experimentally study the dynamic response of single cells upon surface attachment, we also review recent experimental approaches that could be employed to study bacterial surface sensing, which ultimately could lead to an improved understanding of how biofilm formation could be prevented.
Collapse
Affiliation(s)
- Tom E P Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| |
Collapse
|
7
|
Hersch SJ, Watanabe N, Stietz MS, Manera K, Kamal F, Burkinshaw B, Lam L, Pun A, Li M, Savchenko A, Dong TG. Envelope stress responses defend against type six secretion system attacks independently of immunity proteins. Nat Microbiol 2020; 5:706-714. [PMID: 32094588 PMCID: PMC7190449 DOI: 10.1038/s41564-020-0672-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/16/2020] [Indexed: 11/23/2022]
Abstract
The arms race among microbes is a key driver in the evolution of not only the weapons but also defence mechanisms. Many gram-negative bacteria use the type six secretion system (T6SS) to deliver toxic effectors directly into neighbouring cells. Defence against effectors requires cognate immunity proteins. However, here we show immunity-independent protection mediated by envelope stress responses in Escherichia coli and Vibrio cholerae against a V. cholerae T6SS effector, TseH. We demonstrate that TseH is a PAAR-dependent species-specific effector highly potent against Aeromonas species but not against its V. cholerae immunity mutant or E. coli. Structural analysis reveals TseH is likely a NlpC/P60 family cysteine endopeptidase. We determine that two envelope stress response pathways, Rcs and BaeSR, protect E. coli from TseH toxicity by mechanisms including capsule synthesis. The two-component system WigKR (VxrAB) is critical for protecting V. cholerae from its own T6SS despite expressing immunity genes. WigR also regulates T6SS expression, suggesting a dual role in attack and defence. This deepens our understanding of how bacteria survive T6SS attacks and suggests that defending against the T6SS represents a major selective pressure driving the evolution of species-specific effectors and protective mechanisms mediated by envelope stress responses and capsule synthesis.
Collapse
Affiliation(s)
- Steven J Hersch
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Nobuhiko Watanabe
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Maria Silvina Stietz
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Kevin Manera
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Fatima Kamal
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Brianne Burkinshaw
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Linh Lam
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Alexander Pun
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Meixin Li
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada
| | - Alexei Savchenko
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Tao G Dong
- Department of Ecosystem and Public Health, University of Calgary, Calgary, Canada. .,State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
| |
Collapse
|
8
|
Kettles RA, Tschowri N, Lyons KJ, Sharma P, Hengge R, Webber MA, Grainger DC. The Escherichia coli MarA protein regulates the ycgZ-ymgABC operon to inhibit biofilm formation. Mol Microbiol 2019; 112:1609-1625. [PMID: 31518447 PMCID: PMC6900184 DOI: 10.1111/mmi.14386] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work, we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ-ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ-ymgABC promoter is recognised by σ38 (RpoS)-associated RNA polymerase (RNAP). Surprisingly, MarA does not influence σ38 -dependent transcription. Instead, MarA drives transcription by the housekeeping σ70 -associated RNAP. The effects of MarA on ycgZ-ymgABC expression are coupled with biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.
Collapse
Affiliation(s)
- Rachel A Kettles
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Natalia Tschowri
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Kevin J Lyons
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Prateek Sharma
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - David C Grainger
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| |
Collapse
|
9
|
Giannakopoulou N, Mendis N, Zhu L, Gruenheid S, Faucher SP, Le Moual H. The Virulence Effect of CpxRA in Citrobacter rodentium Is Independent of the Auxiliary Proteins NlpE and CpxP. Front Cell Infect Microbiol 2018; 8:320. [PMID: 30280092 PMCID: PMC6153362 DOI: 10.3389/fcimb.2018.00320] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/22/2018] [Indexed: 02/06/2023] Open
Abstract
Citrobacter rodentium is a murine pathogen used to model the intestinal infection caused by Enteropathogenic and Enterohemorrhagic Escherichia coli (EPEC and EHEC), two diarrheal pathogens responsible for morbidity and mortality in developing and developed countries, respectively. During infection, these bacteria must sense and adapt to the gut environment of the host. In order to adapt to changing environmental cues and modulate expression of specific genes, bacteria can use two-component signal transduction systems (TCS). We have shown that the deletion of the Cpx TCS in C. rodentium leads to a marked attenuation in virulence in C3H/HeJ mice. In E. coli, the Cpx TCS is reportedly activated in response to signals from the outer-membrane lipoprotein NlpE. We therefore investigated the role of NlpE in C. rodentium virulence. We also assessed the role of the reported negative regulator of CpxRA, CpxP. We found that as opposed to the ΔcpxRA strain, neither the ΔnlpE, ΔcpxP nor the ΔnlpEΔcpxP strains were significantly attenuated, and had similar in vivo localization to wild-type C. rodentium. The in vitro adherence of the Cpx auxiliary protein mutants, ΔnlpE, ΔcpxP, ΔnlpEΔcpxP, was comparable to wild-type C. rodentium, whereas the ΔcpxRA strain showed significantly decreased adherence. To further elucidate the mechanisms behind the contrasting virulence phenotypes, we performed microarrays in order to define the regulon of the Cpx TCS. We detected 393 genes differentially regulated in the ΔcpxRA strain. The gene expression profile of the ΔnlpE strain is strikingly different than the profile of ΔcpxRA with regards to the genes activated by CpxRA. Further, there is no clear inverse correlation in the expression pattern of the ΔcpxP strain in comparison to ΔcpxRA. Taken together, these data suggest that in these conditions, CpxRA activates gene expression in a largely NlpE- and CpxP-independent manner. Compared to wildtype, 161 genes were downregulated in the ΔcpxRA strain, while being upregulated or unchanged in the Cpx auxiliary protein deletion strains. This group of genes, which we hypothesize may contribute to the loss of virulence of ΔcpxRA, includes T6SS components, ompF, the regulator for colanic acid synthesis, and several genes involved in maltose metabolism.
Collapse
Affiliation(s)
| | - Nilmini Mendis
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Lei Zhu
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Sebastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Hervé Le Moual
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| |
Collapse
|
10
|
Abstract
RcsB, a response regulator of the FixJ/NarL family, is at the center of a complex network of regulatory inputs and outputs. Cell surface stress is sensed by an outer membrane lipoprotein, RcsF, which regulates interactions of the inner membrane protein IgaA, lifting negative regulation of a phosphorelay. In vivo evidence supports a pathway in which histidine kinase RcsC transfers phosphate to phosphotransfer protein RcsD, resulting in phosphorylation of RcsB. RcsB acts either alone or in combination with RcsA to positively regulate capsule synthesis and synthesis of small RNA (sRNA) RprA as well as other genes, and to negatively regulate motility. RcsB in combination with other FixJ/NarL auxiliary proteins regulates yet other functions, independent of RcsB phosphorylation. Proper expression of Rcs and its targets is critical for success of Escherichia coli commensal strains, for proper development of biofilm, and for virulence in some pathogens. New understanding of how the Rcs phosphorelay works provides insight into the flexibility of the two-component system paradigm.
Collapse
Affiliation(s)
- Erin Wall
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA; emails: , ,
| | - Nadim Majdalani
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA; emails: , ,
| | - Susan Gottesman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA; emails: , ,
| |
Collapse
|
11
|
Zhang Y, Burkhardt DH, Rouskin S, Li GW, Weissman JS, Gross CA. A Stress Response that Monitors and Regulates mRNA Structure Is Central to Cold Shock Adaptation. Mol Cell 2018; 70:274-286.e7. [PMID: 29628307 DOI: 10.1016/j.molcel.2018.02.035] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/19/2018] [Accepted: 02/27/2018] [Indexed: 11/16/2022]
Abstract
Temperature influences the structural and functional properties of cellular components, necessitating stress responses to restore homeostasis following temperature shift. Whereas the circuitry controlling the heat shock response is well understood, that controlling the E. coli cold shock adaptation program is not. We found that during the growth arrest phase (acclimation) that follows shift to low temperature, protein synthesis increases, and open reading frame (ORF)-wide mRNA secondary structure decreases. To identify the regulatory system controlling this process, we screened for players required for increased translation. We identified a two-member mRNA surveillance system that enables recovery of translation during acclimation: RNase R assures appropriate mRNA degradation and the Csps dynamically adjust mRNA secondary structure to globally modulate protein expression level. An autoregulatory switch in which Csps tune their own expression to cellular demand enables dynamic control of global translation. The universality of Csps in bacteria suggests broad utilization of this control mechanism.
Collapse
Affiliation(s)
- Yan Zhang
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David H Burkhardt
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Graduate Group in Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Silvi Rouskin
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Gene-Wei Li
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA; Center for RNA Systems Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
| |
Collapse
|
12
|
Lee J, Kim DJ, Yeom JH, Lee K. Bdm-Mediated Regulation of Flagellar Biogenesis in Escherichia coli and Salmonella enterica Serovar Typhimurium. Curr Microbiol 2017; 74:1015-1020. [PMID: 28603807 DOI: 10.1007/s00284-017-1270-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/23/2017] [Indexed: 11/24/2022]
Abstract
Synthesis of the flagellar apparatus in Escherichia coli is mediated via complex regulatory pathways. A previous study indicated that the protein encoded by the biofilm-dependent modulation (bdm) gene is linked closely with a regulatory pathway for flagellar assembly. However, the specific role of Bdm in flagellar biogenesis remains unknown. Herein, we showed that Bdm interacts with FlgM and inhibits its function as an anti-σ28 factor, which induces the transcription of flagellar late-class genes in E. coli. In addition, we observed that deletion of the yddX gene, a potential Salmonella enterica serovar Typhimurium homolog of bdm, also resulted in downregulation of flagellar late-class genes and in the formation of short flagella, leading to decreased virulence in mice. The expression levels of late-class flagellar genes in yddX-deleted S. Typhimurium cells were restored to those of the wild type when either E. coli bdm or S. Typhimurium yddX was expressed exogenously. These results suggest that Bdm-mediated regulation of flagellar assembly is a conserved regulatory pathway in those members of the Enterobacteriaceae family whose genomes show the existence of homologs of bdm.
Collapse
Affiliation(s)
- Jaejin Lee
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Dae-Jun Kim
- Sejong Science High School, Guro-gu, Seoul, 08258, Republic of Korea
| | - Ji-Hyun Yeom
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea.
| | - Kangseok Lee
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea.
| |
Collapse
|
13
|
Smith C, Stringer AM, Mao C, Palumbo MJ, Wade JT. Mapping the Regulatory Network for Salmonella enterica Serovar Typhimurium Invasion. mBio 2016; 7:e01024-16. [PMID: 27601571 PMCID: PMC5013294 DOI: 10.1128/mbio.01024-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/10/2016] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Salmonella enterica pathogenicity island 1 (SPI-1) encodes proteins required for invasion of gut epithelial cells. The timing of invasion is tightly controlled by a complex regulatory network. The transcription factor (TF) HilD is the master regulator of this process and senses environmental signals associated with invasion. HilD activates transcription of genes within and outside SPI-1, including six other TFs. Thus, the transcriptional program associated with host cell invasion is controlled by at least 7 TFs. However, very few of the regulatory targets are known for these TFs, and the extent of the regulatory network is unclear. In this study, we used complementary genomic approaches to map the direct regulatory targets of all 7 TFs. Our data reveal a highly complex and interconnected network that includes many previously undescribed regulatory targets. Moreover, the network extends well beyond the 7 TFs, due to the inclusion of many additional TFs and noncoding RNAs. By comparing gene expression profiles of regulatory targets for the 7 TFs, we identified many uncharacterized genes that are likely to play direct roles in invasion. We also uncovered cross talk between SPI-1 regulation and other regulatory pathways, which, in turn, identified gene clusters that likely share related functions. Our data are freely available through an intuitive online browser and represent a valuable resource for the bacterial research community. IMPORTANCE Invasion of epithelial cells is an early step during infection by Salmonella enterica and requires secretion of specific proteins into host cells via a type III secretion system (T3SS). Most T3SS-associated proteins required for invasion are encoded in a horizontally acquired genomic locus known as Salmonella pathogenicity island 1 (SPI-1). Multiple regulators respond to environmental signals to ensure appropriate timing of SPI-1 gene expression. In particular, there are seven transcription regulators that are known to be involved in coordinating expression of SPI-1 genes. We have used complementary genome-scale approaches to map the gene targets of these seven regulators. Our data reveal a highly complex and interconnected regulatory network that includes many previously undescribed target genes. Moreover, our data functionally implicate many uncharacterized genes in the invasion process and reveal cross talk between SPI-1 regulation and other regulatory pathways. All datasets are freely available through an intuitive online browser.
Collapse
Affiliation(s)
- Carol Smith
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Anne M Stringer
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Chunhong Mao
- Biocomplexity Institute of Virginia Tech, Virginia Tech, Blacksburg, Virginia, USA
| | - Michael J Palumbo
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Joseph T Wade
- Wadsworth Center, New York State Department of Health, Albany, New York, USA Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
| |
Collapse
|
14
|
Guo XP, Ren GX, Zhu H, Mao XJ, Sun YC. Differential regulation of the hmsCDE operon in Yersinia pestis and Yersinia pseudotuberculosis by the Rcs phosphorelay system. Sci Rep 2015; 5:8412. [PMID: 25672461 PMCID: PMC4325325 DOI: 10.1038/srep08412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/19/2015] [Indexed: 11/19/2022] Open
Abstract
Yersinia pestis, the agent of plague, forms a biofilm in its flea vector to enhance transmission. Y. pestis biofilm development is positively regulated by hmsT and hmsD, encoding diguanylate cyclases (DGCs) involved in synthesis of the bacterial second messenger c-di-GMP. rcsA, encoding an auxiliary protein in Rcs phosphorelay, is nonfunctional in Y. pestis, while in Yersinia pseudotuberculosis, rcsA is functional and represses biofilms. Previously we showed that Rcs phosphorelay negatively regulates transcription of hmsT in Y. pestis and its ancestor Yersinia pseudotuberculosis. In this study, we show that Rcs positively regulates hmsCDE operon (encoding HmsD) in Y. pestis; while in the presence of functional rcsA, Rcs represses hmsCDE operon in Y. pseudotuberculosis. Loss of rcsA's function in Y. pestis not only causes derepression of hmsT but also causes activation of hmsD, which may account for the increased biofilm formation in Y. pestis. In addition, differential regulation of the two DGCs, HmsT and HmsD by Rcs may help Y. pestis to adapt to different environment.
Collapse
Affiliation(s)
- Xiao-Peng Guo
- MOH key laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9, Dongdan Santiao, Dongcheng District, Beijing, 100730, China
| | - Gai-Xian Ren
- MOH key laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9, Dongdan Santiao, Dongcheng District, Beijing, 100730, China
| | - Hui Zhu
- MOH key laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9, Dongdan Santiao, Dongcheng District, Beijing, 100730, China
| | - Xu-Jian Mao
- MOH key laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9, Dongdan Santiao, Dongcheng District, Beijing, 100730, China
| | - Yi-Cheng Sun
- MOH key laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9, Dongdan Santiao, Dongcheng District, Beijing, 100730, China
| |
Collapse
|
15
|
Oropeza R, Salgado-Bravo R, Calva E. Deletion analysis of RcsC reveals a novel signalling pathway controlling poly-N-acetylglucosamine synthesis and biofilm formation in Escherichia coli. MICROBIOLOGY-SGM 2015; 161:903-13. [PMID: 25667010 DOI: 10.1099/mic.0.000050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/29/2015] [Indexed: 12/22/2022]
Abstract
RcsC is a hybrid histidine kinase that forms part of a phospho-relay signal transduction pathway with RcsD and RcsB. Besides the typical domains of a sensor kinase, i.e. the periplasmic (P), linker (L), dimerization and H-containing (A), and ATP-binding (B) domains, RcsC possesses a receiver domain (D) at the carboxy-terminal domain. To study the role played by each of the RcsC domains, four plasmids containing several of these domains were constructed (PLAB, LAB, AB and ABD) and transformed into Escherichia coli K-12 strain BW25113. Different amounts of biofilm were produced, depending on the RcsC domains expressed: the plasmid expressing the ABD subdomains produced the highest amount of biofilm. This phenotype was also observed when the plasmids were transformed in a ΔrcsCDB strain. Biofilm formation was abolished in the pgaABCD and nhaR backgrounds. The results indicate the existence of a novel signalling pathway that depends on RcsC, yet independent of RcsD and RcsB, that activates the pgaABCD operon and, as a consequence, biofilm formation. This signalling pathway involves the secondary metabolite acetyl phosphate and the response regulator OmpR.
Collapse
Affiliation(s)
- Ricardo Oropeza
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Rosalva Salgado-Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Edmundo Calva
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| |
Collapse
|
16
|
Functional role of bdm during flagella biogenesis in Escherichia coli. Curr Microbiol 2014; 70:369-73. [PMID: 25398323 DOI: 10.1007/s00284-014-0729-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/06/2014] [Indexed: 10/24/2022]
Abstract
The biofilm-dependent modulation gene (bdm) has recently been shown to play a role in osmotic-induced formation of biofilm in Escherichia coli. In this study, we demonstrated that deletion of bdm results in down-regulation of flagella biosynthesis genes and, consequently, a defect in E. coli motility. In addition, we employed atomic force microscopy to confirm the absence of flagella-like structures on the surface of bdm-null cells. These findings indicate that bdm plays a key role in regulatory pathway for the formation of flagella.
Collapse
|
17
|
Response of extraintestinal pathogenic Escherichia coli to human serum reveals a protective role for Rcs-regulated exopolysaccharide colanic acid. Infect Immun 2013; 82:298-305. [PMID: 24166954 DOI: 10.1128/iai.00800-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extraintestinal Escherichia coli (ExPEC) organisms are the leading cause of Gram-negative bacterial bloodstream infections. These bacteria adapt to survival in the bloodstream through expression of factors involved in scavenging of nutrients and resisting the killing activity of serum. In this study, the transcriptional response of a prototypic ExPEC strain (CFT073) to human serum was investigated. Resistance of CFT073 to the bactericidal properties of serum involved increased expression of envelope stress regulators, including CpxR, σE, and RcsB. Many of the upregulated genes induced by active serum were regulated by the Rcs two-component system. This system is triggered by envelope stress such as changes to cell wall integrity. RcsB-mediated serum resistance was conferred through induction of the exopolysaccharide colanic acid. Production of this exopolysaccharide may be protective while cell wall damage caused by serum components is repaired.
Collapse
|
18
|
Pieper R, Zhang Q, Clark DJ, Parmar PP, Alami H, Suh MJ, Kuntumalla S, Braisted JC, Huang ST, Tzipori S. Proteomic View of Interactions of Shiga Toxin-Producing Escherichia coli with the Intestinal Environment in Gnotobiotic Piglets. PLoS One 2013; 8:e66462. [PMID: 23840478 PMCID: PMC3686733 DOI: 10.1371/journal.pone.0066462] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/05/2013] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Shiga toxin (Stx)-producing Escherichia coli cause severe intestinal infections involving colonization of epithelial Peyer's patches and formation of attachment/effacement (A/E) lesions. These lesions trigger leukocyte infiltration followed by inflammation and intestinal hemorrhage. Systems biology, which explores the crosstalk of Stx-producing Escherichia coli with the in vivo host environment, may elucidate novel molecular pathogenesis aspects. METHODOLOGY/PRINCIPAL FINDINGS Enterohemorrhagic E. coli strain 86-24 produces Shiga toxin-2 and belongs to the serotype O157:H7. Bacterial cells were scrapped from stationary phase cultures (the in vitro condition) and used to infect gnotobiotic piglets via intestinal lavage. Bacterial cells isolated from the piglets' guts constituted the in vivo condition. Cell lysates were subjected to quantitative 2D gel and shotgun proteomic analyses, revealing metabolic shifts towards anaerobic energy generation, changes in carbon utilization, phosphate and ammonia starvation, and high activity of a glutamate decarboxylase acid resistance system in vivo. Increased abundance of pyridine nucleotide transhydrogenase (PntA and PntB) suggested in vivo shortage of intracellular NADPH. Abundance changes of proteins implicated in lipopolysaccharide biosynthesis (LpxC, ArnA, the predicted acyltransferase L7029) and outer membrane (OM) assembly (LptD, MlaA, MlaC) suggested bacterial cell surface modulation in response to activated host defenses. Indeed, there was evidence for interactions of innate immunity-associated proteins secreted into the intestines (GP340, REG3-γ, resistin, lithostathine, and trefoil factor 3) with the bacterial cell envelope. SIGNIFICANCE Proteomic analysis afforded insights into system-wide adaptations of strain 86-24 to a hostile intestinal milieu, including responses to limited nutrients and cofactor supplies, intracellular acidification, and reactive nitrogen and oxygen species-mediated stress. Protein and lipopolysaccharide compositions of the OM were altered. Enhanced expression of type III secretion system effectors correlated with a metabolic shift back to a more aerobic milieu in vivo. Apparent pathogen pattern recognition molecules from piglet intestinal secretions adhered strongly to the bacterial cell surface.
Collapse
Affiliation(s)
- Rembert Pieper
- J. Craig Venter Institute, Rockville, Maryland, United States of America
- * E-mail:
| | - Quanshun Zhang
- Division of Infectious Diseases, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, United States of America
| | - David J. Clark
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | | | - Hamid Alami
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Moo-Jin Suh
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | | | - John C. Braisted
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Shih-Ting Huang
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Saul Tzipori
- Division of Infectious Diseases, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, United States of America
| |
Collapse
|
19
|
Kamenšek S, Žgur-Bertok D. Global transcriptional responses to the bacteriocin colicin M in Escherichia coli. BMC Microbiol 2013; 13:42. [PMID: 23421615 PMCID: PMC3599342 DOI: 10.1186/1471-2180-13-42] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 02/18/2013] [Indexed: 01/17/2023] Open
Abstract
Background Bacteriocins are protein antimicrobial agents that are produced by all prokaryotic lineages. Escherichia coli strains frequently produce the bacteriocins known as colicins. One of the most prevalent colicins, colicin M, can kill susceptible cells by hydrolyzing the peptidoglycan lipid II intermediate, which arrests peptidoglycan polymerization steps and provokes cell lysis. Due to the alarming rise in antibiotic resistance and the lack of novel antimicrobial agents, colicin M has recently received renewed attention as a promising antimicrobial candidate. Here the effects of subinhibitory concentrations of colicin M on whole genome transcription in E. coli were investigated, to gain insight into its ecological role and for purposes related to antimicrobial therapy. Results Transcriptome analysis revealed that exposure to subinhibitory concentrations of colicin M altered expression of genes involved in envelope, osmotic and other stresses, including genes of the CreBC two-component system, exopolysaccharide production and cell motility. Nonetheless, there was no induction of biofilm formation or genes involved in mutagenesis. Conclusion At subinhibitory concentrations colicin M induces an adaptive response primarily to protect the bacterial cells against envelope stress provoked by peptidoglycan damage. Among the first induced were genes of the CreBC two-component system known to promote increased resistance against colicins M and E2, providing novel insight into the ecology of colicin M production in natural environments. While an adaptive response was induced nevertheless, colicin M application did not increase biofilm formation, nor induce SOS genes, adverse effects that can be provoked by a number of traditional antibiotics, providing support for colicin M as a promising antimicrobial agent.
Collapse
Affiliation(s)
- Simona Kamenšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
| | | |
Collapse
|
20
|
The response regulator RcsB activates expression of Mat fimbriae in meningitic Escherichia coli. J Bacteriol 2012; 194:3475-85. [PMID: 22522901 DOI: 10.1128/jb.06596-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The common colonization factor of Escherichia coli, the Mat (also termed ECP) fimbria, functions to advance biofilm formation on inert surfaces as well as bacterial adherence to epithelial cells and subsequent colonization. We used global mini-Tn5 transposon mutagenesis to identify novel regulators of biofilm formation by the meningitic E. coli isolate IHE 3034. Of the 4,418 transformants, we found 17 that were impaired in biofilm formation. Most of these mutants were affected in lipopolysaccharide synthesis and were reduced in growth but not in Mat fimbria expression. In contrast, two mutants grew well but did not express Mat fimbria. The insertions in these two mutants were located at different sites of the rcsB gene, which encodes a DNA-binding response regulator of the Rcs response regulon. The mutations abrogated temperature-dependent biofilm formation by IHE 3034, and the phenotype correlated with loss of mat expression. The defect in biofilm formation in the rcsB mutant was reversed upon complementation with rcsB as well as by overexpression of structural mat genes but not by overexpression of the fimbria-specific activator gene matA. Monitoring of the mat operon promoter activity with chromosomal reporter fusions showed that the RcsB protein and an RcsAB box in the mat regulatory region, but not RcsC, RcsD, AckA, and Pta, are essential for initiation of mat transcription. Gel retardation assays showed that RcsB specifically binds to the mat promoter DNA, which enables its function in promoting biofilm formation by E. coli.
Collapse
|
21
|
Mika F, Busse S, Possling A, Berkholz J, Tschowri N, Sommerfeldt N, Pruteanu M, Hengge R. Targeting of csgD by the small regulatory RNA RprA links stationary phase, biofilm formation and cell envelope stress in Escherichia coli. Mol Microbiol 2012; 84:51-65. [PMID: 22356413 PMCID: PMC3465796 DOI: 10.1111/j.1365-2958.2012.08002.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
RprA is a small regulatory RNA known to weakly affect the translation of σS (RpoS) in Escherichia coli. Here we demonstrate that csgD, which encodes a stationary phase-induced biofilm regulator, as well as ydaM, which encodes a diguanylate cyclase involved in activating csgD transcription, are novel negatively controlled RprA targets. As shown by extensive mutational analysis, direct binding of RprA to the 5′-untranslated and translational initiation regions of csgD mRNA inhibits translation and reduces csgD mRNA levels. In the case of ydaM mRNA, RprA base-pairs directly downstream of the translational start codon. In a feedforward loop, RprA can thus downregulate > 30 YdaM/CsgD-activated genes including those for adhesive curli fimbriae. However, during early stationary phase, when csgD transcription is strongly activated, the synthesis of csgD mRNA exceeds that of RprA, which allows the accumulation of CsgD protein. This situation is reversed when csgD transcription is shut off – for instance, later in stationary phase or during biofilm formation – or by conditions that further activate RprA expression via the Rcs two-component system. Thus, antagonistic regulation of csgD and RprA at the mRNA level integrates cell envelope stress signals with global gene expression during stationary phase and biofilm formation.
Collapse
Affiliation(s)
- Franziska Mika
- Institut für Biologie - Mikrobiologie, Freie Universität Berlin, 14195 Berlin, Germany
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Battesti A, Majdalani N, Gottesman S. The RpoS-mediated general stress response in Escherichia coli. Annu Rev Microbiol 2012; 65:189-213. [PMID: 21639793 DOI: 10.1146/annurev-micro-090110-102946] [Citation(s) in RCA: 636] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Under conditions of nutrient deprivation or stress, or as cells enter stationary phase, Escherichia coli and related bacteria increase the accumulation of RpoS, a specialized sigma factor. RpoS-dependent gene expression leads to general stress resistance of cells. During rapid growth, RpoS translation is inhibited and any RpoS protein that is synthesized is rapidly degraded. The complex transition from exponential growth to stationary phase has been partially dissected by analyzing the induction of RpoS after specific stress treatments. Different stress conditions lead to induction of specific sRNAs that stimulate RpoS translation or to induction of small-protein antiadaptors that stabilize the protein. Recent progress has led to a better, but still far from complete, understanding of how stresses lead to RpoS induction and what RpoS-dependent genes help the cell deal with the stress.
Collapse
Affiliation(s)
- Aurelia Battesti
- Laboratory of Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892, USA.
| | | | | |
Collapse
|
23
|
Kavalchuk K, Madhusudan S, Schnetz K. RNase III initiates rapid degradation of proU mRNA upon hypo-osmotic stress in Escherichia coli. RNA Biol 2012; 9:98-109. [PMID: 22258144 DOI: 10.4161/rna.9.1.18228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Hyper-osmotic stress strongly induces expression of the Escherichia coli proU operon encoding a high affinity uptake system for the osmoprotectants glycine betaine and proline betaine. Osmoregulation of proU takes place at the transcriptional level by upregulation of the promoter at high osmolarity and repression of transcription by the nucleoid-associated protein H-NS at low osmolarity. In the present study, we describe an additional level of proU osmoregulation that is independent of transcriptional regulation. We show that osmoregulation occurs at a post-transcriptional level involving RNase III. RNase III specifically processes the proU mRNA within a conserved secondary structure extending from position +203 to +293 of the transcript. Processing is efficient at low osmolarity, but inhibited at high osmolarity. Blocking of RNase III processing by mutation of the processing site eliminates post-transcriptional osmoregulation of proU. Further, the proU mRNA is relatively stable at high osmolarity with a half-life of approximately 65 sec. However, upon osmotic downshift, RNase III immediately processes the proU mRNA which reduces its half-life to less than 4 sec. The data suggest that the primary role of RNase III-mediated processing of proU mRNA is to ensure rapid shutdown of proU upon hypo-osmotic stress.
Collapse
|
24
|
Shalá AA, Restrepo S, González Barrios AF. A network model for biofilm development in Escherichia coli K-12. Theor Biol Med Model 2011; 8:34. [PMID: 21939518 PMCID: PMC3224578 DOI: 10.1186/1742-4682-8-34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 09/22/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In nature, bacteria often exist as biofilms. Biofilms are communities of microorganisms attached to a surface. It is clear that biofilm-grown cells harbor properties remarkably distinct from planktonic cells. Biofilms frequently complicate treatments of infections by protecting bacteria from the immune system, decreasing antibiotic efficacy and dispersing planktonic cells to distant body sites. In this work, we employed enhanced Boolean algebra to model biofilm formation. RESULTS The network obtained describes biofilm formation successfully, assuming - in accordance with the literature - that when the negative regulators (RscCD and EnvZ/OmpR) are off, the positive regulator (FlhDC) is on. The network was modeled under three different conditions through time with satisfactory outcomes. Each cluster was constructed using the K-means/medians Clustering Support algorithm on the basis of published Affymetrix microarray gene expression data from biofilm-forming bacteria and the planktonic state over four time points for Escherichia coli K-12. CONCLUSIONS The different phenotypes obtained demonstrate that the network model of biofilm formation can simulate the formation or repression of biofilm efficiently in E. coli K-12.
Collapse
Affiliation(s)
- Andrew A Shalá
- Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes. Carrera 1E No. 19ª14 Bogotá, Colombia
| | - Silvia Restrepo
- Laboratorio de Micología y Fitopatología (LAMFU), Facultad de Ciencias Biológicas, Universidad de los Andes, Universidad de los Andes. Carrera 1E No. 19ª14 Bogotá, Colombia
| | - Andrés F González Barrios
- Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes. Carrera 1E No. 19ª14 Bogotá, Colombia
| |
Collapse
|
25
|
BglJ-RcsB heterodimers relieve repression of the Escherichia coli bgl operon by H-NS. J Bacteriol 2010; 192:6456-64. [PMID: 20952573 DOI: 10.1128/jb.00807-10] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RcsB is the response regulator of the complex Rcs two-component system, which senses perturbations in the outer membrane and peptidoglycan layer. BglJ is a transcriptional regulator whose constitutive expression causes activation of the H-NS- and StpA-repressed bgl (aryl-β,D-glucoside) operon in Escherichia coli. RcsB and BglJ both belong to the LuxR-type family of transcriptional regulators with a characteristic C-terminal DNA-binding domain. Here, we show that BglJ and RcsB interact and form heterodimers that presumably bind upstream of the bgl promoter, as suggested by mutation of a sequence motif related to the consensus sequence for RcsA-RcsB heterodimers. Heterodimerization of BglJ-RcsB and relief of H-NS-mediated repression of bgl by BglJ-RcsB are apparently independent of RcsB phosphorylation. In addition, we show that LeuO, a pleiotropic LysR-type transcriptional regulator, likewise binds to the bgl upstream regulatory region and relieves repression of bgl independently of BglJ-RcsB. Thus, LeuO can affect bgl directly, as shown here, and indirectly by activating the H-NS-repressed yjjQ-bglJ operon, as shown previously. Taken together, heterodimer formation of RcsB and BglJ expands the role of the Rcs two-component system and the network of regulators affecting the bgl promoter.
Collapse
|
26
|
Clarke DJ. The Rcs phosphorelay: more than just a two-component pathway. Future Microbiol 2010; 5:1173-84. [DOI: 10.2217/fmb.10.83] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Rcs phosphorelay is a complex signaling pathway found in many, but not all, members of the Enterobacteriaceae. The complexity of this pathway is due to the direct involvement of three proteins (RcsC, RcsD and RcsB) in the phosphorelay and the presence of multiple accessory proteins with important roles in modulating the inputs and outputs associated with this signaling pathway. This article will discuss the various inputs and outputs associated with the Rcs phosphorelay and also present a model suggesting an important role for this signaling pathway in the temporal control of virulence in Salmonella enterica and biofilm formation in Escherichia coli.
Collapse
Affiliation(s)
- David J Clarke
- Department of Microbiology & Alimentary Pharmabiotic Centre, University College Cork, Ireland
| |
Collapse
|
27
|
Sim SH, Yeom JH, Shin C, Song WS, Shin E, Kim HM, Cha CJ, Han SH, Ha NC, Kim SW, Hahn Y, Bae J, Lee K. Escherichia coli ribonuclease III activity is downregulated by osmotic stress: consequences for the degradation of bdm mRNA in biofilm formation. Mol Microbiol 2009; 75:413-25. [PMID: 19943899 DOI: 10.1111/j.1365-2958.2009.06986.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During the course of experiments aimed at identifying genes with ribonuclease III (RNase III)-dependent expression in Escherichia coli, we found that steady state levels of bdm mRNA were dependent on cellular concentrations of RNase III. The half-lives of adventitiously overexpressed bdm mRNA and the activities of a transcriptional bdm'-'cat fusion were observed to be dependent on cellular concentrations of RNase III, indicating the existence of cis-acting elements in bdm mRNA responsive to RNase III. In vitro and in vivo cleavage analyses of bdm mRNA identified two RNase III cleavage motifs, one in the 5'-untranslated region and the other in the coding region of bdm mRNA, and indicated that RNase III cleavages in the coding region constitute a rate-determining step for bdm mRNA degradation. We also discovered that downregulation of the ribonucleolytic activity of RNase III is required for the sustained elevation of RcsB-induced bdm mRNA levels during osmotic stress and that cells overexpressing bdm form biofilms more efficiently. These findings indicate that the Rcs signalling system has an additional regulatory pathway that functions to modulate bdm expression and consequently, adapt E. coli cells to osmotic stress.
Collapse
Affiliation(s)
- Se-Hoon Sim
- Department of Life Science (BK21 program), Chung-Ang University, Seoul, Republic of Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Glover WA, Yang Y, Zhang Y. Insights into the molecular basis of L-form formation and survival in Escherichia coli. PLoS One 2009; 4:e7316. [PMID: 19806199 PMCID: PMC2752164 DOI: 10.1371/journal.pone.0007316] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 09/02/2009] [Indexed: 11/30/2022] Open
Abstract
L-forms have been shown to occur among many species of bacteria and are suspected to be involved in persistent infections. Since their discovery in 1935, numerous studies characterizing L-form morphology, growth, and pathogenic potential have been conducted. However, the molecular mechanisms underlying the formation and survival of L-forms remain unknown. Using unstable L-form colonies of Escherichia coli as a model, we performed genome-wide transcriptome analysis and screened a deletion mutant library to study the molecular mechanisms involved in formation and survival of L-forms. Microarray analysis of L-form versus classical colonies revealed many up-regulated genes of unknown function as well as multiple over-expressed stress pathways shared in common with persister cells and biofilms. Mutant screens identified three groups of mutants which displayed varying degrees of defects in L-form colony formation. Group 1 mutants, which showed the strongest defect in L-form colony formation, belonged to pathways involved in cell envelope stress, DNA repair, iron homeostasis, outer membrane biogenesis, and drug efflux/ABC transporters. Four (Group 1) mutants, rcsB, a positive response regulator of colanic acid capsule synthesis, ruvA, a recombinational junction binding protein, fur, a ferric uptake regulator and smpA a small membrane lipoprotein were selected for complementation. Complementation of the mutants using a high-copy overexpression vector failed, while utilization of a low-copy inducible vector successfully restored L-form formation. This work represents the first systematic genetic evaluation of genes and pathways involved in the formation and survival of unstable L-form bacteria. Our findings provide new insights into the molecular mechanisms underlying L-form formation and survival and have implications for understanding the emergence of antibiotic resistance, bacterial persistence and latent infections and designing novel drugs and vaccines.
Collapse
Affiliation(s)
- William A. Glover
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yanqin Yang
- Bioinformatics Core, The Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Ying Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| |
Collapse
|
29
|
Tschowri N, Busse S, Hengge R. The BLUF-EAL protein YcgF acts as a direct anti-repressor in a blue-light response of Escherichia coli. Genes Dev 2009; 23:522-34. [PMID: 19240136 DOI: 10.1101/gad.499409] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The blue light using FAD (BLUF)-EAL protein YcgF is a known blue-light sensor of Escherichia coli, but its direct regulatory output and physiological function have remained unknown. Here, we demonstrate that unlike other EAL domain proteins, YcgF does not degrade the signaling molecule c-di-GMP, but directly binds to and releases the MerR-like repressor YcgE from its operator DNA upon blue-light irradiation. As a consequence, a distinct regulon of eight small proteins (of 71-126 amino acids) is strongly induced. These include YmgA and YmgB, which, via the RcsC/RcsD/RcsB two-component phosphorelay system, activate production of the biofilm matrix substance colanic acid as well as acid resistance genes and the biofilm-associated bdm gene and down-regulate adhesive curli fimbriae. Thus, small proteins under YcgF/YcgE control seem to act as "connectors" that provide additional signal input into a two-component signaling pathway. Moreover, we found ycgF and ycgE expression to be strongly activated at low temperature, and we elucidate how blue light, cold, and starvation signals are integrated in the expression and activity of the YcgF/YcgE/small protein signaling pathway. In conclusion, this pathway may modulate biofilm formation via the two-component network when E. coli has to survive in an extrahost aquatic environment.
Collapse
Affiliation(s)
- Natalia Tschowri
- Institut für Biologie-Mikrobiologie, Freie Universität Berlin, 14195 Berlin, Germany
| | | | | |
Collapse
|
30
|
Oberto J, Nabti S, Jooste V, Mignot H, Rouviere-Yaniv J. The HU regulon is composed of genes responding to anaerobiosis, acid stress, high osmolarity and SOS induction. PLoS One 2009; 4:e4367. [PMID: 19194530 PMCID: PMC2634741 DOI: 10.1371/journal.pone.0004367] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Accepted: 12/17/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The Escherichia coli heterodimeric HU protein is a small DNA-bending protein associated with the bacterial nucleoid. It can introduce negative supercoils into closed circular DNA in the presence of topoisomerase I. Cells lacking HU grow very poorly and display many phenotypes. METHODOLOGY/PRINCIPAL FINDINGS We analyzed the transcription profile of every Escherichia coli gene in the absence of one or both HU subunits. This genome-wide in silico transcriptomic approach, performed in parallel with in vivo genetic experimentation, defined the HU regulon. This large regulon, which comprises 8% of the genome, is composed of four biologically relevant gene classes whose regulation responds to anaerobiosis, acid stress, high osmolarity, and SOS induction. CONCLUSIONS/SIGNIFICANCE The regulation a large number of genes encoding enzymes involved in energy metabolism and catabolism pathways by HU explains the highly pleiotropic phenotype of HU-deficient cells. The uniform chromosomal distribution of the many operons regulated by HU strongly suggests that the transcriptional and nucleoid architectural functions of HU constitute two aspects of a unique protein-DNA interaction mechanism.
Collapse
Affiliation(s)
- Jacques Oberto
- Laboratoire de Physiologie Bactérienne, CNRS, UPR 9073, Institut de Biologie Physico-chimique, Paris, France
- * E-mail: (JO); (JR-Y)
| | - Sabrina Nabti
- Laboratoire de Physiologie Bactérienne, CNRS, UPR 9073, Institut de Biologie Physico-chimique, Paris, France
| | - Valérie Jooste
- INSERM, UMR 866, Epidemiology and Biostatistics group, University of Dijon, Dijon, France
| | | | - Josette Rouviere-Yaniv
- Laboratoire de Physiologie Bactérienne, CNRS, UPR 9073, Institut de Biologie Physico-chimique, Paris, France
- * E-mail: (JO); (JR-Y)
| |
Collapse
|
31
|
Genome expression analyses revealing the modulation of the Salmonella Rcs regulon by the attenuator IgaA. J Bacteriol 2009; 191:1855-67. [PMID: 19124574 DOI: 10.1128/jb.01604-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intracellular growth attenuator A (IgaA) was identified as a Salmonella enterica regulator limiting bacterial growth inside fibroblasts. Genetic evidence further linked IgaA to repression of the RcsCDB regulatory system, which responds to envelope stress. How IgaA attenuates this system is unknown. Here, we present genome expression profiling data of S. enterica serovar Typhimurium igaA mutants grown at high osmolarity and displaying exacerbated Rcs responses. Transcriptome data revealed that IgaA attenuates gene expression changes requiring phosphorylated RcsB (RcsB~P) activity. Some RcsB-regulated genes, yciGFE and STM1862 (pagO)-STM1863-STM1864, were equally expressed in wild-type and igaA strains, suggesting a maximal expression at low levels of RcsB ~P. Other genes, such as metB, ypeC, ygaC, glnK, glnP, napA, glpA, and nirB, were shown for the first time and by independent methods to be regulated by the RcsCDB system. Interestingly, IgaA-deficient strains with reduced RcsC or RcsD levels exhibited different Rcs responses and distinct virulence properties. spv virulence genes were differentially expressed in most of the analyzed strains. spvA expression required RcsB and IgaA but, unexpectedly, was also impaired upon stimulation of the RcsC-->RcsD-->RcsB phosphorelay. Overproduction of either RcsB(+) or a nonphosphorylatable RcsB(D56Q) variant in strains displaying low spvA expression unveiled that both dephosphorylated RcsB and RcsB~P are required for optimal spvA expression. Taken together, our data support a model with IgaA attenuating the RcsCDB system by favoring the switch of RcsB~P to the dephosphorylated state. This role of IgaA in constantly fine-tuning the RcsB~P/RcsB ratio may ensure the proper expression of important virulence factors, such as the Spv proteins.
Collapse
|
32
|
Mariscotti JF, García-Del Portillo F. Instability of the Salmonella RcsCDB signalling system in the absence of the attenuator IgaA. MICROBIOLOGY-SGM 2008; 154:1372-1383. [PMID: 18451046 DOI: 10.1099/mic.0.2007/015891-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
IgaA is a Salmonella enterica membrane protein that attenuates the response of the RcsCDB signalling system to envelope stress. This protein is essential unless the RcsCDB system is inactivated, suggesting that IgaA may constantly adjust the magnitude of the response. Such a functional link is also supported by the concurrence of the igaA and rcsD-rcsB-rcsC loci in genomes of enteric bacteria and the selection of spontaneous mutations in the RcsCDB system following IgaA deprivation. However, the exact nature of the spontaneous mutations rendering IgaA dispensable remains undefined. In this work, we examined how the transduction of an igaA null allele affects the status of the RcsCDB system. Loss of RcsCDB response was registered in approximately 90 % of the IgaA-defective clones, which failed to produce the capsule material positively regulated by this system. About half of these non-mucoid clones suppressed the loss of IgaA with large deletions encompassing variable regions of the rcsD-rcsB-rcsC locus. Unexpectedly, mucoid transductants were also reproducibly obtained and indicated the capacity of S. enterica to retain a functional RcsCDB system in the absence of IgaA. Decreased levels of either RcsC or RcsD were shown in 'mucoid' clones lacking IgaA and displaying low responsiveness to stimuli. Taken together, these data demonstrate that the stability and responsiveness of the RcsCDB system relies on its attenuator IgaA. The type of suppressions found also support a model with IgaA controlling the level of signal flowing through RcsC and RcsD.
Collapse
Affiliation(s)
- Javier F Mariscotti
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain
| | - Francisco García-Del Portillo
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain
| |
Collapse
|
33
|
Hinchliffe SJ, Howard SL, Huang YH, Clarke DJ, Wren BW. The importance of the Rcs phosphorelay in the survival and pathogenesis of the enteropathogenic yersiniae. Microbiology (Reading) 2008; 154:1117-1131. [DOI: 10.1099/mic.0.2007/012534-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Stewart J. Hinchliffe
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Sarah L. Howard
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Yahui H. Huang
- Department of Biology and Biochemistry, University of Bath, BA2 7AY, UK
| | - David J. Clarke
- Department of Biology and Biochemistry, University of Bath, BA2 7AY, UK
| | - Brendan W. Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| |
Collapse
|
34
|
Kannan G, Wilks JC, Fitzgerald DM, Jones BD, Bondurant SS, Slonczewski JL. Rapid acid treatment of Escherichia coli: transcriptomic response and recovery. BMC Microbiol 2008; 8:37. [PMID: 18302792 PMCID: PMC2270276 DOI: 10.1186/1471-2180-8-37] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Accepted: 02/26/2008] [Indexed: 11/10/2022] Open
Abstract
Background Many E. coli genes show pH-dependent expression during logarithmic growth in acid (pH 5–6) or in base (pH 8–9). The effect of rapid pH change, however, has rarely been tested. Rapid acid treatment could distinguish between genes responding to external pH, and genes responding to cytoplasmic acidification, which occurs transiently following rapid external acidification. It could reveal previously unknown acid-stress genes whose effects are transient, as well as show which acid-stress genes have a delayed response. Results Microarray hybridization was employed to observe the global gene expression of E. coli K-12 W3110 following rapid acidification of the external medium, from pH 7.6 to pH 5.5. Fluorimetric observation of pH-dependent tetR-YFP showed that rapid external acidification led to a half-unit drop in cytoplasmic pH (from pH 7.6 to pH 6.4) which began to recover within 20 s. Following acid treatment, 630 genes were up-regulated and 586 genes were down-regulated. Up-regulated genes included amino-acid decarboxylases (cadA, adiY, gadA), succinate dehydrogenase (sdhABCD), biofilm-associated genes (bdm, gatAB, and ymgABC), and the Gad, Fur and Rcs regulons. Genes with response patterns consistent with cytoplasmic acid stress were revealed by addition of benzoate, a membrane-permeant acid that permanently depresses cytoplasmic pH without affecting external pH. Several genes (yagU, ygiN, yjeI, and yneI) were up-regulated specifically by external acidification, while other genes (fimB, ygaC, yhcN, yhjX, ymgABC, yodA) presented a benzoate response consistent with cytoplasmic pH stress. Other genes (the nuo operon for NADH dehydrogenase I, and the HslUV protease) showed delayed up-regulation by acid, with expression rising by 10 min following the acid shift. Conclusion Transcriptomic profiling of E. coli K-12 distinguished three different classes of change in gene expression following rapid acid treatment: up-regulation with or without recovery, and delayed response to acid. For eight genes showing acid response and recovery (fimB, ygaC, yhcN, yhjX, ymgABC, yodA), responses to the permeant acid benzoate revealed expression patterns consistent with sensing of cytoplasmic pH. The delayed acid response of nuo genes shows that NADH dehydrogenase I is probably induced as a secondary result of acid-associated metabolism, not as a direct response to cytoplasmic acidification.
Collapse
Affiliation(s)
- Geetha Kannan
- Department of Biology, Kenyon College, Gambier, OH, 43022 USA.
| | | | | | | | | | | |
Collapse
|
35
|
Abstract
The Rcs phosphorelay, consisting of a hybrid sensor kinase, a phosphotransferase, and a response regulator, regulates a large number of bacterial functions. These include capsule production, the target originally defined for these regulators, a small regulatory RNA, and a growing list of additional genes, many of unknown function. At the core of this phosphorelay is the response regulator RcsB that activates the expression of the target genes. In addition to RcsB, some but not all of these targets require a co-regulator. One such co-regulator is RcsA, which has not been described as working except with RcsB; RcsA is itself regulated at both the transcriptional and post-transcriptional levels. Signaling to the system is also complex, and numerous plasmids, mutations, and environmental conditions have been described as activating this system. Activation of the system on cell surfaces and the nature of some of the regulated functions suggest a role for this phosphorelay in biofilm formation. Here, we describe reporters and mutants that allow the genetic dissection of the system from two directions. In cases where a condition activates the system, for instance, causing an increase in capsule synthesis (a phenotype easily observed in colonies), specific tests can identify at what stage the signal feeds into the system. In cases where a target of the phosphorelay is identified, specific tests can define the genetic requirements for regulation of the target. Finally, in cases where overproduction of capsule interferes with other studies, mutants allow the study of cells in the absence of capsule formation.
Collapse
Affiliation(s)
- Nadim Majdalani
- Laboratory of Molecular Biology, National Cancer Institute, Bethesda, MD, USA
| | | |
Collapse
|
36
|
Lee J, Page R, García-Contreras R, Palermino JM, Zhang XS, Doshi O, Wood TK, Peti W. Structure and function of the Escherichia coli protein YmgB: a protein critical for biofilm formation and acid-resistance. J Mol Biol 2007; 373:11-26. [PMID: 17765265 PMCID: PMC2185545 DOI: 10.1016/j.jmb.2007.07.037] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 07/12/2007] [Accepted: 07/16/2007] [Indexed: 10/23/2022]
Abstract
The Escherichia coli gene cluster ymgABC was identified in transcriptome studies to have a role in biofilm development and stability. In this study, we showed that YmgB represses biofilm formation in rich medium containing glucose, decreases cellular motility, and protects the cell from acid indicating that YmgB has a major role in acid-resistance in E. coli. Our data show that these phenotypes are potentially mediated through interactions with the important cell signal indole. In addition, gel mobility-shift assays suggest that YmgB may be a non-specific DNA-binding protein. Using nickel-enrichment DNA microarrays, we showed that YmgB binds, either directly or indirectly, via a probable ligand, genes important for biofilm formation. To advance our understanding of the function of YmgB, we used X-ray crystallography to solve the structure of the protein to 1.8 A resolution. YmgB is a biological dimer that is structurally homologous to the E. coli gene regulatory protein Hha, despite having only 5% sequence identity. This supports our DNA microarray data showing that YmgB is a gene regulatory protein. Therefore, this protein, which clearly has a critical role in acid-resistance in E. coli, has been renamed as AriR for regulator of acid resistance influenced by indole.
Collapse
Affiliation(s)
- Jintae Lee
- Artie McFerrin Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02912
| | - Rodolfo García-Contreras
- Artie McFerrin Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122
| | - Jeanne-Marie Palermino
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI, 02912
| | - Xue-Song Zhang
- Artie McFerrin Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122
| | - Ojus Doshi
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02912
| | - Thomas K. Wood
- Artie McFerrin Department of Chemical Engineering, Texas A & M University, College Station, TX 77843-3122
- Department of Biology, Texas A & M University, College Station, TX 77843-3122
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI, 02912
- Address correspondence to: Wolfgang Peti, PhD, Laboratories of Molecular Medicine, 70 Ship Street, GE-3, Providence, RI, 02912. Fax: 401-863-6087 ;
| |
Collapse
|
37
|
Castanié-Cornet MP, Treffandier H, Francez-Charlot A, Gutierrez C, Cam K. The glutamate-dependent acid resistance system in Escherichia coli: essential and dual role of the His-Asp phosphorelay RcsCDB/AF. MICROBIOLOGY-SGM 2007; 153:238-46. [PMID: 17185552 DOI: 10.1099/mic.0.29278-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The RcsCDB signal transduction system is an atypical His-Asp phosphorelay. Notably, the response regulator RcsB can be activated either by phosphorylation through the RcsCD pathway or by an accessory cofactor RcsA. Although conserved in Enterobacteriaceae, the role of this system in adaptation to environmental stress conditions is largely unknown. This study reveals that the response regulator RcsB is essential to glutamate-dependent acid resistance, a condition pertinent to the lifestyle of Escherichia coli. The requirement for RcsB is independent of its activation by either the RcsCD or the RcsA pathway. The basal activity of RcsB appears to be necessary and sufficient for acid resistance. The sensitivity of the rcsB strain to low pH is correlated to a strong reduction of the expression of the glutamate decarboxylase genes, gadA and gadB, during the stationary phase of growth. This effect on gadA/B expression is not mediated by the general stress sigma factor RpoS, but does require a functional gadE allele and the previously identified GadE box. Therefore activation of gadAB expression and acid resistance absolutely requires both GadE and RcsB. In contrast, an increase in RcsB activity through the activation of the RcsCD phosphorelay or the RcsA pathway or through overproduction of the protein leads to general repression of the expression of the gad genes and a corresponding reduction in acid resistance.
Collapse
Affiliation(s)
- Marie-Pierre Castanié-Cornet
- Laboratoire de Microbiologie et de Génétique Moléculaire, Centre National de la Recherche Scientifique, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France
| | | | | | | | | |
Collapse
|
38
|
Majdalani N, Heck M, Stout V, Gottesman S. Role of RcsF in signaling to the Rcs phosphorelay pathway in Escherichia coli. J Bacteriol 2005; 187:6770-8. [PMID: 16166540 PMCID: PMC1251585 DOI: 10.1128/jb.187.19.6770-6778.2005] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rcs phosphorelay pathway components were originally identified as regulators of capsule synthesis. In addition to the transmembrane sensor kinase RcsC, the RcsA coregulator, and the response regulator RcsB, two new components have been characterized, RcsD and RcsF. RcsD, the product of the yojN gene, now renamed rcsD, acts as a phosphorelay between RcsC and RcsB. Transcription of genes for capsule synthesis (cps) requires both RcsA and RcsB; transcription of other promoters, including that for the small RNA RprA, requires only RcsB. RcsF was described as an alternative sensor kinase for RcsB. We have examined the role of RcsF in the activation of both the rprA and cps promoters. We find that a number of signals that lead to activation of the phosphorelay require both RcsF and RcsC; epistasis experiments place RcsF upstream of RcsC. The RcsF sequence is characteristic of lipoproteins, consistent with a role in sensing cell surface perturbation and transmitting this signal to RcsC. Activation of RcsF does not require increased transcription of the gene, suggesting that modification of the RcsF protein may act as an activating signal. Signals from RcsC require RcsD to activate RcsB. Sequencing of an rcsC allele, rcsC137, that leads to high-level constitutive expression of both cps and rprA suggests that the response regulator domain of RcsC plays a role in negatively regulating the kinase activity of RcsC. The phosphorelay and the variation in the activation mechanism (dependent upon or independent of RcsA) provide multiple steps for modulating the output from this system.
Collapse
Affiliation(s)
- Nadim Majdalani
- National Cancer Institute, 9000 Rockville Pike, Bldg. 37, Bethesda, MD 20892, USA
| | | | | | | |
Collapse
|