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Böhme K, Heroven AK, Lobedann S, Guo Y, Stolle AS, Dersch P. The Small Protein YmoA Controls the Csr System and Adjusts Expression of Virulence-Relevant Traits of Yersinia pseudotuberculosis. Front Microbiol 2021; 12:706934. [PMID: 34413840 PMCID: PMC8369931 DOI: 10.3389/fmicb.2021.706934] [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] [Received: 05/08/2021] [Accepted: 07/12/2021] [Indexed: 11/24/2022] Open
Abstract
Virulence gene expression of Yersinia pseudotuberculosis changes during the different stages of infection and this is tightly controlled by environmental cues. In this study, we show that the small protein YmoA, a member of the Hha family, is part of this process. It controls temperature- and nutrient-dependent early and later stage virulence genes in an opposing manner and co-regulates bacterial stress responses and metabolic functions. Our analysis further revealed that YmoA exerts this function by modulating the global post-transcriptional regulatory Csr system. YmoA pre-dominantly enhances the stability of the regulatory RNA CsrC. This involves a stabilizing stem-loop structure within the 5′-region of CsrC. YmoA-mediated CsrC stabilization depends on H-NS, but not on the RNA chaperone Hfq. YmoA-promoted reprogramming of the Csr system has severe consequences for the cell: we found that a mutant deficient of ymoA is strongly reduced in its ability to enter host cells and to disseminate to the Peyer’s patches, mesenteric lymph nodes, liver and spleen in mice. We propose a model in which YmoA controls transition from the initial colonization phase in the intestine toward the host defense phase important for the long-term establishment of the infection in underlying tissues.
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Affiliation(s)
- Katja Böhme
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Stephanie Lobedann
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Yuzhu Guo
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), Medical Faculty Münster, University of Münster, Münster, Germany
| | - Anne-Sophie Stolle
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), Medical Faculty Münster, University of Münster, Münster, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), Medical Faculty Münster, University of Münster, Münster, Germany
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2
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Knittel V, Sadana P, Seekircher S, Stolle AS, Körner B, Volk M, Jeffries CM, Svergun DI, Heroven AK, Scrima A, Dersch P. RovC - a novel type of hexameric transcriptional activator promoting type VI secretion gene expression. PLoS Pathog 2020; 16:e1008552. [PMID: 32966346 PMCID: PMC7535981 DOI: 10.1371/journal.ppat.1008552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/05/2020] [Accepted: 08/01/2020] [Indexed: 12/05/2022] Open
Abstract
Type VI secretion systems (T6SSs) are complex macromolecular injection machines which are widespread in Gram-negative bacteria. They are involved in host-cell interactions and pathogenesis, required to eliminate competing bacteria, or are important for the adaptation to environmental stress conditions. Here we identified regulatory elements controlling the T6SS4 of Yersinia pseudotuberculosis and found a novel type of hexameric transcription factor, RovC. RovC directly interacts with the T6SS4 promoter region and activates T6SS4 transcription alone or in cooperation with the LysR-type regulator RovM. A higher complexity of regulation was achieved by the nutrient-responsive global regulator CsrA, which controls rovC expression on the transcriptional and post-transcriptional level. In summary, our work unveils a central mechanism in which RovC, a novel key activator, orchestrates the expression of the T6SS weapons together with a global regulator to deploy the system in response to the availability of nutrients in the species' native environment.
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Affiliation(s)
- Vanessa Knittel
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Pooja Sadana
- Young Investigator Group Structural Biology of Autophagy, Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Stephanie Seekircher
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Anne-Sophie Stolle
- Institute for Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Britta Körner
- Institute for Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Marcel Volk
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Cy M. Jeffries
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Andrea Scrima
- Young Investigator Group Structural Biology of Autophagy, Department of Structure and Function of Proteins, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
- German Center for Infection Research, Baunschweig, Germany
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3
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Phenotypic Diversification of Microbial Pathogens—Cooperating and Preparing for the Future. J Mol Biol 2019; 431:4645-4655. [DOI: 10.1016/j.jmb.2019.06.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/22/2022]
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4
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Kusmierek M, Hoßmann J, Witte R, Opitz W, Vollmer I, Volk M, Heroven AK, Wolf-Watz H, Dersch P. A bacterial secreted translocator hijacks riboregulators to control type III secretion in response to host cell contact. PLoS Pathog 2019; 15:e1007813. [PMID: 31173606 PMCID: PMC6583979 DOI: 10.1371/journal.ppat.1007813] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 06/19/2019] [Accepted: 05/02/2019] [Indexed: 02/05/2023] Open
Abstract
Numerous Gram-negative pathogens use a Type III Secretion System (T3SS) to promote virulence by injecting effector proteins into targeted host cells, which subvert host cell processes. Expression of T3SS and the effectors is triggered upon host cell contact, but the underlying mechanism is poorly understood. Here, we report a novel strategy of Yersinia pseudotuberculosis in which this pathogen uses a secreted T3SS translocator protein (YopD) to control global RNA regulators. Secretion of the YopD translocator upon host cell contact increases the ratio of post-transcriptional regulator CsrA to its antagonistic small RNAs CsrB and CsrC and reduces the degradosome components PNPase and RNase E levels. This substantially elevates the amount of the common transcriptional activator (LcrF) of T3SS/Yop effector genes and triggers the synthesis of associated virulence-relevant traits. The observed hijacking of global riboregulators allows the pathogen to coordinate virulence factor expression and also readjusts its physiological response upon host cell contact.
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Affiliation(s)
- Maria Kusmierek
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jörn Hoßmann
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Rebekka Witte
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Wiebke Opitz
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ines Vollmer
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectiology, University of Münster, Germany
| | - Marcel Volk
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectiology, University of Münster, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Hans Wolf-Watz
- Department of Molecular Biology, Umea University, Sweden
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectiology, University of Münster, Germany
- * E-mail:
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5
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Thanikkal EJ, Gahlot DK, Liu J, Fredriksson Sundbom M, Gurung JM, Ruuth K, Francis MK, Obi IR, Thompson KM, Chen S, Dersch P, Francis MS. The Yersinia pseudotuberculosis Cpx envelope stress system contributes to transcriptional activation of rovM. Virulence 2019; 10:37-57. [PMID: 30518290 PMCID: PMC6298763 DOI: 10.1080/21505594.2018.1556151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The Gram-negative enteropathogen Yersinia pseudotuberculosis possesses a number of regulatory systems that detect cell envelope damage caused by noxious extracytoplasmic stresses. The CpxA sensor kinase and CpxR response regulator two-component regulatory system is one such pathway. Active Cpx signalling upregulates various factors designed to repair and restore cell envelope integrity. Concomitantly, this pathway also down-regulates key determinants of virulence. In Yersinia, cpxA deletion accumulates high levels of phosphorylated CpxR (CpxR~P). Accumulated CpxR~P directly repressed rovA expression and this limited expression of virulence-associated processes. A second transcriptional regulator, RovM, also negatively regulates rovA expression in response to nutrient stress. Hence, this study aimed to determine if CpxR~P can influence rovA expression through control of RovM levels. We determined that the active CpxR~P isoform bound to the promoter of rovM and directly induced its expression, which naturally associated with a concurrent reduction in rovA expression. Site-directed mutagenesis of the CpxR~P binding sequence in the rovM promoter region desensitised rovM expression to CpxR~P. These data suggest that accumulated CpxR~P inversely manipulates the levels of two global transcriptional regulators, RovA and RovM, and this would be expected to have considerable influence on Yersinia pathophysiology and metabolism.
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Affiliation(s)
- Edvin J Thanikkal
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Dharmender K Gahlot
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Junfa Liu
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | | | - Jyoti M Gurung
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Kristina Ruuth
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Monika K Francis
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Ikenna R Obi
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
| | - Karl M Thompson
- c Department of Microbiology , College of Medicine, Howard University , Washington , DC , USA.,d Interdisciplinary Research Building , Howard University , Washington , DC , USA
| | - Shiyun Chen
- e Key Laboratory of Special Pathogens and Biosafety , Wuhan Institute of Virology, Chinese Academy of Sciences , Wuhan , China
| | - Petra Dersch
- f Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
| | - Matthew S Francis
- a Department of Molecular Biology , Umeå University , Umeå , Sweden.,b Umeå Centre for Microbial Research , Umeå University , Umeå , Sweden
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Knittel V, Vollmer I, Volk M, Dersch P. Discovering RNA-Based Regulatory Systems for Yersinia Virulence. Front Cell Infect Microbiol 2018; 8:378. [PMID: 30460205 PMCID: PMC6232918 DOI: 10.3389/fcimb.2018.00378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/05/2018] [Indexed: 12/26/2022] Open
Abstract
The genus Yersinia includes three human pathogenic species, Yersinia pestis, the causative agent of the bubonic and pneumonic plague, and enteric pathogens Y. enterocolitica and Y. pseudotuberculosis that cause a number of gut-associated diseases. Over the past years a large repertoire of RNA-based regulatory systems has been discovered in these pathogens using different RNA-seq based approaches. Among them are several conserved or species-specific RNA-binding proteins, regulatory and sensory RNAs as well as various RNA-degrading enzymes. Many of them were shown to control the expression of important virulence-relevant factors and have a very strong impact on Yersinia virulence. The precise targets, the molecular mechanism and their role for Yersinia pathogenicity is only known for a small subset of identified genus- or species-specific RNA-based control elements. However, the ongoing development of new RNA-seq based methods and data analysis methods to investigate the synthesis, composition, translation, decay, and modification of RNAs in the bacterial cell will help us to generate a more comprehensive view of Yersinia RNA biology in the near future.
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Affiliation(s)
- Vanessa Knittel
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ines Vollmer
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Marcel Volk
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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7
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Phenotypic heterogeneity: a bacterial virulence strategy. Microbes Infect 2018; 20:570-577. [DOI: 10.1016/j.micinf.2018.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 11/21/2022]
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8
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Durica-Mitic S, Göpel Y, Görke B. Carbohydrate Utilization in Bacteria: Making the Most Out of Sugars with the Help of Small Regulatory RNAs. Microbiol Spectr 2018; 6. [PMID: 29573258 DOI: 10.1128/microbiolspec.rwr-0013-2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Indexed: 12/11/2022] Open
Abstract
Survival of bacteria in ever-changing habitats with fluctuating nutrient supplies requires rapid adaptation of their metabolic capabilities. To this end, carbohydrate metabolism is governed by complex regulatory networks including posttranscriptional mechanisms that involve small regulatory RNAs (sRNAs) and RNA-binding proteins. sRNAs limit the response to substrate availability and set the threshold or time required for induction and repression of carbohydrate utilization systems. Carbon catabolite repression (CCR) also involves sRNAs. In Enterobacteriaceae, sRNA Spot 42 cooperates with the transcriptional regulator cyclic AMP (cAMP)-receptor protein (CRP) to repress secondary carbohydrate utilization genes when a preferred sugar is consumed. In pseudomonads, CCR operates entirely at the posttranscriptional level, involving RNA-binding protein Hfq and decoy sRNA CrcZ. Moreover, sRNAs coordinate fluxes through central carbohydrate metabolic pathways with carbohydrate availability. In Gram-negative bacteria, the interplay between RNA-binding protein CsrA and its cognate sRNAs regulates glycolysis and gluconeogenesis in response to signals derived from metabolism. Spot 42 and cAMP-CRP jointly downregulate tricarboxylic acid cycle activity when glycolytic carbon sources are ample. In addition, bacteria use sRNAs to reprogram carbohydrate metabolism in response to anaerobiosis and iron limitation. Finally, sRNAs also provide homeostasis of essential anabolic pathways, as exemplified by the hexosamine pathway providing cell envelope precursors. In this review, we discuss the manifold roles of bacterial sRNAs in regulation of carbon source uptake and utilization, substrate prioritization, and metabolism.
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Affiliation(s)
- Svetlana Durica-Mitic
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Yvonne Göpel
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
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9
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Regulation of host–pathogen interactions via the post-transcriptional Csr/Rsm system. Curr Opin Microbiol 2018; 41:58-67. [DOI: 10.1016/j.mib.2017.11.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/20/2017] [Indexed: 12/22/2022]
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10
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Abstract
Bacterial pathogens must endure or adapt to different environments and stresses during transmission and infection. Posttranscriptional gene expression control by regulatory RNAs, such as small RNAs and riboswitches, is now considered central to adaptation in many bacteria, including pathogens. The study of RNA-based regulation (riboregulation) in pathogenic species has provided novel insight into how these bacteria regulate virulence gene expression. It has also uncovered diverse mechanisms by which bacterial small RNAs, in general, globally control gene expression. Riboregulators as well as their targets may also prove to be alternative targets or provide new strategies for antimicrobials. In this article, we present an overview of the general mechanisms that bacteria use to regulate with RNA, focusing on examples from pathogens. In addition, we also briefly review how deep sequencing approaches have aided in opening new perspectives in small RNA identification and the study of their functions. Finally, we discuss examples of riboregulators in two model pathogens that control virulence factor expression or survival-associated phenotypes, such as stress tolerance, biofilm formation, or cell-cell communication, to illustrate how riboregulation factors into regulatory networks in bacterial pathogens.
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11
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Circuitry Linking the Catabolite Repression and Csr Global Regulatory Systems of Escherichia coli. J Bacteriol 2016; 198:3000-3015. [PMID: 27551019 DOI: 10.1128/jb.00454-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/12/2016] [Indexed: 01/21/2023] Open
Abstract
Cyclic AMP (cAMP) and the cAMP receptor protein (cAMP-CRP) and CsrA are the principal regulators of the catabolite repression and carbon storage global regulatory systems, respectively. cAMP-CRP controls the transcription of genes for carbohydrate metabolism and other processes in response to carbon nutritional status, while CsrA binds to diverse mRNAs and regulates translation, RNA stability, and/or transcription elongation. CsrA also binds to the regulatory small RNAs (sRNAs) CsrB and CsrC, which antagonize its activity. The BarA-UvrY two-component signal transduction system (TCS) directly activates csrB and csrC (csrB/C) transcription, while CsrA does so indirectly. We show that cAMP-CRP inhibits csrB/C transcription without negatively regulating phosphorylated UvrY (P-UvrY) or CsrA levels. A crp deletion caused an elevation in CsrB/C levels in the stationary phase of growth and increased the expression of csrB-lacZ and csrC-lacZ transcriptional fusions, although modest stimulation of CsrB/C turnover by the crp deletion partially masked the former effects. DNase I footprinting and other studies demonstrated that cAMP-CRP bound specifically to three sites located upstream from the csrC promoter, two of which overlapped the P-UvrY binding site. These two proteins competed for binding at the overlapping sites. In vitro transcription-translation experiments confirmed direct repression of csrC-lacZ expression by cAMP-CRP. In contrast, cAMP-CRP effects on csrB transcription may be mediated indirectly, as it bound nonspecifically to csrB DNA. In the reciprocal direction, CsrA bound to crp mRNA with high affinity and specificity and yet exhibited only modest, conditional effects on expression. Our findings are incorporated into an emerging model for the response of Csr circuitry to carbon nutritional status. IMPORTANCE Csr (Rsm) noncoding small RNAs (sRNAs) CsrB and CsrC of Escherichia coli use molecular mimicry to sequester the RNA binding protein CsrA (RsmA) away from lower-affinity mRNA targets, thus eliciting major shifts in the bacterial lifestyle. CsrB/C transcription and turnover are activated by carbon metabolism products (e.g., formate and acetate) and by a preferred carbon source (glucose), respectively. We show that cAMP-CRP, a mediator of classical catabolite repression, inhibits csrC transcription by binding to the upstream region of this gene and also inhibits csrB transcription, apparently indirectly. We propose that glucose availability activates pathways for both synthesis and turnover of CsrB/C, thus shaping the dynamics of global signaling in response to the nutritional environment by poising CsrB/C sRNA levels for rapid response.
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12
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Nuss AM, Heroven AK, Dersch P. RNA Regulators: Formidable Modulators of Yersinia Virulence. Trends Microbiol 2016; 25:19-34. [PMID: 27651123 DOI: 10.1016/j.tim.2016.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/08/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
Abstract
A large repertoire of RNA-based regulatory mechanisms, including a plethora of cis- and trans-acting noncoding RNAs (ncRNAs), sensory RNA elements, regulatory RNA-binding proteins, and RNA-degrading enzymes have been uncovered lately as key players in the regulation of metabolism, stress responses, and virulence of the genus Yersinia. Many of them are strictly controlled in response to fluctuating environmental conditions sensed during the course of the infection, and certain riboregulators have already been shown to be crucial for virulence. Some of them are highly conserved among the family Enterobacteriaceae, while others are genus-, species-, or strain-specific and could contribute to the difference in Yersinia pathogenicity. Importantly, the analysis of Yersinia riboregulators has not only uncovered crucial elements and regulatory mechanisms governing host-pathogen interactions, it also revealed exciting new venues for the design of novel anti-infectives.
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Affiliation(s)
- Aaron M Nuss
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.
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13
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RsmW, Pseudomonas aeruginosa small non-coding RsmA-binding RNA upregulated in biofilm versus planktonic growth conditions. BMC Microbiol 2016; 16:155. [PMID: 27430253 PMCID: PMC4950607 DOI: 10.1186/s12866-016-0771-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 07/12/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biofilm development, specifically the fundamentally adaptive switch from acute to chronic infection phenotypes, requires global regulators and small non-coding regulatory RNAs (sRNAs). This work utilized RNA-sequencing (RNA-seq) to detect sRNAs differentially expressed in Pseudomonas aeruginosa biofilm versus planktonic state. RESULTS A computational algorithm was devised to detect and categorize sRNAs into 5 types: intergenic, intragenic, 5'-UTR, 3'-UTR, and antisense. Here we report a novel RsmY/RsmZ-type sRNA, termed RsmW, in P. aeruginosa up-transcribed in biofilm versus planktonic growth. RNA-Seq, 5'-RACE and Mfold predictions suggest RsmW has a secondary structure with 3 of 7 GGA motifs located on outer stem loops. Northern blot revealed two RsmW binding bands of 400 and 120 bases, suggesting RsmW is derived from the 3'-UTR of the upstream hypothetical gene, PA4570. RsmW expression is elevated in late stationary versus logarithmic growth phase in PB minimal media, at higher temperatures (37 °C versus 28 °C), and in both gacA and rhlR transposon mutants versus wild-type. RsmW specifically binds to RsmA protein in vitro and restores biofilm production and reduces swarming in an rsmY/rsmZ double mutant. PA4570 weakly resembles an RsmA/RsmN homolog having 49 % and 51 % similarity, and 16 % and 17 % identity to RsmA and RsmN amino acid sequences, respectively. PA4570 was unable to restore biofilm and swarming phenotypes in ΔrsmA deficient strains. CONCLUSION Collectively, our study reveals an interesting theme regarding another sRNA regulator of the Rsm system and further unravels the complexities regulating adaptive responses for Pseudomonas species.
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14
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McNally A, Thomson NR, Reuter S, Wren BW. 'Add, stir and reduce': Yersinia spp. as model bacteria for pathogen evolution. Nat Rev Microbiol 2016; 14:177-90. [PMID: 26876035 DOI: 10.1038/nrmicro.2015.29] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pathogenic species in the Yersinia genus have historically been targets for research aimed at understanding how bacteria evolve into mammalian pathogens. The advent of large-scale population genomic studies has greatly accelerated the progress in this field, and Yersinia pestis, Yersinia pseudotuberculosis and Yersinia enterocolitica have once again acted as model organisms to help shape our understanding of the evolutionary processes involved in pathogenesis. In this Review, we highlight the gene gain, gene loss and genome rearrangement events that have been identified by genomic studies in pathogenic Yersinia species, and we discuss how these findings are changing our understanding of pathogen evolution. Finally, as these traits are also found in the genomes of other species in the Enterobacteriaceae, we suggest that they provide a blueprint for the evolution of enteropathogenic bacteria.
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Affiliation(s)
- Alan McNally
- Pathogen Research Group, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK
| | - Nicholas R Thomson
- Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Sandra Reuter
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Brendan W Wren
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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15
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Temperature-responsive in vitro RNA structurome of Yersinia pseudotuberculosis. Proc Natl Acad Sci U S A 2016; 113:7237-42. [PMID: 27298343 DOI: 10.1073/pnas.1523004113] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RNA structures are fundamentally important for RNA function. Dynamic, condition-dependent structural changes are able to modulate gene expression as shown for riboswitches and RNA thermometers. By parallel analysis of RNA structures, we mapped the RNA structurome of Yersinia pseudotuberculosis at three different temperatures. This human pathogen is exquisitely responsive to host body temperature (37 °C), which induces a major metabolic transition. Our analysis profiles the structure of more than 1,750 RNAs at 25 °C, 37 °C, and 42 °C. Average mRNAs tend to be unstructured around the ribosome binding site. We searched for 5'-UTRs that are folded at low temperature and identified novel thermoresponsive RNA structures from diverse gene categories. The regulatory potential of 16 candidates was validated. In summary, we present a dynamic bacterial RNA structurome and find that the expression of virulence-relevant functions in Y. pseudotuberculosis and reprogramming of its metabolism in response to temperature is associated with a restructuring of numerous mRNAs.
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16
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Chen S, Thompson KM, Francis MS. Environmental Regulation of Yersinia Pathophysiology. Front Cell Infect Microbiol 2016; 6:25. [PMID: 26973818 PMCID: PMC4773443 DOI: 10.3389/fcimb.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022] Open
Abstract
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
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Affiliation(s)
- Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University Washington, DC, USA
| | - Matthew S Francis
- Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå UniversityUmeå, Sweden
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17
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Porcheron G, Schouler C, Dozois CM. Survival games at the dinner table: regulation of Enterobacterial virulence through nutrient sensing and acquisition. Curr Opin Microbiol 2016; 30:98-106. [PMID: 26871481 DOI: 10.1016/j.mib.2016.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/12/2016] [Accepted: 01/19/2016] [Indexed: 10/22/2022]
Abstract
The ability of bacterial pathogens to colonize specific host niches is largely dependent on acquisition of essential metabolites and co-factors for growth and sensing and adapting in response to specific environmental cues. Nutrient availability in host environments is strongly influenced by host physiology and immunity, diet, and competition with other members of the host microbiota. Rapid adaptation to environmental cues and nutrient availability is a hallmark of bacterial fitness and virulence. This adaptability requires complex regulatory networks that tightly link sensing of nutrient availability to expression of virulence genes accordingly. This review focuses on recent findings highlighting the ability of bacterial pathogens to compete for nutrient acquisition in the host-microbiota environment, and emphasizes key aspects mediating the multi-tiered regulatory cascades that coordinately control nutrient sensing and expression of virulence genes in pathogenic Enterobacteria.
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Affiliation(s)
- Gaëlle Porcheron
- INRS-Institut Armand Frappier, Laval, Québec, Canada; Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, Canada
| | - Catherine Schouler
- INRA, UMR1282 Infectiologie et Santé Publique, 37 380 Nouzilly, France; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, 37 000 Tours, France
| | - Charles M Dozois
- INRS-Institut Armand Frappier, Laval, Québec, Canada; Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, Canada.
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18
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Martínez-Chavarría LC, Vadyvaloo V. Yersinia pestis and Yersinia pseudotuberculosis infection: a regulatory RNA perspective. Front Microbiol 2015; 6:956. [PMID: 26441890 PMCID: PMC4585118 DOI: 10.3389/fmicb.2015.00956] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/28/2015] [Indexed: 12/27/2022] Open
Abstract
Yersinia pestis, responsible for causing fulminant plague, has evolved clonally from the enteric pathogen, Y. pseudotuberculosis, which in contrast, causes a relatively benign enteric illness. An ~97% nucleotide identity over 75% of their shared protein coding genes is maintained between these two pathogens, leaving much conjecture regarding the molecular determinants responsible for producing these vastly different disease etiologies, host preferences and transmission routes. One idea is that coordinated production of distinct factors required for host adaptation and virulence in response to specific environmental cues could contribute to the distinct pathogenicity distinguishing these two species. Small non-coding RNAs that direct posttranscriptional regulation have recently been identified as key molecules that may provide such timeous expression of appropriate disease enabling factors. Here the burgeoning field of small non-coding regulatory RNAs in Yersinia pathogenesis is reviewed from the viewpoint of adaptive colonization, virulence and divergent evolution of these pathogens.
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Affiliation(s)
- Luary C Martínez-Chavarría
- Departamento de Patología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, México Mexico
| | - Viveka Vadyvaloo
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA USA
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19
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Erhardt M, Dersch P. Regulatory principles governing Salmonella and Yersinia virulence. Front Microbiol 2015; 6:949. [PMID: 26441883 PMCID: PMC4563271 DOI: 10.3389/fmicb.2015.00949] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/27/2015] [Indexed: 11/13/2022] Open
Abstract
Enteric pathogens such as Salmonella and Yersinia evolved numerous strategies to survive and proliferate in different environmental reservoirs and mammalian hosts. Deciphering common and pathogen-specific principles for how these bacteria adjust and coordinate spatiotemporal expression of virulence determinants, stress adaptation, and metabolic functions is fundamental to understand microbial pathogenesis. In order to manage sudden environmental changes, attacks by the host immune systems and microbial competition, the pathogens employ a plethora of transcriptional and post-transcriptional control elements, including transcription factors, sensory and regulatory RNAs, RNAses, and proteases, to fine-tune and control complex gene regulatory networks. Many of the contributing global regulators and the molecular mechanisms of regulation are frequently conserved between Yersinia and Salmonella. However, the interplay, arrangement, and composition of the control elements vary between these closely related enteric pathogens, which generate phenotypic differences leading to distinct pathogenic properties. In this overview we present common and different regulatory networks used by Salmonella and Yersinia to coordinate the expression of crucial motility, cell adhesion and invasion determinants, immune defense strategies, and metabolic adaptation processes. We highlight evolutionary changes of the gene regulatory circuits that result in different properties of the regulatory elements and how this influences the overall outcome of the infection process.
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Affiliation(s)
- Marc Erhardt
- Young Investigator Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research Braunschweig, Germany
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20
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Vakulskas CA, Potts AH, Babitzke P, Ahmer BMM, Romeo T. Regulation of bacterial virulence by Csr (Rsm) systems. Microbiol Mol Biol Rev 2015; 79:193-224. [PMID: 25833324 PMCID: PMC4394879 DOI: 10.1128/mmbr.00052-14] [Citation(s) in RCA: 243] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Most bacterial pathogens have the remarkable ability to flourish in the external environment and in specialized host niches. This ability requires their metabolism, physiology, and virulence factors to be responsive to changes in their surroundings. It is no surprise that the underlying genetic circuitry that supports this adaptability is multilayered and exceedingly complex. Studies over the past 2 decades have established that the CsrA/RsmA proteins, global regulators of posttranscriptional gene expression, play important roles in the expression of virulence factors of numerous proteobacterial pathogens. To accomplish these tasks, CsrA binds to the 5' untranslated and/or early coding regions of mRNAs and alters translation, mRNA turnover, and/or transcript elongation. CsrA activity is regulated by noncoding small RNAs (sRNAs) that contain multiple CsrA binding sites, which permit them to sequester multiple CsrA homodimers away from mRNA targets. Environmental cues sensed by two-component signal transduction systems and other regulatory factors govern the expression of the CsrA-binding sRNAs and, ultimately, the effects of CsrA on secretion systems, surface molecules and biofilm formation, quorum sensing, motility, pigmentation, siderophore production, and phagocytic avoidance. This review presents the workings of the Csr system, the paradigm shift that it generated for understanding posttranscriptional regulation, and its roles in virulence networks of animal and plant pathogens.
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Affiliation(s)
- Christopher A Vakulskas
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Anastasia H Potts
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Brian M M Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Tony Romeo
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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21
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Nuss AM, Heroven AK, Waldmann B, Reinkensmeier J, Jarek M, Beckstette M, Dersch P. Transcriptomic profiling of Yersinia pseudotuberculosis reveals reprogramming of the Crp regulon by temperature and uncovers Crp as a master regulator of small RNAs. PLoS Genet 2015; 11:e1005087. [PMID: 25816203 PMCID: PMC4376681 DOI: 10.1371/journal.pgen.1005087] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/20/2015] [Indexed: 12/20/2022] Open
Abstract
One hallmark of pathogenic yersiniae is their ability to rapidly adjust their life-style and pathogenesis upon host entry. In order to capture the range, magnitude and complexity of the underlying gene control mechanisms we used comparative RNA-seq-based transcriptomic profiling of the enteric pathogen Y. pseudotuberculosis under environmental and infection-relevant conditions. We identified 1151 individual transcription start sites, multiple riboswitch-like RNA elements, and a global set of antisense RNAs and previously unrecognized trans-acting RNAs. Taking advantage of these data, we revealed a temperature-induced and growth phase-dependent reprogramming of a large set of catabolic/energy production genes and uncovered the existence of a thermo-regulated ‘acetate switch’, which appear to prime the bacteria for growth in the digestive tract. To elucidate the regulatory architecture linking nutritional status to virulence we also refined the CRP regulon. We identified a massive remodelling of the CRP-controlled network in response to temperature and discovered CRP as a transcriptional master regulator of numerous conserved and newly identified non-coding RNAs which participate in this process. This finding highlights a novel level of complexity of the regulatory network in which the concerted action of transcriptional regulators and multiple non-coding RNAs under control of CRP adjusts the control of Yersinia fitness and virulence to the requirements of their environmental and virulent life-styles. Many bacterial pathogens cycle between environmental sources and mammalian hosts. Adaptation to the different natural habitats and host niches is achieved through complex regulatory networks which adjust synthesis of the large repertoire of crucial virulence factors and fitness determinants. To uncover underlying control circuits, we determined the first in-depth single-nucleotide resolution transcriptome of Yersinia. This revealed important novel genetic information, such as global locations of transcriptional start sites, non-coding RNAs, potential riboswitches and provided a set of virulence-relevant expression profiles, which constitute a valuable tool for the research community. The analysis further uncovered a temperature-induced global reprogramming of central metabolic functions, likely to support intestinal colonization of the pathogen. This is accompanied by a major reorganization of the CRP regulon, which involves a multitude of regulatory RNAs. The primary consequence is a fine-tuned, coordinated control of metabolism and virulence through a plethora of environmentally controlled regulatory RNAs allowing rapid adaptation and high flexibility during life-style changes.
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Affiliation(s)
- Aaron M. Nuss
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Barbara Waldmann
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jan Reinkensmeier
- Faculty of Technology and Center for Biotechnology (CeBiTec), Bielefeld University, Germany
| | - Michael Jarek
- Department of Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Beckstette
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- * E-mail:
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22
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Reprogramming of Yersinia from virulent to persistent mode revealed by complex in vivo RNA-seq analysis. PLoS Pathog 2015; 11:e1004600. [PMID: 25590628 PMCID: PMC4295882 DOI: 10.1371/journal.ppat.1004600] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 12/03/2014] [Indexed: 11/19/2022] Open
Abstract
We recently found that Yersinia pseudotuberculosis can be used as a model of persistent bacterial infections. We performed in vivo RNA-seq of bacteria in small cecal tissue biopsies at early and persistent stages of infection to determine strategies associated with persistence. Comprehensive analysis of mixed RNA populations from infected tissues revealed that Y. pseudotuberculosis undergoes transcriptional reprogramming with drastic down-regulation of T3SS virulence genes during persistence when the pathogen resides within the cecum. At the persistent stage, the expression pattern in many respects resembles the pattern seen in vitro at 26oC, with for example, up-regulation of flagellar genes and invA. These findings are expected to have impact on future rationales to identify suitable bacterial targets for new antibiotics. Other genes that are up-regulated during persistence are genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress, which indicates the influence of different environmental cues. We found that the Crp/CsrA/RovA regulatory cascades influence the pattern of bacterial gene expression during persistence. Furthermore, arcA, fnr, frdA, and wrbA play critical roles in persistence. Our findings suggest a model for the life cycle of this enteropathogen with reprogramming from a virulent to an adapted phenotype capable of persisting and spreading by fecal shedding. To establish infection and colonize within a host, infecting pathogens have to cope with a variety of destructive surroundings. The food-borne pathogen Y. pseudotuberculosis can cause persistent infection in mice. Upon infection, Y. pseudotuberculosis passes the anti-microbial gastrointestinal milieu and finally remains associated with lymphoid follicles in cecal tissue surrounded by polymorphonuclear leukocytes, indicating that the bacteria are exposed to multiple environmental cues. We performed complex RNA-seq of small cecal biopsies of infected mice to reveal Y. pseudotuberculosis gene expression in vivo. We found that Y. pseudotuberculosis underwent reprogramming from a virulent phenotype, expressing virulence genes during early infection, to an adapted phenotype capable of persisting in the harsh cecal environment. Persistence was characterized by a novel expression pattern with down-regulation of virulence genes and up-regulation of genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress. Mutagenesis of selected genes revealed that the regulator rovA was critical for the establishment of infection, and that arcA, fnr, frdA, and wrbA play critical roles in maintaining infection for long periods of time. Our study shows the power of RNA deep sequencing, which can be used to reveal the in vivo expression patterns of small amounts of bacteria in complex intestinal environments.
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23
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Heroven AK, Dersch P. Coregulation of host-adapted metabolism and virulence by pathogenic yersiniae. Front Cell Infect Microbiol 2014; 4:146. [PMID: 25368845 PMCID: PMC4202721 DOI: 10.3389/fcimb.2014.00146] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/30/2014] [Indexed: 01/07/2023] Open
Abstract
Deciphering the principles how pathogenic bacteria adapt their metabolism to a specific host microenvironment is critical for understanding bacterial pathogenesis. The enteric pathogenic Yersinia species Yersinia pseudotuberculosis and Yersinia enterocolitica and the causative agent of plague, Yersinia pestis, are able to survive in a large variety of environmental reservoirs (e.g., soil, plants, insects) as well as warm-blooded animals (e.g., rodents, pigs, humans) with a particular preference for lymphatic tissues. In order to manage rapidly changing environmental conditions and interbacterial competition, Yersinia senses the nutritional composition during the course of an infection by special molecular devices, integrates this information and adapts its metabolism accordingly. In addition, nutrient availability has an impact on expression of virulence genes in response to C-sources, demonstrating a tight link between the pathogenicity of yersiniae and utilization of nutrients. Recent studies revealed that global regulatory factors such as the cAMP receptor protein (Crp) and the carbon storage regulator (Csr) system are part of a large network of transcriptional and posttranscriptional control strategies adjusting metabolic changes and virulence in response to temperature, ion and nutrient availability. Gained knowledge about the specific metabolic requirements and the correlation between metabolic and virulence gene expression that enable efficient host colonization led to the identification of new potential antimicrobial targets.
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Affiliation(s)
- Ann Kathrin Heroven
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Institut für Mikrobiology, Technische Universität Braunschweig Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Institut für Mikrobiology, Technische Universität Braunschweig Braunschweig, Germany
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