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Raghunandanan S, Zhang K, Zhang Y, Sze CW, Priya R, Luo Y, Lynch MJ, Crane BR, Li C, Yang XF. MCP5, a methyl-accepting chemotaxis protein regulated by both the Hk1-Rrp1 and Rrp2-RpoN-RpoS pathways, is required for the immune evasion of Borrelia burgdorferi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.10.598185. [PMID: 38915556 PMCID: PMC11195095 DOI: 10.1101/2024.06.10.598185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Borrelia (or Borreliella) burgdorferi, the causative agent of Lyme disease, is a motile and invasive zoonotic pathogen, adept at navigating between its arthropod vector and mammalian host. While motility and chemotaxis are well established as essential for its enzootic cycle, the function of methyl-accepting chemotaxis proteins (MCPs) in the infectious cycle of B. burgdorferi remains unclear. In this study, we demonstrate that MCP5, one of the most abundant MCPs in B. burgdorferi, is differentially expressed in response to environmental signals as well as at different stages of the pathogen's enzootic cycle. Specifically, the expression of mcp5 is regulated by the Hk1-Rrp1 and Rrp2-RpoN-RpoS pathways, which are critical for the spirochete's colonization of the tick vector and mammalian host, respectively. Infection experiments with an mcp5 mutant revealed that spirochetes lacking MCP5 could not establish infections in either C3H/HeN mice or Severe Combined Immunodeficiency (SCID) mice, which are defective in adaptive immunity, indicating the essential role of MCP5 in mammalian infection. However, the mcp5 mutant could establish infection and disseminate in NOD SCID Gamma (NSG) mice, which are deficient in both adaptive and most innate immune responses, suggesting a crucial role of MCP5 in evading host innate immunity. In the tick vector, the mcp5 mutants survived feeding but failed to transmit to mice, highlighting the importance of MCP5 in transmission. Our findings reveal that MCP5, regulated by the Rrp1 and Rrp2 pathways, is critical for the establishment of infection in mammalian hosts by evading host innate immunity and is important for the transmission of spirochetes from ticks to mammalian hosts, underscoring its potential as a target for intervention strategies.
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Affiliation(s)
- Sajith Raghunandanan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Kai Zhang
- Department of Oral Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - Yan Zhang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China, 325035
| | - Ching Wooen Sze
- Department of Oral Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - Raj Priya
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Yongliang Luo
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China, 325035
| | - Michael J Lynch
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, 23298
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
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Raghunandanan S, Priya R, Alanazi F, Lybecker MC, Schlax P, Yang X. A Fur family protein BosR is a novel RNA-binding protein that controls rpoS RNA stability in the Lyme disease pathogen. Nucleic Acids Res 2024; 52:5320-5335. [PMID: 38366569 PMCID: PMC11109971 DOI: 10.1093/nar/gkae114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024] Open
Abstract
The σ54-σS sigma factor cascade plays a central role in regulating differential gene expression during the enzootic cycle of Borreliella burgdorferi, the Lyme disease pathogen. In this pathway, the primary transcription of rpoS (which encodes σS) is under the control of σ54 which is activated by a bacterial enhancer-binding protein (EBP), Rrp2. The σ54-dependent activation in B. burgdorferi has long been thought to be unique, requiring an additional factor, BosR, a homologue of classical Fur/PerR repressor/activator. However, how BosR is involved in this σ54-dependent activation remains unclear and perplexing. In this study, we demonstrate that BosR does not function as a regulator for rpoS transcriptional activation. Instead, it functions as a novel RNA-binding protein that governs the turnover rate of rpoS mRNA. We further show that BosR directly binds to the 5' untranslated region (UTR) of rpoS mRNA, and the binding region overlaps with a region required for rpoS mRNA degradation. Mutations within this 5'UTR region result in BosR-independent RpoS production. Collectively, these results uncover a novel role of Fur/PerR family regulators as RNA-binding proteins and redefine the paradigm of the σ54-σS pathway in B. burgdorferi.
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Affiliation(s)
- Sajith Raghunandanan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Raj Priya
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Fuad Alanazi
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Meghan C Lybecker
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Center for Disease Control and Prevention, Fort Collins, CO, USA
| | - Paula Jean Schlax
- Department of Chemistry and Biochemistry, Bates College, Lewiston, ME, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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3
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Smith EL, Goley ED. House of CarDs: Functional insights into the transcriptional regulator CdnL. Mol Microbiol 2024. [PMID: 38664995 DOI: 10.1111/mmi.15268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/12/2024] [Accepted: 04/11/2024] [Indexed: 07/07/2024]
Abstract
Regulation of bacterial transcription is a complex and multi-faceted phenomenon that is critical for growth and adaptation. Proteins in the CarD_CdnL_TRCF family are widespread, often essential, regulators of transcription of genes required for growth and metabolic homeostasis. Research in the last decade has described the mechanistic and structural bases of CarD-CdnL-mediated regulation of transcription initiation. More recently, studies in a range of bacteria have begun to elucidate the physiological roles of CarD-CdnL proteins as well as mechanisms by which these proteins, themselves, are regulated. A theme has emerged wherein regulation of CarD-CdnL proteins is central to bacterial adaptation to stress and/or changing environmental conditions.
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Affiliation(s)
- Erika L Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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4
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. PNAS NEXUS 2024; 3:pgae154. [PMID: 38650860 PMCID: PMC11034885 DOI: 10.1093/pnasnexus/pgae154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers guanosine 5'-diphosphate 3'-diphosphate and guanosine 5'-triphosphate 3'-diphosphate (collectively known as (p)ppGpp), which affect transcription by binding RNA polymerase (RNAP) to down-regulate anabolic genes. (p)ppGpp also impacts the expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important are unclear. In this study, we show that CdnL is down-regulated posttranslationally during starvation in a manner dependent on SpoT and the ClpXP protease. Artificial stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gaël Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Patrick H Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572625. [PMID: 38187569 PMCID: PMC10769358 DOI: 10.1101/2023.12.20.572625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers (p)ppGpp, which affect transcription by binding RNA polymerase to downregulate anabolic genes. (p)ppGpp also impacts expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important is unclear. Here, we show that CdnL is downregulated post-translationally during starvation in a manner dependent on SpoT and the ClpXP protease. Inappropriate stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L. Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
| | - Gaäl Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
- BlueRock Therapeutics, Cambridge, Massachusetts, 02142 (current)
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, Massachusetts, 01003
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
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6
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Grassmann AA, Tokarz R, Golino C, McLain MA, Groshong AM, Radolf JD, Caimano MJ. BosR and PlzA reciprocally regulate RpoS function to sustain Borrelia burgdorferi in ticks and mammals. J Clin Invest 2023; 133:e166710. [PMID: 36649080 PMCID: PMC9974103 DOI: 10.1172/jci166710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/10/2023] [Indexed: 01/18/2023] Open
Abstract
The RNA polymerase alternative σ factor RpoS in Borrelia burgdorferi (Bb), the Lyme disease pathogen, is responsible for programmatic-positive and -negative gene regulation essential for the spirochete's dual-host enzootic cycle. RpoS is expressed during tick-to-mammal transmission and throughout mammalian infection. Although the mammalian-phase RpoS regulon is well described, its counterpart during the transmission blood meal is unknown. Here, we used Bb-specific transcript enrichment by tick-borne disease capture sequencing (TBDCapSeq) to compare the transcriptomes of WT and ΔrpoS Bb in engorged nymphs and following mammalian host-adaptation within dialysis membrane chambers. TBDCapSeq revealed dramatic changes in the contours of the RpoS regulon within ticks and mammals and further confirmed that RpoS-mediated repression is specific to the mammalian-phase of Bb's enzootic cycle. We also provide evidence that RpoS-dependent gene regulation, including repression of tick-phase genes, is required for persistence in mice. Comparative transcriptomics of engineered Bb strains revealed that the Borrelia oxidative stress response regulator (BosR), a noncanonical Fur family member, and the cyclic diguanosine monophosphate (c-di-GMP) effector PlzA reciprocally regulate the function of RNA polymerase complexed with RpoS. BosR is required for RpoS-mediated transcription activation and repression in addition to its well-defined role promoting transcription of rpoS by the RNA polymerase alternative σ factor RpoN. During transmission, ligand-bound PlzA antagonizes RpoS-mediated repression, presumably acting through BosR.
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Affiliation(s)
| | - Rafal Tokarz
- Center for Infection and Immunity and
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Caroline Golino
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | | | - Ashley M. Groshong
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
| | - Justin D. Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
- Department of Molecular Biology and Biophysics
- Department of Genetics and Genome Sciences, and
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Melissa J. Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics
- Department of Molecular Biology and Biophysics
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7
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Pan L, Gardner CL, Beliakoff R, da Silva D, Zuo R, Pagliai FA, Padgett-Pagliai KA, Merli ML, Bahadiroglu E, Gonzalez CF, Lorca GL. PrbP modulates biofilm formation in Liberibacter crescens. Environ Microbiol 2021; 23:7121-7138. [PMID: 34431209 DOI: 10.1111/1462-2920.15740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/17/2021] [Accepted: 08/22/2021] [Indexed: 12/31/2022]
Abstract
In Liberibacter asiaticus, PrbP is a transcriptional regulatory protein involved in survival and persistence during host infection. Tolfenamic acid was previously found to inhibit interactions between PrbP and the promotor region of rplK, resulting in reduced survival of L. asiaticus in the citrus host. In this study, we performed transcriptome analyses to elucidate the PrbP regulon in L. crescens, as it is phylogenetically the closest related species to L. asiaticus that can be grown in laboratory conditions. Chemical inhibition of PrbP with tolfenamic acid revealed that PrbP is involved in the regulation of diverse cellular processes, including stress response, cell motility, cell cycle and biofilm formation. In vitro DNA binding and bacterial two-hybrid assays also suggested that PrbP is a global regulator of multiple transcription factors (RpoH, VisN, PleD, MucR, MocR and CtrA) at both transcriptional and/or post-transcriptional levels. Sub-lethal concentrations of tolfenamic acid significantly reduced the attachment of L. crescens during biofilm formation and decreased long-term persistence in biofilm structures. Overall, our findings show the importance of PrbP in regulating diverse biological processes through direct and indirect interactions with other transcriptional regulators in L. crescens.
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Affiliation(s)
- Lei Pan
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Christopher L Gardner
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Reagan Beliakoff
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Danilo da Silva
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Ran Zuo
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Fernando A Pagliai
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Kaylie A Padgett-Pagliai
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Marcelo L Merli
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Erol Bahadiroglu
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Claudio F Gonzalez
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
| | - Graciela L Lorca
- Microbiology and Cell Science Department, Genetics Institute, Institute of Food and Agricultural Science, University of Florida, Gainesville, FL, USA
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8
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Coburn J, Garcia B, Hu LT, Jewett MW, Kraiczy P, Norris SJ, Skare J. Lyme Disease Pathogenesis. Curr Issues Mol Biol 2020; 42:473-518. [PMID: 33353871 DOI: 10.21775/cimb.042.473] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lyme disease Borrelia are obligately parasitic, tick- transmitted, invasive, persistent bacterial pathogens that cause disease in humans and non-reservoir vertebrates primarily through the induction of inflammation. During transmission from the infected tick, the bacteria undergo significant changes in gene expression, resulting in adaptation to the mammalian environment. The organisms multiply and spread locally and induce inflammatory responses that, in humans, result in clinical signs and symptoms. Borrelia virulence involves a multiplicity of mechanisms for dissemination and colonization of multiple tissues and evasion of host immune responses. Most of the tissue damage, which is seen in non-reservoir hosts, appears to result from host inflammatory reactions, despite the low numbers of bacteria in affected sites. This host response to the Lyme disease Borrelia can cause neurologic, cardiovascular, arthritic, and dermatologic manifestations during the disseminated and persistent stages of infection. The mechanisms by which a paucity of organisms (in comparison to many other infectious diseases) can cause varied and in some cases profound inflammation and symptoms remains mysterious but are the subjects of diverse ongoing investigations. In this review, we provide an overview of virulence mechanisms and determinants for which roles have been demonstrated in vivo, primarily in mouse models of infection.
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Affiliation(s)
- Jenifer Coburn
- Center For Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd., TBRC C3980, Milwaukee, WI 53226, USA
| | - Brandon Garcia
- Department of Microbiology and Immunology, East Carolina University, Brody School of Medicine, Greenville, NC 27858, USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Vice Dean of Research, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
| | - Mollie W Jewett
- Immunity and Pathogenesis Division Head, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Blvd. Orlando, FL 32827, USA
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt, Germany
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, P.O. Box 20708, Houston, TX 77225, USA
| | - Jon Skare
- Professor and Associate Head, Texas A and M University, 8447 Riverside Pkwy, Bryan, TX 77807, USA
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9
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Pal U, Kitsou C, Drecktrah D, Yaş ÖB, Fikrig E. Interactions Between Ticks and Lyme Disease Spirochetes. Curr Issues Mol Biol 2020; 42:113-144. [PMID: 33289683 DOI: 10.21775/cimb.042.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Borrelia burgdorferi sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and Ixodes spp. ticks. In the Northeastern United States, I. scapularis is the main vector, while wild rodents serve as the mammalian reservoir host. As B. burgdorferi is transmitted only by I. scapularis and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of B. burgdorferi infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between B. burgdorferi and Ixodes ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the B. burgdorferi life cycle.
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Affiliation(s)
- Utpal Pal
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Özlem Büyüktanir Yaş
- Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Istinye University, Zeytinburnu, İstanbul, 34010, Turkey
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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10
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Zhang Y, Chen T, Raghunandanan S, Xiang X, Yang J, Liu Q, Edmondson DG, Norris SJ, Yang XF, Lou Y. YebC regulates variable surface antigen VlsE expression and is required for host immune evasion in Borrelia burgdorferi. PLoS Pathog 2020; 16:e1008953. [PMID: 33048986 PMCID: PMC7584230 DOI: 10.1371/journal.ppat.1008953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/23/2020] [Accepted: 09/02/2020] [Indexed: 02/08/2023] Open
Abstract
Borrelia burgdorferi, the Lyme disease pathogen causes persistent infection by evading the host immune response. Differential expression of the surface-exposed lipoprotein VlsE that undergoes antigenic variation is a key immune evasion strategy employed by B. burgdorferi. Most studies focused on the mechanism of VlsE antigen variation, but little is known about VlsE regulation and factor(s) that regulates differential vlsE expression. In this study, we investigated BB0025, a putative YebC family transcriptional regulator (and hence designated BB0025 as YebC of B. burgdorferi herein). We constructed yebC mutant and complemented strain in an infectious strain of B. burgdorferi. The yebC mutant could infect immunocompromised SCID mice but not immunocompetent mice, suggesting that YebC plays an important role in evading host adaptive immunity. RNA-seq analyses identified vlsE as one of the genes whose expression was most affected by YebC. Quantitative RT-PCR and Western blot analyses confirmed that vlsE expression was dependent on YebC. In vitro, YebC and VlsE were co-regulated in response to growth temperature. In mice, both yebC and vlsE were inversely expressed with ospC in response to the host adaptive immune response. Furthermore, EMSA proved that YebC directly binds to the vlsE promoter, suggesting a direct transcriptional control. These data demonstrate that YebC is a new regulator that modulates expression of vlsE and other genes important for spirochetal infection and immune evasion in the mammalian host.
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Affiliation(s)
- Yan Zhang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Optometry and Eye Hospital and School of Ophthalmology, School of Biomedical Engineering, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Tong Chen
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, United States of America
| | - Sajith Raghunandanan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xuwu Xiang
- Department of Anesthesiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Yang
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Qiang Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Diane G. Edmondson
- Department of Pathology and Laboratory Medicine, UTHealth Medical School, Houston, Texas, United States of America
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, UTHealth Medical School, Houston, Texas, United States of America
| | - X. Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Yongliang Lou
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
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11
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Woldemeskel SA, Daitch AK, Alvarez L, Panis G, Zeinert R, Gonzalez D, Smith E, Collier J, Chien P, Cava F, Viollier PH, Goley ED. The conserved transcriptional regulator CdnL is required for metabolic homeostasis and morphogenesis in Caulobacter. PLoS Genet 2020; 16:e1008591. [PMID: 31961855 PMCID: PMC6994171 DOI: 10.1371/journal.pgen.1008591] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 01/31/2020] [Accepted: 01/01/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial growth and division require regulated synthesis of the macromolecules used to expand and replicate components of the cell. Transcription of housekeeping genes required for metabolic homeostasis and cell proliferation is guided by the sigma factor σ70. The conserved CarD-like transcriptional regulator, CdnL, associates with promoter regions where σ70 localizes and stabilizes the open promoter complex. However, the contributions of CdnL to metabolic homeostasis and bacterial physiology are not well understood. Here, we show that Caulobacter crescentus cells lacking CdnL have severe morphological and growth defects. Specifically, ΔcdnL cells grow slowly in both rich and defined media, and are wider, more curved, and have shorter stalks than WT cells. These defects arise from transcriptional downregulation of most major classes of biosynthetic genes, leading to significant decreases in the levels of critical metabolites, including pyruvate, α-ketoglutarate, ATP, NAD+, UDP-N-acetyl-glucosamine, lipid II, and purine and pyrimidine precursors. Notably, we find that ΔcdnL cells are glutamate auxotrophs, and ΔcdnL is synthetic lethal with other genetic perturbations that limit glutamate synthesis and lipid II production. Our findings implicate CdnL as a direct and indirect regulator of genes required for metabolic homeostasis that impacts morphogenesis through availability of lipid II and other metabolites.
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Affiliation(s)
- Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Allison K. Daitch
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Laura Alvarez
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Gaël Panis
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, MA, United States of America
| | - Diego Gonzalez
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Justine Collier
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, MA, United States of America
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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Zhu DX, Garner AL, Galburt EA, Stallings CL. CarD contributes to diverse gene expression outcomes throughout the genome of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2019; 116:13573-13581. [PMID: 31217290 PMCID: PMC6613185 DOI: 10.1073/pnas.1900176116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ability to regulate gene expression through transcription initiation underlies the adaptability and survival of all bacteria. Recent work has revealed that the transcription machinery in many bacteria diverges from the paradigm that has been established in Escherichia coliMycobacterium tuberculosis (Mtb) encodes the RNA polymerase (RNAP)-binding protein CarD, which is absent in E. coli but is required to form stable RNAP-promoter open complexes (RPo) and is essential for viability in Mtb The stabilization of RPo by CarD has been proposed to result in activation of gene expression; however, CarD has only been examined on limited promoters that do not represent the typical promoter structure in Mtb In this study, we investigate the outcome of CarD activity on gene expression from Mtb promoters genome-wide by performing RNA sequencing on a panel of mutants that differentially affect CarD's ability to stabilize RPo In all CarD mutants, the majority of Mtb protein encoding transcripts were differentially expressed, demonstrating that CarD had a global effect on gene expression. Contrary to the expected role of CarD as a transcriptional activator, mutation of CarD led to both up- and down-regulation of gene expression, suggesting that CarD can also act as a transcriptional repressor. Furthermore, we present evidence that stabilization of RPo by CarD could lead to transcriptional repression by inhibiting promoter escape, and the outcome of CarD activity is dependent on the intrinsic kinetic properties of a given promoter region. Collectively, our data support CarD's genome-wide role of regulating diverse transcription outcomes.
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Affiliation(s)
- Dennis X Zhu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Ashley L Garner
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Eric A Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110
| | - Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110;
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The Ferredoxin-Like Protein FerR Regulates PrbP Activity in Liberibacter asiaticus. Appl Environ Microbiol 2019; 85:AEM.02605-18. [PMID: 30552192 DOI: 10.1128/aem.02605-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 12/08/2018] [Indexed: 12/26/2022] Open
Abstract
In Liberibacter asiaticus, PrbP is an important transcriptional accessory protein that regulates gene expression through interactions with the RNA polymerase β-subunit and a specific sequence on the promoter region. The constitutive expression of prbP observed upon chemical inactivation of PrbP-DNA interactions in vivo indicated that the expression of prbP was not autoregulated at the level of transcription. This observation suggested that a modulatory mechanism via protein-protein interactions may be involved. In silico genome association analysis identified FerR (CLIBASIA_01505), a putative ferredoxin-like protein, as a PrbP-interacting protein. Using a bacterial two-hybrid system and immunoprecipitation assays, interactions between PrbP and FerR were confirmed. In vitro transcription assays were used to show that FerR can increase the activity of PrbP by 16-fold when present in the PrbP-RNA polymerase reaction mixture. The FerR protein-protein interaction surface was predicted by structural modeling and followed by site-directed mutagenesis. Amino acids V20, V23, and C40 were identified as the most important residues in FerR involved in the modulation of PrbP activity in vitro The regulatory mechanism of FerR abundance was examined at the transcription level. In contrast to prbP of L. asiaticus (prbP Las), mRNA levels of ferR of L. asiaticus (ferR Las) are induced by an increase in osmotic pressure. The results of this study revealed that the activity of the transcriptional activator PrbPLas is modulated via interactions with FerRLas The induction of ferR Las expression by osmolarity provides insight into the mechanisms of adjusting gene expression in response to host environmental signals in L. asiaticus IMPORTANCE The rapid spread and aggressive progression of huanglongbing (HLB) in the major citrus-producing areas have raised global recognition of and vigilance to this disease. As a result, the causative agent, Liberibacter asiaticus, has been investigated from various perspectives. However, gene expression regulatory mechanisms that are important for the survival and persistence of this intracellular pathogen remain largely unexplored. PrbP is a transcriptional accessory protein important for L. asiaticus survival in the plant host. In this study, we investigated the interactions between PrbP in L. asiaticus (PrbPLas) and a ferredoxin-like protein (FerR) in L. asiaticus, FerRLas We show that the presence of FerR stabilizes and augments the activity of PrbPLas In addition, we demonstrate that the expression of ferR is induced by increases in osmolarity in Liberibacter crescens Altogether, these results suggest that FerRLas and PrbPLas may play important roles in the regulation of gene expression in response to changing environmental signals during L. asiaticus infection in the citrus host.
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