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Takacs CN, Wachter J, Xiang Y, Ren Z, Karaboja X, Scott M, Stoner MR, Irnov I, Jannetty N, Rosa PA, Wang X, Jacobs-Wagner C. Author Correction: Polyploidy, regular patterning of genome copies, and unusual control of DNA partitioning in the Lyme disease spirochete. Nat Commun 2023; 14:6298. [PMID: 37813840 PMCID: PMC10562455 DOI: 10.1038/s41467-023-42035-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023] Open
Affiliation(s)
- Constantin N Takacs
- Department of Biology, Stanford University, Palo Alto, CA, USA
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
| | - Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
- Bacterial Vaccine Development Group, Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada
| | - Yingjie Xiang
- Department of Mechanical Engineering, Yale University, New Haven, CT, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
| | - Zhongqing Ren
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Xheni Karaboja
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Molly Scott
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Matthew R Stoner
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Irnov Irnov
- Department of Biology, Stanford University, Palo Alto, CA, USA
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
| | - Nicholas Jannetty
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, IN, USA.
| | - Christine Jacobs-Wagner
- Department of Biology, Stanford University, Palo Alto, CA, USA.
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA.
- The Howard Hughes Medical Institute, Palo Alto, CA, USA.
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Kasumba IN, Tilly K, Lin T, Norris SJ, Rosa PA. Strict Conservation yet Non-Essential Nature of Plasmid Gene bba40 in the Lyme Disease Spirochete Borrelia burgdorferi. Microbiol Spectr 2023; 11:e0047723. [PMID: 37010416 PMCID: PMC10269632 DOI: 10.1128/spectrum.00477-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/10/2023] [Indexed: 04/04/2023] Open
Abstract
The highly segmented genome of Borrelia burgdorferi, the tick-borne bacterium that causes Lyme disease, is composed of a linear chromosome and more than 20 co-existing endogenous plasmids. Many plasmid-borne genes are unique to B. burgdorferi and some have been shown to provide essential functions at discrete points of the infectious cycle between a tick vector and rodent host. In this study, we investigated the role of bba40, a highly conserved and differentially expressed gene on a ubiquitous linear plasmid of B. burgdorferi. In a prior genome-wide analysis, inactivation of bba40 by transposon insertion was linked with a noninfectious phenotype in mice, suggesting that conservation of the gene in the Lyme disease spirochete reflected a critical function of the encoded protein. To address this hypothesis, we moved the bba40::Tn allele into a similar wild-type background and compared the phenotypes of isogenic wild-type, mutant and complemented strains in vitro and throughout the in vivo mouse/tick infectious cycle. In contrast to the previous study, we identified no defect in the ability of the bba40 mutant to colonize the tick vector or murine host, or to be efficiently transmitted between them. We conclude that bba40 joins a growing list of unique, highly conserved, yet fully dispensable plasmid-borne genes of the Lyme disease spirochete. We infer that the experimental infectious cycle, while including the tick vector and murine host, lacks key selective forces imposed during the natural enzootic cycle. IMPORTANCE The key finding of this study contradicts our premise that the ubiquitous presence and strict sequence conservation of a unique gene in the Lyme disease spirochete, Borrelia burgdorferi, reflect a critical role in either the murine host or tick vector in which these bacteria are maintained in nature. Instead, the outcome of this investigation illustrates the inadequate nature of the experimental infectious cycle currently employed in the laboratory to fully model the enzootic cycle of the Lyme disease spirochete. This study also highlights the importance of complementation for accurate interpretation of mutant phenotypes in genetic studies of Borrelia burgdorferi.
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Affiliation(s)
- Irene N. Kasumba
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kit Tilly
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Tao Lin
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Steven J. Norris
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, Texas, USA
| | - Patricia A. Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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Wachter J, Cheff B, Hillman C, Carracoi V, Dorward DW, Martens C, Barbian K, Nardone G, Renee Olano L, Kinnersley M, Secor PR, Rosa PA. Coupled induction of prophage and virulence factors during tick transmission of the Lyme disease spirochete. Nat Commun 2023; 14:198. [PMID: 36639656 PMCID: PMC9839762 DOI: 10.1038/s41467-023-35897-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 01/06/2023] [Indexed: 01/15/2023] Open
Abstract
The alternative sigma factor RpoS plays a central role in the critical host-adaptive response of the Lyme disease spirochete, Borrelia burgdorferi. We previously identified bbd18 as a negative regulator of RpoS but could not inactivate bbd18 in wild-type spirochetes. In the current study we employed an inducible bbd18 gene to demonstrate the essential nature of BBD18 for viability of wild-type spirochetes in vitro and at a unique point in vivo. Transcriptomic analyses of BBD18-depleted cells demonstrated global induction of RpoS-dependent genes prior to lysis, with the absolute requirement for BBD18, both in vitro and in vivo, circumvented by deletion of rpoS. The increased expression of plasmid prophage genes and the presence of phage particles in the supernatants of lysing cultures indicate that RpoS regulates phage lysis-lysogeny decisions. Through this work we identify a mechanistic link between endogenous prophages and the RpoS-dependent adaptive response of the Lyme disease spirochete.
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Affiliation(s)
- Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA. .,Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Britney Cheff
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Chad Hillman
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Valentina Carracoi
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - David W Dorward
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Craig Martens
- Genomics Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kent Barbian
- Genomics Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Glenn Nardone
- Protein Chemistry Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - L Renee Olano
- Protein Chemistry Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Margie Kinnersley
- Division of Biological Sciences, The University of Montana, Missoula, MT, USA
| | - Patrick R Secor
- Division of Biological Sciences, The University of Montana, Missoula, MT, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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4
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Takacs CN, Wachter J, Xiang Y, Ren Z, Karaboja X, Scott M, Stoner MR, Irnov I, Jannetty N, Rosa PA, Wang X, Jacobs-Wagner C. Polyploidy, regular patterning of genome copies, and unusual control of DNA partitioning in the Lyme disease spirochete. Nat Commun 2022; 13:7173. [PMID: 36450725 PMCID: PMC9712426 DOI: 10.1038/s41467-022-34876-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
Borrelia burgdorferi, the tick-transmitted spirochete agent of Lyme disease, has a highly segmented genome with a linear chromosome and various linear or circular plasmids. Here, by imaging several chromosomal loci and 16 distinct plasmids, we show that B. burgdorferi is polyploid during growth in culture and that the number of genome copies decreases during stationary phase. B. burgdorferi is also polyploid inside fed ticks and chromosome copies are regularly spaced along the spirochete's length in both growing cultures and ticks. This patterning involves the conserved DNA partitioning protein ParA whose localization is controlled by a potentially phage-derived protein, ParZ, instead of its usual partner ParB. ParZ binds its own coding region and acts as a centromere-binding protein. While ParA works with ParZ, ParB controls the localization of the condensin, SMC. Together, the ParA/ParZ and ParB/SMC pairs ensure faithful chromosome inheritance. Our findings underscore the plasticity of cellular functions, even those as fundamental as chromosome segregation.
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Affiliation(s)
- Constantin N Takacs
- Department of Biology, Stanford University, Palo Alto, CA, USA
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
| | - Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
- Bacterial Vaccine Development Group, Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada
| | - Yingjie Xiang
- Department of Mechanical Engineering, Yale University, New Haven, CT, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
| | - Zhongqing Ren
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Xheni Karaboja
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Molly Scott
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Matthew R Stoner
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Irnov Irnov
- Department of Biology, Stanford University, Palo Alto, CA, USA
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
| | - Nicholas Jannetty
- The Howard Hughes Medical Institute, Palo Alto, CA, USA
- Microbial Sciences Institute, Yale West Campus, West Haven, CT, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Xindan Wang
- Department of Biology, Indiana University, Bloomington, IN, USA.
| | - Christine Jacobs-Wagner
- Department of Biology, Stanford University, Palo Alto, CA, USA.
- Sarafan ChEM-H Institute, Stanford University, Palo Alto, CA, USA.
- The Howard Hughes Medical Institute, Palo Alto, CA, USA.
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5
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Abstract
Genetic studies in Borrelia require special consideration of the highly segmented genome, complex growth requirements and evolutionary distance of spirochetes from other genetically tractable bacteria. Despite these challenges, a robust molecular genetic toolbox has been constructed to investigate the biology and pathogenic potential of these important human pathogens. In this review we summarize the tools and techniques that are currently available for the genetic manipulation of Borrelia, including the relapsing fever spirochetes, viewing them in the context of their utility and shortcomings. Our primary objective is to help researchers discern what is feasible and what is not practical when thinking about potential genetic experiments in Borrelia. We have summarized published methods and highlighted their critical elements, but we are not providing detailed protocols. Although many advances have been made since B. burgdorferi was first transformed over 25 years ago, some standard genetic tools remain elusive for Borrelia. We mention these limitations and why they persist, if known. We hope to encourage investigators to explore what might be possible, in addition to optimizing what currently can be achieved, through genetic manipulation of Borrelia.
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Affiliation(s)
- Patricia A. Rosa
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St. Hamilton, MT 59840 USA
| | - Mollie W. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, 6900 Lake Nona Blvd, Orlando, FL 32827 USA
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Hillman C, Stewart PE, Strnad M, Stone H, Starr T, Carmody A, Evans TJ, Carracoi V, Wachter J, Rosa PA. Visualization of Spirochetes by Labeling Membrane Proteins With Fluorescent Biarsenical Dyes. Front Cell Infect Microbiol 2019; 9:287. [PMID: 31482073 PMCID: PMC6710359 DOI: 10.3389/fcimb.2019.00287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 07/24/2019] [Indexed: 01/06/2023] Open
Abstract
Numerous methods exist for fluorescently labeling proteins either as direct fusion proteins (GFP, RFP, YFP, etc.—attached to the protein of interest) or utilizing accessory proteins to produce fluorescence (SNAP-tag, CLIP-tag), but the significant increase in size that these accompanying proteins add may hinder or impede proper protein folding, cellular localization, or oligomerization. Fluorescently labeling proteins with biarsenical dyes, like FlAsH, circumvents this issue by using a short 6-amino acid tetracysteine motif that binds the membrane-permeable dye and allows visualization of living cells. Here, we report the successful adaptation of FlAsH dye for live-cell imaging of two genera of spirochetes, Leptospira and Borrelia, by labeling inner or outer membrane proteins tagged with tetracysteine motifs. Visualization of labeled spirochetes was possible by fluorescence microscopy and flow cytometry. A subsequent increase in fluorescent signal intensity, including prolonged detection, was achieved by concatenating two copies of the 6-amino acid motif. Overall, we demonstrate several positive attributes of the biarsenical dye system in that the technique is broadly applicable across spirochete genera, the tetracysteine motif is stably retained and does not interfere with protein function throughout the B. burgdorferi infectious cycle, and the membrane-permeable nature of the dyes permits fluorescent detection of proteins in different cellular locations without the need for fixation or permeabilization. Using this method, new avenues of investigation into spirochete morphology and motility, previously inaccessible with large fluorescent proteins, can now be explored.
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Affiliation(s)
- Chadwick Hillman
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Philip E Stewart
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Martin Strnad
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States.,Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
| | - Hunter Stone
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Tregei Starr
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Aaron Carmody
- Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Tyler J Evans
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Valentina Carracoi
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
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Jutras BL, Savage CR, Arnold WK, Lethbridge KG, Carroll DW, Tilly K, Bestor A, Zhu H, Seshu J, Zückert WR, Stewart PE, Rosa PA, Brissette CA, Stevenson B. The Lyme disease spirochete's BpuR DNA/RNA-binding protein is differentially expressed during the mammal-tick infectious cycle, which affects translation of the SodA superoxide dismutase. Mol Microbiol 2019; 112:973-991. [PMID: 31240776 PMCID: PMC6736767 DOI: 10.1111/mmi.14336] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2019] [Indexed: 12/24/2022]
Abstract
When the Lyme disease spirochete, Borrelia burgdorferi, transfers from a feeding tick into a human or other vertebrate host, the bacterium produces vertebrate‐specific proteins and represses factors needed for arthropod colonization. Previous studies determined that the B. burgdorferi BpuR protein binds to its own mRNA and autoregulates its translation, and also serves as co‐repressor of erp transcription. Here, we demonstrate that B. burgdorferi controls transcription of bpuR, expressing high levels of bpuR during tick colonization but significantly less during mammalian infection. The master regulator of chromosomal replication, DnaA, was found to bind specifically to a DNA sequence that overlaps the bpuR promoter. Cultured B. burgdorferi that were genetically manipulated to produce elevated levels of BpuR exhibited altered levels of several proteins, although BpuR did not impact mRNA levels. Among these was the SodA superoxide dismutase, which is essential for mammalian infection. BpuR bound to sodA mRNA in live B. burgdorferi, and a specific BpuR‐binding site was mapped 5′ of the sodA open reading frame. Recognition of posttranscriptional regulation of protein levels by BpuR adds another layer to our understanding of the B. burgdorferi regulome, and provides further evidence that bacterial protein levels do not always correlate directly with mRNA levels.
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Affiliation(s)
- Brandon L Jutras
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Christina R Savage
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - William K Arnold
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Kathryn G Lethbridge
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Dustin W Carroll
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Kit Tilly
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Aaron Bestor
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Haining Zhu
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Janakiram Seshu
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Wolfram R Zückert
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Philip E Stewart
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Catherine A Brissette
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, USA.,Department of Entomology, University of Kentucky, Lexington, KY, USA
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Takacs CN, Kloos ZA, Scott M, Rosa PA, Jacobs-Wagner C. Fluorescent Proteins, Promoters, and Selectable Markers for Applications in the Lyme Disease Spirochete Borrelia burgdorferi. Appl Environ Microbiol 2018; 84:e01824-18. [PMID: 30315081 PMCID: PMC6275353 DOI: 10.1128/aem.01824-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022] Open
Abstract
Lyme disease is the most widely reported vector-borne disease in the United States. Its incidence is rapidly increasing, and disease symptoms can be debilitating. The need to understand the biology of the disease agent, the spirochete Borrelia burgdorferi, is thus evermore pressing. Despite important advances in B. burgdorferi genetics, the array of molecular tools available for use in this organism remains limited, especially for cell biological studies. Here, we adapt a palette of bright and mostly monomeric fluorescent proteins for versatile use and multicolor imaging in B. burgdorferi We also characterize two novel antibiotic selection markers and establish the feasibility of their use in conjunction with extant markers. Last, we describe a set of promoters of low and intermediate strengths that allow fine-tuning of gene expression levels. These molecular tools complement and expand current experimental capabilities in B. burgdorferi, which will facilitate future investigation of this important human pathogen. To showcase the usefulness of these reagents, we used them to investigate the subcellular localization of BB0323, a B. burgdorferi lipoprotein essential for survival in the host and vector environments. We show that BB0323 accumulates at the cell poles and future division sites of B. burgdorferi cells, highlighting the complex subcellular organization of this spirochete.IMPORTANCE Genetic manipulation of the Lyme disease spirochete B. burgdorferi remains cumbersome, despite significant progress in the field. The scarcity of molecular reagents available for use in this pathogen has slowed research efforts to study its unusual biology. Of interest, B. burgdorferi displays complex cellular organization features that have yet to be understood. These include an unusual morphology and a highly fragmented genome, both of which are likely to play important roles in the bacterium's transmission, infectivity, and persistence. Here, we complement and expand the array of molecular tools available for use in B. burgdorferi by generating and characterizing multiple fluorescent proteins, antibiotic selection markers, and promoters of varied strengths. These tools will facilitate investigations in this important human pathogen, as exemplified by the polar and midcell localization of the cell envelope regulator BB0323, which we uncovered using these reagents.
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Affiliation(s)
- Constantin N Takacs
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
| | - Zachary A Kloos
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Microbiology Program, Yale University, New Haven, Connecticut, USA
| | - Molly Scott
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale West Campus, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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9
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Bhatia B, Hillman C, Carracoi V, Cheff BN, Tilly K, Rosa PA. Infection history of the blood-meal host dictates pathogenic potential of the Lyme disease spirochete within the feeding tick vector. PLoS Pathog 2018; 14:e1006959. [PMID: 29621350 PMCID: PMC5886588 DOI: 10.1371/journal.ppat.1006959] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/02/2018] [Indexed: 11/18/2022] Open
Abstract
Lyme disease in humans is caused by several genospecies of the Borrelia burgdorferi sensu lato (s.l.) complex of spirochetal bacteria, including B. burgdorferi, B. afzelii and B. garinii. These bacteria exist in nature as obligate parasites in an enzootic cycle between small vertebrate hosts and Ixodid tick vectors, with humans representing incidental hosts. During the natural enzootic cycle, infected ticks in endemic areas feed not only upon naïve hosts, but also upon seropositive infected hosts. In the current study, we considered this environmental parameter and assessed the impact of the immune status of the blood-meal host on the phenotype of the Lyme disease spirochete within the tick vector. We found that blood from a seropositive host profoundly attenuates the infectivity (>104 fold) of homologous spirochetes within the tick vector without killing them. This dramatic neutralization of vector-borne spirochetes was not observed, however, when ticks and blood-meal hosts carried heterologous B. burgdorferi s.l. strains, or when mice lacking humoral immunity replaced wild-type mice as blood-meal hosts in similar experiments. Mechanistically, serum-mediated neutralization does not block induction of host-adapted OspC+ spirochetes during tick feeding, nor require tick midgut components. Significantly, this study demonstrates that strain-specific antibodies elicited by B. burgdorferi s.l. infection neutralize homologous bacteria within feeding ticks, before the Lyme disease spirochetes enter a host. The blood meal ingested from an infected host thereby prevents super-infection by homologous spirochetes, while facilitating transmission of heterologous B. burgdorferi s.l. strains. This finding suggests that Lyme disease spirochete diversity is stably maintained within endemic populations in local geographic regions through frequency-dependent selection of rare alleles of dominant polymorphic surface antigens.
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Affiliation(s)
- Bharti Bhatia
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
| | - Chad Hillman
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
| | - Valentina Carracoi
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
| | - Britney N. Cheff
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
| | - Kit Tilly
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
| | - Patricia A. Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT United States of America
- * E-mail:
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Jackson KM, Schwartz C, Wachter J, Rosa PA, Stewart PE. A widely conserved bacterial cytoskeletal component influences unique helical shape and motility of the spirochete Leptospira biflexa. Mol Microbiol 2018; 108:77-89. [PMID: 29363884 DOI: 10.1111/mmi.13917] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/27/2017] [Accepted: 01/22/2018] [Indexed: 12/16/2022]
Abstract
Leptospires and other members of the evolutionarily ancient phylum of Spirochaetes are bacteria often characterized by long, highly motile spiral- or wave-shaped cells. Morphology and motility are critical factors in spirochete physiology, contributing to the ability of these bacteria to successfully colonize diverse environments. However, the mechanisms conferring the helical structure of Leptospira spp. have yet to be fully elucidated. We have identified five Leptospira biflexa bactofilin proteins, a recently characterized protein family with cytoskeletal properties. These five bactofilins are conserved in all species of the Leptospiraceae, indicating that these proteins arose early in the evolution of this family. One member of this protein family, LbbD, confers the optimal pitch distance in the helical structure of L. biflexa. Mutants lacking lbbD display a unique compressed helical morphology, a reduced motility and a decreased ability to tolerate cell wall stressors. The change in the helical spacing, combined with the motility and cell wall integrity defects, showcases the intimate relationship and coevolution between shape and motility in these spirochetes.
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Affiliation(s)
- Katrina M Jackson
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Cindi Schwartz
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Jenny Wachter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Patricia A Rosa
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Philip E Stewart
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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Abstract
Borrelia burgdorferi is a symbiont of ticks of the Ixodes ricinus complex. These ticks serve as vectors to disseminate the spirochete to a variety of susceptible vertebrate hosts, which, in turn, act as reservoirs for naïve ticks to become infected, perpetuating the infectious life cycle of B. burgdorferi. The pivotal role of ticks in this life cycle and tick-spirochete interactions are the focus of this chapter. Here, we describe the challenging physiological environment that spirochetes encounter within Ixodes ticks, and the genetic factors that B. burgdorferi uses to successfully infect, persist, and be transmitted from the vector.
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Affiliation(s)
- Philip E Stewart
- Laboratory of Zoonotic Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St., Hamilton, MT, 59840, USA.
| | - Patricia A Rosa
- Laboratory of Zoonotic Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St., Hamilton, MT, 59840, USA.
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12
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Tilly K, Bestor A, Rosa PA. Functional Equivalence of OspA and OspB, but Not OspC, in Tick Colonization by Borrelia burgdorferi. Infect Immun 2016; 84:1565-1573. [PMID: 26953324 PMCID: PMC4862709 DOI: 10.1128/iai.00063-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/26/2016] [Indexed: 01/21/2023] Open
Abstract
Borrelia burgdorferi, a Lyme disease agent, makes different major outer surface lipoproteins at different stages of its mouse-tick infectious cycle. Outer surface protein A (OspA) coats the spirochetes from the time they enter ticks until they are transmitted to a mammal. OspA is required for normal tick colonization and has been shown to bind a tick midgut protein, indicating that OspA may serve as a tick midgut adhesin. Tick colonization by spirochetes lacking OspA is increased when the infecting blood meal is derived from mice that do not produce antibody, indicating that OspA may protect the spirochetes from host antibody, which will not recognize tick-specific proteins such as OspA. To further study the importance of OspA during tick colonization, we constructed a form of B. burgdorferi in which the ospA open reading frame, on lp54, was replaced with the ospC gene or the ospB gene, encoding a mammal-specific or tick-specific lipoprotein, respectively. These fusions yielded a strain that produces OspC within a tick (from the fusion gene) and during early mammalian infection (from the normal ospC locus) and a strain that produces OspB in place of OspA within ticks. Here we show that the related, tick-specific protein OspB can fully substitute for OspA, whereas the unrelated, mammal-specific protein OspC cannot. These data were derived from three different methods of infecting ticks, and they confirm and extend previous studies indicating that OspA both protects spirochetes within ticks from mammalian antibody and serves an additional role during tick colonization.
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Affiliation(s)
- Kit Tilly
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Aaron Bestor
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Patricia A Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
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13
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Kasumba IN, Bestor A, Tilly K, Rosa PA. Virulence of the Lyme disease spirochete before and after the tick bloodmeal: a quantitative assessment. Parasit Vectors 2016; 9:129. [PMID: 26951688 PMCID: PMC4780146 DOI: 10.1186/s13071-016-1380-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/12/2016] [Indexed: 11/10/2022] Open
Abstract
Background Borrelia burgdorferi, the tick-transmitted agent of Lyme disease, adapts to different environments as it cycles between an arthropod vector and vertebrate host. Signals encountered during nymphal tick feeding prior to transmission activate a regulon that is controlled by the alternative sigma factors RpoN and RpoS, which are required for mammalian infection. The ingested bloodmeal also provides nutrients that stimulate spirochete replication. Although the influence of tick feeding on spirochete growth and gene expression is well documented, a quantitative assessment of spirochete virulence before and after tick feeding has not been made. Methods Homogenates were prepared from unfed and fed infected Ixodes scapularis nymphs that had acquired B. burgdorferi as larvae. Serially diluted tick homogenates were needle-inoculated into mice to determine the infectious dose of tick-derived spirochetes before and after the bloodmeal. Mouse infection was assessed by sero-reactivity with B. burgdorferi whole cell lysates on immunoblots and attempted isolation of spirochetes from mouse tissues. Viable spirochetes in tick-derived inocula were quantified by colony formation in solid media. Results We found that an inoculum containing as many as 104B. burgdorferi from unfed ticks is largely non-infectious, while the calculated ID50 for spirochetes from fed ticks is ~30 organisms. Engineered constitutive production of the essential virulence factor OspC by spirochetes within unfed ticks did not confer an infectious phenotype. Conclusion Conditional priming of B. burgdorferi during tick feeding induces changes in addition to OspC that are required for infection of the mammalian host.
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Affiliation(s)
- Irene N Kasumba
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA. .,Current address: Center for Vaccine Development, Department of Geographic Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Aaron Bestor
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.
| | - Kit Tilly
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.
| | - Patricia A Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.
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Rego ROM, Bestor A, Štefka J, Rosa PA. Population bottlenecks during the infectious cycle of the Lyme disease spirochete Borrelia burgdorferi. PLoS One 2014; 9:e101009. [PMID: 24979342 PMCID: PMC4076273 DOI: 10.1371/journal.pone.0101009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/30/2014] [Indexed: 12/16/2022] Open
Abstract
Borrelia burgdorferi is a zoonotic pathogen whose maintenance in nature depends upon an infectious cycle that alternates between a tick vector and mammalian hosts. Lyme disease in humans results from transmission of B. burgdorferi by the bite of an infected tick. The population dynamics of B. burgdorferi throughout its natural infectious cycle are not well understood. We addressed this topic by assessing the colonization, dissemination and persistence of B. burgdorferi within and between the disparate mammalian and tick environments. To follow bacterial populations during infection, we generated seven isogenic but distinguishable B. burgdorferi clones, each with a unique sequence tag. These tags resulted in no phenotypic changes relative to wild type organisms, yet permitted highly sensitive and specific detection of individual clones by PCR. We followed the composition of the spirochete population throughout an experimental infectious cycle that was initiated with a mixed inoculum of all clones. We observed heterogeneity in the spirochete population disseminating within mice at very early time points, but all clones displayed the ability to colonize most mouse tissues by 3 weeks of infection. The complexity of clones subsequently declined as murine infection persisted. Larval ticks typically acquired a reduced and variable number of clones relative to what was present in infected mice at the time of tick feeding, and maintained the same spirochete population through the molt to nymphs. However, only a random subset of infectious spirochetes was transmitted to naïve mice when these ticks next fed. Our results clearly demonstrate that the spirochete population experiences stochastic bottlenecks during both acquisition and transmission by the tick vector, as well as during persistent infection of its murine host. The experimental system that we have developed can be used to further explore the forces that shape the population of this vector-borne bacterial pathogen throughout its infectious cycle.
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Affiliation(s)
- Ryan O. M. Rego
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Aaron Bestor
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Jan Štefka
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Parasitology, ASCR, Biology Centre, České Budějovice, Czech Republic
| | - Patricia A. Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
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15
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Ellis TC, Jain S, Linowski AK, Rike K, Bestor A, Rosa PA, Halpern M, Kurhanewicz S, Jewett MW. Correction: In Vivo Expression Technology Identifies a Novel Virulence Factor Critical for Borrelia burgdorferi Persistence in Mice. PLoS Pathog 2014; 10:e1004260. [PMID: 24950221 PMCID: PMC4065136 DOI: 10.1371/journal.ppat.1004260] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Analysis of the transcriptome of Borrelia burgdorferi, the causative agent of Lyme disease, during infection has proven difficult due to the low spirochete loads in the mammalian tissues. To overcome this challenge, we have developed an In Vivo Expression Technology (IVET) system for identification of B. burgdorferi genes expressed during an active murine infection. Spirochetes lacking linear plasmid (lp) 25 are non-infectious yet highly transformable.Mouse infection can be restored to these spirochetes by expression of the essential lp25-encoded pnc A gene alone. Therefore, this IVET-based approach selects for in vivo-expressed promoters that drive expression of pncA resulting in the recovery of infectious spirochetes lacking lp25 following a three week infection in mice.Screening of approximately 15,000 clones in mice identified 289 unique in vivo-expressed DNA fragments from across all 22 replicons of the B. burgdorferi B31 genome. The in vivo-expressed candidate genes putatively encode proteins in various functional categories including antigenicity, metabolism, motility, nutrient transport and unknown functions. Candidate gene bbk46 on essential virulence plasmid lp36 was found to be highly induced in vivo and to be RpoS-independent. The bbk46 gene was dispensable for B. burgdorferi infection in mice. Our findings highlight the power of the IVET-based approach for identification of B. burgdorferi in vivo-expressed genes, which might not be discovered using other genome-wide gene expression methods. Further investigation of the novel in vivo-expressed candidate genes will contribute to advancing the understanding of molecular mechanisms of B.burgdorferi survival and pathogenicity in the mammalian host.
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Affiliation(s)
- Tisha Choudhury Ellis
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
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16
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Dulebohn DP, Hayes BM, Rosa PA. Global repression of host-associated genes of the Lyme disease spirochete through post-transcriptional modulation of the alternative sigma factor RpoS. PLoS One 2014; 9:e93141. [PMID: 24671196 PMCID: PMC3966842 DOI: 10.1371/journal.pone.0093141] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/28/2014] [Indexed: 11/18/2022] Open
Abstract
Borrelia burgdorferi, the agent of Lyme disease, is a vector-borne pathogen that transits between Ixodes ticks and vertebrate hosts. During the natural infectious cycle, spirochetes must globally adjust their transcriptome to survive in these dissimilar environments. One way B. burgdorferi accomplishes this is through the use of alternative sigma factors to direct transcription of specific genes. RpoS, one of only three sigma factors in B. burgdorferi, controls expression of genes required during tick-transmission and infection of the mammalian host. How spirochetes switch between different sigma factors during the infectious cycle has remained elusive. Here we establish a role for a novel protein, BBD18, in the regulation of the virulence-associated sigma factor RpoS. Constitutive expression of BBD18 repressed transcription of RpoS-dependent genes to levels equivalent to those observed in an rpoS mutant. Consistent with the global loss of RpoS-dependent transcripts, we were unable to detect RpoS protein. However, constitutive expression of BBD18 did not diminish the amount of rpoS transcript, indicating post-transcriptional regulation of RpoS by BBD18. Interestingly, BBD18-mediated repression of RpoS is independent of both the rpoS promoter and the 5’ untranslated region, suggesting a mechanism of protein destabilization rather than translational control. We propose that BBD18 is a novel regulator of RpoS and its activity likely represents a first step in the transition from an RpoS-ON to an RpoS-OFF state, when spirochetes transition from the host to the tick vector.
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Affiliation(s)
- Daniel P. Dulebohn
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
| | - Beth M. Hayes
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Patricia A. Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
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17
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Ellis TC, Jain S, Linowski AK, Rike K, Bestor A, Rosa PA, Halpern M, Kurhanewicz S, Jewett MW. In vivo expression technology identifies a novel virulence factor critical for Borrelia burgdorferi persistence in mice. PLoS Pathog 2013; 9:e1003567. [PMID: 24009501 PMCID: PMC3757035 DOI: 10.1371/journal.ppat.1003567] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/01/2013] [Indexed: 12/15/2022] Open
Abstract
Analysis of the transcriptome of Borrelia burgdorferi, the causative agent of Lyme disease, during infection has proven difficult due to the low spirochete loads in the mammalian tissues. To overcome this challenge, we have developed an In Vivo Expression Technology (IVET) system for identification of B. burgdorferi genes expressed during an active murine infection. Spirochetes lacking linear plasmid (lp) 25 are non-infectious yet highly transformable. Mouse infection can be restored to these spirochetes by expression of the essential lp25-encoded pncA gene alone. Therefore, this IVET-based approach selects for in vivo-expressed promoters that drive expression of pncA resulting in the recovery of infectious spirochetes lacking lp25 following a three week infection in mice. Screening of approximately 15,000 clones in mice identified 289 unique in vivo-expressed DNA fragments from across all 22 replicons of the B. burgdorferi B31 genome. The in vivo-expressed candidate genes putatively encode proteins in various functional categories including antigenicity, metabolism, motility, nutrient transport and unknown functions. Candidate gene bbk46 on essential virulence plasmid lp36 was found to be highly induced in vivo and to be RpoS-independent. Immunocompetent mice inoculated with spirochetes lacking bbk46 seroconverted but no spirochetes were recovered from mouse tissues three weeks post inoculation. However, the bbk46 gene was not required for B. burgdorferi infection of immunodeficient mice. Therefore, through an initial IVET screen in B. burgdorferi we have identified a novel in vivo-induced virulence factor critical for the ability of the spirochete to evade the humoral immune response and persistently infect mice.
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Affiliation(s)
- Tisha Choudhury Ellis
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Sunny Jain
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Angelika K. Linowski
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Kelli Rike
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Aaron Bestor
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Patricia A. Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Micah Halpern
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Stephanie Kurhanewicz
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
| | - Mollie W. Jewett
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida, United States of America
- * E-mail:
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18
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Tilly K, Bestor A, Rosa PA. Lipoprotein succession in Borrelia burgdorferi: similar but distinct roles for OspC and VlsE at different stages of mammalian infection. Mol Microbiol 2013; 89:216-27. [PMID: 23692497 PMCID: PMC3713631 DOI: 10.1111/mmi.12271] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2013] [Indexed: 12/21/2022]
Abstract
Borrelia burgdorferi alternates between ticks and mammals, requiring variable gene expression and protein production to adapt to these diverse niches. These adaptations include shifting among the major outer surface lipoproteins OspA, OspC, and VlsE at different stages of the infectious cycle. We hypothesize that these proteins carry out a basic but essential function, and that OspC and VlsE fulfil this requirement during early and persistent stages of mammalian infection respectively. Previous work by other investigators suggested that several B. burgdorferi lipoproteins, including OspA and VlsE, could substitute for OspC at the initial stage of mouse infection, when OspC is transiently but absolutely required. In this study, we assessed whether vlsE and ospA could restore infectivity to an ospC mutant, and found that neither gene product effectively compensated for the absence of OspC during early infection. In contrast, we determined that OspC production was required by B. burgdorferi throughout SCID mouse infection if the vlsE gene were absent. Together, these results indicate that OspC can substitute for VlsE when antigenic variation is unnecessary, but that these two abundant lipoproteins are optimized for their related but specific roles during early and persistent mammalian infection by B. burgdorferi.
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Affiliation(s)
- Kit Tilly
- Laboratory of Zoonotic Pathogens, NIAID, NIH, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.
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19
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Ristow LC, Miller HE, Padmore LJ, Chettri R, Salzman N, Caimano MJ, Rosa PA, Coburn J. The β₃-integrin ligand of Borrelia burgdorferi is critical for infection of mice but not ticks. Mol Microbiol 2012; 85:1105-18. [PMID: 22758390 DOI: 10.1111/j.1365-2958.2012.08160.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
P66 is a Borrelia burgdorferi surface protein with β₃ integrin binding and channel forming activities. In this study, the role of P66 in mammalian and tick infection was examined. B. burgdorferiΔp66 strains were not infectious in wild-type, TLR2⁻/⁻- or MyD88⁻/⁻-deficient mice. Strains with p66 restored to the chromosome restored near wild-type infectivity, while complementation with p66 on a shuttle vector did not restore infectivity. Δp66 mutants are cleared quickly from the site of inoculation, but analyses of cytokine expression and cellular infiltrates at the site of inoculation did not reveal a specific mechanism of clearance. The defect in these mutants cannot be attributed to nutrient limitation or an inability to adapt to the host environment in vivo as Δp66 bacteria were able to survive as well as wild type in dialysis membrane chambers in the rat peritoneum. Δp66 bacteria were able to survive in ticks through the larva to nymph moult, but were non-infectious in mice when delivered by tick bite. Independent lines of evidence do not support any increased susceptibility of the Δp66 strains to factors in mammalian blood. This study is the first to define a B. burgdorferi adhesin as essential for mammalian, but not tick infection.
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Affiliation(s)
- Laura C Ristow
- Graduate Program in Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, USA
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20
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Abstract
Borrelia burgdorferi has multiple linear and circular plasmids that are faithfully replicated and partitioned as the bacterium grows and divides. The low copy number of these replicons implies that active partitioning contributes to plasmid stability. Analyzing the requirements for plasmid replication and partition in B. burgdorferi is complicated by the complexity of the genome and the possibility that products may act in trans. Consequently, we have studied the replication-partition region (bbb10-13) of the B. burgdorferi 26kb circular plasmid (cp26) in Escherichia coli, by fusion with a partition-defective miniF plasmid. Our analysis demonstrated that bbb10, bbb11, and bbb13 are required for stable miniF maintenance, whereas bbb12 is dispensable. To validate these results, we attempted to inactivate two of these genes in B. burgdorferi. bbb12 mutants were obtained at a typical frequency, suggesting that the bbb12 product is dispensable for cp26 maintenance as well. We could not directly measure cp26 stability in the bbb12 mutant, because cp26 carries essential genes, and bacteria that have lost cp26 are inviable. Conversely, we were unable to inactivate bbb10 on cp26 of B. burgdorferi. Our results suggest that bbb12 is dispensable for cp26 maintenance, whereas bbb10, bbb11, and bbb13 play crucial roles in that process.
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Affiliation(s)
- Kit Tilly
- Laboratory of Zoonotic Pathogens, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.
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21
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Jewett MW, Jain S, Linowski AK, Sarkar A, Rosa PA. Molecular characterization of the Borrelia burgdorferi in vivo-essential protein PncA. Microbiology (Reading) 2011; 157:2831-2840. [PMID: 21778210 DOI: 10.1099/mic.0.051706-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The conversion of nicotinamide to nicotinic acid by nicotinamidase enzymes is a critical step in maintaining NAD(+) homeostasis and contributes to numerous important biological processes in diverse organisms. In Borrelia burgdorferi, the nicotinamidase enzyme, PncA, is required for spirochaete survival throughout the infectious cycle. Mammals lack nicotinamidases and therefore PncA may serve as a therapeutic target for Lyme disease. Contrary to the in vivo importance of PncA, the current annotation for the pncA ORF suggests that the encoded protein may be inactive due to the absence of an N-terminal aspartic acid residue that is a conserved member of the catalytic triad of characterized PncA proteins. Herein, we have used genetic and biochemical strategies to determine the N-terminal sequence of B. burgdorferi PncA. Our data demonstrate that the PncA protein is 24 aa longer than the currently annotated sequence and that pncA translation is initiated from the rare, non-canonical initiation codon AUU. These findings are an important first step in understanding the catalytic function of this in vivo-essential protein.
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Affiliation(s)
- Mollie W Jewett
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida (UCF), Orlando, FL 32827, USA.,Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT 59840, USA
| | - Sunny Jain
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida (UCF), Orlando, FL 32827, USA
| | - Angelika K Linowski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida (UCF), Orlando, FL 32827, USA
| | - Amit Sarkar
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT 59840, USA
| | - Patricia A Rosa
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT 59840, USA
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Abstract
Regulation of gene expression is critical for the ability of Borrelia burgdorferi to adapt to different environments during its natural infectious cycle. Reporter genes have been used successfully to study gene regulation in multiple organisms. We have introduced a lacZ gene into B. burgdorferi, and we show that B. burgdorferi produces a protein with detectable β-galactosidase activity in both liquid and solid media when lacZ is expressed from a constitutive promoter. Furthermore, when lacZ is expressed from the ospC promoter, β-galactosidase activity is detected only in B. burgdorferi clones that express ospC, and it accurately monitors endogenous gene expression. The addition of lacZ to the repertoire of genetic tools available for use in B. burgdorferi should contribute to a better understanding of how B. burgdorferi gene expression is regulated during the infectious cycle.
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Affiliation(s)
- Beth M Hayes
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.
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Sarkar A, Tilly K, Stewart P, Bestor A, Battisti JM, Rosa PA. Borrelia burgdorferi resistance to a major skin antimicrobial peptide is independent of outer surface lipoprotein content. Antimicrob Agents Chemother 2009; 53:4490-4. [PMID: 19651916 PMCID: PMC2764146 DOI: 10.1128/aac.00558-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2009] [Revised: 06/19/2009] [Accepted: 07/23/2009] [Indexed: 11/20/2022] Open
Abstract
We hypothesize a potential role for Borrelia burgdorferi OspC in innate immune evasion at the initial stage of mammalian infection. We demonstrate that B. burgdorferi is resistant to high levels (>200 microg/ml) of cathelicidin and that this antimicrobial peptide exhibits limited binding to the spirochetal outer membrane, irrespective of OspC or other abundant surface lipoproteins. We conclude that the essential role of OspC is unrelated to resistance to this component of innate immunity.
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Affiliation(s)
- Amit Sarkar
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, 903 S. 4th Street, Hamilton, MT 59840, USA.
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24
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Tilly K, Bestor A, Dulebohn DP, Rosa PA. OspC-independent infection and dissemination by host-adapted Borrelia burgdorferi. Infect Immun 2009; 77:2672-82. [PMID: 19398538 PMCID: PMC2708573 DOI: 10.1128/iai.01193-08] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 11/04/2008] [Accepted: 04/20/2009] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi OspC is required for the spirochete to establish infection in a mammal by tick transmission or needle inoculation. After a brief essential period, the protein no longer is required and the gene can be shut off. Using a system in which spirochetes contain only an unstable wild-type copy of the ospC gene, we can obtain mice persistently infected with bacteria lacking OspC. We implanted pieces of infected mouse skin subcutaneously in naïve mice, using donors carrying wild-type or ospC mutant spirochetes, and found that both could infect mice by this method, with similar numbers of wild-type or ospC mutant spirochetes disseminated throughout the tissues of recipient mice. Recipient mouse immune responses to tissue transfer-mediated infection with wild-type or ospC mutant spirochetes were similar. These experiments demonstrate that mammalian host-adapted spirochetes can infect and disseminate in mice in the absence of OspC, thereby circumventing this hallmark of tick-derived or in vitro-grown spirochetes. We propose a model in which OspC is one of a succession of functionally equivalent, essential proteins that are synthesized at different stages of mammalian infection. In this model, another protein uniquely present on host-adapted spirochetes performs the same essential function initially fulfilled by OspC. The strict temporal control of B. burgdorferi outer surface protein gene expression may reflect immunological constraints rather than distinct functions.
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Affiliation(s)
- Kit Tilly
- Laboratory of Zoonotic Pathogens, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA
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25
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Abstract
Borrelia burgdorferi is an obligate parasite with a limited genome that severely narrows its metabolic and biosynthetic capabilities. Thus survival of this spirochaete in an arthropod vector and mammalian host requires that it can scavenge amino acids, fatty acids and nucleosides from a blood meal or various host tissues. Additionally, the utilization of ribonucleotides for DNA synthesis is further complicated by the lack of a ribonucleotide reductase for the conversion of nucleoside-5′-diphosphates to deoxynucleosides-5′-diphosphates. The data presented here demonstrate that B. burgdorferi must rely on host-derived sources of purine bases, deoxypurines and deoxypyrimidines for the synthesis of DNA. However, if deoxyguanosine (dGuo) is limited in host tissue, the enzymatic activities of a 2′-deoxyribosyltransferase (DRTase, encoded by bb0426), IMP dehydrogenase (GuaB) and GMP synthase (GuaA) catalyse the multistep conversion of hypoxanthine (Hyp) to dGMP for DNA synthesis. This pathway provides additional biochemical flexibility for B. burgdorferi when it colonizes and infects different host tissues.
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Affiliation(s)
- Kevin A Lawrence
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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26
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Battisti JM, Bono JL, Rosa PA, Schrumpf ME, Schwan TG, Policastro PF. Outer surface protein A protects Lyme disease spirochetes from acquired host immunity in the tick vector. Infect Immun 2008; 76:5228-37. [PMID: 18779341 PMCID: PMC2573341 DOI: 10.1128/iai.00410-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 05/19/2008] [Accepted: 08/29/2008] [Indexed: 11/20/2022] Open
Abstract
The Lyme disease spirochete Borrelia burgdorferi alters the expression of outer surface protein (osp) genes as the bacterium cycles between ticks and mammals. OspA is produced as borreliae enter the tick vector and remains a major surface antigen during midgut colonization. To elucidate the role of OspA in the vector, we created an insertional deletion of ospA in strain B31-A3. The ospA mutant infects mice when it is injected intradermally and is acquired by larval ticks fed on these mice, where it persists through the molt to the nymph stage. Bacterial survival rates in artificially infected tick larvae fed on naïve mice were compared with those in the vector fed on immune mice. The ospA mutant proliferates in larvae if it is exposed to blood from naïve mice, but it declines in density after larval feeding if the blood is from immune mice. When uninfected larvae are fed on B-cell-deficient mice infected with the ospA mutant, larvae show borrelial densities and persistence that are significantly greater than those fed on infected, immunocompetent mice. We conclude that OspA serves a critical antibody-shielding role during vector blood meal uptake from immune hosts and is not required for persistence in the tick vector.
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Affiliation(s)
- James M Battisti
- Rocky Mountain Laboratories, NIAID, NIH, 903 S. 4th Street, Hamilton, MT 59840, USA
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27
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Jewett MW, Byram R, Bestor A, Tilly K, Lawrence K, Burtnick MN, Gherardini F, Rosa PA. Genetic basis for retention of a critical virulence plasmid of Borrelia burgdorferi. Mol Microbiol 2007; 66:975-90. [PMID: 17919281 PMCID: PMC2229028 DOI: 10.1111/j.1365-2958.2007.05969.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The genome of Borrelia burgdorferi is composed of one linear chromosome and approximately 20 linear and circular plasmids. Although some plasmids are required by B. burgdorferi in vivo, most plasmids are dispensable for growth in vitro. However, circular plasmid (cp) 26 is present in all natural isolates and has never been lost during in vitro growth. This plasmid carries ospC, which is critical for mammalian infection. We previously showed that cp26 encodes essential functions, including the telomere resolvase, ResT, and hence cannot be displaced. Here we identify two additional essential genes on cp26, bbb26 and bbb27, through a systematic attempt to inactivate each open reading frame (ORF). Furthermore, an incompatible plasmid carrying resT, bbb26 and bbb27 could displace cp26. Computational and experimental analyses suggested that both BBB26 and BBB27 are membrane-associated, periplasmic proteins. These data indicate that bbb26 and bbb27 encode essential but possibly redundant functions and that one or the other of these cp26 genes, in addition to resT, is required for bacterial viability. We conclude that the genetic linkage of critical physiological and virulence functions on cp26 is pertinent to its stable maintenance throughout the evolution of B. burgdorferi.
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Affiliation(s)
- Mollie W Jewett
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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28
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Jewett MW, Lawrence K, Bestor AC, Tilly K, Grimm D, Shaw P, VanRaden M, Gherardini F, Rosa PA. The critical role of the linear plasmid lp36 in the infectious cycle of Borrelia burgdorferi. Mol Microbiol 2007; 64:1358-74. [PMID: 17542926 PMCID: PMC1974800 DOI: 10.1111/j.1365-2958.2007.05746.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Borrelia burgdorferi, the aetiological agent of Lyme disease, follows a life cycle that involves passage between the tick vector and the mammalian host. To investigate the role of the 36 kb linear plasmid, lp36 (also designated the B. burgdorferi K plasmid), in the infectious cycle of B. burgdorferi, we examined a clone lacking this plasmid, but containing all other plasmids known to be required for infectivity. Our results indicated that lp36 was not required for spirochete survival in the tick, but the clone lacking lp36 demonstrated low infectivity in the mammal. Restoration of lp36 to the mutant strain confirmed that the infectivity defect was due to loss of lp36. Moreover, spirochetes lacking lp36 exhibited a nearly 4-log increase in ID50 relative to the isogenic lp36+ clone. The infectivity defect of lp36-minus spirochetes was localized, in part, to loss of the bbk17 (adeC) gene, which encodes an adenine deaminase. This work establishes a vital role for lp36 in the infectious cycle of B. burgdorferi and identifies the bbk17 gene as a component of this plasmid that contributes to mammalian infectivity.
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Affiliation(s)
- Mollie W Jewett
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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29
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Botkin DJ, Abbott AN, Stewart PE, Rosa PA, Kawabata H, Watanabe H, Norris SJ. Identification of potential virulence determinants by Himar1 transposition of infectious Borrelia burgdorferi B31. Infect Immun 2006; 74:6690-9. [PMID: 17015459 PMCID: PMC1698074 DOI: 10.1128/iai.00993-06] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lyme disease Borrelia organisms are highly invasive spirochetes that alternate between vertebrate and arthropod hosts and that establish chronic infections and elicit inflammatory reactions in mammals. Although progress has been made in the targeted mutagenesis of individual genes in infectious Borrelia burgdorferi, the roles of the vast majority of gene products in pathogenesis remain unresolved. In this study, we examined the feasibility of using transposon mutagenesis to identify infectivity-related factors in B. burgdorferi. The transformable, infectious strain 5A18 NP1 was transformed with the spirochete-adapted Himar1 transposon delivery vector pMarGent to create a small library of 33 insertion mutants. Single mouse inoculations followed by culture of four tissue sites and serology were used to screen the mutants for infectivity phenotypes. Mutants that appeared attenuated (culture positive at some sites) or noninfectious (negative at all sites) and contained the virulence-associated plasmids lp25 and lp28-1 were examined in more extensive animal studies. Three of these mutants (including those with insertions in the putative fliG-1-encoded flagellar motor switch protein and the guaB-encoded IMP dehydrogenase) were noninfectious, whereas four clones appeared to exhibit reduced infectivity. Serological reactivity in VlsE enzyme-linked immunosorbent assays correlated with the assignment of mutants to the noninfectious or attenuated-infectivity groups. The results of this study indicate that random transposon mutagenesis of infectious B. burgdorferi is feasible and will be of value in studying the pathogenesis of Lyme disease Borrelia.
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Affiliation(s)
- Douglas J Botkin
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX 77225-0708, USA
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30
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Tourand Y, Bankhead T, Wilson SL, Putteet-Driver AD, Barbour AG, Byram R, Rosa PA, Chaconas G. Differential telomere processing by Borrelia telomere resolvases in vitro but not in vivo. J Bacteriol 2006; 188:7378-86. [PMID: 16936037 PMCID: PMC1636258 DOI: 10.1128/jb.00760-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Causative agents of Lyme disease and relapsing fever, including Borrelia burgdorferi and Borrelia hermsii, respectively, are unusual among bacteria in that they possess a segmented genome with linear DNA molecules terminated by hairpin ends, known as telomeres. During replication, these telomeres are processed by the essential telomere resolvase, ResT, in a unique biochemical reaction known as telomere resolution. In this study, we report the identification of the B. hermsii resT gene through cross-species hybridization. Sequence comparison of the B. hermsii protein with the B. burgdorferi orthologue revealed 67% identity, including all the regions currently known to be crucial for telomere resolution. In vitro studies, however, indicated that B. hermsii ResT was unable to process a replicated B. burgdorferi type 2 telomere substrate. In contrast, in vivo cross-species complementation in which the native resT gene of B. burgdorferi was replaced with B. hermsii resT had no discernible effect, even though B. burgdorferi strain B31 carries at least two type 2 telomere ends. The B. burgdorferi ResT protein was also able to process two telomere spacing mutants in vivo that were unresolvable in vitro. The unexpected differential telomere processing in vivo versus in vitro by the two telomere resolvases suggests the presence of one or more accessory factors in vivo that are normally involved in the reaction. Our current results are also expected to facilitate further studies into ResT structure and function, including possible interaction with other Borrelia proteins.
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Affiliation(s)
- Yvonne Tourand
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1 Canada
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31
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Guyard C, Battisti JM, Raffel SJ, Schrumpf ME, Whitney AR, Krum JG, Porcella SF, Rosa PA, DeLeo FR, Schwan TG. Relapsing fever spirochaetes produce a serine protease that provides resistance to oxidative stress and killing by neutrophils. Mol Microbiol 2006; 60:710-22. [PMID: 16629672 DOI: 10.1111/j.1365-2958.2006.05122.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The spirochaetes that cause tick-borne relapsing fever and Lyme disease are closely related human pathogens, yet they differ significantly in their ecology and pathogenicity. Genome sequencing of two species of relapsing fever spirochaetes, Borrelia hermsii and Borrelia turicatae, identified a chromosomal open reading frame, designated bhpA, not present in the Lyme disease spirochaete Borrelia burgdorferi. The predicted amino acid sequence of bhpA was homologous with the HtrA serine proteases, which are involved with stress responses and virulence in other bacteria. B. hermsii produced an active serine protease that was recognized by BhpA antibodies and the recombinant BhpA protein-degraded beta-casein. bhpA was transcribed in vitro at all growth temperatures and transcription levels were slightly elevated at higher temperatures. These results correlated with the synthesis of BhpA during B. hermsii infection in mice. With the exception of Borrelia recurrentis, the bhpA gene, protein and enzymatic activity were found in all relapsing fever spirochaetes, but not in Lyme disease or related spirochaetes. Heterologous expression of bhpA in B. burgdorferi increased the spirochaete's resistance to both oxidative stress and killing by human neutrophils. Therefore, we propose that bhpA encodes a unique and functional serine protease in relapsing fever spirochaetes. This periplasmic enzyme may prevent the accumulation of proteins damaged by the innate immune response and contribute to the ability of the relapsing fever spirochaetes to achieve high cell densities in blood.
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Affiliation(s)
- Cyril Guyard
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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32
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Stewart PE, Wang X, Bueschel DM, Clifton DR, Grimm D, Tilly K, Carroll JA, Weis JJ, Rosa PA. Delineating the requirement for the Borrelia burgdorferi virulence factor OspC in the mammalian host. Infect Immun 2006; 74:3547-53. [PMID: 16714587 PMCID: PMC1479289 DOI: 10.1128/iai.00158-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously demonstrated that outer surface protein C (OspC) of Borrelia burgdorferi is essential for establishing mammalian infection. However, the role of OspC in mammalian infection is unknown. Here, we report experiments designed to distinguish between two models of OspC function in the mammalian host: (i) OspC fulfills an essential physiological role for growth and host adaptation or (ii) OspC provides a protective role for evasion of components of the innate immune response. We found that a B. burgdorferi ospC mutant, previously demonstrated to be noninfectious in both immunocompetent and SCID mice, could survive in the relatively immune-privileged environment of dialysis membrane chambers implanted within the peritoneum of a rat. The ospC mutant also adapts to the mammalian environment, as determined by the protein profiles of the chamber-cultivated spirochetes. Therefore, OspC does not appear to provide a physiological function for the survival of B. burgdorferi within the mammalian host. The second model, evasion of the innate immune system, was tested by assessing the infectivity of the ospC mutant in mice deficient for myeloid differentiation protein 88 (MyD88). Recent studies have shown that B. burgdorferi is prevented from reaching high cell numbers in the mammalian host by MyD88-dependent signaling pathways. The ospC mutant was incapable of infecting MyD88-deficient mice, suggesting that the role of OspC cannot be related solely to evasion of MyD88-mediated innate immunity. These results reiterate the importance of OspC in mammalian infection and eliminate simple models of function for this enigmatic protein.
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Affiliation(s)
- Philip E Stewart
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, 903 South 4th St., Hamilton, MT 59840, USA.
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33
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Grimm D, Tilly K, Bueschel DM, Fisher MA, Policastro PF, Gherardini FC, Schwan TG, Rosa PA. Defining plasmids required by Borrelia burgdorferi for colonization of tick vector Ixodes scapularis (Acari: Ixodidae). J Med Entomol 2005; 42:676-84. [PMID: 16119559 DOI: 10.1093/jmedent/42.4.676] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Maintenance in nature of Borrelia burgdorferi, the pathogenic bacterium that causes Lyme disease, requires transmission through an infectious cycle that includes a tick vector and a mammalian host. The genetic requirements for persistence in these disparate environments have not been well defined. B. burgdorferi has a complex genome composed of a chromosome and >20 plasmids. Previous work has demonstrated that B. burgdorferi requires two plasmids, lp25 and lp28-1, in the mammalian host. To investigate the requirement for these same two plasmids during tick infection, we experimentally infected larval ticks with B. burgdorferi lacking either lp25 or lp28-1 and then assessed the spirochete load in ticks at different points of the infection. Whereas plasmid lp28-1 was dispensable in ticks, plasmid lp25 was essential for tick infection. Furthermore, we investigated the requirement in ticks for the lp25 gene bbe22, which encodes a nicotinamidase that is necessary and sufficient for mammalian infection by B. burgdorferi clones lacking lp25. This gene was also sufficient in ticks to restore survival of spirochetes lacking lp25. This is the first study to investigate the requirement for specific plasmids by B. burgdorferi within the tick vector, and it begins to establish the genomic components required for persistence of this pathogen throughout its natural infectious cycle.
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Affiliation(s)
- Dorothee Grimm
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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Fisher MA, Grimm D, Henion AK, Elias AF, Stewart PE, Rosa PA, Gherardini FC. Borrelia burgdorferi sigma54 is required for mammalian infection and vector transmission but not for tick colonization. Proc Natl Acad Sci U S A 2005; 102:5162-7. [PMID: 15743918 PMCID: PMC555983 DOI: 10.1073/pnas.0408536102] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous studies have shown that a sigma54-sigma(S) cascade regulates the expression of a few key lipoproteins in Borrelia burgdorferi, the agent of Lyme disease. Here, we demonstrate that these sigma factors, both together and independently, regulate a much more extensive number of genes and cellular processes. Microarray analyses of sigma54 and sigma(S) mutant strains identified 305 genes regulated by sigma54 and 145 regulated by sigma(S), whereas the sigma54-sigma(S) regulatory cascade appears to control 48 genes in B. burgdorferi. In silico analyses revealed that nearly 80% of genes with altered expression in the sigma54 mutant were linked to potential sigma54-dependent promoters. Many sigma54-regulated genes are expressed in vivo, and through genetic complementation of the mutant, we demonstrated that sigma54 was required by B. burgdorferi to infect mammals. Surprisingly, sigma54 mutants were able to infect Ixodes scapularis ticks and be maintained for at least 24 wk after infection, suggesting the sigma54-sigma(S) regulatory network was not involved in long-term survival in ticks. However, sigma54 mutants did not enter the salivary glands during tick feeding, indicating that sigma54-regulated genes were involved in the transmission process.
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Affiliation(s)
- Mark A Fisher
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
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35
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Abstract
Lyme disease is the most commonly reported vector-borne disease in North America and Europe, yet we know little about which components of the causative agent, Borrelia burgdorferi, are critical for infection or virulence. Molecular genetics has provided a powerful means by which to address these topics in other bacterial pathogens. Certain features of B. burgdorferi have hampered the development of an effective system of genetic analysis, but basic tools are now available and their application has begun to provide information about the identities and roles of key bacterial components in both the tick vector and the mammalian host. Increased genetic analysis of B. burgdorferi should advance our understanding of the infectious cycle and the pathogenesis of Lyme disease.
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Affiliation(s)
- Patricia A Rosa
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th Street, Hamilton, Montana 59840, USA.
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36
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Stewart PE, Byram R, Grimm D, Tilly K, Rosa PA. The plasmids of Borrelia burgdorferi: essential genetic elements of a pathogen. Plasmid 2005; 53:1-13. [PMID: 15631949 DOI: 10.1016/j.plasmid.2004.10.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 10/15/2004] [Accepted: 10/19/2004] [Indexed: 11/27/2022]
Abstract
The spirochete Borrelia burgdorferi, the causative agent of Lyme disease, has an unusual genome comprised of a linear chromosome and the largest plasmid complement of any characterized bacterium. Certain plasmid-encoded elements are required for virulence and viability, both in vitro and in vivo. The genetic tools to manipulate B. burgdorferi are sufficiently developed for precise molecular genetic investigations. B. burgdorferi now represents a prime system with which to address basic questions of plasmid biology and plasmid contributions to bacterial virulence and disease pathogenesis.
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Affiliation(s)
- Philip E Stewart
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St., Hamilton, MT 59840, USA.
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37
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Stewart PE, Hoff J, Fischer E, Krum JG, Rosa PA. Genome-wide transposon mutagenesis of Borrelia burgdorferi for identification of phenotypic mutants. Appl Environ Microbiol 2004; 70:5973-9. [PMID: 15466540 PMCID: PMC522107 DOI: 10.1128/aem.70.10.5973-5979.2004] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The spirochete Borrelia burgdorferi is the causative agent of Lyme disease, the leading vector-borne illness in the United States. Many of the genetic factors affecting spirochete morphology and physiology are unknown due to the limited genetic tools available and the large number of open reading frames with unknown functions. By adapting a mariner transposon to function in B. burgdorferi, we have developed a random mutagenesis system that tags the mutated locus for rapid identification. Transposition occurs at saturating levels in B. burgdorferi and appears to be random, targeting both linear and circular replicons. By combining the transposon system with a screen for factors affecting growth rate, mutations were readily identified in genes putatively involved in cell division and chemotaxis and a hypothetical open reading frame involved in outer membrane integrity. The successful adaptation of a mariner transposon to function in B. burgdorferi should aid in identifying virulence factors and novel gene products related to spirochete physiology.
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Affiliation(s)
- Philip E Stewart
- Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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Grimm D, Eggers CH, Caimano MJ, Tilly K, Stewart PE, Elias AF, Radolf JD, Rosa PA. Experimental assessment of the roles of linear plasmids lp25 and lp28-1 of Borrelia burgdorferi throughout the infectious cycle. Infect Immun 2004; 72:5938-46. [PMID: 15385497 PMCID: PMC517563 DOI: 10.1128/iai.72.10.5938-5946.2004] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 05/19/2004] [Accepted: 07/16/2004] [Indexed: 11/20/2022] Open
Abstract
Borrelia burgdorferi, which causes Lyme disease in humans, has an unusual genome composed of a linear chromosome and up to 21 extrachromosomal elements. Experimental data suggest that two of these elements, linear plasmids lp25 and lp28-1, play essential roles for infectivity in mice. In this study, we prove the essential natures of these two plasmids by selectively displacing lp25 or lp28-1 in an infectious wild-type clone with incompatible shuttle vectors derived from the native plasmids, rendering the respective transformants noninfectious to mice. Conversely, restoration of plasmid lp25 or lp28-1 in noninfectious clones that naturally lack the corresponding plasmid reestablished infectivity in mice. This approach establishes the ability to manipulate the plasmid content of strains by eliminating or introducing entire plasmids in B. burgdorferi and will be valuable in assessing the roles of plasmids even in unsequenced B. burgdorferi strains.
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Affiliation(s)
- Dorothee Grimm
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA
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Zückert WR, Lloyd JE, Stewart PE, Rosa PA, Barbour AG. Cross-species surface display of functional spirochetal lipoproteins by recombinant Borrelia burgdorferi. Infect Immun 2004; 72:1463-9. [PMID: 14977951 PMCID: PMC356051 DOI: 10.1128/iai.72.3.1463-1469.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surface-exposed lipoproteins of relapsing fever (RF) and Lyme borreliosis Borrelia spirochetes mediate certain interactions of the bacteria with their arthropod and vertebrate hosts. RF spirochetes such as Borrelia hermsii serially evade the host's antibody response by multiphasic antigenic variation of Vsp and Vlp proteins. Furthermore, the expression of Vsp1 and Vsp2 by Borrelia turicatae is associated with neurotropism and higher blood densities, respectively. In contrast to RF Borrelia species, the Lyme borreliosis spirochete Borrelia burgdorferi is amenable to genetic manipulation. To facilitate structure-function analyses of RF surface lipoproteins, we used recombinant plasmids to introduce full-length vsp1 and vsp2 as well as two representative vlp genes into B. burgdorferi cells. Recombinant B. burgdorferi cells constitutively expressed the proteins under the control of the B. burgdorferi flaB promoter. Antibody and protease accessibility assays indicated proper surface exposure and folding. Expression of Vsp1 and Vsp2 conferred glycosaminoglycan binding to recombinant B. burgdorferi cells that was similar to that observed with purified recombinant proteins and B. turicatae expressing native Vsp. These data demonstrate that the lipoprotein modification and export mechanisms in the genus Borrelia are conserved. They also validate the use of recombinant B. burgdorferi in studies of surface lipoprotein structure-function and the biogenesis of spirochete membranes.
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Affiliation(s)
- Wolfram R Zückert
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
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40
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Elias AF, Bono JL, Kupko JJ, Stewart PE, Krum JG, Rosa PA. New antibiotic resistance cassettes suitable for genetic studies in Borrelia burgdorferi. J Mol Microbiol Biotechnol 2004; 6:29-40. [PMID: 14593251 DOI: 10.1159/000073406] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In this report we describe two distinct approaches to develop new antibiotic resistance cassettes that allow for efficient selection of Borrelia burgdorferi transformants. The first approach utilizes fusions of borrelial flagellar promoters to antibiotic resistance markers from other bacteria. The AACC1 gene, which encodes a gentamicin acetyltransferase, conferred a high level of gentamicin resistance in B. Burfdorferi when expressed from these promoters. No cross-resistance occurred between this cassette and the kanamycin resistance cassette, which was previously developed in an analogous fashion. A second and different approach was taken to develop an efficient selectable marker that confers resistance to the antibiotic coumermycin A1. A synthetic gene was designed from the GYRB301 allele of the coumermycin-resistant B. Burgdorferi strain B31-NGR by altering the coding sequence at the wobble position. The resulting gene, GYRB(SYN), encodes a protein identical to the product of GYRB301, but the genes share only 66% nucleotide identity. The nucleotide sequence of GYRB(SYN)is sufficiently divergent from the endogenous B. Burgdorferi GYRB gene to prevent recombination between them. The cassettes described in this paper improve our repertoire of genetic tools in B. Burgdorferi. These studies also provide insight into parameters governing recombination and gene expression in B. Burgdorferi.
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Affiliation(s)
- Abdallah F Elias
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Mont., USA
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Grimm D, Tilly K, Byram R, Stewart PE, Krum JG, Bueschel DM, Schwan TG, Policastro PF, Elias AF, Rosa PA. Outer-surface protein C of the Lyme disease spirochete: a protein induced in ticks for infection of mammals. Proc Natl Acad Sci U S A 2004; 101:3142-7. [PMID: 14970347 PMCID: PMC365757 DOI: 10.1073/pnas.0306845101] [Citation(s) in RCA: 327] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Environmentally responsive synthesis of surface proteins represents a hallmark of the infectious cycle of the Lyme disease agent, Borrelia burgdorferi. Here we created and analyzed a B. burgdorferi mutant lacking outer-surface protein C (OspC), an abundant Osp that spirochetes normally synthesize in the tick vector during the blood meal and down-regulate after transmission to the mammal. We demonstrate that B. burgdorferi strictly requires OspC to infect mice but not to localize or migrate appropriately in the tick. The induction of a spirochetal virulence factor preceding the time and host in which it is required demonstrates a developmental sequence for transmission of this arthropod-borne pathogen.
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Affiliation(s)
- Dorothee Grimm
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT 59840, USA
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42
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Abstract
Borrelia burgdorferi causes Lyme disease in humans. The genome of the sequenced type strain B31 MI consists of a linear chromosome, 12 linear plasmids, and 9 circular plasmids. Previous studies by other investigators indicated that some of these plasmids are essential for the survival of the spirochetes in vivo but not in vitro. We have studied plasmid stability during in vitro growth at 23 and 35 degrees C, conditions that approximate the temperatures of the tick vector and the mammalian host, respectively. Starting with two clones that have all 21 plasmids, we investigated plasmid maintenance within the population and on a clonal level. After three passages (27 generations), the cultures were no longer homogeneous and some derivative clones had already lost multiple plasmids. Despite this, one of six clones analyzed after 25 passages (225 generations) retained all but one plasmid (cp9) and was able to complete the mouse-tick-mouse infectious cycle. We analyzed protein composition and regulation of gene expression of clones differing in plasmid content after serial passages. All clones tested exhibited temperature-regulated expression of several proteins, including OspC. In addition, analysis of cultures inoculated from frozen stocks suggests that freezing and/or thawing contributes to heterogeneity in the outgrowth population with respect to plasmid content. Our investigations show that in vitro propagation of a clone leads to a heterogeneous population but that virulent clones can persist through extended passage. We therefore conclude that isogenicity of clones must be confirmed irrespective of their in vitro passage history.
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Affiliation(s)
- Dorothee Grimm
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA.
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Abstract
Clonal Borrelia burgdorferi N40 (cN40) passaged 75 times in vitro (N40-75) infects mice but does not cause disease. N40-75 passaged 45 times further in vitro (N40-120) was no longer infectious and lacked genes encoded on linear plasmids 38 and 28-1, among other differences. These data suggest that B. burgdorferi cN40, N40-75, and N40-120 have distinct phenotypes that can be used to dissect the genetic elements responsible for pathogenicity and infectivity.
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Affiliation(s)
- V Thomas
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Ibba M, Curnow AW, Bono J, Rosa PA, Woese CR, Söll D. Archaeal aminoacyl-tRNA synthesis: unique determinants of a universal genetic code? Biol Bull 1999; 196:335-337. [PMID: 10390832 DOI: 10.2307/1542964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- M Ibba
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA
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Abstract
Lysyl-tRNAs are essential for protein biosynthesis by ribosomal mRNA translation in all organisms. They are synthesized by lysyl-tRNA synthetases (EC 6.1.1.6), a group of enzymes composed of two unrelated families. In bacteria and eukarya, all known lysyl-tRNA synthetases are subclass IIc-type aminoacyl-tRNA synthetases, whereas some archaea have been shown to contain an unrelated class I-type lysyl-tRNA synthetase. Examination of the preliminary genomic sequence of the bacterial pathogen Borrelia burgdorferi, the causative agent of Lyme disease, indicated the presence of an open reading frame with over 55% similarity at the amino acid level to archaeal class I-type lysyl-tRNA synthetases. In contrast, no coding region with significant similarity to any class II-type lysyl-tRNA synthetase could be detected. Heterologous expression of this open reading frame in Escherichia coli led to the production of a protein with canonical lysyl-tRNA synthetase activity in vitro. Analysis of B. burgdorferi mRNA showed that the lysyl-tRNA synthetase-encoding gene is highly expressed, confirming that B. burgdorferi contains a functional class I-type lysyl-tRNA synthetase. The detection of an archaeal-type lysyl-tRNA synthetase in B. burgdorferi and other pathogenic spirochetes, but not to date elsewhere in bacteria or eukarya, indicates that the gene that encodes this enzyme has a common origin with its orthologue from the archaeal kingdom. This difference between the lysyl-tRNA synthetases of spirochetes and their hosts may be readily exploitable for the development of anti-spirochete therapeutics.
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Affiliation(s)
- M Ibba
- Department of Molecular Biophysics and Biochemistry, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8114, USA
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Mateicka F, Kozáková D, Rosa PA, Kmety E. Identification of Borrelia burgdorferi sensu lato tick isolates from Slovakia by PCR typing with 16S rRNA primers. Zentralbl Bakteriol 1997; 286:355-61. [PMID: 9361381 DOI: 10.1016/s0934-8840(97)80092-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The first four strains of Borrelia burgdorferi isolated in Slovakia from ticks and mice were studied using monoclonal antibodies, the polymerase chain reaction (PCR) with 16S rRNA specific primers and plasmid profiles. Two tick isolates were typed as Borrelia garinii, one strain isolated from Apodemus flavicollis was found to be B. afzelii and the fourth tick isolate reacted as a mixed culture of B. garinii and B. afzelii. All four strains harboured several plasmids ranging from 6-50 kbp including a plasmid with a size of approximately 41 kbp.
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Affiliation(s)
- F Mateicka
- Research Institute of Rheumatic Diseases, Piestany, Slovakia
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Abstract
This article reviews the natural history, taxonomy, physical structure, growth requirements, and molecular structure of Borrelia burgdorferi sensu lato, the causative agent of Lyme disease. These spirochetal bacteria are maintained in nature through an infectious cycle between wild mammals and ticks. Borreliae are fastidious, slow-growing bacteria, found only in association with their arthropod or mammalian hosts in nature, and propagatable in the laboratory in a rich growth medium. The characteristic shape of borreliae is imposed by periplasmic flagella, located beneath the outer membrane and attached to the protoplasmic cylinder. The outer membrane of borreliae contains a number of abundant lipoproteins that are of serodiagnostic utility and currently under consideration as vaccine targets. The borrelial genome is unique in structure, organization, and copy number. Recent experiments demonstrate the feasibility of specific gene inactivation as a means with which to study the biology of borreliae and the pathogenesis of Lyme disease.
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Affiliation(s)
- P A Rosa
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories of the NIAID, NIH, Hamilton, Montana 59840, USA
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Casjens S, van Vugt R, Tilly K, Rosa PA, Stevenson B. Homology throughout the multiple 32-kilobase circular plasmids present in Lyme disease spirochetes. J Bacteriol 1997; 179:217-27. [PMID: 8982001 PMCID: PMC178682 DOI: 10.1128/jb.179.1.217-227.1997] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We have characterized seven different 32-kb circular plasmids carried by Borrelia burgdorferi isolate B31. Restriction endonuclease recognition site mapping and partial sequencing of these plasmids indicated that all seven are probably closely related to each other throughout their lengths and have substantial relationships to cp8.3, an 8.3-kb circular plasmid of B. burgdorferi sensu lato isolate Ip21. With the addition of the seven 32-kb plasmids, this bacterial strain is known to carry at least 10 linear and 9 circular plasmids. Variant cultures of B. burgdorferi B31 lacking one or more of the 32-kb circular plasmids are viable and, at least in some cases, infectious. We have examined a number of different natural isolates of Lyme disease borreliae and found that all of the B. burgdorferi sensu stricto isolates and most of the B. burgdorferi sensu lato isolates tested appear to carry multiple 32-kb circular plasmids related to those of B. burgdorferi B31. The ubiquity of these plasmids suggests that they may be important in the natural life cycle of these organisms. They may be highly conjugative plasmids or prophage genomes, which could prove to be useful in genetically manipulating B. burgdorferi.
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Affiliation(s)
- S Casjens
- Department of Oncological Sciences, University of Utah, Salt Lake City 84132, USA.
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Abstract
We have identified four loci in Borrelia burgdorferi B31 that contain open reading frames capable of encoding six proteins that are related to the antigenic proteins OspE and OspF. We have designated these proteins Erp, for OspEF-related protein, and named their respective genes erp. The erpA and erpB genes are linked, as are erpC and erpD, and the pairs probably constitute two operons. The erpG and erpH genes appear to be monocistronic. The ErpA and ErpC proteins are expressed by B. burgdorferi B31 in culture and are recognized by a polyclonal antiserum raised against the OspE protein of B. burgdorferi N40. The four erp loci are each located on different 32-kb circular plasmids that contain additional DNA sequences that are homologous to each other and to an 8.3-kb circular plasmid of B. burgdorferi sensu lato Ip2l. All four 32-kb plasmids can be maintained within a single bacterium, which may provide a model for the study of plasmid replication and segregation in B. burgdorferi.
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Affiliation(s)
- B Stevenson
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
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50
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Abstract
Previous studies have demonstrated that Borrelia burgdorferi in the midguts of infected ticks shows increased expression of the antigenic outer surface protein OspC after the ticks have ingested a blood meal. This differential expression is at least partly due to a change in temperature, as an increase in OspC levels is also observed when cultures are shifted from 23 to 35 degrees C. Immunoblotting of bacterial lysates with sera from infected mice indicated that the levels of several additional antigens were also increased in bacterial cultures shifted to 35 degrees C; we have identified one antigen as OspE. We have also observed differential expression of OspF, which has been proposed to be coexpressed in an operon with the gene encoding OspE.
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Affiliation(s)
- B Stevenson
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA
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