Identification and Characterization of a Linear-Plasmid-Encoded Factor H-Binding Protein (FhbA) of the Relapsing Fever Spirochete Borrelia hermsii

ABSTRACT In North America, tick-borne relapsing fever (TBRF) is caused by the spirochete species Borrelia hermsii, Borrelia parkeri, and Borrelia turicatae. We previously demonstrated that some isolates of B. hermsii and B. parkeri are capable of binding factor H and that cell-bound factor H can participate in the factor I-mediated cleavage of C3b. Isolates that bound factor H expressed a factor H-binding protein (FHBP) that we estimated to be approximately 19 to 20 kDa in size and thus, pending further characterization, temporarily designated FHBP19. Until this report, none of the FHBPs of the TBRF spirochetes had been characterized. Here we have recovered the gene encoding the FHBP of B. hermsii YOR from a lambda ZAP II library and determined its sequence. The gene encodes a full-length protein of 22.7 kDa, which after processing is predicted to be 20.5 kDa. This protein, which we redesignate factor H-binding protein A (FhbA), is unique to B. hermsii. Two-dimensional pulsed-field gel electrophoresis and hybridization analyses revealed that the B. hermsii gene encoding FhbA is a single genetic locus that maps to a linear plasmid of approximately 220 kb. The general properties of FhbA were also assessed. The protein was found to be surface exposed and lipidated. Analysis of the antibody response to FhbA in infected mice revealed that it is antigenic during infection, indicating expression during infection. The identification and characterization of FhbA provides further insight into the molecular mechanisms of pathogenesis of the relapsing fever spirochetes.

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BhCRASP-1 of the relapsing fever spirochete Borrelia hermsii is a factor H- and plasminogen-binding protein

International Journal of Medical Microbiology ◽

10.1016/j.ijmm.2008.02.003 ◽

2008 ◽

Vol 298 ◽

pp. 272-283 ◽

Cited By ~ 3

Author(s):

Evelyn Rossmann ◽

Peter Kraiczy ◽

Pia Herzberger ◽

Christine Skerka ◽

Michael Kirschfink ◽

...

Keyword(s):

Binding Protein ◽

Factor H ◽

Relapsing Fever ◽

Borrelia Hermsii

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Identification and characterization of the gene encoding human cytoplasmic polyadenylation element binding protein

Gene ◽

10.1016/s0378-1119(00)00588-6 ◽

2001 ◽

Vol 263 (1-2) ◽

pp. 113-120 ◽

Cited By ~ 22

Author(s):

Joseph F Welk ◽

Amanda Charlesworth ◽

Gary D Smith ◽

Angus M MacNicol

Keyword(s):

Binding Protein ◽

Gene Encoding ◽

Cytoplasmic Polyadenylation ◽

Element Binding Protein ◽

Identification And Characterization

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Immunological and Molecular Analyses of the Borrelia hermsii Factor H and Factor H-Like Protein 1 Binding Protein, FhbA: Demonstration of Its Utility as a Diagnostic Marker and Epidemiological Tool for Tick-Borne Relapsing Fever

Infection and Immunity ◽

10.1128/iai.00377-06 ◽

2006 ◽

Vol 74 (8) ◽

pp. 4519-4529 ◽

Cited By ~ 25

Author(s):

Kelley M. Hovis ◽

Martin E. Schriefer ◽

Sonia Bahlani ◽

Richard T. Marconi

Keyword(s):

Binding Protein ◽

Pcr Primers ◽

Factor H ◽

Antigenic Structure ◽

Diagnostic Tools ◽

Relapsing Fever ◽

Borrelia Hermsii ◽

Specific Pcr ◽

Epidemiological Tool ◽

Species Specific

ABSTRACT It has been demonstrated that Borrelia hermsii, a causative agent of relapsing fever, produces a factor H (FH) and FH-like protein 1 (FHL-1) binding protein. The binding protein has been designated FhbA. To determine if FH/FHL-1 binding is widespread among B. hermsii isolates, a diverse panel of strains was tested for the FH/FHL-1 binding phenotype and FhbA production. Most isolates (23/24) produced FhbA and bound FH/FHL-1. Potential variation in FhbA among isolates was analyzed by DNA sequence analyses. Two genetically distinct FhbA types, designated fhbA1 and fhbA2, were delineated, and type-specific PCR primers were generated to allow for rapid differentiation. Pulsed-field gel electrophoresis and hybridization analyses demonstrated that all isolates that possess the gene carry it on a 200-kb linear plasmid (lp200), whereas isolates that lack the gene lack lp200 and instead carry an lp170. To determine if FhbA is antigenic during infection and to assess the specificity of the response, recombinant FhbA1 (rFhbA1) and rFhbA2 were screened with serum from infected mice and humans. FhbA was found to be expressed and antigenic and to elicit a potentially type-specific FhbA response. To localize the epitopes of FhbA1 and FhbA2, truncations were generated and screened with infection serum. The epitopes were determined to be conformationally defined. Collectively, these analyses indicate that FH/FHL-1 binding is a widespread virulence mechanism for B. hermsii and provide insight into the genetic and antigenic structure of FhbA. The data also have potential implications for understanding the epidemiology of relapsing fever in North America and can be applied to the future development of species-specific diagnostic tools.

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Identification and characterization of mouse GTPBP3 gene encoding a mitochondrial GTP-binding protein involved in tRNA modification

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2003.10.187 ◽

2003 ◽

Vol 312 (3) ◽

pp. 747-754 ◽

Cited By ~ 5

Author(s):

Xiaoming Li ◽

Min-Xin Guan

Keyword(s):

Binding Protein ◽

Trna Modification ◽

Gtp Binding Protein ◽

Gene Encoding ◽

Gtp Binding ◽

Identification And Characterization

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The Borrelia hermsii Factor H Binding Protein FhbA Is Not Required for Infectivity in Mice or for Resistance to Human ComplementIn Vitro

Infection and Immunity ◽

10.1128/iai.01892-14 ◽

2014 ◽

Vol 82 (8) ◽

pp. 3324-3332 ◽

Cited By ~ 9

Author(s):

Lindy M. Fine ◽

Daniel P. Miller ◽

Katherine L. Mallory ◽

Brittney K. Tegels ◽

Christopher G. Earnhart ◽

...

Keyword(s):

Genetic Manipulation ◽

Binding Protein ◽

Factor H ◽

Negative Regulator ◽

Human Complement ◽

Relapsing Fever ◽

Borrelia Hermsii ◽

Content Type

ABSTRACTThe primary causative agent of tick-borne relapsing fever in North America isBorrelia hermsii. It has been hypothesized thatB. hermsiievades complement-mediated destruction by binding factor H (FH), a host-derived negative regulator of complement.In vitro,B. hermsiiproduces a single FH binding protein designated FhbA (FH binding protein A). The properties and ligand binding activity of FhbA suggest that it plays multiple roles in pathogenesis. It binds plasminogen and has been identified as a significant target of a B1b B cell-mediated IgM response in mice. FhbA has also been explored as a potential diagnostic antigen forB. hermsiiinfection in humans. The ability to test the hypothesis that FhbA is a critical virulence factorin vivohas been hampered by the lack of well-developed systems for the genetic manipulation of the relapsing fever spirochetes. In this report, we have successfully generated aB. hermsiifhbAdeletion mutant (theB. hermsiiYORΔfhbAstrain) through allelic exchange mutagenesis. Deletion offhbAabolished FH binding by the YORΔfhbAstrain and eliminated cleavage of C3b on the cell surface. However, the YORΔfhbAstrain remained infectious in mice and retained resistance to killingin vitroby human complement. Collectively, these results indicate thatB. hermsiiemploys an FhbA/FH-independent mechanism of complement evasion that allows for resistance to killing by human complement and persistence in mice.

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