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Deletion in the genes encoding outer surface proteins OspA and OspB of Borrelia garinii isolated from patients in
J Wang1, T Masuzawa, M Li
1Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka, Japan. gp061@ys2.u-shizuoka-ken.ac.jp
Abstract:
We detected the expression of outer surface proteins OspA and OspB, and characterized the genes encoding the two Osps of eight Borrelia garinii isolates from patients in Japan. Six of the eight strains shared a common antigenic epitope in their OspA and/or OspB proteins to monoclonal antibody P3134 against OspB, and were identified to have a conserved carboxyl terminus on their ospA and ospB genes by Southern blot hybridization. One strain, JEM4, did not express OspB protein, which was due to lack of the ospB gene. Gene cloning and sequencing analysis revealed that it had only one osp open reading frame with 819 nucleotides, which was similar to the ospA gene. The deletion of the ospB gene could be explained by a homologous recombination based on the common C-terminal sequences on the ospAB operon.
Insights
This study investigated Borrelia garinii outer surface proteins (OspA and OspB) in Japanese patients. One strain lacked OspB due to gene deletion, likely caused by homologous recombination.
Area of Science:
- Microbiology
- Genetics
- Immunology
Background:
- Borrelia garinii is a pathogen causing Lyme disease.
- Outer surface proteins (OspA and OspB) are crucial for Borrelia pathogenesis and immune evasion.
Purpose of the Study:
- To characterize the outer surface proteins OspA and OspB and their encoding genes in Borrelia garinii isolates from Japan.
- To investigate the genetic basis for the absence of OspB expression in a specific isolate.
Main Methods:
- Detection of OspA and OspB expression.
- Gene characterization using Southern blot hybridization.
- Gene cloning and nucleotide sequencing.
Main Results:
- Six of eight Borrelia garinii isolates shared common antigenic epitopes in OspA/OspB and conserved gene sequences.
- One isolate (JEM4) lacked OspB expression due to the absence of the ospB gene.
- Sequence analysis revealed a single osp open reading frame in JEM4, similar to ospA, suggesting gene deletion via homologous recombination.
Conclusions:
- Borrelia garinii isolates from Japan exhibit variations in OspA and OspB expression and gene structure.
- Homologous recombination is a likely mechanism for the deletion of the ospB gene in certain isolates.