J Vet Sci.  2010 Dec;11(4):333-340. 10.4142/jvs.2010.11.4.333.

Sequence and phylogenetic analysis of the gp200 protein of Ehrlichia canis from dogs in Taiwan

• Huang CC
• Hsieh YC
• Tsang CL
• Chung YT

• KMID: 1072183
• DOI: http://doi.org/10.4142/jvs.2010.11.4.333

Abstract

Ehrlichia (E.) canis is a Gram-negative obligate intracellular bacterium responsible for canine monocytic ehrlichiosis. Currently, the genetic diversity of E. canis strains worldwide is poorly defined. In the present study, sequence analysis of the nearly full-length 16S rDNA (1,620 bp) and the complete coding region (4,269 bp) of the gp200 gene, which encodes the largest major immunoreactive protein in E. canis, from 17 Taiwanese samples was conducted. The resultant 16S rDNA sequences were found to be identical to each other and have very high homology (99.4~100%) with previously reported E. canis sequences. Additionally, phylogenetic analysis of gp200 demonstrated that the E. canis Taiwanese genotype was genetically distinct from other reported isolates obtained from the United States, Brazil, and Israel, and that it formed a separate clade. Remarkable variations unique to the Taiwanese genotype were found throughout the deduced amino acid sequence of gp200, including 15 substitutions occurring in two of five known species-specific epitopes. The gp200 amino acid sequences of the Taiwanese genotype bore 94.4~94.6 identities with those of the isolates from the United States and Brazil, and 93.7% homology with that of the Israeli isolate. Taken together, these results suggest that the Taiwanese genotype represents a novel strain of E. canis that has not yet been characterized.

Keyword

canine ehrlichiosis; Ehrlichia canis; gp200 gene; phylogenetic analysis; sequence analysis

MeSH Terms

Amino Acid Sequence
Animals
Bacterial Proteins/chemistry/*genetics
Dogs
Ehrlichia canis/*classification/*genetics
Genotype
Molecular Sequence Data
*Phylogeny
RNA, Ribosomal, 16S/genetics
Sequence Alignment
Sequence Analysis, Protein
Taiwan