Molecular Characterization of a 28 kDa Surface Antigen Gene Family of the Tribe Ehrlichiae

Reddy, G. R.; Sulsona, Carlos R.; Barbet, Anthony F.; Mahan, Suman M.; Burridge, M. J.; Alleman, A. Rick

doi:10.1006/bbrc.1998.8844

Cited by 82 publications

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“…This may be explained by the fact that in the present study we used two specific primers for each paralog and prepared cDNA using random hexamer primers, whereas previously we used map1 cluster-specific primers to generate the cDNA. Discrepancies in gene transcription have also been reported from studies in monocyte cultures of the p28 and p30 multigene families in E. chaffeensis and E. canis (23,24,30,42). The same gene families were also studied in vivo in dogs and in tick vectors.…”

Section: Discussionmentioning

confidence: 84%

“…Feeding ticks transmit E. ruminantium to vertebrate hosts in their saliva and/or by gut regurgitation (8,19). Phylogenetic studies have revealed a close relationship between E. ruminantium, Ehrlichia canis, and Ehrlichia chaffeensis (30,39).In infections with these ehrlichial agents, the serological response is mainly directed against outer-membrane proteins of approximately 30 kDa. The genes coding for these proteins have been designated the major antigenic protein 1 (map1) in E. ruminantium (32,40), the outer membrane protein p28 (omp-1) in E. chaffeensis, and the p30 outer membrane protein (p30) in E. canis (27,28,30,35,36,42,43).…”

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confidence: 99%

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confidence: 99%

“…The genes coding for these proteins have been designated the major antigenic protein 1 (map1) in E. ruminantium (32,40), the outer membrane protein p28 (omp-1) in E. chaffeensis, and the p30 outer membrane protein (p30) in E. canis (27,28,30,35,36,42,43). The OMP-1 and P30 protein families are each encoded by a multigene family consisting of 22 genes arranged in a cluster between a hypothetical transcriptional regulator (upstream) and the secA gene (downstream).…”

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Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

et al. 2005

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Ehrlichia ruminantium, an obligate intracellular bacterium transmitted by ticks of the genus Amblyomma, causes heartwater disease in ruminants. The gene coding for the major antigenic protein MAP1 is part of a multigene family consisting of a cluster containing 16 paralogs. In the search for differentially regulated genes between E. ruminantium grown in endothelial and tick cell lines that could be used in vaccine development and to determine if differences in the map1 gene cluster exist between different isolates of E. ruminantium, we analyzed the map1 gene cluster of the Senegal and Gardel isolates of E. ruminantium. Both isolates contained the same number of genes, and the same organization as found in the genome sequence of the Welgevonden isolate (H. Van Heerden, N. E. Collins, K. A. Brayton, C. Rademeyer, and B. A. Allsopp, Gene 330:159-168, 2004). However, comparison of two subpopulations of the Gardel isolate maintained in different laboratories demonstrated that recombination between map1-3 and map1-2 had occurred in one subpopulation with deletion of one entire gene. Reverse transcription-PCR on E. ruminantium derived mRNA from infected cells using gene-specific primers revealed that all 16 map1 paralogs were transcribed in endothelial cells. In one vector (Amblyomma variegatum) and several nonvector tick cell lines infected with E. ruminantium, transcripts were found for between 4 and 11 paralogs. In all these cases the transcript for the map1-1 gene was detected and was predominant. Our results indicate that the map1 gene cluster is relatively conserved but can be subject to recombination, and differences in the transcription of map1 multigenes in host and vector cell environments exist.Ehrlichia ruminantium (formerly Cowdria ruminantium [12]) is the causative agent of heartwater, a rickettsial disease transmitted by ticks of the genus Amblyomma which causes major economic losses in wild and domestic ruminants. The disease is endemic in sub-Saharan Africa and also is present on some Caribbean islands (33), where it poses a risk of spreading to the American mainland. Feeding ticks transmit E. ruminantium to vertebrate hosts in their saliva and/or by gut regurgitation (8,19). Phylogenetic studies have revealed a close relationship between E. ruminantium, Ehrlichia canis, and Ehrlichia chaffeensis (30,39).In infections with these ehrlichial agents, the serological response is mainly directed against outer-membrane proteins of approximately 30 kDa. The genes coding for these proteins have been designated the major antigenic protein 1 (map1) in E. ruminantium (32,40), the outer membrane protein p28 (omp-1) in E. chaffeensis, and the p30 outer membrane protein (p30) in E. canis (27,28,30,35,36,42,43). The OMP-1 and P30 protein families are each encoded by a multigene family consisting of 22 genes arranged in a cluster between a hypothetical transcriptional regulator (upstream) and the secA gene (downstream). The 5Ј end of the cluster contains paralogs with short intergenic spaces, whereas the paralogs at t...

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Section: Discussionmentioning

confidence: 84%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

et al. 2005

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“…Three pairs of tandem repeat protein (TRP) orthologs have been molecularly characterized in E. chaffeensis and E. canis, including TRP120/ TRP140, TRP47/TRP36, and TRP32/TRP19 and major continuous species-specific epitopes mapped to serine-rich acidic tandem repeat (TR) regions (3,13,15). Other major immunoreactive proteins that have been molecularly characterized include an ankyrin repeat protein (Ank200) and an outer membrane protein family (OMP-1) (14,22,23,25). Recently, putative lipoproteins have been identified in the E. chaffeensis genome, and dogs immunized with four of these proteins develop specific antibody and cell-mediated immune responses (7).…”

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Tyrosine-Phosphorylated Ehrlichia chaffeensis and Ehrlichia canis Tandem Repeat Orthologs Contain a Major Continuous Cross-Reactive Antibody Epitope in Lysine-Rich Repeats

et al. 2011

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A small subset of major immunoreactive proteins have been identified in Ehrlichia chaffeensis and Ehrlichia canis, including three molecularly and immunologically characterized pairs of immunoreactive tandem repeat protein (TRP) orthologs with major continuous species-specific epitopes within acidic tandem repeats (TR) that stimulate strong antibody responses during infection. In this study, we identified a fourth major immunoreactive TR-containing ortholog pair and defined a major cross-reactive epitope in homologous nonidentical 24-amino-acid lysine-rich TRs. Antibodies from patients and dogs with ehrlichiosis reacted strongly with recombinant TR regions, and epitopes were mapped to the N-terminal TR region (18 amino acids) in E. chaffeensis and the complete TR (24 amino acids) in E. canis. Two less-dominant epitopes were mapped to adjacent glutamate/aspartate-rich and aspartate/tyrosine-rich regions in the acidic C terminus of E. canis TRP95 but not in E. chaffeensis TRP75. Major immunoreactive proteins in E. chaffeensis (75-kDa) and E. canis (95-kD) whole-cell lysates and supernatants were identified with TR-specific antibodies. Consistent with other ehrlichial TRPs, the TRPs identified in ehrlichial whole-cell lysates and the recombinant proteins migrated abnormally slow electrophoretically a characteristic that was demonstrated with the positively charged TR and negatively charged C-terminal domains. E. chaffeensis TRP75 and E. canis TRP95 were immunoprecipitated with anti-pTyr antibody, demonstrating that they are tyrosine phosphorylated during infection of the host cell.

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Ehrlichia

Dumler¹,

Rikihisa²,

Dasch³

2015

Bergey's Manual of Systematics of Archaea and Bacteria

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Ehr.lich' i.a . M.L. fem. n. Ehrlichia named after Paul Ehrlich, a German bacteriologist. Proteobacteria / Alphaproteobacteria / Rickettsiales / Anaplasmataceae / Ehrlichia Coccoid to ellipsoidal cells . Found in cytoplasmic vacuoles in endothelial or hemopoietic mammalian host cells , including macrophages, monocytes, neutrophils, and cells of the bone marrow, liver, spleen, or lymph nodes. Often occur in clusters (morulae). Pleomorphic; occur as reticulate cells and “ dense core forms ” with condensed cytoplasm (Popov et al., 1998). Gram negative. Nonmotile. Some species grow in cultured tick cells or in cultured mammalian monocytes, macrophages, or endothelial cells. Cause disease in ruminants , canids , rodents , and humans . Ticks are the primary vectors and hosts . Belong to the Alphaproteobacteria by 16S rDNA gene sequence analysis; the organisms exhibit ≥97.6% 16S rRNA gene sequence identity with one another. Where studied, these bacteria possess surface protein antigen genes that are tandemly arranged in the chromosome and have a high degree of sequence similarity (Ohashi et al., 1998a, b; Reddy et al., 1998; McBride et al., 2000; Yu et al., 2000a). The mol % G + C of the DNA is : 30–56. Type species : Ehrlichia canis (Donatien and Lestoquard 1935) Moshkovski 1945, 18 ( Rickettsia canis Donatien and Lestoquard 1935, 419) emend. Dumler, Barbet, Bekker, Dasch, Palmer, Ray, Rikihisa and Rurangirwa 2001, 2159.

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Molecular Characterization of a 28 kDa Surface Antigen Gene Family of the Tribe Ehrlichiae

Cited by 82 publications

References 33 publications

Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

Tyrosine-Phosphorylated Ehrlichia chaffeensis and Ehrlichia canis Tandem Repeat Orthologs Contain a Major Continuous Cross-Reactive Antibody Epitope in Lysine-Rich Repeats

Ehrlichia

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