EXPLOITING Anaplasma marginale GENOME

MORETTA ROSALIA; RUYBAL PAULA; PETRIGH ROMINA; WILCOWSKY SILVINA; FARBER MARISA

Iguazú, Misiones, Argentina

Congreso; XL Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2004

The obligate intraerythrocytic bacterium Anaplasma marginale (Rickettsiales: Anaplasmataceae) is the most prevalent tick-borne livestock pathogen worldwide and is a severe constraint to animal health and production in tropic and subtropical regions of the world. Whole -genome sequencing of bacteria together with in silico analysis and different kinds of genomic approaches are powerful tools that allow prediction of genes that take part in microbial pathogenesis. Using the information that became available with the complete sequence of A. marginale, our study aimed at selecting approaches that led us to the identification of genes that code for putative virulence factors or immunogens. The selected methods were:- PhoA fusion system for identifying exported proteins;- PCRbased subtractive hybridization for detecting differential genes between two species;-Bioinformatics analysis. We studied eight gene products so far: five were identified using the PhoA fusion system, two were selected from the differential subtraction library and one was identified by bioinformatics analysis. We also found a polymorphic tandem repeats of 11 nucleotides located in a noncoding region of the genome. Among the selected genes, four are currently being evaluated to determine their antigenic potential and one of them is being characterized to elucidate its role as a virulence determinant. In addition, the tandem-repeat non-coding region is being validated as a diagnostic and epidemiological tool. Anaplasma marginale (Rickettsiales: Anaplasmataceae) is the most prevalent tick-borne livestock pathogen worldwide and is a severe constraint to animal health and production in tropic and subtropical regions of the world. Whole -genome sequencing of bacteria together with in silico analysis and different kinds of genomic approaches are powerful tools that allow prediction of genes that take part in microbial pathogenesis. Using the information that became available with the complete sequence of A. marginale, our study aimed at selecting approaches that led us to the identification of genes that code for putative virulence factors or immunogens. The selected methods were:- PhoA fusion system for identifying exported proteins;- PCRbased subtractive hybridization for detecting differential genes between two species;-Bioinformatics analysis. We studied eight gene products so far: five were identified using the PhoA fusion system, two were selected from the differential subtraction library and one was identified by bioinformatics analysis. We also found a polymorphic tandem repeats of 11 nucleotides located in a noncoding region of the genome. Among the selected genes, four are currently being evaluated to determine their antigenic potential and one of them is being characterized to elucidate its role as a virulence determinant. In addition, the tandem-repeat non-coding region is being validated as a diagnostic and epidemiological tool.