%0 Journal Article
%T Mariner mutagenesis of Brucella melitensis reveals genes with previously uncharacterized roles in virulence and survival
%A Qingmin Wu
%A Jianwu Pei
%A Carol Turse
%A Thomas A Ficht
%J BMC Microbiology
%D 2006
%I BioMed Central
%R 10.1186/1471-2180-6-102
%X Although previously identified groups or classes of genes required for virulence and survival were represented in the screen, additional novel identifications were revealed and may be attributable to the difference in insertion sequence biases of the two transposons. Mutants identified using a fluorescence-based macrophage screen were further evaluated using gentamicin-based protection assay in macrophages, survival in the mouse splenic clearance model and growth in vitro to identify mutants with reduced growth rates.The identification of novel genes within previously described groups was expected, and nearly two-thirds of the 95 genes had not been previously reported as contributing to survival and virulence using random Tn5-based mutagenesis. The results of this work provide added insight with regard to the regulatory elements, nutritional demands and mechanisms required for efficient intracellular growth and survival of the organism.Previous studies designed to identify genes related to Brucella virulence and survival utilized Tn5-based mutagenesis strategies. Although useful in identifying numerous factors, this approach may be restricted in potential by the sequence bias for integration of Tn5 in GC-rich DNA sequences [1]. In contrast, Himar1 transposable element has a different target specificity and integrates at TA base pairs [2]. As a result of these different specificities, the two transposons are expected to provide complementary tools for gene discovery related to virulence and intracellular survival. However, rather than identifying completely new classes of genes, the expectation was that additional genes within previously described groups would be identified.Functional characterization and sequence analysis of the Brucella genome have identified few classically defined virulence genes. When narrowly defined, virulence factors are those functions specifically designed to interact with the host cell, to enhance replication or survival, and have no effec
%U http://www.biomedcentral.com/1471-2180/6/102