Article: article from journal or magazin.
The BatR/BatS two-component regulatory system controls the adaptive response of Bartonella henselae during human endothelial cell infection.
Journal of Bacteriology
Here, we report the first comprehensive study of Bartonella henselae gene expression during infection of human endothelial cells. Expression of the main cluster of upregulated genes, comprising the VirB type IV secretion system and its secreted protein substrates, is shown to be under the positive control of the transcriptional regulator BatR. We demonstrate binding of BatR to the promoters of the virB operon and a substrate-encoding gene and provide biochemical evidence that BatR and BatS constitute a functional two-component regulatory system. Moreover, in contrast to the acid-inducible (pH 5.5) homologs ChvG/ChvI of Agrobacterium tumefaciens, BatR/BatS are optimally activated at the physiological pH of blood (pH 7.4). By conservation analysis of the BatR regulon, we show that BatR/BatS are uniquely adapted to upregulate a genus-specific virulence regulon during hemotropic infection in mammals. Thus, we propose that BatR/BatS two-component system homologs represent vertically inherited pH sensors that control the expression of horizontally transmitted gene sets critical for the diverse host-associated life styles of the alphaproteobacteria.
Bacterial Proteins/genetics, Bacterial Proteins/metabolism, Bartonella henselae/metabolism, Cell Line, Cell Line, Tumor, Electrophoresis, Polyacrylamide Gel, Electrophoretic Mobility Shift Assay, Flow Cytometry, Gene Expression Regulation, Bacterial/physiology, Genetic Complementation Test, Green Fluorescent Proteins/genetics, Green Fluorescent Proteins/metabolism, Humans, Hydrogen-Ion Concentration, Immunoblotting, Operon/genetics, Phylogeny, Promoter Regions, Genetic/genetics, Promoter Regions, Genetic/physiology, Protein Binding/genetics, Protein Binding/physiology, Recombinant Proteins/genetics, Recombinant Proteins/metabolism, Reverse Transcriptase Polymerase Chain Reaction
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