All Posts Tagged With: "endothelial cell infection"

Excerpt:

Here we report the first comprehensive study of B. henselae gene
expression during infection of human endothelial cells.
Expression of the main cluster of up-regulated 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 (pH5.5) homolog ChvG/ChvI of Agrobacterium
tumefaciens, BatR/BatS is optimally activated at the
physiological pH of blood (pH7.4). By conservation analysis of
the BatR regulon, we show that BatR/BatS is uniquely adapted to
up-regulate 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 alpha-proteobacteria.