Characterization of the ToxR Regulon Vibrio cholerae El Tor
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ABSTRACT: The transcriptional factor ToxR initiates a virulence regulatory cascade required for V. cholerae to express critical host colonization factors and cause disease. Genome-wide expression studies suggest that ToxR regulates many genes important for V. cholerae pathogenesis, yet our knowledge of the direct regulon controlled by ToxR is limited to just four genes. Here, we determine ToxR’s genome-wide DNA-binding profile and show that ToxR is a global regulator of both progenitor genome-encoded genes and horizontally acquired islands encoding the majority of V. cholerae’s major virulence factors. Our results suggest that ToxR has gained regulatory control over important acquired elements that not only drive V. cholerae pathogenesis but that also define the major transitions of V. cholerae pandemic lineages. We demonstrate that ToxR shares nearly half its regulon with the histone-like nucleoid structuring protein H-NS, and antagonizes H-NS for control of critical colonization functions. This regulatory interaction is the major role of ToxR in V. cholerae colonization since deletion of H-NS abrogates the need of ToxR in V. cholerae host colonization. By comparing the genome-wide binding profiles of ToxR and other critical virulence regulators, we show that despite similar predicted DNA binding requirements, ToxR is unique in its global control of progenitor-encoded and acquired genes. Our results suggest that, like H-NS, factors in addition to linear DNA sequence drive selection of ToxR binding sites.
ORGANISM(S): Vibrio cholerae O1 str. C6706
PROVIDER: GSE72473 | GEO | 2016/03/23
SECONDARY ACCESSION(S): PRJNA294111
REPOSITORIES: GEO
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