The regulon of the pleiotropic transcription factor Spx in Bacillus subtilis

The transcriptional regulator Spx plays a key role in maintaining the redox homeostasis of Bacillus subtilis cells exposed to disulfide stress. Defects in Spx were previously shown to lead to differential expression of numerous genes but direct and indirect regulatory effects could not be distinguished. Wild-type strain and spx mutant cells exposed or not to diamide stress were subjected to tiling array gene expression analysis. To distinguish direct and indirect effects, the genomic sites bound by the Spx-RNAP complex were mapped using a chromatine immunoprecipitation approach. This allowed the identification of 144 transcription units comprising 275 genes under direct Spx regulation. This data set contains 4 samples. Immunoprecipitated (IP) DNA from Bacillus subtilis Bas044 strain (BSB1, a tryptophan-prototrophic derivative 168 strain expressing a SPA-tagged Spx protein) were extracted from bacterial cultures in absence or presence of diamide. IP and whole cell extract DNA were hybridized on tiling array to generate ChIP-on-chip profiles. Two biological replicates were analyzed.