FIG 4.

Redox stress-specific recruitment of SigH within thioredoxin promoters. In vivo recruitment of (A) SigH and (B) PhoP within thioredoxin promoters was examined by ChIP-qPCR using WT H37Rv grown under normal conditions and in the presence of 5 mM diamide. FLAG-tagged SigH or PhoP was expressed in WT-H37Rv, and immunoprecipitation was carried out with anti-FLAG antibody to determine fold PCR enrichment due to binding of regulators, as described in Materials and Methods. “trxC ORF” refers to a part of the trxB2 gene that remains adjacent to trxC, and “espAup” refers to the upstream regulatory region (positions −957 to −580 relative to the transcription start site of espA [Rv3616c]) comprising PhoP binding site (9). Each piece of data collected in duplicate qPCR measurements (technical repeats) using biological duplicates was normalized relative to ChIP samples from cells grown under normal conditions (*, P ≤ 0.05; **, P ≤ 0.01). To examine PhoP recruitment within espAup (as a positive control), IP samples from cells grown under redox stress were normalized to 1.