Fig. 6.

Rv0081 is upregulated by NO in M. tuberculosis but is repressed following Rv0081 overproduction. (A) qRT-PCR was performed on RNA derived from wild-type M. tuberculosis H37Rv grown in the absence (white bars) or presence (black bars) of NO. Expression levels for various genes, including dosR and representatives of the Rv0081-Rv0088 locus, were normalized to rrs. Expression levels in NO-treated cultures are presented as the fold induction relative to those from untreated cultures, which were set to 1.0. Asterisks denote statistical significance between NO-treated versus untreated cultures (P < 0.05). (B) Relative expression levels of Rv0081 in M. tuberculosis H37Rv or an isogenic ΔRv0081 mutant expressing hsp60-Rv0081 from an integrated vector (TB222). Cultures were grown in the absence (white bars) or presence (black bars) of NO. Expression levels were normalized to rrs. Expression was presented as the fold induction relative to that observed in the wild-type strain in the absence of treatment, which was set to 1.0. Asterisks denote statistical significance between NO-treated versus untreated cultures (P < 0.05).