FIG. 3.

Autoregulation of xylR gene expression and expression from the Ps promoters in ς⁵⁴-deficient and -proficient P. putida hosts. Overnight cultures of strains P. putida KT2440(pWW0), P. putida KT2440::rpoN(pWW0), and P. putida KT2440::rpoN(pWWΩXylR) were cultured and treated as described in the legend to Fig. 2. Two sets of reactions were carried out in parallel with primers to detect mRNAs from Pr promoters and Ps promoters. The resulting cDNAs were run in independent sequencing gels. (A) Pr1 and Pr2 indicate 208- and 180-bp cDNAs, respectively; (B) Ps1 indicates a cDNA of 208 bp; (C) Ps2 indicates a cDNA of 77 bp.