Fig 1.

H-NS modulates the expression of class I and III RNRs. (A) Fluorescence was measured in strains MG1655 and MG1655Δhns harboring plasmids pETS150 (PnrdAB-GFP), pETS152 (PnrdDG-GFP), and pETS151 (PnrdHIEF-GFP). The hns gene cloned into plasmid pLGHNSEC was used to complement hns deficiency in strain MG1655Δhns. The measurements at different points of growth at 37°C in LB were background subtracted using the normalized fluorescence from a culture of MG1655 at the points indicated (A₅₅₀ = 0.2, 0.5, and 1.5). The fluorescence was normalized to the optical density at 550 nm (OD₅₅₀) and is given in relative units. The points represent the mean of three independent experiments, and the error bars denote the standard deviations. (B) Expression of the PnrdAB::lacZ transcriptional fusion inserted as a single chromosomal copy (ETS119 and ETS122). β-Galactosidase activity was determined in strains ETS119 and ETS122 harboring the chromosomal fusion. Samples were collected at different stages of growth in LB medium at 37°C. The values are in Miller units. The points represent the means from three independent experiments, and the error bars denote the standard deviations. (C) Immunodetection of NrdA protein in aerobic cultures of strains MG1655 and MG1655Δhns.