Figure 8. In vivo activity of the rsd P2 promoter in different strain background.

Relative transcription activities of the rsd P2 promoter were determined by quantitative primer extension reaction from RNA extracted from strains with defects in defined growth rate regulatory genes. Total RNA was extracted during exponential (log) or stationary (stat) growth phases or before or after induction of the stringent response by serine hydroxamate (SHX). The diagrams represent relative amounts of P2-derived transcripts normalized to the RNA 1 transcript. The mean of two to three independent experiments is shown. In all comparisons the rsd P2 expression level during stationary phase was set to 1. RNAs from strains with mutations in the following genes were analyzed in comparison to the RNAs from their respective wild-types: (a) relA, (b) dksA, (c) rsd, (d) rpoS, (e) hns, (f) fis, (g) dam. For the different E. coli strains see Table S1. In (h) a representative example for the primer extension of the analysis from dam ⁺/dam ⁻ strains is shown. Primer extension products specific for RNA 1, rsd P2 and rsd P1 are indicated.