FIG. 5.

Responses of separated promoter elements to nutritional stress. Wild-type relA⁺ cells containing the indicated lacZ promoter fusion constructs were grown in MM1 and were treated with SHX (A and B) or with α-MG (C and D) for the indicated times. The relative activities of the promoter fragments of rrnO and rrnJ were measured by densitometric scans of autoradiograms from RNA slot blots before and after treatments. The values were calculated as described in the legend for Fig. 3. (E and F) The chemical half-lives of lacZ mRNAs transcribed from the isolated P1 or P2 elements of rrnO and rrnJ were determined and plotted as described in the legend for Fig. 1C and D.