Figure 3.

Primer extension analysis of total RNA isolated from the E. coli strain WJW45 (wt) and the csdA deficient strain WJW45ΔcsdA (csdA-) grown to an OD₆₀₀ of 0.4 at 24°C. Top: The product of the RNase III cleavage within the rpoS leader (position G₋₁₁₂) accumulated only in the wild-type strain (lane 5) and was hardly detectable in the csdA deficient strain (lane 6). Lanes 1–4, sequencing ladder. The experiment was performed in triplicate. One representative autoradiograph is shown. Bottom: The DsrA RNA levels and 5S rRNA levels (loading control) of the wt and csdA-strain grown at 24°C were determined by northern-blot analysis as described in Materials and Methods. The Hfq protein levels in both strains were determined by western-blotting using equal amounts of total protein of the two strains at the time the cells were harvested for preparation of total RNA.