FIG 5.

Mutations constructed in the putative CsrA regulatory elements resulted in elevated levels of expression at the exponential phase. The expression of effector (indicated below the bars) wild-type lacZ fusions (white bars) and lacZ fusions of the same genes containing a mutation in a putative CsrA binding site (waved bars) were examined at the exponential phase in the L. pneumophila wild-type strain. The mutations constructed are marked by asterisks in Fig. 3. β-Galactosidase activity was measured as described in Materials and Methods. The data are the averages ± standard deviations (error bars) of the results of at least three different experiments. The genes were divided according to their levels of expression.