FIG. 1.

Level of expression of the icmR::lacZ fusion in E. coli. E. coli containing different plasmids was grown to exponential phase, and the level of expression of the icmR::lacZ fusion was determined without (white) and with (gray) IPTG induction. The plasmids examined were the vector (pOG-BRR3), the clone isolated from the genetic screen (pOG-RR16), the vector harboring the L. pneumophila cpxR gene by itself (pOG-RCPR3), and the vector harboring the E. coli cpxR gene (pOG-BCC2). The β-galactosidase specific activity is presented as an average of the results of at least three different experiments. The error bars represent standard deviations.