The Dot/Icm system and the PmrAB system are essential for intracellular replication and delivery of <i>C. burnetii</i> effector proteins.

<p>(A) Indicated are the locations of transposon insertions in the chromosomal regions encoding the Dot/Icm system from 1559100 bp to 1591800 bp, and (B) the PmrAB two-component regulatory system from 1176500 to 1179500 bp. The site of each transposon insertion is represented by an arrow. The mutants that could not replicate intracellularly were assigned red arrows, mutants that produced normal CCVs were assigned black arrows, and mutants that formed small vacuoles were assigned grey arrows. (C) The plasmids pBlaM and pBlaM-77 were introduced into <i>C burnetii</i> NMII (black bars) and <i>pmrA</i>::Tn (grey bars) to determine whether the PmrAB system was essential for effector translocation. Cleavage of the fluorescent β-lactamase substrate CC4F-AM was determined by calculating the ratio of fluorescence at 460 nm to 535 nm relative to uninfected cells. The graph shows the mean ± SD calculated for three independent samples.