Fig. 2. Repressor activities of mutant ParA proteins under autogenous control. Results of a typical experiment measuring β-galactosidase levels of a parB::lacZ fusion in the presence or absence of wild-type and mutant ParAs. The diagram above the graph describes the arrangement of pBEF131 and its mutant derivatives. These plasmids were used to transform DH5Δlac, and β-galactosidase assays were performed as described by Miller (1992). The error bars represent the variation in duplicate readings in this experiment. WT, wild type.