FIG 1.

Transcriptional cross-regulation between lrg and cid operons. The level of lrg or cid expression was measured using qRT-PCR in cid and lrg derivative strains, respectively, in comparison to that of the wild-type strain. (A) The expression of lrgA was measured at early (OD₆₀₀ = 0.2) and late (OD₆₀₀ = 0.9) exponential growth phases of UA159 (wild type [WT]) and various cid mutant strains (ΔcidA, ΔcidB, and ΔcidAB). (B) The expression of cidA was measured under the same conditions as those for panel A with UA159 (WT) and various lrg mutant strains (ΔlrgA, ΔlrgB, and ΔlrgAB). Data are averages of three independent biological replicates. Differences in relative gene expression between strains were evaluated for statistical significance by Student's t test. *, P < 0.05; **, P < 0.005.