Hierarchical clustering of the transcriptional response of B. bronchiseptica strain RB53, a Bvg+ phase-locked mutant, during late-log-phase and stationary-phase growth. (A) Expression profiles representing global transcriptional changes. (B) Expression profiles representing transcriptional changes of genes positively regulated by BvgAS, along with 16S RNA and rpoH. Transcriptional changes identified by comparing cDNA from mid-log phase (15 h) to that from late log phase (24 h) are represented under “late-log phase,” and the transcriptional changes identified by comparing cDNA from mid-log phase (15 h) to that from late stationary phase (48 h) are represented under “stationary phase.” Data are mean centered for each array element and averaged from three biological replicates. All expression profiles of genes are in rows and are represented using the color scale at top, with gray indicating missing data.