Regulation of a 27 kb gene cluster on Chromosome 3. (A) Cluster analysis of genes in the afcA and shvR genomic regions with decreased (green), increased (red) or no change (black) in expression in each mutant compared to K56-2 according to microarray analysis. Arrows indicated putative (dashed lines) or experimentally-determined (solid lines) transcriptional units. Gene name and function are derived from B. cenocepacia . Mean change (fold) in expression is indicated for the displayed group of genes for each mutant. (B) Expression of afcA was monitored throughout growth in K56-2ΔcepR and K56-2cciIR mutants compared to K56-2 in PTSB plus 100 μg/ml of Tp. The expression of afcA::lux (pAfcA) is significantly greater in K56-2cciIR than K56-2 from 6 to 10 h along the time course (P < 0.05, unpaired t-test, Welch corrected). All values are the means ± SD of triplicate cultures and are representative of two individual trials.