Fig. 6: CRP activates the transcription of ArcZ in K. pneumoniae.

a Multiple sequence alignment of the ArcZ promoter region. The putative CRP-binding site is labeled. b Expression of ArcZ requires the transcriptional regulator CRP. Northern blot was performed using 10 mg total RNA extracted from the indicated strains. Pre-ArcZ was detected using probe YCO-1838, the mature ArcZ was detected using probe YCO-1745. 5S rRNA served as loading control. Experiment was performed three times. Uncropped blots in Source Data. c Northern blot analysis to identify critical region in arcZ promoter. ArcZ expression from pZE12-based plasmids carrying different arcZ genomic regions. Vec, empty vector control (pJV300); arcZ, plasmid carrying an arcZ gene with native promoter; Mut: mutation of the conserved TCACA sequence. Trunc: truncation of the ArcZ promoter from −41 bp upwards without disturbing the arcZ gene. 5S rRNA was probed as loading control. Experiment was performed three times. Uncropped blots in Source Data. d CRP negatively regulates HMV. Overnight cultures of the indicated strains were centrifuged at 1000 g for 5 min. N = 3 biological replicates, bars indicate mean ± SD. *, p < 0.05; **, p < 0.01; two-tailed Student’s t-test.