Fig. 6.

Identification of a BoxA element in Citrobacter koseri. β-galactosidase activity of wild-type (‘wt boxA’) and boxA mutant (‘C4A’) transcriptional fusions of CKO_00699 (R82A mutant, to avoid potential toxicity to E. coli in the absence of the anti-toxin) to lacZ in E. coli wild-type (‘wt’; dark grey bars) or nusB deletion (‘ΔnusB”; yellow bars) strains. CKO_00699-lacZ transcription was driven by a constitutive promoter²⁵. Error bars represent ±1 standard deviation from the mean (n = 3)