Figure 2.

The activation of promoter activity by CRP-cAMP with the UP element. β-Galactosidase activities were measured in VH1000crp⁺/VH1000Δcrp cells carrying different Class I CRP-dependent promoters cloned into the lac expression vector pRW50. Promoter activation by CRP-cAMP is calculated as the crp⁺ value at each distance divided by the average Δcrp value. Cells were grown exponentially in Luria–Bertani broth containing 35μg/ml tetracycline, and β-galactosidase expression was measured by the Miller protocol; activities are expressed in Miller units of β-galactosidase activity. Each value is the mean ± S.D. of at least three independent assays.