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. 2010 Aug 2;78(10):4122–4133. doi: 10.1128/IAI.00566-10

FIG. 4.

FIG. 4.

Effects of TcpP-binding site mutations on toxT-lacZ and CT reporter activities in a ΔtcpP background (toxR+) with TcpP-HSV overexpression. The positions of single- and multiple-base-pair transversions in the parental promoter are indicated relative to the toxT transcription start site. Black bars, values for ΔtcpP/pMMB207 strains; gray bars, values for O395/pMMB207 strains; white bars, values for ΔtcpP/pEK41 strains overexpressing TcpP-HSV. (A) β-Galactosidase activities for 3.5-h cultures of strains carrying either pTG24 alone (empty vector) or derivatives in which the parental promoter or its transversion derivatives drive the expression of the lacZ reporter. Values represent the averages from at least three independent cultures (n ≥ 3). (B) CtxB levels secreted by 20-h cultures of strains carrying modified chromosomal toxT promoters. toxTΔpro is a chromosomal deletion of the toxT promoter region from position −112 to +1. Values represent the averages from at least six independent cultures (n ≥ 6). N, not determined. Error bars represent the standard deviation for each data set. Statistical variance (Student's t test) from parental promoter values: *, P ≤ 0.05; **, P ≤ 0.005. Strains were grown under ToxR-inducing conditions in the presence of 1 mM IPTG.