FIG. 6.

VirB alleviates H-NS-mediated repression of the icsB promoter in vitro. In vitro transcription was carried out with supercoiled pKK282.3proicsB plasmid DNA in the presence of H-NS with VirB at the indicated concentrations. Radiolabeled transcript was electrophoresed, and the resulting gel was subjected to autoradiography. The bands on the autoradiograph were quantified by densitometry. Data obtained from three separate experiments were averaged and used to plot the graph. Results obtained in the absence and presence of H-NS are represented by diamonds and squares, respectively, and are labeled. The error bars around each datum point show the standard deviation.