FIG. 3.

Effects of the 5′-deletion and base-substitution mutations in the cis-regulatory Sp1 elements and RCE on WRN promoter activity. WRN-Luc plasmids containing various base-substitution mutations in three Sp1 elements and an RCE motif were generated. Their promoter activities were measured by transfection into HeLa cells and compared with the promoter activity of pGL3/N to -R. The diagram on the left shows the structure of each of the 5′-deletion and base-substitution mutants of the WRN promoter; the substituted bases are represented by lowercase boldface letters. Promoter activities in the modified WRN promoter region are shown as luciferase activity on the right. Each value represents the mean activity of luciferase detected in at least three independent experiments. Bars indicate standard deviations of the mean activities, expressed as RLU (relative light units) as specified by the manufacturer (EG&G Bertholdo).