The role of c.131C>T and c.134C>A polymorphisms on cryptic promoter activity. (a) Schematic representations of the firefly luciferase reporter constructs used. The position of both polymorphisms is indicated. (b) HeLa cells were transfected with the indicated constructs together with a plasmid containing CMV-Renilla luciferase. Cell lysates were prepared 24 hours post-transfection and the activity of the firefly luciferase was normalized to that of Renilla luciferase. For each construct at least three independent experiments were performed using different DNA preparations. Error bars represent standard error of the mean. The P-value of Student's t test is shown.