Influence of SNV on promoter activity. Changes in relative promoter activity of pGL4.10 XYLT1 promoter cloning construct c.-1031 to c.+1complete were determined in response to SNV-associated base exchange by site-directed mutagenesis. Promoter activities are expressed relative to the activity of construct c.-1031 to c.+1complete, which was defined as 100%. Plasmids were transfected into SW1353 cells and promoter activity was determined by dual luciferase assay. Values are means ± SEM of triplicates from at least two or three independent experiments. ns = not significant; ***p < 0.001 (Mann-Whitney U-test).