Figure 2.

The effectiveness of the UGT1A1 promoters containing the variable (ta) repeats using a luciferase reporter. Promoter activity was analyzed in two human hepatoma cell lines: HepG2 (A and C) and HuH7 (B and D). The shorter promoter constructs (C and D) were 229 bp for the (ta)₆, and the longer constructs (A and B) were an additional 32 bp in length. Promoter activity with a firefly luciferase reporter gene was compared with an internal control of Renilla luciferase with an simian virus 40 promoter. Mean values of three to six replicate wells and their standard errors are shown. The short UGT1A1 constructs in HepG2 cells (C) were assayed 24 hr after transfections instead of 48 hr because the cells had reached confluency. The “wild type” (ta)₆ is shown as a solid bar; the variants are shown as open bars. Note that the (ta)₉ promoter was made by mutagenesis. All other promoters are naturally occurring.