Effect of serial 5'-deletions of the human HL promoter region on transcriptional activity in HepG2 cells. HepG2 cells were transiently transfected with the indicated promoter-reporter constructs. At 48 h post-transfection, transcriptional activity was determined as the firefly over renilla luciferase activity. Data are expressed as percentage of the ratio measured in the hHL-685luc – transfected cells. Data are means ± SD from 4 independent experiments, each performed in quadruplicate. *: P < 0.05; n.s.: not significant.