Figure 1

Activation of human SND1 gene promoter activity and expression by endoplasmic reticulum stress. A) HepG2 cells were transfected with a luciferase reporter gene driven by six different constructs of the human SND1 gene promoter SND/1-6 and used 24 hours later. Cells were incubated with 5 μg/ml tunicamycin (black) or 1 μM thapsigargin (grey) or the corresponding vehicle (white, control) 2 hours before transfection. Luciferase activity was calculated using a dual luciferase assay and expressed as fold increase relative to the activity of the SND/6 fragment in control cells as described in Methods. B) Levels of SND1 mRNA were determined by quantitative real-time PCR in treated and non-treated HepG2 cells and expressed as relative units, setting to 1.0 the value for control cells. C) SND1 and chaperones GRP78 and GRP94 protein expression was determined by western blotting using β-tubulin as a loading control and expressed as relative units, setting to 1.0 the value for control cells. Data are presented as mean ± SD from at least three independent experiments. * P < 0.05, ** P < 0.01, *** P < 0.005.