FIG. 4.

Cul3 contributes to the regulation of Nrf2-dependent gene expression. (a) 293T cells were transfected with the 4×ARE firefly luciferase reporter and a plasmid encoding Renilla luciferase in the absence or presence of plasmids expressing short hairpin RNA against Keap1 or Cul3. Cells were collected, and luciferase activity was measured with a luminometer. Error bars represent the standard deviation for three independent experiments. (b) Same as panel a except that cells were either mock treated or treated with 100 μM tBHQ for 16 h. (c) Mock-transfected wild-type MEFs and PERK^−/− MEFs transfected as indicated were treated with 2.5 μg of tunicamycin (Tun) per ml for 0, 2, or 4 h. Cells were stained with propidium iodide, and the percentage of propidium iodide-positive cells (y axis) was determined. Error bars represent the standard deviation for three independent experiments.