FIGURE 12.

Nrf2-dependent gene transcription is abrogated by RNF4. HepG2 cells were co-transfected with 0.2 μg each of HO-1-ARE-luc reporter gene construct and heterologous Nrf2 (pCI-Nrf2) as inducer (19, 22), with or without plasmid pCMV6-RNF4-myc-DDK (OriGene Technologies) expressing RNF4. When needed, empty vector pCI-Neo (0.2 μg) or pCMV6-myc-DDK (0.2 μg) was also transfected. The total amount of DNA in each well was 0.6 μg. The electrophile tBHQ (20 μm) was added 24 h after transfection, and promoter activity was measured 8 h later, as described (19, 22). A, Nrf2-dependent gene promoter activity is inhibited by RNF4. B, tBHQ-enhanced Nrf2-dependent gene transcription is inhibited by RNF4. Values plotted are means ± S.E. for duplicate assays from 3 to 4 different experiments. *, statistically different (p < 0.05).