Bach2 regulates the HO-1 promoter. (A) 293T cells were transiently transfected with vectors encoding BACH2 or vehicle (control) and harvested after 2 days. Cell lysates were separated on 10% SDS-PAGE and immunoblotted with anti–HO-1, anti-Bach2, and antiactin antibodies. The bar graph shows the densitometry of the bands indicating the HO-1/actin ratio. The image is representative of 4 independent experiments. (B) Jurkat cells were transiently transfected with luciferase reporter constructs and plasmids containing vehicle (-), 4.9 kb HO-1 promoter (4.9 kb), MARE mutant M1, mutant M2, both M1+M2 site mutants, and 3.8 kb promoter region (3.8 kb) devoid of MARE sites, together with Bach2 expression vector (+) or vehicle (-). Luciferase activity was examined after 24 hours and measured as luciferase–Renilla luciferase activity ratio. The results are the mean ± standard deviation of 3 independent experiments, each carried out in duplicate. *Differences in activity of the indicated assays in the presence or absence of Bach2 are statistically significant according to the Mann-Whitney U test (P < .05).