The importance of the E box, ISRE, and κB site in the constitutive and cytokine-induced β₂m promoter activity.

(A) Transient transfection of wild-type β₂m and E box-, ISRE-, or κB-mutated reporter constructs in Jurkat, Raji, and THP-1 cells revealing the importance of each regulatory site to the constitutive promoter activity in lymphoid and monocytic cells. (B) Transient transfection of the β₂m reporter construct in Tera-2 cells induced with TNF-α, IFN-α, IFN-β, or IFN-γ (each 500 U/mL) for 48 hours. β₂m is induced by all cytokines of which IFN-γ is the most potent. The induction ratios are indicated above the histogram. (C) Transient transfection of wild-type β₂m and E box-, ISRE-, or κB-mutated reporter constructs in Tera-2 cells induced with TNF-α or IFN-γ (each 500 U/mL) for 48 hours. All boxes are important in the TNF-α– and IFN-γ–induced β₂m promoter activity. The induction ratios are indicated above the histogram. The luciferase activity values were normalized with the Renilla luciferase activity values and are expressed as mean ± SD of 4 experiments. RLU indicates relative light units.