Transactivation of the MBP P2 promoter by C/EBPα, C/EBPβ, and C/EBPδ. Ten micrograms of pXP2 or pXP2-MBP was transfected into Jurkat cells along with 10 μg of pEF-mC/EBPα, pEF-hC/EBPβ, or pEF-mC/EBPδ. pCMV-βGal was included as an internal control. Luciferase and β-galactosidase activities were assayed 24 hours later. Data are shown as the mean of three independent experiments (±SEM).