FIG. 8.

Transactivation of the mim-1 enhancer by v-Myb, C/EBPβ, and p300. Reporter genes containing only the mim-1 promoter (p-240-Luc), the mim-1 enhancer (Enh) upstream of the tk promoter (mim3tk81-Luc), or the mim-1 enhancer upstream of the mim-1 promoter (mim3mim-Luc) are shown schematically at the top. QT6 cells were transfected with 2 μg of the indicated reporter genes and different combinations of expression vectors for v-Myb (pCDE26v-myb; 1 μg), C/EBPβ (pCDNA3-CCR; 1 μg), p300 (pCMVβ-p300CHA; 5 μg), or a HAT-deficient mutant of p300 (p300HA-DI1485AL; 5 μg), as indicated at the bottom. Controls contained the equivalent amount of empty expression vector. pCMVβ (0.2 μg) was included in all transfections to control the transfection efficiencies. Luciferase and β-galactosidase activities were determined 24 h after transfection. Bars show the average luciferase activity normalized with respect to the β-galactosidase activity. The activity of each reporter gene in the absence of any exogenous factor was designated 1. The T bars show standard deviations.