FIG. 4.

DEX induces C/EBP-alpha expression in cultured cells, and C/EBP-alpha activates the bICP0 early promoter. (A) Neuro-2A cells were treated with 1 μM DEX, and cell lysate was collected at various times after treatment (hours). A total of 100 μg of protein was electrophoresed, and Western blot analysis was performed using a C/EBP-alpha or β-actin antiserum that was diluted 1:500. The molecular mass is in kilodaltons. (B) Neuro-2A cells were cotransfected with 1 μg of the designated bICP0 E promoter construct and 0.1 μg of wt C/EBP-alpha (filled columns) or the DNA binding mutant of C/EBP-alpha (open columns). Constant amounts of DNA were used for all transfections by adding pcDNA3.1, a blank expression vector. At 48 h posttransfection, cells were collected and processed for CAT activity as described in Materials and Methods. CAT activity of the cells transfected with the control pCAT basic vector was given a value of 1. All other values are expressed as the relative increase in activation with respect to the control. The results are the average of four independent experiments.