Effect of C/EBPα mutants on transcriptional activation by wildtype C/EBPα.

C/EBPα mutants lack a dominant-negative effect on transcriptional activation by wildtype C/EBPα. NIH3T3 cells were transfected with empty expression vector (400 ng) or pCMV-C/EBPα₄₂ (50 ng) with C/EBPα₃₀ (100 ng) or with mutant samples F3901, J3, and F3820 (100 ng). To test for a dominant-negative effect, the cells were cotransfected with pCMV-C/EBPα₄₂ (50 ng) and increasing amounts of the mutants (100 and 300 ng). Luciferase activities were measured and normalized and fold changes determined (y-axis).