Transcriptional activation activity of the amino terminus of c/ebp1.

(A) The GAL4 DNA-binding domain (GAL4 DBD) from yeast was fused to the cDNAs encoding regions of c/ebp1 or human C/EBPε, as indicated. (B) Transfection with increasing amounts ofGAL4-c/ebp1 (1-87) as indicated. (C) Transfection with 500 ngGAL4-c/ebp1 (1-87): c/ebp1; human C/EBPε (1-162): C/EBPε; or human C/EBPε (1-70): C/EBPε (1-70). NIH3T3 cells were transfected with 1 μg GAL4-luc reporter and various expression constructs. Transfections were normalized by cotransfection with a β-galactosidase expression vector and samples were all transfected in duplicate. The experiments shown in panels B and C are representative of 3 independent transfections. The y-axes represent fold inductions by the expression constructs relative to induction by a GAL4 DBD vector without an activation domain.