Fig. 4.

Contribution of C/EBP binding sites on the basal promoter activity. a Reporter genes harboring the long (PL) or short promoter (PS) segment were transfected into HepG2 or MAC-T cells. The relative luciferase activity was determined 48 h later and was expressed as multiple of the activity of the promoter-less vector pGLbasic (abscissa). Position of the distal and proximal C/EBP binding sites is indicated (C/EBP_D; C/EBP_P). b Activity of reporter genes in which either the distal C/EBP binding site (at −1020; PL-MD) or both sites were mutated (PL-MB). In addition, the proximal binding site (at −10) was mutated on the short promoter alone and the effect was recorded using the construct PS-MP. Values are the means from two experiments, each assayed in triplicate. Asterisks indicate the statistical significance of the difference towards the construct with the respective wt-promoter