Fig. 4

C/EBP binding site mutations in proximal and distal Cps1 enhancer regions impaired NOB-mediated reporter activation. a Diagram of distal and proximal C/EBP sites on the Cps1 promoter region. b and c Hepa1-6 cells were transfected with reporter constructs containing wild-type (WT; white bars) and C/EBP binding site mutated (black bars) enhancer regions, and treated with NOB at the indicated doses. Co-transfection of C/EBPα expression construct was also carried out in parallel. Each value represented mean ± SEM of three replicates from a single assay. The results are representative of at least three independent experiments. b and c show results from reporter constructs containing distal and proximal WT and mutant enhancers respectively. Two-way ANOVA with Bonferroni post-hoc tests: significant main effects of plasmid construct, (b) F = 81.43, p < 0.001, (c) F = 254.97, p < 0.0001; NOB concentration effect, (b) F = 47.39, p < 0.0001, (c) F = 42.01, p < 0.0001; and a significant interaction between constructs and NOB concentration, (b) F = 23, p < 0.0001, (c) F = 24.37, p < 0.0001