FIGURE 6.

The NF complexes act through the upstream regulatory elements and the core promoter of the c-fos gene. A, the reporter gene plasmids contained deletion mutants of the c-fos enhancer/promoter region as indicated on the left. Each reporter plasmid was transfected into C3H10T1/2 cells together with the plasmid expressing NF45 and that expressing NF90 or NF110. The middle panel shows the relative levels of the luciferase activities in the presence of NF45-NF90 or NF45-NF110. The columns on the right indicate the values of -fold activation by NF45-NF90 and NF45-NF110. B, the structure of the reporter gene that harbors the wild-type or mutant c-fos gene promoter is indicated on the left. The filled boxes indicate the mutated SRE, FAP-1, and CRE. The wild-type or mutant reporter gene was introduced into HEK293 cells with the expression vectors for NF45 and NF90 or those with NF45 and NF110. The middle panel shows the relative levels of the luciferase activities in the presence of NF45-NF90 or NF45-NF110. The bars indicate S.E. of three independent experiments. The columns on the right indicate the values of -fold activation by NF45-NF90 and NF45-NF110.