Figure 8. AP-1 proteins modulate human APP promoter activity in N2a and A2 cells.
The AP-1 element, TGATTCA at position −350 base pairs upstream of the transcription start site was mutated to TCCTTCA by site-directed mutagenesis. (A) Cells were co-transfected with the wild-type human APP promoter or AP-1-site mutant APP promoter constructs and increasing concentrations of a c-jun expression construct. (B) Cells were transfected the wild-type human APP promoter with increasing concentrations of a JunB or Fra-2 expression constructs. Cell homogenates were assayed for APP promoter activity, as described in Methods. Results are the mean fold-change in APP promoter activity in A2 cells compared to N2a cells ± SD of four determinations. Statistical significance was determined using the Student’s t test, p < 0.05.