FIG. 6.

A-CREB, but not other acidic leucine-zippers (A-ZIPs), inhibits cAMP activation of CRE-mediated gene expression. Transcriptional activation of pAF42CRE was evoked by forskolin. For this experiment, PC12 cells were transfected with pAF42CRE, α-globin expression vector, and expression vectors encoding the indicated A-ZIP proteins (3 μg each). Two days later, cells were treated with forskolin (Fsk; 10 μM, 1 h) or were left untreated and an RPA was performed. This experiment was performed two times with similar results.