FIGURE 5.

AP1 activity dictates the axon growth-related RAG expression profile. A and B, gene expression and axon growth correlation for RAGs. A, representative plot of Arg1 normalized Bt₂cAMP-induced expression levels (y axis) versus axon growth on MAG-CHO cells (x axis) of DRG neurons with the indicated manipulations. Data were normalized between 0 and 100, where the value for GFP = 0 and the maximum response = 100. B, correlation coefficients of all RAGs. When all manipulations were considered, only the profile of Arg1 expression was significantly correlated with axon growth (p = 0.0003, Pearson's test), indicating that the CREB-sufficient but AP1-dependent transcriptome is relevant for promoting axon growth. C, scheme for the transcriptional regulation of cAMP-induced RAG expression. Bt₂cAMP activates the transcription of Arg1 in a CREB-sufficient but AP1-dependent manner. Activated CREB synergizes with cAMP-induced AP1 activity to drive higher levels of Arg1 transcription as well as neurite growth (red arrows).