Figure 7.

Expression of a dominant negative mutant or a constitutively active mutant of CREB attenuates BDNF-promoted increases in cypin expression. A, Hippocampal neurons were transfected with pEGFP-CREB WT (wild type, control) vector (control) with pEGFP-CREB DN (dominant negative form, Ser119Ala) or pEGFP-CREB CA (constitutively active form, Ser119Asp) at 6 DIV and treated with either DMSO (vehicle) or BDNF (25 ng/ml) at 7 DIV for 72 h. Neurons were immunostained using a polyclonal cypin antibody. Arrows point to transfected neurons. Scale bar, 100 μm. B, Average fluorescence intensity (A.U., Arbitrary units) of cypin immunostaining was assessed in individual cells. Expression of CREB DN blocks and expression of CREB CA occludes BDNF-promoted increases in cypin expression. n = 20 neurons for each condition, *p < 0.05, **p < 0.01 by ANOVA followed by Student-Newman–Keuls multiple-comparison test compared to DMSO-treated neurons expressing CREB WT. ns, No significance compared to DMSO-treated neurons.