Figure 5.

NA deletion mutant of c-Fos impairs differentiation in neuronal cultures and abrogates c-Fos-dependent lipid synthesis activation. A, neuronal cultures were transfected at seeding with NA-YFP (pseudocolored red, bottom row), NB-YFP (pseudocolored red, middle row), or the empty vector as a control (pseudocolored red, top row) and were fixed after 48 h of culture. Cells were subjected to immunofluorescence against βIII-tubulin (green, second column). Scale bar, 20 μm. B, morphological quantification of neuronal differentiation stages in both NA-YFP– and NB-YFP–transfected cells at different fixation times. The results of one of three independent experiments are shown. A normality Kolmogorov–Smirnov test was performed, where the deviation from the distribution with respect to the NB-transfected cells was evaluated. *, p < 0.05; ***, p < 0.001; n.s., nonsignificant; n = 15 from each condition were examined. C, evaluation of ³²P-phospholipid labeling capacity of neuron homogenates in the presence of c-Fos (+c-Fos), NA (+NA), or both (+c-Fos +NA 1:1 and +c-Fos +NA 1:3). Elution buffer was used as a control (Control). Results are the mean of three independent experiments performed in triplicate. The results are expressed as the mean ± S.D. (error bars), with one-way ANOVA. ***, p < 0.001 with respect to control conditions.