Fig. 8.

A, Overexpression of c-Rel promotes survival in NGF-deprived neurons. Shown are images of NGF-deprived neurons after injection with either c-Rel or c-Rel(1–359) expression vectors. Neurons were microinjected and then deprived of NGF for 48 hr. Cells were then stained with Hoechst dye and visualized by phase-contrast and fluorescence microscopy. Shown are phase-contrast views, rhodamine-positive cells (injected cells), and Hoechst-stained nuclei in one field of view for each injected DNA.Arrowheads for c-Rel injections indicate healthy looking injected cells with normal nuclear chromatin. Arrowheadsfor c-Rel(1–359) indicate injected cells containing condensed nuclear chromatin. B, Overexpression of c-Rel is sufficient to prevent neuronal cell death caused by NGF deprivation. Cultured neurons were microinjected with plasmids encoding either c-Rel, c-Rel(1–359), or LacZ, and then deprived of NGF for 48 hr as described in Materials and Methods. Survival was assayed on the basis of cellular morphology (as viewed by phase-contrast microscopy) and by the presence or absence of condensed chromatin (detected with Hoechst dye). The results (mean ± SEM) from at least three independent experiments are shown. Survival for c-Rel-injected cells was significantly different from LacZ- or c-Rel(1–359)-injected neurons (two-tailedt test; p < 0.0001 in both cases).