Figure 9.

Blocking c-Fos with a specific antibody blocks neuritogenesis, whereas blocking c-Jun only affects the triggering of neuritogenesis. (A) Cells cultured with NGF for 4 d were fed a lipid-mediated delivery system to transfect c-Fos or c-Jun antibody into PC12 cells at 0 h of NGF treatment (second and third rows) or after 2 d of culturing in the presence of NGF (forth and fifth rows). At 4 d in culture, cells were immunostained without addition of antibody for c-Fos or c-Jun (left) and with the addition of α-Tub antibody (right). The remaining protocol for immunostaining was as indicated for Figure 1. Morphometric quantification data obtained as in Fig. 1 are posted to the right of the corresponding row. (B) Cells mock transfected or transfected to deliver c-Fos antibody were single (top row) or double (bottom row) immunostained with c-Fos antibody (left) and the ER marker calnexin (middle). c-Fos colocalized with the ER marker only when cultures were performed in the absence of intracellular c-Fos antibody (right). Note that no additional c-Fos antibody was added during the immunocytochemical staining procedure of cells transfected with antibody to evidence the presence of antibody delivered during cell culture. Bar, 10 μm.