Fig. 1. Effect of GDNF on GS cell proliferation. (A) Effect of GDNF on cell recovery after 6 days in culture on MEFs (left) or laminin (right) (mean±s.e.m.; n=5). (B) Appearance of wild-type (left and center) and myr-Akt-Mer (right) GS cells, 6 days after passage on laminin. (C) Apoptosis of GS cells in the absence of GDNF. Apoptotic cells were detected by TMR red staining. Apoptotic cells were observed when GDNF was removed from the culture medium. (D) Analysis of cell cycle distribution, 5 days after passage on laminin. Significantly more cells are in the S phase in the presence of GDNF or 4OHT. (E) Growth curve for myr-Akt-Mer GS cells that were maintained by 4OHT on laminin. (F) Effect of EGF and bFGF on cell recovery after 5 days of culture on laminin (mean±s.e.m.; n=5). Whereas the wild-type GS cells can grow in the presence of EGF, myr-Akt-Mer GS cells are unable to respond to EGF. Scale bars: in B,C, 100 µm.