Fig. 5. FGF-2 induces a cell fate switch in clonal cultures and slice overlay assays. (A) Dissociated E15 cortical GFP cells were diluted 1:1000 with wild-type E15 cortical cells and plated on glass coverslips in medium supplemented with 10 ng/ml CNTF, 10 ng/ml PDGF, 10 ng/ml EGF, or 10 ng/ml FGF2. The percentage of clones that were composed only of neurons (filled bars), only of glia (open bars), and both neurons and glia (mixed clones; hatched bars) are shown as a percentage of the total number of GFP+ clones. Asterisks indicate statistically significant differences (P<0.05) between the experimental condition and control (medium) for the indicated clonal type. (B) Quantification of the number of neurons (filled bars) and glia (open bars) over E18 slices expressed as a percentage of the total number of GFP+ cells on top of the slice under indicated experimental conditions. Bar heights represent mean ± s.e.m. (C,D) Dissociated E15 GFP cells were cultured over rat E18 cortical slices for 5 DIV in the absence (C) or presence (D) of 50 ng/ml of recombinant FGF2, and then processed for double immunofluorescence with anti-GFP (green channel) and anti-MAP-2 (red channel) antibodies. The GFP cells differentiate into neurons (C: white arrowhead) under normal conditions, and into glia (D: yellow arrowhead) in the presence of FGF2.
