Figure 4.

GFRα1 Functions Independently of GDNF and RET to Control PC Migration

(A) Expression of GDNF in E12.5 cerebellum primordium of Gdnf^bgal mice visualized by X-gal staining (green). Upper panels show counterstaining with Lhx5 and lower panels with Pax2 (red). Progenitor areas c1 to c4 are indicated. VZ, ventricular zone; RL, rhombic lip. Right panels show higher magnifications of boxed areas. Scale bar 100 μm, left panels; 50 μm, right panels.

(B) Expression of RET in E12.5 cerebellum of Ret^EGFP mice visualized by immunostaining (green). Upper panels show counterstaining with Lhx5, middle panels with Pax2, and lower panels with Lmx1 (red). Progenitor areas c1 to c3 are indicated. VZ, ventricular zone; RL, rhombic lip. Right panels show higher magnifications of boxed areas. Scale bars, 100 μm, left panels; 50 μm, right panels.

(C) Quantitative analysis of the proportion of PC progenitors that migrated from the VZ to the MZ in Ret^WT and Ret^EGFP/EGFP E14.5 embryos injected with BrdU at E12.5. Histogram shows average ± SEM. n.s., not significant (n = 5 mice; p = 0.64).

(D) Quantitative analysis of the proportion of PC progenitors that migrated from the VZ to the MZ in Gdnf^WT and Gdnf^KO E14.5 embryos injected with BrdU at E12.5. Histogram shows average ± SEM. n.s., not significant (n = 12 mice; p = 0.69).

(E) Relative cumulative frequency of Lhx5⁺ cells exiting wild-type E12.5 cerebellar explants in the presence and absence of GDNF coated onto the nanofiber surface. The difference was not significant (blue, n = 49 explants; red, n = 51 explants; Kolmogorov–Smirnov test, p > 0.05).

(F) No effect of soluble GDNF on PC migration in cerebellar explants from wild-type embryos (blue, n = 213 explants; red, n = 132 explants; Kolmogorov–Smirnov test, p > 0.05).

(G) No effect of soluble GDNF on PC migration in cerebellar explants from Gfra1^KO embryos (blue, n = 67 explants; red, n = 43 explants; Kolmogorov–Smirnov test, p > 0.05).