Disruption of the anterior PCL but apparently normal RG scaffold in the <i>Fgfr2</i> cKO CbA.

<p>(<b>A–N</b>) Representative confocal overviews (A,B,E,F) and close-up views (C,D,G–N) of the anterior CbA on sagittal sections from control (A,C,E,G,I,K,M) and <i>Fgfr2</i> cKO (B,D,F,H,J,L,N) embryos at E18.5 (n = 5 embryos/genotype), immunostained for Pax6 (cyan/green in A–D; a marker for GCPs) and Calb1 (red in A–D; a marker for PCs), or Ccnd1 (cyan/green in E–J; a marker for cycling GCPs and RG/BG precursors/cells) and Glast (red in E–H,K,L; a marker for RG/BG fibers), and counterstained with DAPI (blue in A–H,M,N; a nuclear marker). (C,D) and (G,H) are close-up views of the boxed areas in (A,B) and (E,F), respectively, (G,I,K,M) were taken from an adjacent section to the one shown in (E). (I–N) are single color channel views of (G,H), respectively. Yellow arrowheads in (D) delimit the lacking Calb1⁺ anterior PCL in the mutant embryos, and in (H,J) point at ectopically located Ccnd1⁺ RG/BG precursors within the mutant cerebellar VZ. White arrowheads in (H,J) delimit the distorted Ccnd1⁺ anterior outer EGL in the mutant embryos. EGL, external granular layer; PCL, Purkinje cell layer; VZ, cerebellar ventricular zone. Scale bars: 100 µm (A); 30 µm (C); 50 µm (E).