Fig. 1. Cyclin D1 (brown) is expressed at high levels in the EGL during early cerebellar development. (A-D) The E16.5 cerebellum (A, with high-power views of boxed areas shown in B-D) expresses cyclin D1 strongly in the ventricular region (B) and anterior EGL (C), with fewer positive cells in the posterior EGL (D). (E-H) The P0 cerebellum (E, with high-power views of boxed areas shown in F-H) shows some remaining ventricular expression (F), and strong expression in the EGL extending much further posteriorly with enlarged anterior (G) and posterior (H) views of the EGL, although the extreme posterior still has fewer positive cells (H). (I,J) P6 cerebellum (I, with high-power of view of boxed area in J) shows strong staining in the outer EGL throughout the entire AP axis. (K,L) At P12, only background staining of blood vessels and meninges is seen (arrows) (K, with high-power of view of boxed area in L). Brackets indicate the width of the EGL. Nuclei are lightly stained purple with Hematoxylin and Eosin. Scale bars: 50 µm.