Figure 4

EGFP is not expressed in post-mitotic calbindin+ Purkinje progenitors (E13.5–E16.5). A: lower power view of the lateral portion (future hemisphere) of the E13.5 Cb plate illustrating the broad subcortical distribution of calbindin+ PCs. B: higher power view of the boxed area in (A), illustrating the contacts between post-mitotic calbindin+ EGFP-negative PC precursors (white dots) and EGFP+ radial glial processes. Arrowheads point to the non specific red fluorescence of small capillaries. C: at E16.5, the radial glia-derived EGFP+ cell population is greatly increased. D-F: no matter which region of the Cb primordium is examined, the EGFP+ and calbindin+ populations are clearly separate entities. Most EGFP+ cells are connected to the pial surface via their apical process, constituting the so-called secondary radial glial scaffold used by the EGL population of GPs during their postnatal phase of radial migration.