Fig. 3. COUP-TFI-positive cells in the MZ of the cortex originate from the basal telencephalon. (A) A grafting experiment performed at E13.5, in which dorsally migrating cells are analysed. The box delineates the area shown in C-H. (B) Example of an MLGE transplant that shows GFP-positive cells migrating dorsally into the ctx, laterally into the pcx, and ventrally into the POa/hypo. (C-H) Double immunofluorescence for GFP (green) and COUP-TFs (red) shows that GFP-positive cells originating from the graft are double positive for COUP-TFI in the MZ (arrowheads in C-E) and in the ventricle-oriented cells deriving from the MZ (arrows in C-E). Arrows in insets show labelling of cells in the intermediate zone (IZ). (F-H) Double immunofluorescence of GFP (green) and COUP-TFII (red) shows no co-localization of these two proteins. ctx, cortex; MZ, marginal zone; pcx, piriform cortex; POa/hypo, pre-opic area/anterior hypothalamus.