Fig. 5. Dicer ablation in the dorsal telencephalon causes progressive apoptosis starting at E12.5. (A-H) Immunofluorescence confocal microscopy (6-µm single optical sections) of 10-µm coronal cryosections through the dorsal telencephalon of control (Emx1^Cre/wt Dicer^flox/wt) and conditional Dicer knockout (Dicer KO, Emx1^Cre/wt Dicer^flox/flox) E10.5 (A,B), E12.5 (C,D), E13.5 (E,F) and E14.5 (G,H) littermate mouse embryos, showing βIII-tubulin (Tuj1, green), TUNEL (red) and DAPI (blue) staining. NL, neuronal layers. Scale bars: 50 µm. (I,J) Quantification of TUNEL-stained (TUNEL+) cells in the cortical wall. Data are the mean of two embryos; for each embryo, the average for three fields along the rostrocaudal axis (one field per cryosection) was calculated; bars indicate the variation of the two embryos from the mean. Note the interruption in the scale of the ordinate to accommodate the data for the E14.5 Dicer KO.