Fig. 3. Reduced thickness of neuronal layers in the Dicer-ablated E13.5 dorsal telencephalon is not due to loss of apical and basal neurogenic progenitors. (A-H) Immunofluorescence microscopy of 10-µm coronal cryosections through the dorsal telencephalon of control [Emx1^Cre/wt Dicer^flox/wt (A,C) or Emx1^Cre/wt Dicer^flox/wt Tis21-GFP^+/- (E,G)] and conditional Dicer knockout [Dicer KO, Emx1^Cre/wt Dicer^flox/flox (B,D) or Emx1^Cre/wt Dicer^flox/flox Tis21-GFP^+/- (F,H)] E13.5 littermate mouse embryos, showing Pax6 (A-D), Tbr2 (E,F) and Tis21-GFP (G,H) staining. nl, neuronal layers; asterisks, ventricular lumen; dashed lines, boundaries of the SVZ; solid lines, basal lamina. Scale bars: 200 µm in A,B; 50 µm in C-H. (I,J) Quantification of Tbr2-positive (I) and Tis21-GFP-positive (J) nuclei in the VZ plus SVZ (as indicated by the upper dashed lines in E-H), each expressed as a percentage of total, DAPI-stained nuclei (not shown). Data are the mean of 28 fields counted per condition (two embryos, seven cryosections along the rostrocaudal axis per embryo, two fields per cryosection); bars indicate s.d.