Fig. 3. Par3 loss-of-function increases the number of deep-layer neurons in vivo. (A-E) Fluorescence micrographs of E18 cortices injected with control (A,B) and Par3b shRNA (C,D) (6 days after injection) immunolabeled for GFP (green) and MAP2 (red) and stained with DAPI (blue). Note the GFP-positive neurons in both upper and deep cortical layers of a control-injected mouse (A,B). By contrast, a single GFP-positive neuron is found in the deep layers of a Par3b shRNA-injected mouse (C,D). (E) Representative section of E18 cortex indicating the different layers analyzed (VZ, SVZ, IZ and CP). (F,G) Histograms representing the proportion of GFP-positive cells in the cortex layers depicted in E (F) and GFP-positive neurons in the upper and deep cortical plate (G) of both control (n=3, 554 cells) and Par3b shRNA (n=3, 318 cells) -injected brains. Note the significant increase in neurons in the deep layers after Par3b shRNA transduction in comparison to the control (^*, P<0.05; unpaired t-test). (H,I) Par3b shRNA-transduced neuron (arrow) colabeled for GFP (green), MAP2 (blue) and Tbr1 (red). VZ, ventricular zone; SVZ, subventricular zone; IZ, intermediate zone; CP, cortical plate. Scale bars: 40 µm in A,B; 50 µm in C,D; 100 µm in H; 25 µm in I.