Fig. 3.

Gli3 conditional inactivation affects cortical size and architecture. (A,B) Dorsal views of E18.5 control (A) and Gli3^cKO (B) brains. Gli3^cKO embryos only form a small olfactory bulb-like structure in the rostral telencephalon, which is not visible in this dorsal view (Amaniti et al., 2015). (C) Graph comparing the surface area of control and Gli3^cKO cerebral cortices. (D-L) Immunohistochemistry on E17.5 control and Gli3^cKO brains using the indicated antibodies. (D-F) Tbr1⁺ neurons occupy a reduced area in the deep cortical plate of the Gli3^cKO cortex. (G-I) Ctip2⁺ neurons occupy deeper positions in the cortical plate of Gli3^cKO embryos. (J-L) Distribution of Satb2⁺ upper layer neurons, which have not completed their migration at this stage. (M-O) Tbr1 and Ctip2 double immunofluorescence on coronal sections of E17.5 brains showed that the relative position of Tbr1⁺ layer VI and Ctip2⁺ layer V neurons is maintained in Gli3^cKO embryos. Moreover, the proportion of Tbr1⁺Ctip2⁺ double positive neurons (arrowheads) is reduced in the mutant (O). (P-U) The formation of Tbr1⁺ neurons is delayed in Gli3^cKO embryos. (P-R) The proportion of Tbr1⁺ neurons born at E12.5 (arrowheads) is reduced in Gli3^cKO embryos. (S-U) BrdU birthdating at E13.5 showed an increase in BrdU⁺Tbr1⁺ neurons (arrowheads) in Gli3^cKO embryos. Note the large number of BrdU⁺Tbr1⁻ neurons (arrows) superficial to the Tbr1 domain in control embryos. All statistical data are presented as mean±95% CI; n=6 (A-C) and n=4 (D-U); *P<0.05; **P<0.01; ***P<0.005; Mann–Whitney test (C,O,R,U) and two-way ANOVA followed by Sidak's multiple comparisons test (F,I,L). MZ, marginal zone; VZ, ventricular zone. Scale bars: in A, 2 mm for A,B; in D,M, 50 µm for D,E,G,H,J,K,M,N,P,Q,S,T.