Figure 8.
E18.5 Gsx2 mutants present an increase in the thickness of both deep and superficial cortical layers. (A) Graphs represent the thickness of deep (white) and superficial (gray) layers in Gsx2 mutants relative to the thickness of Gsx2+/+ control animals in rostrodorsal and caudolateral matched territories based on Tbr1 mRNA differential expression in deep versus superficial layers (rD deep layers: 128.68%, P = 0.0478; superficial layers: 122.45%, P = 0.0122; n = 5 and cL deep layers: 150.13%, P = 0.0146; superficial layers: 120.19%, P = 0.0121). Notably, both deep and superficial layers appear to be thickened in the mutant cortices in a similar manner (rD: P = 0.380; cL: P = 0.20). We controlled that the thickening of cortical layers was not the consequence of a reduction in neuronal density by counting the number of DAPI+ nuclei cells in the CP and we rather observed the opposite effects (120 ± 4.82% mutant/control, n = 3), therefore suggesting that the defects in thickness were likely underestimated. Graphs represents mean ± SEM. *P < 0.05. (B–G) Immunostaining for Tbr1 (B–E) and Cux1/2 (F,G) labeling deep and superficial layers, respectively, confirms a thicker CP comprising both the deep and the superficial layers in E18.5 Gsx2 mutant (C,E,G) compared with Gsx2+/+ control (B,D,F) littermates. (H–O) Immunostaining at rD levels for FoxP2 (H,I), Ctip2 (J,K), and Mef2c (N,O) and in situ hybridization for Cdh8 (L,M), labeling layers V/VI, layer V, and layers II–IV. Except for neurons located in layer VI whose number appears reduced (white bars in H,I), all other markers show a pronounced increase in Gsx2 mutants (I,K,M,O) compared with controls (H,J,L,N). Scale bars: B, 200 μm; D,H,L, 100 μm.