Fig. 7. Upregulation of proneural genes in the dorsal telencephalic midline of Hes1;Hes3;Hes5 cKO mice. (A-D) Neurogenesis (Tuj1⁺) was enhanced in the dorsal telencephalic midline (brackets) of Hes1;Hes3;Hes5 cKO mice at E10.5 and E11.5 (B,D, asterisks), compared with the control (A,C). (E,F) Double immunostaining for Ngn2 and Hes1 in wild-type embryos. Many cells co-expressed Ngn2 and Hes1 at E10.5 (arrowheads), but the expression was mostly segregated at E11.5 (arrows). (G-S) In the dorsal telencephalic midline region (Lmx1a⁺) of control mice, Ngn1 and Ngn2 expression occurred at low levels in subsets of cells at E10.5 (G-I) and was down-regulated at E11.5 (J,K,Q,Q'). By contrast, Ngn1 and Ngn2 expression was highly upregulated in Hes1;Hes3;Hes5 cKO mice at both E10.5 and E11.5 (L-P, asterisks; R,R',S). ^*P<0.01; ^**P<0.001, t-test. Scale bars: 50 µm in A-D,E1,F1,G-I,L-N; 100 µm in J,K,O,P; 20 µm in Q-R'.