Fig. 5. Mash1 inhibits Ngn1 but not Ngn2 expression in the dorsal neural tube. Immunofluorescence (A,B,D,E) and in situ hybridization (G-J) on transverse sections of E10.5 mouse neural tubes. (A-C) There is no change in levels of Ngn2 between wild-type (A) and Mash1^–/– (B) embryos. (D-F) There is no change in expression of Mash1 between wild-type (D) and Ngn2^–/– (E) embryos. (G-J) The dorsal domain of Ngn1 is expanded in Mash1^–/– (H, arrow) and Mash1^–/–;Ngn2^–/– (J, arrow) relative to wild-type (G) embryos. No change was detected in Ngn1 in Ngn2^–/– (I) embryos. Each panel is representative of the phenotype seen in at least three sections from at least three embryos. Scale bar: 50 µm in A,B,D,E; 225 µm in G,H.