Fig. 3

Fig. 3  Delta-Notch signaling is required for LFP and p3 neuronal progenitor cell development. (A–D) nkx2.2b (A, B) and foxa2 (C, D) expression in wild-type control (A, C) and mib^−/− embryos (B, D). In mib^−/− mutants, nkx2.2b and foxa2 are both strongly reduced in the LFP and p3 neuronal progenitor cells in comparison to control (for nkx2.2b in n = 12 (22%) embryos from a clutch of 55 embryos obtained from identified, heterozygous carriers; n = 5/19, 26% for foxa2, n = 8/34, 24% for tal2). Only single cells are detectable. (E, F) Expression of isl1 (in red) and shh (in blue) in wild-type (E) and mib^−/− mutants (F). In control embryos, isl1 is expressed in primary motor and sensory neurons (E). In mib^−/−, isl1 is strongly expanded and is located in cells directly adjacent to the MFP. (G–J) tal2 expression in wild-type (G, I) and mib^−/− (H, J) mutants. In mib^−/− mutants, tal2 expression is strongly reduced in the most ventral cells (arrowhead marks region with absent p3 cells). Panels A–D are dorsal views, panels E, F, I, J are transverse sections and panels G, J are lateral views of embryos at the 16- to 20 s stage. Scale bars: H, 20 μM; J, 10 μM.