Fig. 6

Fig. 6 Gli1 contributes to spinal motor neuron induction. Panels A–D show dorsal views, and panels E–L show lateral views, with anterior to the left. (A, E, and I) In an uninjected 36 hpf wild-type (yot+/+ or +/-) embryo, islet antibody labeling (A) reveals the characteristic organization of the nV neurons in r2 (asterisk), the nVII neurons (white arrowhead), the nX neurons (black arrowhead), and the patterned expression of net1a (E) in the ventral hindbrain and at rhombomere boundaries (arrowheads). Spinal motor neurons (arrowhead, I) are found in characteristic numbers. (B, F, and J) In a yot^ty119+/- heterozygote injected with gli1 MO, nV and nVII neurons are reduced in number (asterisk, arrowhead in B), nX neurons are absent, and net1a expression is significantly reduced in the hindbrain (arrowheads, F). Spinal motor neurons are slightly reduced in number (arrowhead, J). (C, G, and K) In an uninjected yot^ty119 mutant, nV (asterisk, C), nX, and spinal motor neurons (arrowhead, K) are greatly reduced in number, while the nVII neurons (arrowhead, C) show a moderate reduction. Net1a expression is significantly reduced in the hindbrain (arrowheads, G). (D, H, and L) In a yot^ty119 mutant injected with gli1 MO, branchiomotor (D) and spinal motor neurons (L) are completely absent. Net1a expression (arrowheads, H) is also severely reduced in the hindbrain. The strongly labeled cells in the dorsal spinal cord (I–L) are Rohon-Beard sensory neurons, which are unaffected by these treatments.