Zic2a acts before hedgehog signaling to promote maturation of the PT primordium. Embryos of different genetic backgrounds were injected with conMO or zic2aMO and stained for arx expression by ISH, except in panels E, F, which were stained for dlx2a. (A–F) Embryos were derived from a smob641/+ incross. Wildtype and heterozygous siblings were identified by the presence of ptc1 expression (orange), while mutant embryos lacked any ptc1 expression. (A) Wildtype sibling embryos (84/117) have very similar arx expression as (B) mutant siblings (33/107 embryos) at 8s. (C) Wildtype embryos at 12s (70/95 embryos) are indistinguishable from (D) mutant siblings (25/95 embryos). (E) At 18s, dlx2a is strongly expressed in the PT of wildtype embryos (109/143 embryos). (F) Mutant embryos display a dramatic reduction of dlx2a expression by 18s (23/132 embryos). (G, H) Embryos were injected with either conMO (G, 13/13 embryos) or zic2aMO (H, 7/7 embryos), treated with vehicle at 50–60% epiboly and fixed at 12s. (I, J) Embryos were injected with conMO (I, 12/12 embryos) or zic2aMO (J, 8/8 embryos), treated with 10 μM cyclopamine at 50–60% epiboly and fixed at 12s. Embryos are shown in lateral view, anterior to the left.
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