Jak/Stat signaling does generally mediate Wnt-responsive gene expression or the entire neurogenesis program in apc mutants. (A) axin2 mRNA expression, a general marker for Wnt/ß-catenin target gene activation, is increased in apc mutants treated with AG-490 at 36 hpf, compared to controls. Lateral whole-mount views at 36 hpf are shown. (B) Expression of HuC/D, a marker of differentiated neurons, is decreased in the apc mutant hypothalamus, and remains decreased after AG-490 treatment. Confocal projections from the ventral brain surface through the 36 hpf hypothalamus are shown. HuC/D immunohistochemistry is red, TO-PRO-3 nuclear stain is in blue.