Figure 2. bromi is epistatic to Ptch1.

Spinal neural tubes from E9.5 wild-type (WT), bromi, Ptch1, and bromi,Ptch1 mutant embryos immunostained for markers of neural fate. In Ptch1 mutants, Shh, FoxA2, and Nkx2.2 were broadly expressed throughout the open neural tubes and Pax6 expression was absent. The Ptch1 mutant phenotype was strongly suppressed in bromi,Ptch1 double mutants, whose closed neural tubes were small, yet showed similar expression patterns as bromi single mutants.