Fig. 9

Fig. 9 Antisense morpholino-mediated knockdown of wnt8b rescues regional patterning defects in the brain of col embryos. (A–I) The midbrain–hindbrain boundary region marked by pax2 expression is expanded in col mutants (B) as compared to wild-type embryos at 40 dpf (A). Injection of wnt8b MO results in a reduction in MHB tissue in mutant embryos (C). The extent of the MHB region is shown with arrowheads. wnt8b MO injection of mutant embryos abolishes ectopic diencephalic shh expression (F) observed in uninjected col embryos at 32 hpf (E, arrow; see Figs. 8G,H). Injected mutant embryos (F) strongly resemble uninjected wild-type embryos (D). The reduced telencephalic dlx2 expression in uninjected col embryos (H; see Figs. 8E,F) is rescued in injected embryos (I, compare to wild type, G). The telencephalic stripe of dlx2 expression is marked with arrows. Early patterning events during gastrulation are unaffected in wnt8b morpholino-injected col mutants (J–O). gsc expression is down-regulated in the prechordal plate in uninjected (K) and injected (L) col embryos as compared to wild-type embryos at 70% epiboly (J). wnt8 expression is ectopically expressed in the dorsal midline in uninjected (N) and injected (O) col mutant embryos unlike in wild-type embryos (M) at 70% epiboly.