Fig. 6. Knockdown of wnt8b and fz8a alters the anterior brain patterning. The effects of morpholino oligonucleotides for fz8a (fz8a-MO) and wnt8b (wnt8b-MO), and LiCl treatment at late gastrula stage embryos on the expressions of anterior brain markers were analysed at the 100% epiboly stage (A-T). The putative telencephalon domain marked by opl is not affected by morpholinos (B, fz8a-MO; C, wnt8b-MO) or LiCl treatment (D). Note that caudal region of six3 expression domain (eye primordia), which is not affected by fz8a-MO (F), is expanded posteriorly by wnt8b-MO (G). By contrast, LiCl treatment at late gastrula reduces six3 expression (H). The posterior diencephalon marked by caudal domain of fkd5 (arrow) is remarkably reduced by fz8a-MO (J) and wnt8b-MO (K), but LiCl treatment expands fkd5 expression domain (L). The expression of eng2 in midbrain almost disappears after treatment with fz8a-MO (N) and wnt8b-MO (O). However, LiCl treatment does not alter eng2 expression in the putative midbrain domain (P). The putative MHB domain marked by pax2 expression is reduced by fz8a-MO (R), although it is not affected by wnt8b-MO (S) or LiCl treatment (T). Scale bar: 250 µm. The effects of fz8a-MO, wnt8b-MO and hsp-fz8a-CRD-EGFP on the anterior brain patterning were analysed at the seven-somite stage embryos (U-Z'). The expression domains for pax6 and pax2 are remarkably reduced by fz8a-MO (V). However, wnt8b-MO injection reduces pax6 expression domain without any changes of pax2 expression domain (W). In embryos expressing a secreted dominant-negative form of Fz8a DNA under the heat-inducible promoter (hsp-fz8a-CRD-EFGP), pax6 expression domain is reduced without any changes of pax2 expression domain (X), similar to the embryos injected with wnt8b-MO (W). The expression domain for eng2 is remarkably reduced by fz8a-MO (Z) or wnt8b-MO (Z'). Arrowheads and asterisks indicate pax6 expression in the putative posterior diencephalon and pax2 expression in MHB, respectively. Scale bars: in X, 125 µm for U-X; in Z', 125 µm for Y-Z'; 250 µm for A-T.

Return to article