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Fig. 7
Foxo3b inhibits both maternal and zygotic Wnt/β-catenin signaling.
(A) Foxo3b morphants could be rescued by knockdown of β-catenin1. Black box, dead embryos at 24 hpf; A5-A6, dark gray box, embryos with defects at 55 hpf characterized by severe phenotype (as described in Fig. 2B); A3-A4, light gray box, embryos with mild phenotype; A1–A2, white box, un-injected wild-type embryos. A1, A3, A5, lateral views; A2, A4, A6, lateral views with anterior to the left; A1–A7, 55 hpf. (B) Anterior defects caused by loss of foxo3b function could be rescued by co-injection of dnTCF mRNA. (B1–B3, B7) Six3b was expressed abnormally in foxo3b morphants, which could be rescued by co-injection of dnTCF mRNA by 24 hpf. (B4–B6, B8) Tbx5 expression at the eyes was greatly reduced in foxo3b-knockdown embryos. Co-injection of dnTCF mRNA could efficiently restore its expression at the eyes. (B9–B11) Nkx5.1, pax6 and opl expression at the anterior neural plate could also be efficiently rescued by co-injection of dnTCF mRNA. Embryos were injected with 8 ng foxo3b-ATG-MO or 10 pg dnTCF mRNA,wild-type embryos were used as control. B1–B6, dorsal views with anterior to the left; B1–B11, 24 hpf. (C) Foxo3b knockdown resulted in abnormal expression of early Wnt target genes, which could be rescued by co-injection of β-catenin1/2 morpholino. (C1–C8, C15) The morphants showed increased expression of gsc, which could also be rescued by co-injection of β-catenin1 MO. Co-injection of β-catenin2 MO resulted in dramatically reduction of gsc expression (75%, n = 32) compared to control embryos. (C9-C14, C16) The expression level of vox increased dramatically in foxo3b-knockdown embryos, which could be partially rescued by co-injection of β-catenin2 MO. (C17) At 30% epiboly, sqt expression was up-regulated in foxo3b morphants. Co-injection of β-catenin1 morpholino efficiently reduced its expression. Embryos were injected with 8 ng foxo3b-ATG-MO or 8 ng β-catenin1/2 morpholino,wild-type embryos were used as control. C1-C14, dorsal views; C1-C17, 30% epiboly.