Modulation of Wnt signaling affects the PPR polarity and OEPD development also regulates gata3 and foxi1 expression. A–C: XAV939 treated (5–7 hpf) embryos show enhanced yet loosely packed PPR six4.1 expression (B), compared with the control (A). 3F8 (5–7 hpf) treatment enhances six4.1 expression in caudal PPR and a reduction at the anterior most region (C). D–F: foxi1 expression domains are reduced after XAV939 treatment (E), compared with the control (D). 3F8 (5–7 hpf) treatment anteriorly expands foxi1 expression and the bilateral expression domains are fused rostrally (F). G–I: gata3 expressions are enhanced by XAV939 treatment (H) and reduced after 3F8 treatment (I), compared with control (G). J–L: The OEPD but mid-hindbrain boundary (MHB) expression of pax2a is reduced in embryos treated by XAV939 (K), compared with the control (J). 3F8 (5–7 hpf) treatment expands both MHB and OEPD pax2a expression rostra-caudally (L). 12 hpf. Black arrows indicate the OEPD while blue triangles point to the MHB pax2a. M: Real-time RT-PCR reveals that modulating Wnt signaling adjusts foxi1 and gata3 expression levels at 10.5 hpf. Treating embryos with 3F8 at 5–7 hpf increases foxi1 but reduces gata3 expression. On the other hand, the XAV939 treatment of 5–7 hpf enhances gata3 but cuts down foxi1 expression. 10.5 hpf. *P < 0.05; **P < 0.01 ***P < 0.001 (ANOVA test). N: Different from 10.5 hpf, real-time RT-PCR reveals that modulating Wnt signaling adjusts only gata3 expression levels at 8 hpf. Treating embryos with 3F8 at 5–7 hpf reduces gata3 expression. On the other hand, the XAV939 treatment during 5–7 hpf enhances gata3 expression. 8 hpf. **P < 0.01; ***P < 0.001 (ANOVA test). A–L: Dorsal views with anterior to the left. A–C: 11 hpf; D–I: 10.5 hpf; J–L: 12 hpf. Scale bar = 200 µm.
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