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Fig. 3.
Tbx2 down-regulates FGF signaling by repressing Flrt3 expression. (A, B) Four-cell stage embryos were injected in the animal pole region as indicated with FGF8 (1 ng), Tbx2(200 pg), Tbx2 MO (10 ng), Tbx2δC-GR (200 pg) andVP16-Tbx2-GR (200 pg), and animal cap explants were dissected at stage 9, cultured until stage 12 in the absence or presence of dexamethasone (DEX; 10 μM) as indicated and then subjected to RT-PCR analysis. (C) Double in situ hybridization comparing the expression pattern of Tbx2 (red) with that of Flrt3 or Flrt2 (purple) in mid-neurulae. (D) Flrt3 expression in embryos injected dorso-animally with Tbx2 (200 pg), Tbx2 MO (10 ng), Tbx2δC-GR (200 pg) and VP16-Tbx2-GR (200 pg) as indicated. Embryos injected with Tbx2δC-GR or VP16-Tbx2-GR were treated with DEX from stage 12–17. Arrowheads denote expansion of Flrt3 expression. In (C) and (D), embryos are shown in anterior view with dorsal to the top. (E) Quantification of the experiments shown in (D). (F) VMZ explants from the embryos injected ventrally with Tbx2 MO (30 ng), CO MO (30 ng), Flrt3 MO (30 ng) and Flrt3 (200 pg) as indicated were subjected to western blotting. (G) Quantification of the levels of p-ERK (normalized to ERK) from three independent experiments for (F). Error bars indicate the standard error (SE). *p-value <0.05. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) |
