Fig. 1.
Rspo2 inhibits ectoderm response to FGF but not MEK1. (A-G) Four-cell stage embryos were injected animally with Rspo2 RNA (0.5 ng) and Mek1CA RNA (12 pg), as indicated. Ectoderm explants were dissected at stage 8 and treated with 100 ng/ml FGF2 protein. When control embryos reached stage 13, the explant morphology was imaged (A-D) or lysed for immunoblot or RT-qPCR analysis (E-G). (A) control uninjected ectoderm explants. (B) FGF-treated explants. (C) Rspo2-expressing explants stimulated with FGF. (D) Rspo2-expressing explants. Ten ectoderm explants were used per group in each experiment. The experiments were repeated five times. (E,F) Modulation of Erk1 activation by Rspo2. Immunoblotting was carried out with the antibodies against pErk1 and total Erk1. Data represent three to five independent experiments. (G) Rspo2 inhibits FGF-dependent induction of tbxt. RT-qPCR analysis was performed for tbxt and normalized by eef1a1. The graph shows a representative experiment with triplicate samples from three independent experiments. Data are mean±s.d. Statistical significance was assessed by Student's t-test. **P<0.05. Scale bar: 300 µm.