Fig. 3.

Fig. 3.

Smad-mediated BMP signalling is increased in fam20b^−/− chondrocytes. (A-D′) Fluorescence immunostaining showed no clear differences between wild types (A,C,C′) and fam20b mutants (B,D,D′) in the levels of p-Smad1/5/9 in nuclei and non-nuclear regions of condensing ceratohyal mesenchyme at 48 hpf. (E-H′) p-Smad1/5/9 immunoreactivity appeared higher in non-nuclear regions of fam20b^−/− ceratohyal chondrocytes (F,H,H′) at 72 hpf, compared with wild types (E,G,G′). (I-J′) p-Smad1/5/9 immunoreactivity appeared increased in both the nuclei and non-nuclear regions of fam20b^−/− chondrocytes (J,J′), compared with wild types (I,I′), at 84 hpf. (K) Quantitative image analyses (n=3 for each group) demonstrated significant increases in p-Smad1/5/9 levels of fam20b^−/− chondrocytes (*P<0.05, one-way ANOVA and paired Student's t-test). Scale bars: 50 μm. a.u., arbitrary units; ch, ceratohyal; oc, oral cavity; wt, wild type.