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Fig. 8. Non-canonical function of Sf3b4 in BMP signaling. (A) At neurula stage the expression of msx1 is unaffected in Sf3b4MO2-injected embryos (arrows), while sox10 expression is reduced in sibling embryos. Dorsal views, anterior to top. The injected side (right) is indicated by the lineage tracer (Red-Gal). (B) The graph is a quantification of the results from three independent experiments. The number of embryos analyzed (n) is indicated on the top of each bar. (C) Western blot using lysate from embryos injected bilaterally with HSF3B4 mRNA (1 ng) or Sf3B4MO2 (10 ng) alone or in combination with BMP4 mRNA (1 ng) to analyze the levels of phosphorylated and unphosphorylated Smad1/5/8 at stage 10. HSF3B4 and Sf3B4MO2 have no impact on BMP4-mediated Smad1/5/8 phosphorylation (p-Smad1/5/8) and do not affect the levels of unphosphorylated Smad1/5/8. (D) By in situ hybridization, sox2 expression in animal explants neuralized by the BMP antagonist Noggin is unaffected by injection of Xsf3b4 or HSF3B4 mRNA (1 ng each). |
