Smurfs are involved in the regulation of hedgehog signaling pathway in zebrafish.

<p>(A) <i>smurf1</i> and <i>smurf2</i> morphants mimic loss-of-Hh phenotype. Compared with control MO-injected embryos (top panels), embryos injected with 4 ng of <i>smurf1</i>-atg MO (s1MO) or of <i>smurf2</i>-atg MO (s2MO) displayed weakly curled tails, U-shaped somite, and disrupted somitic muscles of the mid-trunk region, as revealed by anti-F59 immunostaining (middle panels), which are similar to but weaker than cyclopamine-treated embryos (bottom panels). (B) Downregulation of three Hh-responsive target genes, <i>hhip</i>, <i>fkd4</i>, and <i>nkx2.2b</i> in <i>smurf</i> MOs. (C) Co-injection of <i>smurf</i> MOs (4 ng) with 4 ng <i>ptc1</i>MO (top two panels) or 100 pg <i>smo</i> mRNA (bottom two panels) can rescue the Hh-like phenotype of <i>smurf1</i> or <i>smurf2</i> MOs. (D) Injection of a low dose of s2MO (2 ng) into <i>smo</i>^+/− embryos resulted in an Hh-like phenotype (bottom panel), but did not show any phenotype in the WT (<i>smo</i>^+/+) embryos (middle panel). Statistical data are shown in the right panel. <i>smo</i>^−/− embryos showed a typical Hh phenotype (top panel), while <i>smo</i>^+/− embryos were normal (middle panel).