Pharmacological activation of Shh pathway or Gli3 KD restores myogenesis in the absence of miR-133 function. (A) Schematic overview of the experimental approach. Posterior somites of HH14/15 embryos were injected with FITC-labelled antagomir-133 (AM133) with purmorphamine (Purm) or FITC-labelled scrambled-antagomir (AMscr) with DMSO as control and the downstream analysis performed by in situ hybridization after 24 h incubation. (B) In situ hybridization showed that Mgn expression was lost (white arrowheads) after AM133 with DMSO injection, n=8/8. Co-injection of AM133 with purmorphamine, a synthetic agonist of the smoothened receptor, rescued myogenesis (black arrowheads). Mgn was expressed and the epithelial nature of the dermomyotome was preserved, but myotome size was reduced, n=14/14. Whole mount and sections are shown. (C) Schematic overview of the experimental approach. Posterior somites of HH14/15 embryos were injected with FITC-labelled antagomir-133 (AM133) with Gli3 MO, electroporated and the downstream analysis performed by in situ hybridization after 24 h incubation. (D) Co-transfection of AM133 with Gli3 MO rescued myogenesis (black arrowheads), although myotome size was reduced (n=7/10). Whole mount and sections are shown. Area measurements were obtained using Fiji/ImageJ. ***P<0.001.