Fig. 5. Gli2^–/–Gli3^–/– embryos exhibit abnormalities in the formation of the myotome and hypaxial muscle progenitor cells. Expression of myogenin (A-A'''), paraxis (B-B'''), Pax7 (C-C'''), Pax3 (D-D'''), Myod1 (E-E'''), Lbx1 (F-F'''), Noggin (G-G'''), and Sim1 (H-H''') was assessed by whole-mount in situ hybridization in wild-type, Gli2^–/–Gli3^+/–, Gli2^+/–Gli3^–/–, and Gli2^–/–Gli3^–/– embryos ranging from E9.0 to E10.0. Red lines indicate the position of transverse sections shown below the whole-mount image. Black arrowheads point to upregulation and/or misexpression of the gene studied. Note that Noggin expression is lost in the notochord of Gli2^–/–Gli3^–/– embryos.