Combinatorial signaling by Sonic hedgehog and Wnt family members induces myogenic bHLH gene expression in the somite.
We have demonstrated previously that a combination of signals from the neural tube and the floor plate/notochord complex synergistically induce the expression of myogenic bHLH genes and myogenic differentiation markers in unspecified somites. In this study we demonstrate that Sonic hedgehog (Shh), which is expressed in the floor plate/notochord, and a subset of Wnt family members (Wnt-1, Wnt-3, and Wnt-4), which are expressed in dorsal regions of the neural tube, mimic the muscle inducing activity of these tissues. In combination, Shh and either Wnt-1 or Wnt-3 are sufficient to induce myogenesis in somitic tissue in vitro. Therefore, we propose that myotome formation in vivo may be directed by the combinatorial activity of Shh secreted by ventral midline tissues (floor plate and notochord) and Wnt ligands secreted by the dorsal neural tube.
D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics*; D004627:Embryonic Induction; D005314:Embryonic and Fetal Development / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D066298:In Vitro Techniques; D008648:Mesoderm / Q000187:drug effects / Q000502:physiology*; D008969:Molecular Sequence Data; D009132:Muscles / Q000196:embryology*; D017570:MyoD Protein / Q000096:biosynthesis / Q000235:genetics; D009420:Nervous System / Q000196:embryology / Q000378:metabolism; D009672:Notochord / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D051761:Paired Box Transcription Factors; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D051153:Wnt Proteins; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D060528:Wnt4 Protein; D029961:Zebrafish Proteins
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D053823:Hedgehog Proteins; D017570:MyoD Protein; D051761:Paired Box Transcription Factors; D011506:Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D060528:Wnt4 Protein; D029961:Zebrafish Proteins; C070835:PAX1 transcription factor