title: Ret signalling integrates a craniofacial muscle module during development.
abstract: An appropriate organisation of muscles is crucial for their function, yet it is not known how functionally related muscles are coordinated with each other during development. In this study, we show that the development of a subset of functionally related head muscles in the zebrafish is regulated by Ret tyrosine kinase signalling. Three genes in the Ret pathway (gfra3, artemin2 and ret) are required specifically for the development of muscles attaching to the opercular bone (gill cover), but not other adjacent muscles. In animals lacking Ret or Gfra3 function, myogenic gene expression is reduced in forming opercular muscles, but not in non-opercular muscles derived from the same muscle anlagen. These animals have a normal skeleton with small or missing opercular muscles and tightly closed mouths. Myogenic defects correlate with a highly restricted expression of artn2, gfra3 and ret in mesenchymal cells in and around the forming opercular muscles. ret(+) cells become restricted to the forming opercular muscles and a loss of Ret signalling results in reductions of only these, but not adjacent, muscles, revealing a specific role of Ret in a subset of head muscles. We propose that Ret signalling regulates myogenesis in head muscles in a modular manner and that this is achieved by restricting Ret function to a subset of muscle precursors.
authors.affiliation: MRC Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK. robert.knight@kcl.ac.uk
authors.forename: Robert D
authors.initials: RD
authors.lastname: Knight
authors.forename: Katharina
authors.initials: K
authors.lastname: Mebus
authors.forename: Arturo
authors.initials: A
authors.lastname: d'Angelo
authors.forename: Kazutomo
authors.initials: K
authors.lastname: Yokoya
authors.forename: Tiffany
authors.initials: T
authors.lastname: Heanue
authors.forename: Henry
authors.initials: H
authors.lastname: Roehl
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D005075:Biological Evolution; D017931:DNA Primers / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D006257:Head; D024510:Muscle Development / Q000235:genetics / Q000502:physiology*; D018482:Muscle, Skeletal / Q000196:embryology; D009154:Mutation; D010641:Phenotype; D051096:Proto-Oncogene Proteins c-ret / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000502:physiology*; D029961:Zebrafish Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
chemical_list: D017931:DNA Primers; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D029961:Zebrafish Proteins; D051096:Proto-Oncogene Proteins c-ret; C546313:Ret protein, zebrafish