title: Requirements for Endothelin type-A receptors and Endothelin-1 signaling in the facial ectoderm for the patterning of skeletogenic neural crest cells in zebrafish.
abstract: Genetic studies in mice and zebrafish have revealed conserved requirements for Endothelin 1 (Edn1) signaling in craniofacial development. Edn1 acts through its cognate type-A receptor (Ednra) to promote ventral skeletal fates and lower-jaw formation. Here, we describe the isolation and characterization of two zebrafish ednra genes - ednra1 and ednra2 - both of which are expressed in skeletal progenitors in the embryonic neural crest. We show that they play partially redundant roles in lower-jaw formation and development of the jaw joint. Knockdown of Ednra1 leads to fusions between upper- and lower-jaw cartilages, whereas the combined loss of Ednra1 and Ednra2 eliminates the lower jaw, similar to edn1-/- mutants. edn1 is expressed in pharyngeal arch ectoderm, mesoderm and endoderm. Tissue-mosaic studies indicate that, among these tissues, a crucial source of Edn1 is the surface ectoderm. This ectoderm also expresses ednrA1 in an edn1-dependent manner, suggesting that edn1 autoregulates its own expression. Collectively, our results indicate that Edn1 from the pharyngeal ectoderm signals through Ednra proteins to direct early dorsoventral patterning of the skeletogenic neural crest.
authors.affiliation: Department of Developmental and Cell Biology, University of California, Irvine, 5210 McGaugh Hall, Irvine, CA 92697-2300, USA.
authors.forename: Sreelaja
authors.initials: S
authors.lastname: Nair
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Robert
authors.initials: R
authors.lastname: Cornell
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Schilling
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning; D018076:DNA, Complementary / Q000235:genetics; D019332:Endothelin-1 / Q000235:genetics* / Q000378:metabolism; D007596:Joints / Q000196:embryology / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D009432:Neural Crest / Q000196:embryology / Q000378:metabolism; D010802:Phylogeny; D044022:Receptor, Endothelin A / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D012886:Skull / Q000196:embryology / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D019332:Endothelin-1; D044022:Receptor, Endothelin A; D029961:Zebrafish Proteins; C414282:edn1 protein, zebrafish