title: Expression of Wnt signaling skeletal development genes in the cartilaginous fish, elephant shark (Callorhinchus milii).
abstract: Jawed vertebrates (Gnasthostomes) are broadly separated into cartilaginous fishes (Chondricthyes) and bony vertebrates (Osteichthyes). Cartilaginous fishes are divided into chimaeras (e.g. ratfish, rabbit fish and elephant shark) and elasmobranchs (e.g. sharks, rays and skates). Both cartilaginous fish and bony vertebrates are believed to have a common armoured bony ancestor (Class Placodermi), however cartilaginous fish are believed to have lost bone. This study has identified and investigated genes involved in skeletal development in vertebrates, in the cartilaginous fish, elephant shark (Callorhinchus milii). Ctnnb1 (β-catenin), Sfrp (secreted frizzled protein) and a single Sost or Sostdc1 gene (sclerostin or sclerostin domain-containing protein 1) were identified in the elephant shark genome and found to be expressed in a number of tissues, including cartilage. β-catenin was also localized in several elephant shark tissues. The expression of these genes, which belong to the Wnt/β-catenin pathway, is required for normal bone formation in mammals. These findings in the cartilaginous skeleton of elephant shark support the hypothesis that the common ancestor of cartilaginous fishes and bony vertebrates had the potential for making bone.
authors.affiliation: School of Medical Sciences, RMIT University, Bundoora 3083, Australia; Health Innovations Research Institute, RMIT University, Bundoora 3083, Australia.
authors.forename: Damian G
authors.initials: DG
authors.lastname: D'Souza
authors.forename: Kesha
authors.initials: K
authors.lastname: Rana
authors.forename: Kristi M
authors.initials: KM
authors.lastname: Milley
authors.forename: Helen E
authors.initials: HE
authors.lastname: MacLean
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Zajac
authors.forename: Justin
authors.initials: J
authors.lastname: Bell
authors.forename: Sydney
authors.initials: S
authors.lastname: Brenner
authors.forename: Byrappa
authors.initials: B
authors.lastname: Venkatesh
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Richardson
authors.forename: Janine A
authors.initials: JA
authors.lastname: Danks
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism; D005260:Female; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D012754:Sharks / Q000235:genetics* / Q000254:growth & development*; D060449:Wnt Signaling Pathway / Q000235:genetics / Q000502:physiology*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism; D000099274:Frizzled-Related Proteins
chemical_list: D029941:Fish Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D051176:beta Catenin; D000099274:Frizzled-Related Proteins
keywords: Bone; Cartilage; Elephant shark; Sclerostin; Secreted frizzled related protein; β-Catenin