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nkx3.2 mutant zebrafish accommodate jaw joint loss through a phenocopy of the head shapes of Paleozoic jawless fish.
Miyashita, Tetsuto; Baddam, Pranidhi; Smeeton, Joanna; Oel, A Phil; Natarajan, Natasha; Gordon, Brogan; Palmer, A Richard; Crump, J Gage; Graf, Daniel; Allison, W Ted.
Afiliación
  • Miyashita T; Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA.
  • Baddam P; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9.
  • Smeeton J; Department of Dentistry, University of Alberta, Edmonton, AB, Canada T6G 2R3.
  • Oel AP; Department of Stem Cell Biology and Regenerative Medicine, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
  • Natarajan N; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9.
  • Gordon B; Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
  • Palmer AR; Department of Stem Cell Biology and Regenerative Medicine, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
  • Crump JG; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9.
  • Graf D; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9.
  • Allison WT; Department of Stem Cell Biology and Regenerative Medicine, W. M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
J Exp Biol ; 223(Pt 15)2020 08 05.
Article en En | MEDLINE | ID: mdl-32527964
The vertebrate jaw is a versatile feeding apparatus. To function, it requires a joint between the upper and lower jaws, so jaw joint defects are often highly disruptive and difficult to study. To describe the consequences of jaw joint dysfunction, we engineered two independent null alleles of a single jaw joint marker gene, nkx3.2, in zebrafish. These mutations caused zebrafish to become functionally jawless via fusion of the upper and lower jaw cartilages (ankylosis). Despite lacking jaw joints, nkx3.2 mutants survived to adulthood and accommodated this defect by: (a) having a remodeled skull with a fixed open gape, reduced snout and enlarged branchial region; and (b) performing ram feeding in the absence of jaw-generated suction. The late onset and broad extent of phenotypic changes in the mutants suggest that modifications to the skull are induced by functional agnathia, secondarily to nkx3.2 loss of function. Interestingly, nkx3.2 mutants superficially resemble ancient jawless vertebrates (anaspids and furcacaudiid thelodonts) in overall head shape. Because no homology exists in individual skull elements between these taxa, the adult nkx3.2 phenotype is not a reversal but rather a convergence due to similar functional requirements of feeding without moveable jaws. This remarkable analogy strongly suggests that jaw movements themselves dramatically influence the development of jawed vertebrate skulls. Thus, these mutants provide a unique model with which to: (a) investigate adaptive responses to perturbation in skeletal development; (b) re-evaluate evolutionarily inspired interpretations of phenocopies generated by gene knockdowns and knockouts; and (c) gain insight into feeding mechanics of the extinct agnathans.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Pez Cebra / Maxilares Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: J Exp Biol Año: 2020 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Pez Cebra / Maxilares Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: J Exp Biol Año: 2020 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Reino Unido