title: Sparc (Osteonectin) functions in morphogenesis of the pharyngeal skeleton and inner ear.
abstract: Sparc (Osteonectin), a matricellular glycoprotein expressed by many differentiated cells, is a major non-collagenous constituent of vertebrate bones. Recent studies indicate that Sparc expression appears early in development, although its function and regulation during embryogenesis are largely unknown. We cloned zebrafish sparc and investigated its role during development, using a mo rpholino antisense oligonucleotide-based knockdown approach. Consistent with its strong expression in the otic vesicle and developing pharyngeal cartilages, knockdown of Sparc function resulted in specific inner ear and cartilage defects that are highlighted by changes in gene expression, morphology and behavior. We rescued the knockdown phenotypes by co-injecting sparc mRNA, providing evidence that the knockdown phenotype is due specifically to impairment of Sparc function. A comparison of the phenotypes of Sparc knockdown and known zebrafish mutants with similar defects places Sparc downstream of sox9 in the genetic network that regulates development of the pharyngeal skeleton and inner ear of vertebrates.
authors.affiliation: Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD 21202, USA. rotllant@iim.csic.es
authors.forename: Josep
authors.initials: J
authors.lastname: Rotllant
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Yin-Lin
authors.initials: YL
authors.lastname: Yan
authors.forename: John H
authors.initials: JH
authors.lastname: Postlethwait
authors.forename: Monte
authors.initials: M
authors.lastname: Westerfield
authors.forename: Shao-Jun
authors.initials: SJ
authors.lastname: Du
mesh_terms: D000818:Animals; D019521:Body Patterning; D007758:Ear, Inner / Q000033:anatomy & histology* / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D017403:In Situ Hybridization; D009024:Morphogenesis; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism*; D010614:Pharynx / Q000033:anatomy & histology* / Q000196:embryology* / Q000378:metabolism; D010641:Phenotype; D012863:Skeleton; D015027:Zebrafish / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016376:Oligonucleotides, Antisense; D015676:Osteonectin; D029961:Zebrafish Proteins