title: Normal function of Myf5 during gastrulation is required for pharyngeal arch cartilage development in zebrafish embryos.
abstract: Myf5, a myogenic regulatory factor, plays a key role in regulating muscle differentiation. However, it is not known if Myf5 has a regulatory role during early embryogenesis. Here, we used myf5-morpholino oligonucleotides [MO] to knock down myf5 expression and demonstrated a series of results pointing to the functional roles of Myf5 during early embryogenesis: (1) reduced head size resulting from abnormal morphology in the cranial skeleton; (2) decreased expressions of the cranial neural crest (CNC) markers foxd3, sox9a, dlx2, and col2a1; (3) defect in the chondrogenic neural crest similar to that of fgf3 morphants; (4) reduced fgf3/fgf8 transcripts in the cephalic mesoderm rescued by co-injection of myf5 wobble-mismatched mRNA together with myf5-MO1 during 12 h postfertilization; (5) abnormal patterns of axial and non-axial mesoderm causing expansion of the dorsal organizer, and (6) increased bmp4 gradient, but reduced fgf3/fgf8 marginal gradient, during gastrulation. Interestingly, overexpression of fgf3 could rescue the cranial cartilage defects caused by myf5-MO1, suggesting that Myf5 modulates craniofacial cartilage development through the fgf3 signaling pathway. Together, the loss of Myf5 function results in a cascade effect that begins with abnormal formation of the dorsal organizer during gastrulation, causing, in turn, defects in the CNC and cranial cartilage of myf5-knockdown embryos.
authors.affiliation: Institute of Molecular and Cellular Biology, National Taiwan University , Taipei, Taiwan .
authors.forename: Cheng-Yung
authors.initials: CY
authors.lastname: Lin
authors.forename: Hung-Chieh
authors.initials: HC
authors.lastname: Lee
authors.forename: Hung-Chun
authors.initials: HC
authors.lastname: Chen
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Hsieh
authors.forename: Huai-Jen
authors.initials: HJ
authors.lastname: Tsai
mesh_terms: D000818:Animals; D001934:Branchial Region / Q000196:embryology*; D002358:Cartilage, Articular / Q000254:growth & development*; D020219:Chondrogenesis; D047108:Embryonic Development; D055785:Gene Knockdown Techniques; D006257:Head / Q000196:embryology; D009132:Muscles / Q000196:embryology; D051787:Myogenic Regulatory Factor 5 / Q000172:deficiency / Q000502:physiology*; D009432:Neural Crest / Q000196:embryology; D015398:Signal Transduction / Q000502:physiology; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000172:deficiency / Q000502:physiology*
chemical_list: D051787:Myogenic Regulatory Factor 5; D029961:Zebrafish Proteins