title: Growth-Arrest-Specific 7 Gene Regulates Neural Crest Formation and Craniofacial Development in Zebrafish.
abstract: Growth-arrest-specific 7 (Gas7) is preferentially expressed in the nervous system and plays an important role during neuritogenesis in vertebrates. We recently demonstrated that gas7 is highly expressed in zebrafish neurons, where it regulates neural development. The possibility that gas7 may also regulate the development of other tissues remains to be examined. In this study, we investigate the role of Gas7 in the development of craniofacial tissues. Knockdown of gas7 using morpholino oligomers produced abnormal phenotypes in neural crest (NC) cells and their derivatives. NC-derived cartilage maturation was altered in Gas7 morphants as revealed by aberrant sox9b and dlx2 expression, a phenotype that could be rescued by coinjection of gas7 mRNA. While rhombomere morphology remained normal in Gas7 morphants, we observed reduced expression of the prechondrogenic genes sox9b and dlx2 in cells populating the posterior pharyngeal arches, but the fundamental structure of pharyngeal arches was preserved. In addition, NC cell sublineages that migrate to form neurons, glial cells, and melanocytes were altered in Gas7 morphants as revealed by aberrant expression of neurod, foxd3, and mitfa, respectively. Development of NC progenitors was also examined in Gas7 morphants at 12 hpf, and we observed that the reduction of cell precursors in Gas7 morphants was due to increased apoptosis level. These results indicate that the formation of NC progenitors and derivatives depends on Gas7 expression. Our observations also suggest that Gas7 regulates the formation of NC derivatives constituting the internal tissues of pharyngeal arches, without affecting the fundamental structure of mesodermal-derived pharyngeal arches.
authors.affiliation: 1 Department of Biochemistry and Molecular Biology, Chang Gung University , Taiwan, Republic of China .
authors.forename: Feng-Chun
authors.initials: FC
authors.lastname: Hung
authors.affiliation: 1 Department of Biochemistry and Molecular Biology, Chang Gung University , Taiwan, Republic of China .|2 Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University , Taiwan, Republic of China .
authors.forename: Hung-Yu
authors.initials: HY
authors.lastname: Shih
authors.affiliation: 1 Department of Biochemistry and Molecular Biology, Chang Gung University , Taiwan, Republic of China .|2 Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University , Taiwan, Republic of China .|3 Chang Gung Memorial Hospital , Taiwan, Republic of China .
authors.forename: Yi-Chuan
authors.initials: YC
authors.lastname: Cheng
authors.affiliation: 1 Department of Biochemistry and Molecular Biology, Chang Gung University , Taiwan, Republic of China .|2 Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University , Taiwan, Republic of China .|3 Chang Gung Memorial Hospital , Taiwan, Republic of China .
authors.forename: Chuck C-K
authors.initials: CC
authors.lastname: Chao
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009432:Neural Crest / Q000196:embryology / Q000378:metabolism*; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins; D051739:Microphthalmia-Associated Transcription Factor; D009419:Nerve Tissue Proteins; D055758:SOX9 Transcription Factor; D014157:Transcription Factors; D029961:Zebrafish Proteins; C088334:Distal-less homeobox proteins; C491002:foxd3 protein, zebrafish; C000611741:gas7a protein, zebrafish; C497237:mitfa protein, zebrafish; C093564:Neurogenic differentiation factor 1