title: Functional analysis of Sox8 during neural crest development in Xenopus.
abstract: Among the families of transcription factors expressed at the neural plate border, Sox proteins have been shown to regulate multiple aspects of neural crest development. Sox8, Sox9 and Sox10, exhibit overlapping expression domains in neural crest progenitors, and studies in mouse suggest that Sox8 functions redundantly with Sox9 and Sox10 during neural crest development. Here, we show that in Xenopus, Sox8 accumulates at the lateral edges of the neural plate at the mid-gastrula stage; in contrast to its mouse and chick orthologs, Sox8 expression precedes that of Sox9 and Sox10 in neural crest progenitors. Later in development, Sox8 expression persists in migrating cranial crest cells as they populate the pharyngeal arches and in trunk neural crest cells, in a pattern that recapitulates both Sox9 and Sox10 expression domains. Although morpholino-mediated knockdown of Sox8 protein did not prevent the formation of neural crest progenitors, the timing of their induction was severely affected. This delay in neural crest specification had dramatic consequences on the development of multiple lineages of the neural crest. We demonstrate that these defects are due to the inability of neural crest cells to migrate into the periphery, rather than to a deficiency in neural crest progenitors specification and survival. These results indicate that the control of Sox8 expression at the neural plate border is a key process in initiating neural crest formation in Xenopus, and highlight species-specific differences in the relative importance of SoxE proteins during neural crest development.
authors.affiliation: Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Donnell
authors.forename: Chang-Soo
authors.initials: CS
authors.lastname: Hong
authors.forename: Xiao
authors.initials: X
authors.lastname: Huang
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Delnicki
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Saint-Jeannet
mesh_terms: D000818:Animals; D002465:Cell Movement; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D009432:Neural Crest / Q000002:abnormalities / Q000166:cytology / Q000196:embryology*; D055758:SOX9 Transcription Factor; D055757:SOXE Transcription Factors; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014981:Xenopus / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D055758:SOX9 Transcription Factor; D055757:SOXE Transcription Factors; C527924:Sox10 protein, mouse; C515009:Sox8 protein, Xenopus; C527933:Sox9 protein, mouse; D014157:Transcription Factors; D029867:Xenopus Proteins