title: Tfap2 and Sox1/2/3 cooperatively specify ectodermal fates in ascidian embryos.
abstract: Epidermis and neural tissues differentiate from the ectoderm in animal embryos. Although epidermal fate is thought to be induced in vertebrate embryos, embryological evidence has indicated that no intercellular interactions during early stages are required for epidermal fate in ascidian embryos. To test this hypothesis, we determined the gene regulatory circuits for epidermal and neural specification in the ascidian embryo. These circuits started with Tfap2-r.b and Sox1/2/3, which are expressed in the ectodermal lineage immediately after zygotic genome activation. Tfap2-r.b expression was diminished in the neural lineages upon activation of fibroblast growth factor signaling, which is known to induce neural fate, and sustained only in the epidermal lineage. Tfap2-r.b specified the epidermal fate cooperatively with Dlx.b, which was activated by Sox1/2/3 This Sox1/2/3-Dlx.b circuit was also required for specification of the anterior neural fate. In the posterior neural lineage, Sox1/2/3 activated Nodal, which is required for specification of the posterior neural fate. Our findings support the hypothesis that the epidermal fate is specified autonomously in ascidian embryos.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan imai@bio.sci.osaka-u.ac.jp yutaka@ascidian.zool.kyoto-u.ac.jp.
authors.forename: Kaoru S
authors.identifier: 0000-0001-9113-6074
authors.initials: KS
authors.lastname: Imai
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hikawa
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan imai@bio.sci.osaka-u.ac.jp yutaka@ascidian.zool.kyoto-u.ac.jp.
authors.forename: Yutaka
authors.identifier: 0000-0001-5193-0708
authors.initials: Y
authors.lastname: Satou
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics; D002938:Ciona intestinalis / Q000196:embryology* / Q000235:genetics; D004475:Ectoderm / Q000196:embryology* / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004817:Epidermis / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055748:SOXB1 Transcription Factors / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D050656:Transcription Factor AP-2 / Q000502:physiology*; D014561:Urochordata / Q000196:embryology* / Q000235:genetics
chemical_list: D055748:SOXB1 Transcription Factors; D050656:Transcription Factor AP-2
keywords: Ectoderm; Epidermis; Neural induction; Sox1/2/3; TFAP2