title: Genetic pathways for differentiation of the peripheral nervous system in ascidians.
abstract: Ascidians belong to tunicates, the sister group of vertebrates. Peripheral nervous systems (PNSs) including epidermal sensory neurons (ESNs) in the trunk and dorsal tail regions of ascidian larvae are derived from cells adjacent to the neural plate, as in vertebrates. On the other hand, peripheral ESNs in the ventral tail region are derived from the ventral ectoderm under the control of BMP signalling, reminiscent of sensory neurons of amphioxus and protostomes. In this study, we show that two distinct mechanisms activate a common gene circuit consisting of Msx, Ascl.b, Tox, Delta.b and Pou4 in the dorsal and ventral regions to differentiate ESNs. Our results suggest that ventral ESNs of the ascidian larva are not directly homologous to vertebrate PNSs. The dorsal ESNs might have arisen via co-option of the original PNS gene circuit to the neural plate border in an ancestral chordate.
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Waki
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.|Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
authors.forename: Kaoru S
authors.initials: KS
authors.lastname: Imai
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.|CREST, JST, Sakyo, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Satou
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D018507:Gene Expression Regulation, Developmental; D017933:Peripheral Nervous System / Q000166:cytology / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism; D014561:Urochordata / Q000166:cytology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D011506:Proteins