title: Ascidian Wnt-5 gene is involved in the morphogenetic movement of notochord cells.
abstract: Wnt proteins play important roles in many developmental events. Wnts are divided into two groups according to biological function. The Wnt-5a class proteins function in morphogenetic movement during embryogenesis. Previously, a Wnt-5 homolog has been isolated from the ascidian, Halocynthia roretzi. HrWnt-5 is expressed in the notochord until the tail-bud stage, implying a role in the notochord. In this study, the function of HrWnt-5 was investigated. When HrWnt-5 mRNA was injected into fertilized eggs, the embryos showed morphologic defects at around the neurula stage. The anterior-posterior axis was shorter than in control embryos. These defects were caused by the abnormal movement of notochord cells. However, the overexpression of HrWnt-5 mRNA did not affect the differentiation of tissues, suggesting that HrWnt-5 solely regulates the morphogenetic movement. Although endogenous HrWnt-5 is expressed in the notochord, the overexpression of HrWnt-5 mRNA caused the defects, suggesting that the amount of HrWnt-5 mRNA in the notochord is strictly regulated. These results suggest that HrWnt-5 regulates the morphogenetic movement of notochord cells during ascidian embryogenesis.
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. sasakura@ascidian.zool.kyoto-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Sasakura
authors.forename: K W
authors.initials: KW
authors.lastname: Makabe
mesh_terms: D000818:Animals; D004527:Egg Proteins / Q000378:metabolism* / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008957:Models, Genetic; D009672:Notochord / Q000378:metabolism* / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D014561:Urochordata; D051153:Wnt Proteins
chemical_list: D004527:Egg Proteins; D012333:RNA, Messenger; D051153:Wnt Proteins; C114699:Wnt-5 protein, Halocynthia roretzi