title: Dorsalization of the neural tube by Xenopus tiarin, a novel patterning factor secreted by the flanking nonneural head ectoderm.
abstract: We have isolated a novel secreted dorsalizing factor of the neural tube, Xenopus Tiarin, which belongs to the olfactomedin-related family. Tiarin expression starts at the late gastrula stage in the nonneural ectoderm adjacent to the anterior neural plate. Overexpression of Tiarin in the embryo causes expansion of dorsal neural markers and suppression of ventral markers. In the eye-forming field, Tiarin overexpression induces the retinal markers and represses optic stalk markers. Tiarin directly dorsalizes neural tissues in the absence of mesodermal tissues and antagonizes the ventralizing activity of Sonic hedghog (Shh). Unlike BMP4, another dorsalizing factor, Tiarin does not display antineuralizing activity on the ectoderm or mesoderm-ventralizing activity. These findings show that Tiarin is a novel patterning signal candidate acting in the specification of the dorsal neural tube.
authors.affiliation: Department of Medical Embryology and Neurobiology, Kyoto University, Sakyo, Kyoto 606-8507, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Noriaki
authors.initials: N
authors.lastname: Sasai
authors.forename: Mami
authors.initials: M
authors.lastname: Matsuo-Takasaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Sakuragi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Murakami
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sasai
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002490:Central Nervous System / Q000196:embryology* / Q000378:metabolism; D004475:Ectoderm / Q000166:cytology / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005123:Eye / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006133:Growth Substances / Q000378:metabolism*; D006257:Head / Q000196:embryology / Q000502:physiology; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009432:Neural Crest / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000502:physiology*; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism
chemical_list: D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D006133:Growth Substances; C449820:OLFM4 protein, Xenopus; D012333:RNA, Messenger; D029867:Xenopus Proteins; C081451:olfactomedin