title: AMPA glutamate receptors are required for sensory-organ formation and morphogenesis in the basal chordate.
abstract: AMPA-type glutamate receptors (GluAs) mediate fast excitatory transmission in the vertebrate central nervous system (CNS), and their function has been extensively studied in the mature mammalian brain. However, GluA expression begins very early in developing embryos, suggesting that they may also have unidentified developmental roles. Here, we identify developmental roles for GluAs in the ascidianCiona intestinalisMammals express Ca2+-permeable GluAs (Ca-P GluAs) and Ca2+-impermeable GluAs (Ca-I GluAs) by combining subunits derived from four genes. In contrast, ascidians have a singlegluAgene. Taking advantage of the simple genomic GluA organization in ascidians, we knocked down (KD) GluAs inCionaand observed severe impairments in formation of the ocellus, a photoreceptive organ used during the swimming stage, and in resorption of the tail and body axis rotation during metamorphosis to the adult stage. These defects could be rescued by injection of KD-resistant GluAs. GluA KD phenotypes could also be reproduced by expressing a GluA mutant that dominantly inhibits glutamate-evoked currents. These results suggest that, in addition to their role in synaptic communication in mature animals, GluAs also have critical developmental functions.
authors.affiliation: Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-0057, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Hirai
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Kohoku, Yokohama, 223-8522, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Hotta
authors.affiliation: Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kubo
authors.affiliation: Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nishino
authors.affiliation: Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Okabe
authors.affiliation: Department of Biology, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
authors.affiliation: Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-0057, Japan; okado-hr@igakuken.or.jp.
authors.forename: Haruo
authors.initials: H
authors.lastname: Okado
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002938:Ciona intestinalis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva; D008297:Male; D009024:Morphogenesis; D009865:Oocytes / Q000502:physiology; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D012679:Sense Organs / Q000254:growth & development* / Q000378:metabolism; D014981:Xenopus
chemical_list: D017470:Receptors, Glutamate; D049452:Green Fluorescent Proteins; D002118:Calcium
keywords: AMPA-type glutamate receptor; ascidian; development; morphogeneis