HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental Figures and Table All Versions of this Article: 22/3/269    most recent 00229.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Okamura, Y. Articles by Mori, Y. Search for Related Content PubMed PubMed Citation Articles by Okamura, Y. Articles by Mori, Y.

CALL FOR PAPERS: Comparative Genomics

Comprehensive analysis of the ascidian genome reveals novel insights into the molecular evolution of ion channel genes

¹ Section of Developmental Neurophysiology, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi
² National Institutes for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi
³ Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto
⁴ Department of Medical Physiology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
⁵ Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
⁶ Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki
⁷ Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Tokyo
⁸ School of Life Science, Graduate University for Advanced Studies, Okazaki, Aichi, Japan

Ion fluxes through membrane ion channels play crucial roles both in neuronal signaling and the homeostatic control of body electrolytes. Despite our knowledge about the respective ion channels, just how diversification of ion channel genes underlies adaptation of animals to the physical environment remains unknown. Here we systematically survey up to 160 putative ion channel genes in the genome of Ciona intestinalis and compare them with corresponding gene sets from the genomes of the nematode Chaenorhabditis elegans, the fruit fly Drosophila melanogaster, and the more closely related genomes of vertebrates. Ciona has a set of so-called "prototype" genes for ion channels regulating neuronal excitability, or for neurotransmitter receptors, suggesting that genes responsible for neuronal signaling in mammals appear to have diversified mainly via gene duplications of the more restricted members of ancestral genomes before the ascidian/vertebrate divergence. Most genes responsible for modulation of neuronal excitability and pain sensation are absent from the ascidian genome, suggesting that these genes arose after the divergence of urochordates. In contrast, the divergent genes encoding connexins, transient receptor potential-related channels and chloride channels, channels involved rather in homeostatic control, indicate gene duplication events unique to the ascidian lineage. Because several invertebrate-unique channel genes exist in Ciona genome, the crown group of extant vertebrates not only acquired novel channel genes via gene/genome duplications but also discarded some ancient genes that have persisted in invertebrates. Such genome-wide information of ion channel genes in basal chordates enables us to begin correlating the innovation and remodeling of genes with the adaptation of more recent chordates to their physical environment.

ascidian; homeostasis; embryogenesis

This article has been cited by other articles:

				G. J. Tompkins-MacDonald, W. J. Gallin, O. Sakarya, B. Degnan, S. P. Leys, and L. M. Boland Expression of a poriferan potassium channel: insights into the evolution of ion channels in metazoans J. Exp. Biol., March 15, 2009; 212(6): 761 - 767. [Abstract] [Full Text] [PDF]

				T. Coric, Y. J. Passamaneck, P. Zhang, A. Di Gregorio, and C. M. Canessa Simple chordates exhibit a proton-independent function of acid-sensing ion channels FASEB J, June 1, 2008; 22(6): 1914 - 1923. [Abstract] [Full Text] [PDF]

				M. Tanaka-Kunishima, K. Takahashi, and F. Watanabe Cell contact induces multiple types of electrical excitability from ascidian two-cell embryos that are cleavage arrested and contain all cell fate determinants Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2007; 293(5): R1976 - R1996. [Abstract] [Full Text] [PDF]

				J. Liu, J. Xia, K.-H. Cho, D. E. Clapham, and D. Ren CatSperbeta, a Novel Transmembrane Protein in the CatSper Channel Complex J. Biol. Chem., June 29, 2007; 282(26): 18945 - 18952. [Abstract] [Full Text] [PDF]

				H. A. Jackson, C. R. Marshall, and E. A. Accili Evolution and structural diversification of hyperpolarization-activated cyclic nucleotide-gated channel genes Physiol Genomics, May 11, 2007; 29(3): 231 - 245. [Abstract] [Full Text] [PDF]

				S. Caveney, W. Cladman, L. Verellen, and C. Donly Ancestry of neuronal monoamine transporters in the Metazoa J. Exp. Biol., December 15, 2006; 209(24): 4858 - 4868. [Abstract] [Full Text] [PDF]

				S. Saito and R. Shingai Evolution of thermoTRP ion channel homologs in vertebrates Physiol Genomics, November 21, 2006; 27(3): 219 - 230. [Abstract] [Full Text] [PDF]

				M. Liang and B. Ventura Physiological genomics in PG and beyond: July to September 2005 Physiol Genomics, October 17, 2005; 23(2): 119 - 124. [Full Text] [PDF]