title: Cilia play a role in breaking left-right symmetry of the sea urchin embryo.
abstract: Left-right asymmetry of bilaterian animals is established during early development. In mice, frogs and fishes, the ciliated left-right organizer plays an essential role in establishing bilateral asymmetry, and leftward flow of extracellular fluid generated by ciliary motion results in Nodal activity on the left side. However, H(+) /K(+) -ATPase activity is also involved in the determination of left-right asymmetry in a variety of animals, and it has been thought to be an ancestral mechanism in deuterostomes. In sea urchin, the determination of the left-right asymmetry based on H(+) /K(+) -ATPase activity was already clarified, but it remains to be uncovered whether ciliary motion is involved in the left-right asymmetry of the embryo. Here, we show evidence that ciliary motion is involved in the establishment of left-right asymmetry of sea urchin embryo. Furthermore, we show that the initial cilia generated on small micromeres during the early stage of embryogenesis may be involved in this process. These results suggest that the cilia-mediated mechanism for the determination of left-right asymmetry may be acquired at the base of the deuterostomes.
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Takemoto
authors.affiliation: Department of Genetics and Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, 734-8553, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyamoto
authors.affiliation: Hiroshima Prefectural Hiroshima Kokutaiji High School, Hiroshima, 730-0042, Japan.|An Educational Project for Exciting Science Learning for Pupils, Hiroshima University, Higashi-Hiroshima, 739-8524, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Simono
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Kurogi
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Mie, 517-0004, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Shirae-Kurabayashi
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.|Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Awazu
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Ken-Ichi T
authors.initials: KT
authors.lastname: Suzuki
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.|Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.|Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
authors.forename: Naoaki
authors.initials: N
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D002923:Cilia; D004625:Embryo, Nonmammalian; D047108:Embryonic Development; D055456:Nodal Signaling Ligands / Q000378:metabolism; D012617:Sea Urchins / Q000196:embryology* / Q000378:metabolism
chemical_list: D055456:Nodal Signaling Ligands