title: Transposon-mediated insertional mutagenesis revealed the functions of animal cellulose synthase in the ascidian Ciona intestinalis.
abstract: Tunicates are the only animals that perform cellulose biosynthesis. The tunicate gene for cellulose synthase, Ci-CesA, was likely acquired by horizontal transfer from bacteria and was a key innovation in the evolution of tunicates. Transposon-based mutagenesis in an ascidian, Ciona intestinalis, has generated a mutant, swimming juvenile (sj). Ci-CesA is the gene responsible for the sj mutant, in which a drastic reduction in cellulose was observed in the tunic. Furthermore, during metamorphosis, which in ascidians convert the vertebrate-like larva into a sessile filter feeder, sj showed abnormalities in the order of metamorphic events. In normal larvae, the metamorphic events in the trunk region are initiated after tail resorption. In contrast, sj mutant larvae initiated the metamorphic events in the trunk without tail resorption. Thus, sj larvae show a "swimming juvenile" phenotype, the juvenile-like trunk structure with a complete tail and the ability to swim. It is likely that ascidian cellulose synthase is required for the coordination of the metamorphic events in the trunk and tail in addition to cellulose biosynthesis.
authors.affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. sasakura@kurofune.shimoda.tsukuba.ac.jp
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sasakura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakashima
authors.forename: Satoko
authors.initials: S
authors.lastname: Awazu
authors.forename: Terumi
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Akie
authors.initials: A
authors.lastname: Nakayama
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Azuma
authors.forename: Nori
authors.initials: N
authors.lastname: Satoh
mesh_terms: D000818:Animals; D002482:Cellulose / Q000096:biosynthesis; D002938:Ciona intestinalis / Q000033:anatomy & histology / Q000201:enzymology* / Q000502:physiology; D004251:DNA Transposable Elements; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism*; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D008675:Metamorphosis, Biological; D016254:Mutagenesis, Insertional; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004251:DNA Transposable Elements; D011993:Recombinant Fusion Proteins; D002482:Cellulose; D005964:Glucosyltransferases; C478648:cellulose synthase