title: RNA interference in the appendicularian Oikopleura dioica reveals the function of the Brachyury gene.
abstract: The appendicularian Oikopleura dioica is a chordate that has a remarkably simple adult body with small cell number. Its transparency, stereotyped cell lineages, short life cycle, and small genome make it a promising new experimental model of chordate developmental biology. However, the functions of its various genes are still poorly understood due to lack of a tool for suppression of gene expression. Here, we applied a double-stranded RNA (dsRNA)-based-RNA interference (RNAi) method in O. dioica. For introducing dsRNA into eggs and embryos, we injected dsRNAs into the ovary. dsRNA, which is specific to EGFP or mCherry mRNA, decreased the exogenous mRNA-derived fluorescence in both eggs and embryos. dsRNA specific to the Brachyury gene of O. dioica, which is a homologous gene of a key notochord transcriptional factor in ascidians, triggered degradation of endogenous Brachyury mRNA and induced malformation or loss of the notochord in the tail. This effect was Brachyury sequence specific, as three dsRNAs covering different sequences produced the same phenotype. The result is in accordance with its expression site and also with the key regulatory function of Brachyury in notochord formation in other chordates. RNAi in O. dioica would be a useful tool for gaining insight into the oogenesis and early developmental processes in chordates.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan. otamazako@bio.sci.osaka-u.ac.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Omotezako
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nishino
authors.forename: Takeshi A
authors.initials: TA
authors.lastname: Onuma
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nishida
mesh_terms: D000818:Animals; D005326:Fetal Proteins / Q000235:genetics* / Q000378:metabolism; D008845:Microinjections / Q000379:methods; D009672:Notochord / Q000196:embryology / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D034622:RNA Interference; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D014561:Urochordata / Q000196:embryology* / Q000378:metabolism; D000098908:Brachyury Protein
chemical_list: D005326:Fetal Proteins; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein