title: DEAD-box protein Ddx46 is required for the development of the digestive organs and brain in zebrafish.
abstract: Spatially and temporally controlled gene expression, including transcription, several mRNA processing steps, and the export of mature mRNA to the cytoplasm, is essential for developmental processes. It is well known that RNA helicases of the DExD/H-box protein family are involved in these gene expression processes, including transcription, pre-mRNA splicing, and rRNA biogenesis. Although one DExD/H-box protein, Prp5, a homologue of vertebrate Ddx46, has been shown to play important roles in pre-mRNA splicing in yeast, the in vivo function of Ddx46 remains to be fully elucidated in metazoans. In this study, we isolated zebrafish morendo (mor), a mutant that shows developmental defects in the digestive organs and brain, and found that it encodes Ddx46. The Ddx46 transcript is maternally supplied, and as development proceeds in zebrafish larvae, its ubiquitous expression gradually becomes restricted to those organs. The results of whole-mount in situ hybridization showed that the expression of various molecular markers in these organs is considerably reduced in the Ddx46 mutant. Furthermore, splicing status analysis with RT-PCR revealed unspliced forms of mRNAs in the digestive organ and brain tissues of the Ddx46 mutant, suggesting that Ddx46 may be required for pre-mRNA splicing during zebrafish development. Therefore, our results suggest a model in which zebrafish Ddx46 is required for the development of the digestive organs and brain, possibly through the control of pre-mRNA splicing.
authors.affiliation: Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.
authors.forename: Shunya
authors.initials: S
authors.lastname: Hozumi
authors.forename: Ryo
authors.initials: R
authors.lastname: Hirabayashi
authors.forename: Akio
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Ogata
authors.forename: Tohru
authors.initials: T
authors.lastname: Ishitani
authors.forename: Makiko
authors.initials: M
authors.lastname: Tsutsumi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kuroiwa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Itoh
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kikuchi
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology*; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D004064:Digestive System / Q000196:embryology*; D009154:Mutation; D038081:Organogenesis / Q000502:physiology*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing / Q000502:physiology; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D029961:Zebrafish Proteins; D053487:DEAD-box RNA Helicases; C587481:Ddx46 protein, zebrafish