Takao Sasado

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We tested the Sleeping Beauty transposable element for its ability to efficiently insert transgenes into the genome of medaka (Oryzias latipes), an important model system for vertebrate development. We show that the SB transposon efficiently mediates integration of a reporter gene into the fish germ line. In pilot experiments, we established 174 transgenic(More)
Medaka (Oryzias latipes) is a small freshwater teleost fish that serves as a model vertebrate organism in various fields of biology including development, genetics, toxicology and evolution. The recent completion of the medaka genome sequencing project has promoted the use of medaka as a comparative and complementary material for research on other(More)
We have established a reverse genetics approach for the routine generation of medaka (Oryzias latipes) gene knockouts. A cryopreserved library of N-ethyl-N-nitrosourea (ENU) mutagenized fish was screened by high-throughput resequencing for induced point mutations. Nonsense and splice site mutations were retrieved for the Blm, Sirt1, Parkin and p53 genes and(More)
Migratory pathways of PGCs to the gonad vary depending on the vertebrate species, yet the underlying regulatory mechanisms guiding PGCs are believed to be largely common. In teleost medaka embryo, PGC migration follows two major steps before colonizing in gonadal areas: (1) bilateral lineup in the trunk and (2) posterior drift of PGCs. kazura (kaz) and(More)
The metameric structure of the vertebrate trunk is generated by repeated formation of somites from the unsegmented presomitic mesoderm (PSM). We report the initial characterization of nine different mutants affecting segmentation that were isolated in a large-scale mutagenesis screen in Medaka (Oryzias latipes). Four mutants were identified that show a(More)
We performed a systematic screen for mutations affecting the trajectory of axons visualized by immunohistochemical staining of Medaka embryos with anti-acetylated tubulin antibody. Among the mutations identified, yanagi (yan) and kazura (kaz) mutations caused specific defects in projection of the posterior lateral line (PLL) nerve. In yan and kaz mutant(More)
A large-scale mutagenesis screen was performed in Medaka to identify genes acting in diverse developmental processes. Mutations were identified in homozygous F3 progeny derived from ENU-treated founder males. In addition to the morphological inspection of live embryos, other approaches were used to detect abnormalities in organogenesis and in specific(More)
We report here mutations affecting various aspects of liver development and function identified by multiple assays in a systematic mutagenesis screen in Medaka. The 22 identified recessive mutations assigned to 19 complementation groups fell into five phenotypic groups. Group 1, showing defective liver morphogenesis, comprises mutations in four genes, which(More)
The development of germ cells has been intensively studied in Medaka (Oryzias latipes). We have undertaken a large-scale screen to identify mutations affecting the development of primordial germ cells (PGCs) in Medaka. Embryos derived from mutagenized founder fish were screened for an abnormal distribution or number of PGCs at embryonic stage 27 by RNA in(More)
The forebrain, consisting of the telencephalon and diencephalon, is essential for processing sensory information. To genetically dissect formation of the forebrain in vertebrates, we carried out a systematic screen for mutations affecting morphogenesis of the forebrain in Medaka. Thirty-three mutations defining 25 genes affecting the morphological(More)