title: Genetic dissection of the formation of the forebrain in Medaka, Oryzias latipes.
abstract: 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 development of the forebrain were grouped into two classes. Class 1 mutants commonly showing a decrease in forebrain size, were further divided into subclasses 1A to 1D. Class 1A mutation (1 gene) caused an early defect evidenced by the lack of bf1 expression, Class 1B mutations (6 genes) patterning defects revealed by the aberrant expression of regional marker genes, Class 1C mutation (1 gene) a defect in a later stage, and Class 1D (3 genes) a midline defect analogous to the zebrafish one-eyed pinhead mutation. Class 2 mutations caused morphological abnormalities in the forebrain without considerably affecting its size, Class 2A mutations (6 genes) caused abnormalities in the development of the ventricle, Class 2B mutations (2 genes) severely affected the anterior commissure, and Class 2C (6 genes) mutations resulted in a unique forebrain morphology. Many of these mutants showed the compromised sonic hedgehog expression in the zona-limitans-intrathalamica (zli), arguing for the importance of this structure as a secondary signaling center. These mutants should provide important clues to the elucidation of the molecular mechanisms underlying forebrain development, and shed new light on phylogenically conserved and divergent functions in the developmental process.
authors.affiliation: Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Daiju
authors.initials: D
authors.lastname: Kitagawa
authors.forename: Tomomi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Kota
authors.initials: K
authors.lastname: Saito
authors.forename: Satoshi
authors.initials: S
authors.lastname: Asaka
authors.forename: Takao
authors.initials: T
authors.lastname: Sasado
authors.forename: Chikako
authors.initials: C
authors.lastname: Morinaga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suwa
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Niwa
authors.forename: Akihito
authors.initials: A
authors.lastname: Yasuoka
authors.forename: Tomonori
authors.initials: T
authors.lastname: Deguchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yoda
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hirose
authors.forename: Thorsten
authors.initials: T
authors.lastname: Henrich
authors.forename: Norimasa
authors.initials: N
authors.lastname: Iwanami
authors.forename: Sanae
authors.initials: S
authors.lastname: Kunimatsu
authors.forename: Masakazu
authors.initials: M
authors.lastname: Osakada
authors.forename: Chritoph
authors.initials: C
authors.lastname: Winkler
authors.forename: Harun
authors.initials: H
authors.lastname: Elmasri
authors.forename: Joachim
authors.initials: J
authors.lastname: Wittbrodt
authors.forename: Felix
authors.initials: F
authors.lastname: Loosli
authors.forename: Rebecca
authors.initials: R
authors.lastname: Quiring
authors.forename: Matthias
authors.initials: M
authors.lastname: Carl
authors.forename: Clemens
authors.initials: C
authors.lastname: Grabher
authors.forename: Sylke
authors.initials: S
authors.lastname: Winkler
authors.forename: Filippo
authors.initials: F
authors.lastname: Del Bene
authors.forename: Akihiro
authors.initials: A
authors.lastname: Momoi
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Katada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishina
authors.forename: Hisato
authors.initials: H
authors.lastname: Kondoh
authors.forename: Makoto
authors.initials: M
authors.lastname: Furutani-Seiki
mesh_terms: D000818:Animals; D009154:Mutation; D009990:Oryzias / Q000196:embryology* / Q000235:genetics*; D010641:Phenotype; D016548:Prosencephalon / Q000002:abnormalities / Q000196:embryology*