title: Isthmus organizer for mesencephalon and metencephalon.
abstract: The vertebrate central nervous system is elaborated from a simple neural tube. Brain vesicles formation is the first sign of regionalization. Classical transplantation using quail and chick embryos revealed that the mesencephalon-metencephalon boundary (isthmus) functions as an organizer of the mesencephalon and metencephalon. Fgf8 is accepted as a main organizing molecule of the isthmus. Strong Fgf8 signal activates the Ras-ERK signaling pathway to differentiate the cerebellum. In this review, the historical background of the means of identifying the isthmus organizer and the molecular mechanisms of signal transduction for tectum and cerebellum differentiation is reviewed.
authors.affiliation: Department of Molecular Neurobiology, Graduate School of Life Sciences, and Institute of Development, Aging and Cancer, Tohoku University, Seiryo-machi 4-1, Aoba-ku, Sendai 980-8575, Japan. nakamura@idac.tohoku.ac.jp
authors.forename: Harukazu
authors.initials: H
authors.lastname: Nakamura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sato
authors.forename: Asuka
authors.initials: A
authors.lastname: Suzuki-Hirano
mesh_terms: D000818:Animals; D002531:Cerebellum / Q000196:embryology*; D002642:Chick Embryo; D015509:Developmental Biology / Q000379:methods*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051524:Fibroblast Growth Factor 8 / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008636:Mesencephalon / Q000378:metabolism / Q000502:physiology*; D020540:Metencephalon / Q000378:metabolism / Q000502:physiology*; D008953:Models, Anatomic; D008954:Models, Biological; D009432:Neural Crest / Q000196:embryology; D011784:Quail; D014157:Transcription Factors / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D051524:Fibroblast Growth Factor 8; D048049:Extracellular Signal-Regulated MAP Kinases; D018631:ras Proteins