title: Hes1 and Hes3 regulate maintenance of the isthmic organizer and development of the mid/hindbrain.
abstract: The isthmic organizer, which is located at the midbrain-hindbrain boundary, plays an essential role in development of the midbrain and anterior hindbrain. It has been shown that homeobox genes regulate establishment of the isthmic organizer, but the mechanism by which the organizer is maintained is not well understood. Here, we found that, in mice doubly mutant for the basic helix-loop-helix genes Hes1 and Hes3, the midbrain and anterior hindbrain structures are missing without any significant cell death. In these mutants, the isthmic organizer cells prematurely differentiate into neurons and terminate expression of secreting molecules such as Fgf8 and Wnt1 and the paired box genes Pax2/5, all of which are essential for the isthmic organizer function. These results indicate that Hes1 and Hes3 prevent premature differentiation and maintain the organizer activity of the isthmic cells, thereby regulating the development of the midbrain and anterior hindbrain.
authors.affiliation: Institute for Virus Research, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hirata
authors.forename: K
authors.initials: K
authors.lastname: Tomita
authors.forename: Y
authors.initials: Y
authors.lastname: Bessho
authors.forename: R
authors.initials: R
authors.lastname: Kageyama
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation; D005260:Female; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D008297:Male; D008636:Mesencephalon / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009436:Neural Tube Defects; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D012097:Repressor Proteins; D012249:Rhombencephalon / Q000196:embryology* / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D000072056:Transcription Factor HES-1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; D000072056:Transcription Factor HES-1; C489734:Hes1 protein, mouse; C411886:Hes3 protein, mouse