title: Rhombomere interactions control the segmental differentiation of hindbrain neurons.
abstract: The embryonic hindbrain is subdivided into a series of metameric units termed rhombomeres, which display features that strongly suggest they are autonomous developmental units. However, some aspects of their phenotype develop nonautonomously. Here we have analyzed the possibility that interrhombomere interactions generate the pattern of segmental neuronal differentiation. The differentiation of both projection interneurons and motor neurons in the hindbrain is retarded in rhombomeres 3 and 5. We demonstrate here that if either rhombomere 3 or 5 is isolated from the influence of their neighbours, either in vitro or in vivo, then these segments no longer display delayed neuronal diufferentiation. We further show that the retardation of motor neurons differentiation in rhombomeres 3 and 5 is, at least in part, mediated by Bmp-4. If this molecule is inhibited, by grafting cells expressing chordin, then the motor neurons of these rhombomeres develop ahead of their normal schedule.
authors.affiliation: MRC Centre for Developmental Neurobiology, Kings College London, New Hunts House, London SE1 1UL, United Kingdom.
authors.forename: B J
authors.initials: BJ
authors.lastname: Eickholt
authors.forename: A
authors.initials: A
authors.lastname: Graham
authors.forename: A
authors.initials: A
authors.lastname: Lumsden
authors.forename: A
authors.initials: A
authors.lastname: Wizenmann
mesh_terms: D020410:Activated-Leukocyte Cell Adhesion Molecule / Q000378:metabolism; D000818:Animals; D019521:Body Patterning / Q000187:drug effects / Q000502:physiology*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016380:Brain Tissue Transplantation; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002642:Chick Embryo / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D006023:Glycoproteins / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D007382:Intermediate Filaments / Q000378:metabolism; D007395:Interneurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009924:Organ Culture Techniques; D012249:Rhombencephalon / Q000166:cytology / Q000196:embryology* / Q000637:transplantation
chemical_list: D020410:Activated-Leukocyte Cell Adhesion Molecule; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; C054234:chordin