Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
1999-7-23
pubmed:abstractText
The organizer at the midbrain-hindbrain boundary (MHB organizer) has been proposed to induce and polarize the midbrain during development. We investigate the requirement for the MHB organizer in acerebellar mutants, which lack a MHB and cerebellum, but retain a tectum, and are mutant for fgf8, a candidate inducer and polarizer. We examine the retinotectal projection in the mutants to assay polarity in the tectum. In mutant tecta, retinal ganglion cell (RGC) axons form overlapping termination fields, especially in the ventral tectum, and along both the anterior-posterior and dorsal-ventral axis of the tectum, consistent with a MHB requirement in generating midbrain polarity. However, polarity is not completely lost in the mutant tecta, in spite of the absence of the MHB. Moreover, graded expression of the ephrin family ligand Ephrin-A5b is eliminated, whereas Ephrin-A2 and Ephrin-A5a expression is leveled in acerebellar mutant tecta, showing that ephrins are differentially affected by the absence of the MHB. Some RGC axons overshoot beyond the mutant tectum, suggesting that the MHB also serves a barrier function for axonal growth. By transplanting whole eye primordia, we show that mapping defects and overshooting largely, but not exclusively, depend on tectal, but not retinal genotype, and thus demonstrate an independent function for Fgf8 in retinal development. The MHB organizer, possibly via Fgf8 itself, is thus required for midbrain polarisation and for restricting axonal growth, but other cell populations may also influence midbrain polarity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0950-1991
pubmed:author
pubmed:issnType
Print
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2967-78
pubmed:dateRevised
2009-9-29
pubmed:meshHeading
pubmed-meshheading:10357940-Animals, pubmed-meshheading:10357940-Brain, pubmed-meshheading:10357940-Ephrin-A2, pubmed-meshheading:10357940-Ephrin-A5, pubmed-meshheading:10357940-Fibroblast Growth Factor 8, pubmed-meshheading:10357940-Fibroblast Growth Factors, pubmed-meshheading:10357940-Gene Expression Regulation, Developmental, pubmed-meshheading:10357940-Genotype, pubmed-meshheading:10357940-Immunohistochemistry, pubmed-meshheading:10357940-In Situ Hybridization, pubmed-meshheading:10357940-Ligands, pubmed-meshheading:10357940-Membrane Proteins, pubmed-meshheading:10357940-Mutation, pubmed-meshheading:10357940-Phenotype, pubmed-meshheading:10357940-RNA, Messenger, pubmed-meshheading:10357940-Tissue Transplantation, pubmed-meshheading:10357940-Transcription Factors, pubmed-meshheading:10357940-Zebrafish
pubmed:year
1999
pubmed:articleTitle
Requirement for the zebrafish mid-hindbrain boundary in midbrain polarisation, mapping and confinement of the retinotectal projection.
pubmed:affiliation
Department of Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't