PUBLICATION
Are pioneer axons guided by regulatory gene expression domains in the zebrafish forebrain? High-resolution analysis of the patterning of the zebrafish brain during axon tract formation
- Authors
- Hjorth, J.T. and Key, B.
- ID
- ZDB-PUB-010220-11
- Date
- 2001
- Source
- Developmental Biology 229(2): 271-286 (Journal)
- Registered Authors
- Key, Brian
- Keywords
- axon guidance; zebrafish; regulatory genes; gene expression borders; neuronal patterning; forebrain
- MeSH Terms
-
- Animals
- Axons/physiology*
- Body Patterning*
- Brain/embryology*
- Embryo, Nonmammalian/physiology
- Embryonic Induction
- Eye Proteins
- Gene Expression Regulation, Developmental*
- Genes, Regulator*
- Hedgehog Proteins
- Homeodomain Proteins/genetics
- In Situ Hybridization, Fluorescence
- Microscopy, Confocal
- Nerve Tissue Proteins/genetics
- Neurons/physiology*
- Paired Box Transcription Factors
- Prosencephalon/embryology*
- Proteins/genetics
- Repressor Proteins
- Trans-Activators*
- Zebrafish/embryology
- PubMed
- 11203695 Full text @ Dev. Biol.
Citation
Hjorth, J.T. and Key, B. (2001) Are pioneer axons guided by regulatory gene expression domains in the zebrafish forebrain? High-resolution analysis of the patterning of the zebrafish brain during axon tract formation. Developmental Biology. 229(2):271-286.
Abstract
Although the principles of axon growth are well understood in vitro the mechanisms guiding axons in vivo are less clear. It has been postulated that growing axons in the vertebrate brain follow borders of neuroepithelial cells expressing specific regulatory genes. In the present study we reexamined this hypothesis by analysing the earliest growing axons in the forebrain of embryonic zebrafish. Confocal laser scanning microscopy was used to determine the spatiotemporal relationship between growing axons and the expression pattern of eight regulatory genes in zebrafish brain. Pioneer axons project either longitudinally or dorsoventrally to establish a scaffold of axon tracts during this developmental period. Each of the regulatory genes was expressed in stereotypical domains and the borders of some were oriented along dorsoventral and longitudinal planes. However, none of these borders clearly defined the trajectories of pioneer axons. In two cases axons coursed in proximity to the borders of shh and pax6, but only for a relatively short portion of their pathway. Only later growing axons were closely apposed to the borders of some gene expression domains. These results suggest that pioneer axons in the embryonic forebrain do not follow continuous pathways defined by the borders of regulatory gene expression domains.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping