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The zebrafish unplugged gene controls motor axon pathway selection
1Department of Cell and Developmental Biology and Department of Pharmacology, University of Pennsylvania Medical Center, Philadelphia, PA 19104-6058, USA.
Development (Cambridge, England)
|April 19, 2000
Summary
The zebrafish unplugged gene guides motor axons at choice points. Mutant embryos show incorrect path selection, indicating unplugged
Area of Science:
- Neuroscience
- Developmental Biology
- Genetics
Background:
- Motor axons navigate complex paths during development.
- Guidance cues at choice points are crucial for correct neural wiring.
- The cellular source and nature of these guidance signals remain largely unknown.
Purpose of the Study:
- To identify genes and cells involved in motor axon guidance at choice points.
- To elucidate the mechanism of action for guidance signals.
- To understand the role of the zebrafish unplugged gene in motor axon navigation.
Main Methods:
- Utilized zebrafish (Danio rerio) as a model organism.
- Generated and analyzed mutations in the unplugged gene.
- Created chimeric embryos to trace cell-specific gene function.
- Observed motor neuron growth cone behavior at choice points.
Main Results:
- Loss of unplugged function in motor axons leads to aberrant pathway choices at choice points.
- Unplugged activity is localized to specific mesodermal cells near the choice point.
- These guiding cells migrate away before growth cone arrival, suggesting contact-independent signaling.
- Unplugged acts as a somite-derived signal influencing motor growth cone decisions.
Conclusions:
- The zebrafish unplugged gene is essential for motor axon navigation at choice points.
- Somite-derived mesodermal cells provide a contact-independent guidance signal.
- Unplugged mediates differential pathway selection by motor growth cones.