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The axonal chemoattractant netrin-1 is also a chemorepellent for trochlear motor axons
S A Colamarino1, M Tessier-Lavigne
1Howard Hughes Medical Institute, Department of Anatomy, University of California, San Francisco 94143-0452, USA.
Cell
|May 19, 1995
Summary
Netrin-1, a guidance molecule, acts as both a chemoattractant and chemorepellent for developing axons. This dual action guides neuronal growth in the vertebrate neural tube, similar to its C. elegans homolog UNC-6.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Axon guidance is crucial for neural circuit formation.
- Diffusible molecules act as chemoattractants and chemorepellents.
- Netrin-1 is a known chemoattractant expressed by floor plate cells.
Purpose of the Study:
- To investigate the role of netrin-1 in guiding trochlear motor axons.
- To determine if netrin-1 exhibits bifunctional guidance properties.
Main Methods:
- In vivo analysis of axon guidance in the developing neural tube.
- Utilizing COS cells to secrete recombinant netrin-1.
Main Results:
- Floor plate cells exert a long-range repulsive effect on dorsal-growing trochlear motor axons.
- Netrin-1 secreted by COS cells mimics this repulsive effect.
- Netrin-1 demonstrates a dual role, attracting some axons while repelling others.
Conclusions:
- Netrin-1 is a bifunctional guidance cue in the vertebrate nervous system.
- This bifunctionality is conserved across species, as seen with UNC-6 in C. elegans.
- Netrin-1 plays a critical role in establishing precise neuronal connections.
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