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Semaphorin 3E/collapsin-5 inhibits growing retinal axons
Karin Steinbach1, Hansjürgen Volkmer, Burkhard Schlosshauer
1NMI Naturwissenschaftliches und Medizinisches Institut, Universität Tübingen, Markwiesenstrasse 55, D-72770, Reutlingen, Germany.
Experimental Cell Research
|September 6, 2002
Summary
Chick semaphorin Sema3E/collapsin-5 acts as a repulsive cue, guiding retinal ganglion cell (RGC) axon growth. This molecule restricts RGC axons to the optic fiber layer during retinal development.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Neural network formation relies on directed neurite extension.
- Retinal ganglion cells (RGCs) are a model for studying axon guidance.
Purpose of the Study:
- To identify novel repulsive cues involved in RGC axon pathfinding.
- To characterize the role of chick semaphorin Sema3E/collapsin-5 in retinal development.
Main Methods:
- Polymerase chain reaction (PCR) for mRNA expression analysis.
- In vitro time-lapse video recording of chick neuronal cultures.
- Alkaline phosphatase fusion proteins for receptor site visualization.
Main Results:
- Sema3E/collapsin-5 expression peaks during intraretinal axon growth.
- Sema3E/collapsin-5 specifically collapses RGC growth cones, not dorsal root ganglia (DRG) neurons.
- Receptor sites for Sema3E/collapsin-5 are present in the optic fiber layer.
Conclusions:
- Chick Sema3E/collapsin-5 functions as a repulsive guidance cue for RGC axons.
- Sema3E/collapsin-5 plays a role in restricting RGC axon growth to the optic fiber layer.
- Sema3E/collapsin-5 exhibits specificity distinct from Sema3A/collapsin-1.