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Semaphorin II can function as a selective inhibitor of specific synaptic arborizations
D J Matthes1, H Sink, A L Kolodkin
1Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
Cell
|May 19, 1995
Summary
Semaphorin II, a secreted protein, acts in vivo to inhibit specific synaptic connections during nerve development. This research clarifies its role in guiding neuronal wiring and synapse formation in Drosophila.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Semaphorins are crucial signaling molecules in neural development.
- Previous studies identified roles for semaphorin I (transmembrane) and chick collapsin (secreted) in growth cone guidance and collapse.
- Semaphorin II is a secreted semaphorin transiently expressed in Drosophila during motoneuron development.
Purpose of the Study:
- To investigate the in vivo function of semaphorin II during Drosophila motoneuron outgrowth and synapse formation.
- To determine if semaphorin II acts as a target-derived signal to regulate synaptic arbor formation.
Main Methods:
- Generated transgenic Drosophila with ectopic semaphorin II expression in muscles.
- Analyzed the effects of ectopic semaphorin II on motoneuron outgrowth and synaptic terminal arbor formation in vivo.
Main Results:
- Ectopic expression of semaphorin II by muscles inhibited the formation of specific synaptic terminal arbors.
- Semaphorin II functions in vivo as a target-derived signal.
- Demonstrated selective inhibition of synaptic branching by semaphorin II.
Conclusions:
- Semaphorin II plays a critical role in regulating synaptic architecture during development.
- This secreted semaphorin acts as a target-derived cue to prevent inappropriate synapse formation.
- Findings contribute to understanding the molecular mechanisms of neural wiring.
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