PUBLICATION

Activity-dependent competition regulates motor neuron axon pathfinding via PlexinA3

Authors
Plazas, P.V., Nicol, X., and Spitzer, N.C.
ID
ZDB-PUB-130124-2
Date
2013
Source
Proceedings of the National Academy of Sciences of the United States of America   110(4): 1524-1529 (Journal)
Registered Authors
Keywords
calcium transients, spontaneous activity, stochastic expression
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Axons/physiology
  • Calcium Signaling
  • Gene Knockdown Techniques
  • Humans
  • Motor Neurons/physiology*
  • Neural Pathways/cytology
  • Neural Pathways/embryology
  • Neural Pathways/physiology
  • Potassium Channels, Inwardly Rectifying/genetics
  • Potassium Channels, Inwardly Rectifying/metabolism
  • Receptors, Cell Surface/antagonists & inhibitors
  • Receptors, Cell Surface/genetics
  • Receptors, Cell Surface/physiology*
  • Recombinant Proteins/genetics
  • Recombinant Proteins/metabolism
  • Synaptic Transmission
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish/physiology
  • Zebrafish Proteins/antagonists & inhibitors
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
PubMed
23302694 Full text @ Proc. Natl. Acad. Sci. USA
Abstract

The role of electrical activity in axon guidance has been extensively studied in vitro. To better understand its role in the intact nervous system, we imaged intracellular Ca2+ in zebrafish primary motor neurons (PMN) during axon pathfinding in vivo. We found that PMN generate specific patterns of Ca2+ spikes at different developmental stages. Spikes arose in the distal axon of PMN and were propagated to the cell body. Suppression of Ca2+ spiking activity in single PMN led to stereotyped errors, but silencing all electrical activity had no effect on axon guidance, indicating that an activity-based competition rule regulates this process. This competition was not mediated by synaptic transmission. Combination of PlexinA3 knockdown with suppression of Ca2+ activity in single PMN produced a synergistic increase in the incidence of pathfinding errors. However, expression of PlexinA3 transcripts was not regulated by activity. Our results provide an in vivo demonstration of the intersection of spontaneous electrical activity with the PlexinA3 guidance molecule receptor in regulation of axon pathfinding.

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