PUBLICATION

Neuromuscular synapses can form in vivo by incorporation of initially aneural postsynaptic specializations

Authors
Flanagan-Steet, H., Fox, M.A., Meyer, D., and Sanes, J.R.
ID
ZDB-PUB-050920-3
Date
2005
Source
Development (Cambridge, England)   132(20): 4471-4481 (Journal)
Registered Authors
Flanagan-Steet, Heather, Meyer, Dirk
Keywords
Acetylcholine receptor, Muscle, Neuromuscular junction, Zebrafish
MeSH Terms
  • Animals
  • Green Fluorescent Proteins/genetics
  • Green Fluorescent Proteins/metabolism
  • Mice
  • Mice, Transgenic
  • Motor Neurons/cytology
  • Motor Neurons/metabolism
  • Muscles/cytology*
  • Muscles/embryology
  • Muscles/metabolism
  • Neurites
  • Neuromuscular Junction/cytology*
  • Neuromuscular Junction/embryology
  • Neuromuscular Junction/genetics
  • Neuromuscular Junction/metabolism
  • Receptors, Cholinergic/metabolism
  • Zebrafish*/embryology
  • Zebrafish*/genetics
  • Zebrafish*/metabolism
PubMed
16162647 Full text @ Development
Abstract
Synapse formation requires the coordination of pre- and postsynaptic differentiation. An unresolved question is which steps in the process require interactions between pre- and postsynaptic cells, and which proceed cell-autonomously. One current model is that factors released from presynaptic axons organize postsynaptic differentiation directly beneath the nerve terminal. Here, we used neuromuscular junctions (NMJs) of the zebrafish primary motor system to test this model. Clusters of neurotransmitter (acetylcholine) receptors (AChRs) formed in the central region of the myotome, destined to be synapse-rich, before axons extended and even when axon extension was prevented. Time-lapse imaging revealed that pre-existing clusters on early-born slow (adaxial) muscle fibers were incorporated into NMJs as axons advanced. Axons were, however, required for the subsequent remodeling and selective stabilization of synaptic clusters that precisely appose post- to presynaptic elements. Thus, motor axons are dispensable for the initial stages of postsynaptic differentiation but are required for later stages. Moreover, many AChR clusters on later-born fast muscle fibers formed at sites that had already been contacted by axons, suggesting heterogeneity in the signaling mechanisms leading to synapse formation by a single axon.
Genes / Markers
Figures
Figure Gallery
Expression
Phenotype
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
Errata and Notes