ZFIN ID: ZDB-PUB-091023-70
Muscle contractions guide Rohon-Beard peripheral sensory axons
Paulus, J.D., Willer, G.B., Willer, J.R., Gregg, R.G., and Halloran, M.C.
Date: 2009
Source: The Journal of neuroscience : the official journal of the Society for Neuroscience   29(42): 13190-13201 (Journal)
Registered Authors: Gregg, Ronald G., Halloran, Mary, Paulus, Jeremiah, Willer, Greg
Keywords: none
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Axons/drug effects
  • Axons/physiology*
  • Body Patterning/drug effects
  • Body Patterning/genetics
  • Chondroitin ABC Lyase/pharmacology
  • Connectin
  • Embryo, Nonmammalian/drug effects
  • Gene Expression Regulation, Developmental
  • Green Fluorescent Proteins/genetics
  • Hedgehog Proteins/metabolism
  • Muscle Contraction/drug effects
  • Muscle Contraction/physiology*
  • Muscle Proteins/genetics
  • Muscle, Skeletal/drug effects
  • Muscle, Skeletal/embryology
  • Muscle, Skeletal/physiology*
  • Mutation/genetics
  • Neuromuscular Nondepolarizing Agents/pharmacology
  • Peripheral Nerves/cytology*
  • Protein Kinases/genetics
  • Sensory Receptor Cells/cytology*
  • Sensory Receptor Cells/drug effects
  • Signal Transduction/drug effects
  • Signal Transduction/physiology
  • Time Factors
  • Tubocurarine/pharmacology
  • Zebrafish
  • Zebrafish Proteins/genetics
PubMed: 19846707 Full text @ J. Neurosci.
Multiple molecular cues guide neuronal axons to their targets during development. Previous studies in vitro have shown that mechanical stimulation also can affect axon growth; however, whether mechanical force contributes to axon guidance in vivo is unknown. We investigated the role of muscle contractions in the guidance of zebrafish peripheral Rohon-Beard (RB) sensory axons in vivo. We analyzed several mutants that affect muscle contraction through different molecular pathways, including a new mutant allele of the titin a (pik) gene, mutants that affect the hedgehog signaling pathway, and a nicotinic acetylcholine receptor mutant. We found RB axon defects in these mutants, the severity of which appeared to correlate with the extent of muscle contraction loss. These axons extend between the muscle and skin and normally have ventral trajectories and repel each other on contact. RB peripheral axons in muscle mutants extend longitudinally instead of ventrally, and the axons fail to repel one another on contact. In addition, we showed that limiting muscle movements by embedding embryos in agarose caused similar defects in peripheral RB axon guidance. This work suggests that the mechanical forces generated by muscle contractions are necessary for proper sensory axon pathfinding in vivo.