Muscle contractions guide rohon-beard peripheral sensory axons
Jeremiah D Paulus1, Gregory B Willer, Jason R Willer
1Departments of Zoology and Anatomy and Cell and Molecular Biology Training Program, University of Wisconsin, Madison, Wisconsin 53706, USA.
Summary
Muscle contractions guide sensory neuron (Rohon-Beard axon) development in zebrafish. Mechanical forces from muscle movement are essential for proper axon pathfinding in vivo, influencing their trajectory and repulsion.
Area of Science:
- Neuroscience
- Developmental Biology
- Biophysics
Background:
- Neuronal axon guidance is crucial for nervous system development.
- Molecular cues are known to guide axons, but the role of mechanical forces in vivo remains unclear.
- Previous in vitro studies suggest mechanical stimulation influences axon growth.
Purpose of the Study:
- To investigate the role of muscle contractions in guiding zebrafish peripheral Rohon-Beard (RB) sensory axons in vivo.
- To determine if mechanical forces generated by muscle activity are essential for sensory axon pathfinding.
Main Methods:
- Analysis of zebrafish mutants affecting muscle contraction (titin a, hedgehog signaling, nicotinic acetylcholine receptor).
- Observation of RB axon guidance in these mutants.
- Experimental manipulation by embedding embryos in agarose to restrict muscle movement.
Main Results:
- RB axon guidance defects were observed in muscle contraction mutants, correlating with the degree of muscle contraction loss.
- Peripheral RB axons in mutants showed altered trajectories (longitudinal instead of ventral) and failed to repel each other.
- Restricting embryonic movement with agarose mimicked these axon guidance defects.
Conclusions:
- Mechanical forces generated by muscle contractions are necessary for proper in vivo sensory axon pathfinding.
- Muscle activity plays a significant role in guiding the development of the nervous system.
- This study highlights the importance of biomechanical factors in neurodevelopment.
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