ZFIN ID: ZDB-PUB-050318-13
Genetic screens for genes controlling motor nerve-muscle development and interactions
Birely, J., Schneider, V.A., Santana, E., Dosch, R., Wagner, D.S., Mullins, M.C., and Granato, M.
Date: 2005
Source: Developmental Biology   280(1): 162-176 (Journal)
Registered Authors: Dosch, Roland, Granato, Michael, Mullins, Mary C., Santana, Evelyn, Schneider, Valerie, Wagner, Daniel
Keywords: Zebrafish; Mutagenesis; Genetic screen; Motor neuron; Adaxial cells; Slow-twitch muscle fibers; Axonal pathfinding; Axonal guidance; Motoneurons
MeSH Terms:
  • Animals
  • Cell Differentiation/physiology
  • Cell Movement/genetics
  • Chimera
  • Embryo, Nonmammalian/anatomy & histology
  • Embryo, Nonmammalian/physiology
  • Genetic Testing*
  • Mesoderm/cytology
  • Morphogenesis/genetics*
  • Motor Neurons/cytology
  • Motor Neurons/physiology*
  • Muscle Development/genetics*
  • Muscle Development/physiology
  • Muscle, Skeletal/cytology
  • Muscle, Skeletal/physiology*
  • Mutation
  • Phenotype
  • Zebrafish/embryology
PubMed: 15766756 Full text @ Dev. Biol.
Motor growth cones navigate long and complex trajectories to connect with their muscle targets. Experimental studies have shown that this guidance process critically depends on extrinsic cues. In the zebrafish embryo, a subset of mesodermal cells, the adaxial cells, delineates the prospective path of pioneering motor growth cones. Genetic ablation of adaxial cells causes profound pathfinding defects, suggesting the existence of adaxial cell derived guidance factors. Intriguingly, adaxial cells are themselves migratory, and as growth cones approach they migrate away from the prospective axonal path to the lateral surface of the myotome, where they develop into slow-twitching muscle fibers. Genetic screens in embryos stained with an antibody cocktail identified mutants with specific defects in differentiation and migration of adaxial cells/slow muscle fibers, as well as mutants with specific defects in axonal pathfinding, including exit from the spinal cord and pathway selection. Together, the genes underlying these mutant phenotypes define pathways essential for nerve and muscle development and interactions between these two cell types.