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ZFIN ID: ZDB-PUB-080714-7
Embryonic motor axon development in the severe SMA mouse
McGovern, V.L., Gavrilina, T.O., Beattie, C.E., and Burghes, A.H.
Date: 2008
Source: Human molecular genetics   17(18): 2900-2909 (Journal)
Registered Authors: Beattie, Christine
Keywords: none
MeSH Terms:
  • Animals
  • Axons/chemistry
  • Axons/pathology
  • Axons/physiology*
  • Cyclic AMP Response Element-Binding Protein/genetics
  • Cyclic AMP Response Element-Binding Protein/metabolism
  • Disease Models, Animal
  • Female
  • Humans
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Motor Neurons/chemistry
  • Motor Neurons/cytology
  • Motor Neurons/pathology
  • Motor Neurons/physiology*
  • Muscular Atrophy, Spinal/embryology*
  • Muscular Atrophy, Spinal/pathology
  • Muscular Atrophy, Spinal/physiopathology
  • Nerve Tissue Proteins/genetics
  • Nerve Tissue Proteins/metabolism
  • Neuromuscular Junction/embryology
  • Neuromuscular Junction/growth & development*
  • Neuromuscular Junction/pathology
  • Neuromuscular Junction/physiopathology
  • RNA-Binding Proteins/genetics
  • RNA-Binding Proteins/metabolism
  • SMN Complex Proteins
  • Spinal Cord/embryology
  • Spinal Cord/growth & development*
  • Spinal Cord/pathology
  • Spinal Cord/physiopathology
  • Survival of Motor Neuron 1 Protein
PubMed: 18603534 Full text @ Hum. Mol. Genet.
Spinal Muscular Atrophy (SMA) is caused by reduced levels of Survival Motor Neuron (SMN) protein. Previously, cultured SMA motor neurons showed reduced growth cone size and axonal length. Furthermore, reduction of SMN in zebrafish resulted in truncation followed by branching of motor neuron axons. In this study, motor neurons labeled with GFP were examined in SMA mice from embryonic day 10.5 (e10.5) to postnatal day two (PND02). SMA motor axons showed no defect in axonal formation or outgrowth at any stage of development. However, a significant increase in synapses lacking motor axon input was detected in embryonic SMA mice. Therefore, one of the earliest detectable morphological defects in the SMA mice is the loss of synapse occupation by motor axons. This indicates that in severe SMA mice there are no defects in motor axon formation however, we find evidence of denervation in embryogenesis.