PUBLICATION

Semaphorin 5A is a bifunctional axon guidance cue for axial motoneurons in vivo

Authors
Hilario, J., Rodino-Klapac, L.R., Wang, C., and Beattie, C.E.
ID
ZDB-PUB-081217-16
Date
2009
Source
Developmental Biology   326(1): 190-200 (Journal)
Registered Authors
Beattie, Christine, Hilario, Jona, Wang, Chunping
Keywords
zebrafish, motor axon guidance, morpholinos, thrombospondin repeat domain
MeSH Terms
  • Animals
  • Axons/physiology*
  • Cell Movement/physiology
  • Embryo, Nonmammalian/physiology
  • Growth Cones/physiology
  • Membrane Proteins/genetics
  • Membrane Proteins/physiology*
  • Motor Neurons/cytology
  • Motor Neurons/physiology*
  • Nerve Tissue Proteins/genetics
  • Nerve Tissue Proteins/physiology
  • Neurogenesis/physiology
  • Protein Structure, Tertiary
  • RNA, Messenger/genetics
  • Rats
  • Semaphorins/genetics
  • Semaphorins/physiology*
  • Zebrafish/embryology
  • Zebrafish/physiology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
PubMed
19059233 Full text @ Dev. Biol.
Abstract
Semaphorins are a large class of proteins that function throughout the nervous system to guide axons. It had previously been shown that Semaphorin 5A (Sema5A) was a bifunctional axon guidance cue for mammalian midbrain neurons. We found that zebrafish sema5A was expressed in myotomes during the period of motor axon outgrowth. To determine whether Sema5A functioned in motor axon guidance, we knocked down Sema5A, which resulted in two phenotypes: a delay in motor axon extension into the ventral myotome and aberrant branching of these motor axons. Both phenotypes were rescued by injection of full-length rat Sema5A mRNA. However, adding back RNA encoding the sema domain alone significantly rescued the branching phenotype in sema5A morphants. Conversely, adding back RNA encoding the thrombospondin repeat (TSR) domain alone into sema5A morphants exclusively rescued delay in ventral motor axon extension. Together, these data show that Sema5A is a bifunctional axon guidance cue for vertebrate motor axons in vivo. The TSR domain promotes growth of developing motor axons into the ventral myotome whereas the sema domain mediates repulsion and keeps these motor axons from branching into surrounding myotome regions.
Genes / Markers
Figures
Expression
Phenotype
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
Errata and Notes