Ephrin-A5 Exerts Positive or Inhibitory Effects on Distinct Subsets of EphA4-Positive Motor Neurons

Johann Eberhart, Jason Barr, Sinead O'Connell, Alleda Flagg, Mary E. Swartz, Karina S. Cramer, Kathryn W. Tosney, Elena B. Pasquale, Catherine E. Krull

Research output: Contribution to journalArticlepeer-review

82 Scopus citations

Abstract

Eph receptor tyrosine kinases and ephrins are required for axon patterning and plasticity in the developing nervous system. Typically, Eph-ephrin interactions promote inhibitory events; for example, prohibiting the entry of neural cells into certain embryonic territories. Here, we show that distinct subsets of motor neurons that express EphA4 respond differently to ephrin-A5. EphA4-positive LMC(l) axons avoid entering ephrin-A5-positive hindlimb mesoderm. In contrast, EphA4-positive MMC(m) axons extend through ephrin-A5-positive rostral half-sclerotome. Blocking EphA4 activation in MMC(m) neurons or expanding the domain of ephrin-A5 expression in the somite results in the aberrant growth of MMC(m) axons into the caudal half-sclerotome. Moreover, premature expression of EphA4 in MMC(m) neurons leads to a portion of their axons growing into novel ephrin-A5-positive territories. Together, these results indicate that EphA4-ephrin-A5 signaling acts in a positive manner to constrain MMC(m) axons to the rostral half-sclerotome. Furthermore, we show that Eph activation localizes to distinct subcellular compartments of LMC(l) and MMC(m) neurons, consistent with distinct EphA4 signaling cascades in these neuronal subpopulations.

Original languageEnglish (US)
Pages (from-to)1070-1078
Number of pages9
JournalJournal of Neuroscience
Volume24
Issue number5
DOIs
StatePublished - Feb 4 2004
Externally publishedYes

Keywords

  • Chick
  • Electroporation
  • Eph
  • Ephrin
  • Mesoderm
  • Motor axon

ASJC Scopus subject areas

  • Neuroscience(all)

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