Drosophila semaphorin2b is required for the axon guidance of a subset of embryonic neurons

Dev Dyn. 2013 Jul;242(7):861-73. doi: 10.1002/dvdy.23979. Epub 2013 May 30.


Background: The process of axon guidance is important in establishing functional neural circuits. The differential expression of cell-autonomous axon guidance factors is crucial for allowing axons of different neurons to take unique trajectories in response to spatially and temporally restricted cell non-autonomous axon guidance factors. A key motivation in the field is to provide adequate explanations for axon behavior with respect to the differential expression of these factors.

Results: We report the characterization of a predicted secreted semaphorin family member, semaphorin2b (Sema-2b) in Drosophila embryonic axon guidance. Misexpression of Sema-2b in neurons causes highly penetrant axon guidance phenotypes in specific longitudinal and motoneuron pathways; however, expression of Sema-2b in muscles traversed by these motoneurons has no effect on axon guidance. In Sema-2b loss-of-function embryos, specific motoneuron and interneuron axon pathways display guidance defects. Specific visualization of the neurons that normally express Sema-2b reveals that this neuronal cohort is strongly affected by Sema-2b loss-of-function alleles.

Conclusions: While secreted semaphorins have been implicated as cell non-autonomous chemorepellants in a variety of contexts, here we report previously undescribed Sema-2b loss-of-function and misexpression phenotypes that are consistent with a cell-autonomous role for Sema-2b.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism
  • Drosophila / embryology*
  • Drosophila / metabolism*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Gene Expression Regulation, Developmental / genetics
  • Gene Expression Regulation, Developmental / physiology
  • Neurons / cytology*
  • Neurons / metabolism*
  • Semaphorins / genetics
  • Semaphorins / metabolism*


  • Drosophila Proteins
  • Semaphorins