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Updated: May 16, 2026
Assaying the Ability of Diffusible Signaling Molecules to Reorient Embryonic Spinal Commissural Axons
Published on: March 8, 2010
Discoidin domain receptors guide axons along longitudinal tracts in C. elegans
Thomas Unsoeld1, Ja-On Park, Harald Hutter
1Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.
Abstract:
Discoidin domain receptors are a family of receptor tyrosine kinases activated by collagens. Here we characterize the role of the two discoidin domain receptors, ddr-1 and ddr-2, of the nematode C. elegans during nervous system development. ddr-2 mutant animals exhibit axon guidance defects in major longitudinal tracts most prominently in the ventral nerve cord. ddr-1 mutants show no significant phenotype on their own but significantly enhance guidance defects of ddr-2 in double mutants. ddr-1 and ddr-2 GFP-reporter constructs are expressed in neurons with axons in all affected nerve tracts. DDR-1 and DDR-2 GFP fusion proteins localize to axons. DDR-2 is required cell-autonomously in the PVPR neuron for the guidance of the PVPR pioneer axon, which establishes the left ventral nerve cord tract and serves as substrate for later outgrowing follower axons. Our results provide the first insight on discoidin domain receptor function in invertebrates and establish a novel role for discoidin domain receptors in axon navigation and axon tract formation.
Insights
Discoidin domain receptors (DDRs) are crucial for nervous system development in C. elegans. DDR-2 and DDR-1 are essential for proper axon guidance and the formation of nerve tracts.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Discoidin domain receptors (DDRs) are receptor tyrosine kinases activated by collagens.
- Their role in invertebrate nervous system development is largely unknown.
Purpose of the Study:
- To investigate the function of DDR-1 and DDR-2 in the nematode C. elegans during nervous system development.
- To elucidate the specific roles of these receptors in axon guidance and nerve tract formation.
Main Methods:
- Utilized C. elegans mutants for ddr-1 and ddr-2.
- Employed GFP-reporter constructs to visualize DDR-1 and DDR-2 expression and localization in neurons.
- Performed genetic analysis of double mutants to assess synergistic effects.
Main Results:
- Mutations in ddr-2 led to significant axon guidance defects, particularly in the ventral nerve cord.
- ddr-1 mutants showed no phenotype alone but exacerbated ddr-2 defects when combined.
- DDR-1 and DDR-2 are expressed in neurons and localize to axons, with DDR-2 playing a cell-autonomous role in pioneer axon guidance.
Conclusions:
- This study provides the first evidence of discoidin domain receptor function in invertebrates.
- Discoidin domain receptors play a novel and critical role in axon navigation and the establishment of nerve tracts.
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