Suppressors of ectopic UNC-5 growth cone steering identify eight genes involved in axon guidance in Caenorhabditis elegans

Dev Biol. 1998 Feb 1;194(1):72-85. doi: 10.1006/dbio.1997.8790.


The UNC-5 guidance receptor, in response to the UNC-6/netrin path cue, orients growing axons in a dorsal direction along the epidermis of Caenorhabditis elegans. When ectopically expressed in the touch neurons, which normally extend ventrally or longitudinally, UNC-5 is able to reorient their axons toward the dorsal side in an UNC-6-dependent manner. This forms the basis of a genetic screen to identify other mutations that, like unc-6 mutations, suppress unc-5-induced growth cone guidance. These mutations may identify new components required for pioneer axon guidance by unc-5. In this paper, we describe eight genes that are required for ectopic unc-5-induced growth cone steering. Mutations in four of these identify the previously known axon guidance genes unc-6, unc-40, unc-34, and unc-44 and mutations in four others identify the novel genes unc-129, seu-1, seu-2, and seu-3. Several of these mutations cause axon guidance defects similar to those found in unc-5 mutants. We propose that some or all of these genes may function in a developmentally important unc-5 signaling pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ankyrins / physiology
  • Axons / physiology*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / physiology
  • Caenorhabditis elegans Proteins*
  • Cytoskeleton / physiology
  • Genes, Helminth*
  • Helminth Proteins / physiology*
  • Membrane Proteins / physiology*
  • Mutation
  • Receptors, Cell Surface*
  • Receptors, Growth Factor / physiology*


  • Ankyrins
  • Caenorhabditis elegans Proteins
  • Helminth Proteins
  • Membrane Proteins
  • Receptors, Cell Surface
  • Receptors, Growth Factor
  • UNC-5 protein, C elegans