Hox Genes Promote Neuronal Subtype Diversification through Posterior Induction in Caenorhabditis elegans

Neuron. 2015 Nov 4;88(3):514-27. doi: 10.1016/j.neuron.2015.09.049.


Although Hox genes specify the differentiation of neuronal subtypes along the anterior-posterior axis, their mode of action is not entirely understood. Using two subtypes of the touch receptor neurons (TRNs) in C. elegans, we found that a "posterior induction" mechanism underlies the Hox control of terminal neuronal differentiation. The anterior subtype maintains a default TRN state, whereas the posterior subtype undergoes further morphological and transcriptional specification induced by the posterior Hox proteins, mainly EGL-5/Abd-B. Misexpression of the posterior Hox proteins transformed the anterior TRN subtype toward a posterior identity both morphologically and genetically. The specification of the posterior subtype requires EGL-5-induced repression of TALE cofactors, which antagonize EGL-5 functions, and the activation of rfip-1, a component of recycling endosomes, which mediates Hox activities by promoting subtype-specific neurite outgrowth. Finally, EGL-5 is required for subtype-specific circuit formation by acting in both the sensory neuron and downstream interneuron to promote functional connectivity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / growth & development*
  • Caenorhabditis elegans Proteins / genetics*
  • Genes, Homeobox / genetics*
  • Homeodomain Proteins / genetics*
  • Interneurons / physiology*
  • Mutation / genetics
  • Sensory Receptor Cells / physiology*
  • Transcription Factors / genetics*


  • Caenorhabditis elegans Proteins
  • Egl-5 protein, C elegans
  • Homeodomain Proteins
  • Transcription Factors