Neuronal target identification requires AHA-1-mediated fine-tuning of Wnt signaling in C. elegans

PLoS Genet. 2013 Jun;9(6):e1003618. doi: 10.1371/journal.pgen.1003618. Epub 2013 Jun 27.

Abstract

Electrical synaptic transmission through gap junctions is a vital mode of intercellular communication in the nervous system. The mechanism by which reciprocal target cells find each other during the formation of gap junctions, however, is poorly understood. Here we show that gap junctions are formed between BDU interneurons and PLM mechanoreceptors in C. elegans and the connectivity of BDU with PLM is influenced by Wnt signaling. We further identified two PAS-bHLH family transcription factors, AHA-1 and AHR-1, which function cell-autonomously within BDU and PLM to facilitate the target identification process. aha-1 and ahr-1 act genetically upstream of cam-1. CAM-1, a membrane-bound receptor tyrosine kinase, is present on both BDU and PLM cells and likely serves as a Wnt antagonist. By binding to a cis-regulatory element in the cam-1 promoter, AHA-1 enhances cam-1 transcription. Our study reveals a Wnt-dependent fine-tuning mechanism that is crucial for mutual target cell identification during the formation of gap junction connections.

Publication types

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

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / physiology
  • Caenorhabditis elegans Proteins / genetics*
  • Cell Communication / genetics
  • Cell Communication / physiology
  • DNA-Binding Proteins / genetics
  • Electrical Synapses / genetics
  • Electrical Synapses / physiology
  • Gap Junctions / genetics
  • Gap Junctions / physiology
  • Interneurons / physiology
  • Mechanoreceptors / physiology
  • Promoter Regions, Genetic
  • Receptor Tyrosine Kinase-like Orphan Receptors / genetics*
  • Receptors, Aryl Hydrocarbon / genetics*
  • Synaptic Transmission / genetics*
  • Synaptic Transmission / physiology
  • Wnt Signaling Pathway / genetics*

Substances

  • AHA-1 protein, C elegans
  • Basic Helix-Loop-Helix Transcription Factors
  • Caenorhabditis elegans Proteins
  • DNA-Binding Proteins
  • Receptors, Aryl Hydrocarbon
  • ahr-1 protein, C elegans
  • CAM-1 protein, C elegans
  • Receptor Tyrosine Kinase-like Orphan Receptors