Neurexin directs partner-specific synaptic connectivity in C. elegans

Elife. 2018 Jul 24;7:e35692. doi: 10.7554/eLife.35692.

Abstract

In neural circuits, individual neurons often make projections onto multiple postsynaptic partners. Here, we investigate molecular mechanisms by which these divergent connections are generated, using dyadic synapses in C. elegans as a model. We report that C. elegans nrx-1/neurexin directs divergent connectivity through differential actions at synapses with partnering neurons and muscles. We show that cholinergic outputs onto neurons are, unexpectedly, located at previously undefined spine-like protrusions from GABAergic dendrites. Both these spine-like features and cholinergic receptor clustering are strikingly disrupted in the absence of nrx-1. Excitatory transmission onto GABAergic neurons, but not neuromuscular transmission, is also disrupted. Our data indicate that NRX-1 located at presynaptic sites specifically directs postsynaptic development in GABAergic neurons. Our findings provide evidence that individual neurons can direct differential patterns of connectivity with their post-synaptic partners through partner-specific utilization of synaptic organizers, offering a novel view into molecular control of divergent connectivity.

Keywords: AChR; C. elegans; dendritic spine; neuroscience; neurotransmission; nicotinic acetylcholine receptor; synapse; synaptic divergence.

Publication types

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

MeSH terms

  • Acetylcholine / metabolism
  • Animals
  • Animals, Genetically Modified / genetics
  • Animals, Genetically Modified / growth & development
  • Animals, Genetically Modified / metabolism*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Adhesion Molecules, Neuronal / genetics
  • Cell Adhesion Molecules, Neuronal / metabolism*
  • GABAergic Neurons / cytology
  • GABAergic Neurons / physiology*
  • Neuromuscular Junction / cytology
  • Neuromuscular Junction / physiology*
  • Receptors, Cholinergic
  • Receptors, Nicotinic / metabolism
  • Synapses
  • Synaptic Transmission*

Substances

  • Caenorhabditis elegans Proteins
  • Cell Adhesion Molecules, Neuronal
  • Receptors, Cholinergic
  • Receptors, Nicotinic
  • nrx-1 protein, C elegans
  • Acetylcholine