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J Neurosci. 2013 Jan 16;33(3):936-49. doi: 10.1523/JNEUROSCI.2749-12.2013.

Two novel DEG/ENaC channel subunits expressed in glia are needed for nose-touch sensitivity in Caenorhabditis elegans.

Author information

1
Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.

Abstract

Neuronal DEG/ENaC (degenerin and epithelial Na(+) channel) Na(+) channels have been implicated in touch sensation. For example, MEC-4 is expressed in touch neurons in Caenorhabditis elegans and mediates gentle-touch response. Similarly, homologous mammalian ASIC2 and ASIC3 are expressed in sensory neurons and produce touch phenotypes when knocked out in mice. Here, we show that novel DEG/ENaC subunits DELM-1 and DELM-2 (degenerin-like channel mechanosensory linked-1 and degenerin-like channel mechanosensory linked-2) are expressed in glia associated with touch neurons in C. elegans and that their knock-out causes defects in mechanosensory behaviors related to nose touch and foraging, which are mediated by OLQ and IL1 sensory neurons. Cell-specific rescue supports that DELM-1 and DELM-2 are required cell-autonomously in glia to orchestrate mechanosensory behaviors. Electron microscopy reveals that in delm-1 knock-outs, OLQ and IL1 sensory neurons and associated glia are structurally normal. Furthermore, we show that knock-out of DELM-1 and DELM-2 does not disrupt the expression or cellular localization of TRPA-1, a TRP channel needed in OLQ and IL1 neurons for touch behaviors. Rather, rescue of the delm-1 nose-touch-insensitive phenotype by expression of a K(+) channel in socket glia and of a cationic channel in OLQ neurons suggests that DELM channels set basal neuronal excitability. Together, our data show that DELM-1 and DELM-2 are expressed in glia associated with touch neurons where they are not needed for neuronal structural integrity or cellular distribution of neuronal sensory channels, but rather for their function.

PMID:
23325233
PMCID:
PMC3711640
DOI:
10.1523/JNEUROSCI.2749-12.2013
[Indexed for MEDLINE]
Free PMC Article

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