Specific expression of channelrhodopsin-2 in single neurons of Caenorhabditis elegans

PLoS One. 2012;7(8):e43164. doi: 10.1371/journal.pone.0043164. Epub 2012 Aug 30.

Abstract

Optogenetic approaches using light-activated proteins like Channelrhodopsin-2 (ChR2) enable investigating the function of populations of neurons in live Caenorhabditis elegans (and other) animals, as ChR2 expression can be targeted to these cells using specific promoters. Sub-populations of these neurons, or even single cells, can be further addressed by restricting the illumination to the cell of interest. However, this is technically demanding, particularly in free moving animals. Thus, it would be helpful if expression of ChR2 could be restricted to single neurons or neuron pairs, as even wide-field illumination would photostimulate only this particular cell. To this end we adopted the use of Cre or FLP recombinases and conditional ChR2 expression at the intersection of two promoter expression domains, i.e. in the cell of interest only. Success of this method depends on precise knowledge of the individual promoters' expression patterns and on relative expression levels of recombinase and ChR2. A bicistronic expression cassette with GFP helps to identify the correct expression pattern. Here we show specific expression in the AVA reverse command neurons and the aversive polymodal sensory ASH neurons. This approach shall enable to generate strains for optogenetic manipulation of each of the 302 C. elegans neurons. This may eventually allow to model the C. elegans nervous system in its entirety, based on functional data for each neuron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / biosynthesis*
  • Caenorhabditis elegans Proteins / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Green Fluorescent Proteins / metabolism
  • Microscopy, Fluorescence / methods
  • Models, Biological
  • Models, Genetic
  • Neurons / metabolism*
  • Plasmids / metabolism
  • Promoter Regions, Genetic
  • Recombinases / metabolism
  • Rhodopsin / biosynthesis*
  • Rhodopsin / genetics
  • Transgenes

Substances

  • Caenorhabditis elegans Proteins
  • Recombinases
  • Green Fluorescent Proteins
  • Rhodopsin

Grant support

This study was supported by Schram Foundation grant T287/18545/2008, Deutsche Forschungsgemeinschaft grants EXC114, SFB807-P11, GO1011/3-1, and Human Frontier Science Program Organization Long Term Fellowship LTF 548/2009-L. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.