A microRNA controlling left/right neuronal asymmetry in Caenorhabditis elegans

Nature. 2003 Dec 18;426(6968):845-9. doi: 10.1038/nature02255. Epub 2003 Dec 14.


How left/right functional asymmetry is layered on top of an anatomically symmetrical nervous system is poorly understood. In the nematode Caenorhabditis elegans, two morphologically bilateral taste receptor neurons, ASE left (ASEL) and ASE right (ASER), display a left/right asymmetrical expression pattern of putative chemoreceptor genes that correlates with a diversification of chemosensory specificities. Here we show that a previously undefined microRNA termed lsy-6 controls this neuronal left/right asymmetry of chemosensory receptor expression. lsy-6 mutants that we retrieved from a genetic screen for defects in neuronal left/right asymmetry display a loss of the ASEL-specific chemoreceptor expression profile with a concomitant gain of the ASER-specific profile. A lsy-6 reporter gene construct is expressed in less than ten neurons including ASEL, but not ASER. lsy-6 exerts its effects on ASEL through repression of cog-1, an Nkx-type homeobox gene, which contains a lsy-6 complementary site in its 3' untranslated region and that has been shown to control ASE-specific chemoreceptor expression profiles. lsy-6 is the first microRNA to our knowledge with a role in neuronal patterning, providing new insights into left/right axis formation.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3' Untranslated Regions / genetics
  • Animals
  • Base Sequence
  • Body Patterning*
  • Caenorhabditis elegans / anatomy & histology
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics*
  • Cell Differentiation
  • Cell Lineage
  • Gene Expression Regulation
  • Genes, Helminth / genetics*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Nervous System / cytology
  • Nervous System / embryology*
  • Nervous System / metabolism*


  • 3' Untranslated Regions
  • MicroRNAs