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Updated: Jun 25, 2026

A Molecular Readout of Long-term Olfactory Adaptation in C. elegans
Published on: December 22, 2012
GPC-1, a G protein gamma-subunit, regulates olfactory adaptation in Caenorhabditis elegans
Koji Yamada1, Takaaki Hirotsu, Masahiro Matsuki
1Department of Biophysics and Biochemistry, Molecular Genetics Research Laboratory, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
Abstract:
Caenorhabditis elegans genome carries two Ggamma genes, gpc-1 and gpc-2, and two Gbeta genes, gpb-1 and gpb-2. Of these, gpc-2 and gpb-1 are expressed ubiquitously and are essential for viability. Through a genetic screen, we identified gpc-1 as essential for olfactory adaptation. While wild-type animals show decreased chemotaxis to the odorant benzaldehyde after a short preexposure to the odorant, gpc-1 mutants are still attracted to the odorant after the same preexposure. Cell-specific rescue experiments show that gpc-1 acts in the AWC olfactory neurons. Coexpression of GPC-1 and GPB-1, but not GPB-2, caused enhanced adaptation, indicating that GPC-1 may act with GPB-1. On the other hand, knock down of gpc-2 by cell-targeted RNAi caused reduced chemotaxis to the odorant in unadapted animals, indicating that GPC-2 mainly act for olfactory sensation and the two Ggamma's have differential functions. Nonetheless, overexpression of gpc-2 in AWC neurons rescued the adaptation defects of gpc-1 mutants, suggesting partially overlapping functions of the two Ggamma's. We further tested genetic interaction of gpc-1 with several other genes involved in olfactory adaptation. Our analyses place goa-1 Goalpha and let-60 Ras in parallel to gpc-1. In contrast, a gain-of-function mutation in egl-30 Gqalpha was epistatic to gpc-1, suggesting the possibility that gpc-1 Ggamma may act upstream of egl-30 Gqalpha.
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