GPC-1, a G protein gamma-subunit, regulates olfactory adaptation in Caenorhabditis elegans.
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.
Yamada
Koji
K
Department of Biophysics and Biochemistry, Molecular Genetics Research Laboratory, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
Hirotsu
Takaaki
T
Matsuki
Masahiro
M
Kunitomo
Hirofumi
H
Iino
Yuichi
Y
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002923:Cilia / Q000378:metabolism; D004843:Epistasis, Genetic; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000502:physiology; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000235:genetics / Q000502:physiology; D044387:GTP-Binding Protein beta Subunits / Q000378:metabolism / Q000502:physiology; D044388:GTP-Binding Protein gamma Subunits / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D009833:Olfactory Pathways / Q000002:abnormalities / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D018631:ras Proteins / Q000235:genetics / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; C479565:Egl-30 protein, C elegans; C516620:GOA-1 protein, C elegans; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; C454139:gpc-1 protein, C elegans; C066646:let-60 protein, C elegans; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D018631:ras Proteins