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Receptor-type guanylate cyclase is required for carbon dioxide sensation by Caenorhabditis elegans.


Hallem EAElissa A , Spencer WC W Clay , McWhirter RD Rebecca D , Zeller G Georg , Henz SR Stefan R , R├Ątsch G Gunnar , Miller DM David M , Horvitz HR H Robert , Sternberg PW Paul W , Ringstad N Niels . Proceedings of the National Academy of Sciences of the United States of America. 2011 1 4; 108(1). 254-9


CO(2) is both a critical regulator of animal physiology and an important sensory cue for many animals for host detection, food location, and mate finding. The free-living soil nematode Caenorhabditis elegans shows CO(2) avoidance behavior, which requires a pair of ciliated sensory neurons, the BAG neurons. Using in vivo calcium imaging, we show that CO(2) specifically activates the BAG neurons and that the CO(2)-sensing function of BAG neurons requires TAX-2/TAX-4 cyclic nucleotide-gated ion channels and the receptor-type guanylate cyclase GCY-9. Our results delineate a molecular pathway for CO(2) sensing and suggest that activation of a receptor-type guanylate cyclase is an evolutionarily conserved mechanism by which animals detect environmental CO(2).