Howard Hughes Medical Institute, Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
Proc Natl Acad Sci U S A. 2011 Jan 4;108(1):254-9. doi: 10.1073/pnas.1017354108. Epub 2010 Dec 20.
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).
二氧化碳既是动物生理学的重要调节因子，也是许多动物探测宿主、定位食物和寻找配偶的重要感官提示。自由生活的土壤线虫秀丽隐杆线虫表现出对二氧化碳的回避行为，这需要一对有纤毛的感觉神经元，BAG 神经元。通过体内钙成像，我们发现二氧化碳特异性地激活 BAG 神经元，而 BAG 神经元的二氧化碳感应功能需要 TAX-2/TAX-4 环核苷酸门控离子通道和受体型鸟苷酸环化酶 GCY-9。我们的结果描绘了一条二氧化碳感应的分子途径，并表明激活受体型鸟苷酸环化酶是动物探测环境二氧化碳的一种保守机制。
