A Single Gene Target of an ETS-Family Transcription Factor Determines Neuronal CO2-Chemosensitivity

Many animals possess neurons specialized for the detection of carbon dioxide (CO 2 ), which acts as a cue to elicit behavioral responses and is also an internally generated product of respiration that regulates animal physiology. In many organisms how such neurons detect CO 2 is poorly understood. We report here a mechanism that endows C. elegans neurons with the ability to detect CO 2 . The ETS-5 transcription factor is necessary for the specification of CO 2 -sensing BAG neurons. Expression of a single ETS-5 target gene, gcy-9 , which encodes a receptor-type guanylate cyclase, is sufficient to bypass a requirement for ets-5 in CO 2 -detection and transforms neurons into CO 2 -sensing neurons. Because ETS-5 and GCY-9 are members of gene families that are conserved between nematodes and vertebrates, a similar mechanism might act in the specification of CO 2 -sensing neurons in other phyla.