Abstract
Caenorhabditis elegans senses environmental stimuli mainly by sensory neurons in the head. Thermal stimulus is sensed by a pair of thermosensory neurons AFD, which has been identified by laser ablation experiments. It has been shown through the analysis of tax-4 mutant that TAX-4 cyclic nucleotide-gated cation channel (CNG channel) plays the critical role on thermosensation in AFD. TAX-4 CNG channel shows higher affinity to cGMP than cAMP, suggesting that cGMP signaling pathway is important for thermosensation in AFD. To molecularly understand thermosensory transduction pathway of AFD, we attempted to identify components that function upstream of TAX-4 CNG channel by reverse generic approach. We constructed deletion mutant library by TMP/UV method and isolated several deletion mutants for gcy genes encoding guanylyl cyclase that produces cGMP. Genetic and behavioral analysis of the deletion mutants revealed that three gcy genes are required and function redundantly for thermosensation in AFD.