Denise S. Walker, Elizabeth Gregory, Nicholas J.D. Gower and Howard A. Baylis. Inositol 1,4,5 trisphosphate receptors (IP3Rs) are ligand-gated Ca2+ channels that control Ca2+ release from intracellular stores. They are central to a wide range of cellular responses. IP3Rs in C. elegans are encoded by a single gene,
itr-1, which is widely expressed, and for which a wide range of functions have been identified. To determine the role of IP3 receptors in the nervous system, we have used the neuronal
unc-119 promoter1 to direct expression of an IP3 sponge2. In a parallel approach we have knocked down
itr-1 by expressing an RNA inverted repeat3 under the control of the
unc-119 promoter. We describe the role of
itr-1 in the aversive response to nose touch, and we present evidence that both
egl-8 (encoding phospholipase C beta) and
plc-3 (encoding phospholipase C gamma) function upstream of
itr-1 in this response. The response to nose touch is mediated by the ASH polymodal sensory neurons, which also mediate avoidance of high osmolarity and volatile and water-soluble repellents4,5. We demonstrate that while
itr-1 does not function in the majority of these responses, it does function in avoidance of benzaldehyde. We are currently investigating the cellular basis of these functions, and the role of signalling pathway components that may function upstream.. 1. Maduro, M. & Pilgrim, D. (1995) Genetics 141, 977-988.. 2. Walker et al. (2002) Mol. Biol. Cell 13, 1329-1337.. 3. Tavernarakis et al. (2000) Nat. Genet. 24, 180-183.. 4. Hart et al. (1999) J. Neurosci. 19, 1952-1958.. 5. Hilliard et al. (2004) EMBO J. 23, 1101-1111.