NCS-1 functions in AIY neurons in the temperature-dependent changes in locomotion. (A) The circuit that controls thermotaxis in C. elegans including information on additional thermosensory neurons . Temperature is sensed by AFD, AWC and ASI neurons, which signal through AIY and AIZ interneurons. Signalling from AIY to RIA results in thermophilic drive whereas signalling from AIZ to RIA results in cryophilic drive. The neurons in green express NCS-1 . Asterisks indicate sensory neurons where expression is driven by the osm-6 promoter. (B) Western blot of ncs-1 null and transgenic worms with ncs-1 expression driven by Pncs-1 or Posm-6 probed with anti-human-NCS-1. (C) Expression of NCS-1 in AIY interneurons rescued the TDL assay phenotype in the ncs-1 null (qa406). Transgenic strains using different promoters to drive ncs-1 expression were generated by injection of expression plasmids derived from genomic ncs-1. Locomotion rates of wild-type N2 and ncs-1 null worms were quantified at room temperature (20°C; open bars) and after elevation of temperature to 28°C for 10 min (filled bars). N2 worms showed a reduction in locomotion at elevated temperature (*; P<0.01) not seen with the ncs-1 null worms. The locomotion at each temperature of three lines of transgenic worms for each condition expressing NCS-1 under the control of indicated promoter was assayed. The data from worm lines were pooled and normalised to the locomotion rate of N2 worms at 20°C and the rate of movement at 20°C and 28°C compared (*; P<0.01, n=15 except for PAIY::ncs-1 where n=45 worms). (D) The ttx-3 mutant worms show increased inhibition of locomotion at 28°C. Locomotion rates of wild-type Bristol N2 and ncs-1 null and ttx-3 mutant worms were quantified at room temperature (20°C; open bars) and then after elevation of temperature to 28°C for 10 min (filled bars) (*; P<0.01, N=20 worms).