OA acts on SER-6 in the AWB, ADL and ASI sensory neurons. (A–D) Fluorescence from ser-6 null animals expressing a ser-6∷gfp transcriptional fusion using confocal microscopy. Merge of GFP fluorescence, DiD staining of a subset of sensory neurons and DIC. (E) Aversive responses to 100% 1-octanol were assayed off food in the presence or absence of exogenous OA (4 mM) in transgenic animals expressing either ser-6 or ser-6RNAi under the AWB (str-1); ADL (sro-1) or ASI (gpa-4) neuron-selective promoters. Black bars, wild-type or null animals; grey bars, wild-type or null animals expressing a transgene; hatched bars, RNAi in wild-type animals. Data are presented as a mean±s.e. and analysed by two-tailed Student's t-test. *P<0.001, significantly different from wild-type animals under identical test conditions; **P<0.01, significantly different from null animals under identical test conditions.