Fig. 1. Cell-specific effects of yz5 and yz6 mutations on 5HT biosynthesis. (A) The position of serotonergic neurons in the head, and the axon from HSN (shown in red). Also shown are the nonserotonergic amphid chemosensory neurons that express both osm-9 and ocr-2 (in green) (Tobin et al., 2002). The drawing is adapted, with permission, from Starich et al. (Starich et al., 1995). (B) GFP expression of an integrated tph-1::gfp fusion gene in wild-type and mutant animals. In wild type, GFP is strongly expressed in the ADF, NSM and HSN neurons. yz5 and yz6 mutations specifically downregulate the GFP expression in the ADF chemosensory neurons. Note that neither the mutation alone, nor yz5;yz6 double mutation affects GFP levels in NSM and HSN. tph-1::gfp expression in ADF is restored in the mutant animals carrying a wild-type osm-9 or ocr-2 transgene, respectively. (C) Anti-5HT antibody staining of wild-type and mutant animals. yz5 and the yz6 mutant animals show reduction or absence of 5HT immunoreactivity in the ADF neurons. ADF 5HT immunoreactivity is recovered in the mutants carrying a wild-type osm-9 or ocr-2 transgene. All the animals shown are adult hermaphrodites. Anterior is towards the left. Quantification of tph-1::gfp expression in various genetic backgrounds is presented in Table 1. (D) A schematic representation of the domain organization of the TRPV subfamily. The approximate site of the yz6 and yz5 mutation in the channel structure is indicated. The drawing is adapted, with permission, from Gunthorpe et al. (Gunthorpe et al., 2002).