Figure 3: The coelomocyte uptake assay allows visualization of FLP-7 secretion in response to serotonergic genes.

(a) Model illustrating the coelomocyte uptake assay for neuropeptide secretion. The FLP-7mCherry fusion protein (marked in red) is expressed from ASI neurons and GFP is expressed in the coelomocytes (marked in green). The ratio of red:green fluorescence is used to quantify the extent of secretion under different experimental conditions. CLM, coelomocytes. (b,c) Representative images of vehicle- and 5-HT-treated wild-type, unc-31, tph-1 and mod-5 animals bearing the FLP-7mCherry and CLM::GFP integrated transgenes, respectively. Left panels, GFP expression in coelomocytes; centre panels, secreted FLP-7mCherry uptake in coelomocytes; right panels (merge). Scale bar, 10 μm. (d) For vehicle- and 5-HT-treated animals bearing integrated FLP-7mCherry and CLM::GFP transgenes, the intensity of FLP-7mCherry fluorescence within a single coelomocyte was quantified and normalized to the area of CLM::GFP expression. Genotypes are indicated in the figure. Data are expressed as a percentage of the normalized FLP-7mCherry fluorescence intensity of vehicle-treated wild-type animals±s.e.m. (n=10–20 animals). *P<0.05 and **P<0.01 by two-way ANOVA. (e) Individual values for the fluorescence intensity of CLM::GFP within a single coelomocyte are shown for each condition. Bars indicate the average value±s.e.m. within each condition. Data are expressed as a percentage of wild-type animals. No significant differences were observed by one-way ANOVA, n=19–46. (f) mCherry fluorescence intensity values are plotted against GFP fluorescence intensity values for each animal across representative experimental conditions, n=103.