Fig. 1
Serotonin regulates the social interaction of Drosophila. A qRT-PCR analysis of Trh mRNA expression in Trh knockdown lines. B Concentration of 5-HT in whole bodies of Trh knockdown and control flies. C, E Social spacing of males (C) and females (E) overexpressing Trh-RNAi with a Tub-Gal4 driver. D, F Cumulative probability distributions of the closest neighbor distance in males (D) and females (F) overexpressing Trh-RNAi with a Tub-Gal4 driver. G Schematic illustration of the WT Trh genome and the Trh01 indel mutant, whose catalytic center is deleted. H Concentration of 5-HT in whole bodies of Canton-S and Trh01 mutant flies. I, K Representative data show the distance to the closest neighbor of Canton-S and Trh01 mutant male (I) or female flies (K). J, L Cumulative probability distributions of the closest neighbor distance in Canton-S and Trh01 mutant males (J) and females (L). The number “50” on Y-axis and its corresponding number of Thr01 on X-axis are marked. M, N Negative geotaxis assay of Trh knockdown (M) and Trh01 (M) mutant flies. O, P Canton-S and Trh01 mutant individual flies displayed a decreased distance to the closest neighbor after feeding 2 mg/mL 5-HTP for 3 days. Q Brains of Canton-S and Trh01 mutant flies with or without 5-HTP feeding for 3 days immunostained with an anti-serotonin antibody (green) and the neuropil marker NC82 antibody (red). R The statistical analysis (mean ± SEM, at least n = 4 brains for each group) of the fluorescence intensity of the brains in Q measured by Fiji (ImageJ) software. Error bars are shown as the mean ± SEM (A, B, H, M, N and R). Other data (C, E, I, K, O and P) are represented in a box and whisker plot of the distance to the closest neighbor in the chamber, with the box representing the 1st quartile (25th percent) and the 3rd quartile (75th percent), the line in the box representing the median, and Tukey’s whiskers excluding the outliers. These data were obtained from at least three independent repeats of 35 – 40 flies per assay. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001