Figure 2.

Synapsin function is required in GABAergic LNs for inducing STH. A, Expression of wild-type synapsin transgene in different cell types of olfactory neurons–LNs (LN1-Gal4> UAS-syn⁺,syn⁹⁷/syn⁹⁷), GABAergic neurons (GAD1-Gal4> UAS-syn⁺,syn⁹⁷/syn⁹⁷), PNs (GH146-Gal4> UAS-syn⁺,syn⁹⁷/syn⁹⁷), and MB neurons (mb247-Gal4> UAS-syn⁺,syn⁹⁷/syn⁹⁷). B, Transgenic expression of synapsin in LN1 or GAD1 subsets of neurons rescue the syn⁹⁷ STH defect. C, D, Expression of synapsin in a different subset of olfactory neurons and temperature-shift protocols are shown in the schematic for conditional rescue and knock down of synapsin using tubGal80^ts. Filled circles correspond to synapsin expression, whereas an open circle represents lack of synapsin in the olfactory neurons. C, Adult-specific expression of synapsin using the conditional Gal80^ts expression system in LN1 neurons is sufficient to reverse the syn⁹⁷ defect for STH (29°C; LN1-Gal4> tub-Gal80^ts; UAS-syn⁺,syn⁹⁷/syn⁹⁷). Two-way ANOVA yielded a significant difference in the behavioral responses of 18 and 29°C-treated flies (F_(1,39) = 19.193, p < 0.001). Post hoc testing (Turkey test) showed no difference between naive and EB-exposed flies at 18°C (q = 1.893, p = 0.189) and a significant difference for 29°C-treated flies (q = 10.655, p < 0.001). D, Conditional knock down of synapsin in LN1 neurons blocks STH at restrictive temperature (29°C; LN1-Gal4/+; tub-Gal80^ts> UAS-syn^RNAi; F_(1,39) = 35.303, p < 0.001, two-way ANOVA; Turkey test for 18°C, q = 12.898, p < 0.001 and for 29°C flies, q = 1.015, p = 0.478). Before and after odorant exposure responses to 10⁻³ concentration of EB are shown in light gray and dark gray bars, respectively. ***p value < 0.001 calculated using Student's t test with Bonferroni correction. Error bars indicate mean ± SEM; N is 9–11 sets of flies for each bar (Table 1).