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. 2024 Dec 20;13:RP102222. doi: 10.7554/eLife.102222

Figure 2. DNT-2 neurons are functionally connected to dopaminergic neurons.

(A) TransTango revealed out-puts of DNT-2 neurons. All neurons express TransTango and expression of the TransTango ligand in DNT-2 neurons identified DNT-2 outputs with Tomato (anti-DsRed). TransTango identified as DNT-2 outputs KC α’β’ MB lobes (anterior brain, arrow, top left); Kenyon and possibly DAN cell bodies (posterior, arrows top right); DAL neurons (bottom left, arrows) and the dorsal layer of the fan shaped body (bottom right, arrow). See also Figure 2—figure supplement 1 for further controls. (B) BAcTrace tests connectivity to a candidate neuron input visualised with LexAop>sybGFP by driving the expression of a ligand from DNT-2GAL4 that will activate QUASTomato in the candidate input neuron (Cachero et al., 2020). Candidate PAM neurons visualised at SMP with GFP (green): Control: R58E02LexA>BAcTrace 806, no GAL4. Test: R58E02LexA, DNT-2GAL4>BAcTrace 806 revealed PAMs are inputs of DNT-2A neurons at SMP (Tomato, bottom). Magenta shows QUAS-Tomato. (C) qRT-PCR showing that TH mRNA levels increased with DNT-2 over-expression at 30°C (tubGAL80ts, DNT-2>DNT-2FL). One-way ANOVA, p=0.0085; post doc Dunnett’s multiple comparison test. Mean ± standard deviation (s.d.). n=4 (left), 5 (middle), 3 (right). (D) FRET cAMP probe Epac1 revealed that DNT-2>Dop2R-RNAi knock-down decreased YFP/CFP ratio over time in DNT-2A neurons, meaning that cAMP levels increased. Two-way ANOVA, genotype factor p<0.0001, time factor p<0.0001; post doc Dunnett’s. Mean ±s.d. n=9,12,17. (E, F) Summary: DNT-2 neurons and DANs are functionally connected and modulate each other. (E) DNT-2 can induce TH expression in DANs; (F) this is followed by negative feedback from DANs to DNT-2 neurons (question marks indicate inferences). TH: tyrosine hydroxylase. Scale bars: (A) 50 µm; (B) 30 µm; (D) 20 µm. p-Values over graphs in (C) refer to group analyses; stars indicate multiple comparisons tests. *p<0.05, **p<0.01, ***p<0.001. For sample sizes and further statistical details, see Supplementary file 2.

Figure 2—source data 1. Quantitative results used to generate graphs in Figure 2C.
Figure 2—source data 2. Quantitative results used to generate graphs in Figure 2D.

Figure 2.

Figure 2—figure supplement 1. TransTango connectivity controls.

Figure 2—figure supplement 1.

(A) UAS-TransTango/+ control, showing background GFP expression in mushroom bodies and Tomato+ signal in sub-oesophageal ganglion (SOG). (B) DNT-2GAL4>UAS-TransTango, revealing the GFP+DNT-2 neurons and Tomato+ signal in DNT-2 neurons. TransTango also reveals what appears to be feedback connections between DNT-2 neurons from SMP to PRW (arrow). These are controls for Figure 2A. Scale bars: (A, B) 50 µm. For further genotypes and sample sizes, see Supplementary file 2.