Figure 2
From: The Neuropeptide Allatostatin A Regulates Metabolism and Feeding Decisions in Drosophila
AstA regulates expression of genes related to AKH and DILP signaling and starvation resistance.
(A,B) Expression of key metabolic genes related to AKH (A) and DILP (B) signaling in flies with increased (AstA > NaChBac) or decreased (AstA > TeTxLC.tnt) AstA neuron activity. Changes in expression of several DILP and AKH related genes in AstA > NaChBac and AstA > TeTxLC.tnt animals, indicate that AstA affects DILP and AKH signaling. Ctrl: AstA-Gal4/+. (C) Starvation resistance in flies lacking AstA (AstASK1 and AstASK1/Df(3R)BSC519) compared to AstASK1/+ heterozygous flies and controls (y2 cho2 v1, y1 w1118 and y2 cho2 v1 x y1 w1118: offspring from crossing these lines). AstASK1 and AstASK1/Df(3R)BSC519 flies were significantly starvation resistant compared to AstASK1/+ heterozygous flies and controls (logrank test: P < 0.0001). (D) Expression of the AKH and DILP target gene tobi in flies lacking AstA (AstASK1 and AstASK1/Df(3R)BSC519) or Akh (AkhSK1). Controls are the same as in C. Error bars indicate standard errors (n = 3–5) (E) Starvation resistance in response to Akh overexpression (Akh > Akh), Dar-2 knock down (Akh > Dar-2-RNAi), Dar-2 knock down and combined with overexpression of Akh (Akh > Akh, Dar-2-RNAi), Akh knock down (Akh > Akh-RNAi) or Akh and Dar-2 knocked down simultaneously (Akh > Akh-RNAi, Dar-2-RNAi). Increased starvation resistance of Akh > Dar-2-RNAi animals compared to the control indicates that knock down of Dar-2 in the APCs reduces AKH signaling. Ctrl: UAS-Dicer2, UAS-Dar-2-RNAi/+. All RNAi flies were significantly starvation resistant compared to the control in all starvation experiments (logrank test: P < 0.0001). Likewise Akh > Akh flies were significantly starvation-sensitive (logrank test: P < 0.0001). (F) Starvation resistance in flies with reduced Dar-2 expression in the IPCs (dilp2 > Dar-2-RNAi) or the DAR-2 producing cells (Dar-2 > Dar-2-RNAi). Increased starvation resistance of dilp2 > Dar-2-RNAi indicates reduced insulin signaling in these animals. Together, this suggests that AstA is a positive regulator of both AKH and DILP. Consistently, starvation resistance was also increased in Dar-2 > Dar-2-RNAi animals with reduced Dar-2 expression in cells expressing the receptor, including the APCs and IPCs. UAS-Dicer2 was included since efficient neuronal knock down often requires overexpression of Dicer2. Ctrl: UAS-Dicer2, UAS-Dar-2-RNAi/+. All RNAi flies were significantly starvation resistant compared to the wild type control in all starvation experiments (logrank test: P < 0.0001). *: P < 0.05; **: P < 0.01; ***: P < 0.001 (Student’s t-test).
