(A, B) Concretion formation of DaGS>Uro-RNAi #1 flies after 14 days of feeding a HY + RU diet supplemented with the indicated concentration of allopurinol (A) or methotrexate (B). (C) The recombinant DaGS::Uro-RNAi #1 line was crossed to w1118 (no additional UAS-locus), b35785 (carrying a no target UAS-mCherry-RNAi), or active UAS-RNAi lines targeting the transcription factor GAL4, PRPP synthetase (PRPS), dihydrofolate reductase (DHFR), or xanthine dehydrogenase (XDH). To measure concretion formation the flies were fed the HY + RU diet for 14 days prior to dissection. (D) Survival curve of DaGS>Uro-RNAi #1 flies fed the HY diet without or with 5 mM AP (+AP) supplementation in presence or absence of RU. (E) As in (D), but 5 μM MTX (+MTX) supplementation. Error bars represent the SE of multiple biological repeats. Supporting data is shown in S3 Fig.