DHR3 regulates dS6K activity.
(A) The DHR3 locus is schematized at the top with the 2 EP insertions indicated (arrows). The RA and RB transcripts encode a DBD sequence (indicated by the grey box). RS is a putative novel transcript whose first AUG is located beyond the DBD-coding sequences. (B–G) Adult wings in which the ap-Gal4 induces expression of the following UAS constructs: (B) ap-Gal4 control; (C) UAS-dS6K; (D) UAS-DHR3-RS; (E) both UAS-dS6K and UAS-DHR3-RS; (F) UAS-DHR3-RS in a dS6Kl-1 mutant escaper; (G) UAS-dS6K, UAS-DHR3-RS, and UAS-DHR3-RNAi together. (H) Upper panel, H2B substrate phosphorylation by dS6K from larval protein extracts. Ubiquitous induction of UAS-DHR3 RNAi, using either a daughterless-Gal4 (da>Ri) or an actin-Gal4 (ac>Ri) driver, provoked a drop in dS6K activity, as compared with control drivers alone (da, ac). Middle and lower panels are western blots detecting dS6K and α-tubulin, respectively.