Forced expression of Pri/Tal peptides induces ectopic ES organ formation. (A-E) Adult nota. (A) Notum of a wild-type fly. (B) Ectopic expression of phyl by Eq-Gal4 induces ectopic ES organs, particularly at the midline region (indicated by arrowhead). (C) The ES organ pattern is largely unaffected in notum expressing EPC05-660 by Eq-Gal4. (D-E) Coexpression of phyl and EPC05-660 (D) or phyl and pri/tal (E) by Eq-Gal4 induces formation of numerous extra ES organs on the notum. (F-M) Adult scutella. (F) Four ES organs (indicated by arrows) located at the wild-type scutellum. (G-I) dpp-Gal4-driven expression of pri/tal (G) or pep1 (I) but not frame-shift mutant pri/tal1-4FS(H), induces ectopic ES organs at the scutellum. In some ES organs, the length of the shaft is reduced (indicated by arrowheads) by ectopic expression of pri/tal or pep1. (J) Expression of phyl alone by dpp-Gal4 generates few ectopic ES organs. The length of the shaft is reduced in some phyl-misexpression ES organs (arrowheads). (K and M) Coexpression of phyl and pri/tal (K) or phyl and pep1 (M) by dpp-Gal4 produces many extra ES organs. (L) Coexpression of phyl and pri/tal1-4FSby dpp-Gal4 results in few ectopic ES organs, a phenotype similar to (J). (N-P) In wild-type (N) or dpp-Gal4 >pri/tal1-4FS(O) pupae at 12-16 hr APF, only four Hnt-positive clusters are observed at the scutella (arrows). In dpp-Gal4 > pri/tal pupae, more than four Hnt-positive clusters are found. (Q) Quantification of the number of the ectopic scutellar ES organs induced by dpp-Gal4. Flies were grown at 18°C for all dpp-Gal4 experiments shown in (F) to (Q).