Fig. 3. phyl negatively regulates Ac protein levels in SOPs. (A-F) Ac expression is shown in red and Sens expression is shown in green. (A-A'') In wild-type pupal thorax at 12-13 hours APF, Ac is expressed at high levels in newly specified SOPs (arrowheads). Ac levels are diminishing in more mature SOPs which express higher levels of Sens (arrows). (B-B'') Thoracic region of Eq-Gal4/UAS-myc-ac wing disk. Although Myc-Ac (red) is clearly detected in most non-SOP disk cells and in newly specified ectopic SOPs that express Sens at low levels (arrowheads), Myc-Ac levels are strongly downregulated in late-stage ectopic SOPs (arrows). (C) Endogenous Ac protein disappears normally from the ap-Gal4>UAS-lacZ control thorax at 14-16 hours APF after a 10-hour incubation at 29°C. (D) When proteasome activity in ap-Gal4>UAS-DTS5 pupal thorax was disrupted under the same incubation condition as C, highly elevated levels of Ac are detected in SOPs. (E-E'') Ac protein levels are maintained in phyl²-mutant SOPs (GFP-negative) at 13-14 hours APF whereas it has disappeared from the neighboring wild-type SOPs. (F,F') Ac protein levels are strongly downregulated within phyl-misexpression clones (GFP positive).