Iro/Irx transcription factors negatively regulate Dpp/TGF-β pathway activity during intestinal tumorigenesis

kept at 29ºC for 10 days to allow the expression of the UAS constructs. Apc2 N175K is a loss-of-function allele, Apc Q8 is a null allele, UAS-Ras V12 and UAS-Tkv Q253 are gain-of-function transgenes. UAS-Tkv DN is a dominant negative transgene. Stocks were obtained form Bloomington Stock Center and VDRC. Staining and antibodies. Adult female flies were dissected in PBS. All the digestive tract was removed and fixed in PBS and 4% electron microscopy grade paraformaldehyde (Polysciences, USA) for 35 minutes. Samples were rinsed 3 times with PBS, 4% BSA, 0.1% Triton X-100 (PBT-BSA), incubated with the primary antibody overnight at 4°C and with the secondary antibody for 2 hours at room temperature. Finally, the samples were rinsed 3 times with PBT-BSA and mounted in DAPI-containing media (Vectashield, USA). All the steps were performed without mechanical agitation. Primary antibody mouse -Dl (1:10), was obtained from the