Overexpressed Punt leads to ectopic P-Mad with or without BLT motif.

(A)vg-GAL4 expression pattern in third instar wing disc as shown by UAS-nlsGFP reporter (green; DAPI in blue), single confocal section. (B) p-Mad detection pattern in WT disc, maximum intensity projection. (C–E) p-Mad signal upon overexpression of intact Punt (C) and protein variants missing part (D) or all (E) of the BLT motif. p-Mad in white, DAPI in blue. Punt (Punt-PstI) and both deletions generate ectopic pMad in the pouch and at anterior side of disc. Widened discs are consistent with overgrowth caused by excess Dpp/BMP signaling (compare widths in C–E to control discs in A and B). Note that these constructs are inserted at random genomic positions with different expression levels, so the degree of ectopic signaling cannot be correlated with protein deletions in this context. Anterior is to the left in all images. Scale bars: 50 μm. BLT, basolateral targeting; WT, wild-type.

(TIFF)