Fig. 7. The final level of SMAD response is sensitive to dpp gene dosage. Confocal projections of embryos stained for Medea (E,F) or PMAD (A-D). 2Xdpp embryos are wild-type (WT) controls, 1Xdpp and 3Xdpp are dpp^H46/dpp⁺ and dpp⁺ P{dpp^H+}/dpp⁺, respectively. (A) Stage 7, 3Xdpp embryos show an expanded dorsal region of PMAD staining, which broadens in the trunk region as amnioserosa cells flatten. (B) Stage 7 1Xdpp embryos have weaker PMAD staining. Stage 8 1Xdpp embryos (D,F) have substantially weaker SMAD responses than WT. (D) Stage 8, 1Xdpp embryo with undetectable PMAD staining and partially ventralized phenotype. (E) In stage 9 WT has strong nuclear Medea accumulation in the amnioserosa and dorsal-midline of cephalic region. (F) Stage 9 1Xdpp embryos often have a weak stripe of nuclear Medea accumulation in the cephalic region and variable but low levels in amnioserosa nuclei.