Figure 1.

The SUMO pathway negatively regulates Dpp signaling. (A) RNA in situ hybridization of Dpp target genes in embryos at the onset of gastrulation that are either wild-type, lwr mutant, or carrying three copies of dpp, as labeled. Dorsal views of the embryos are shown with anterior to the left. lwr mutant embryos were collected from females that were induced to produce lwr¹¹⁸ homozygous mutant germline clones using the FLP-DFS technique. Embryos generated using this method are smaller and more rounded in size than wild-type embryos. The graphs show quantification of the number of expressing cells in the middle of the embryo for each gene; n = 15; error bars are SEM; (*) P < 0.05 compared with wild type (Student’s t-test). (B) Stage 8 wild-type and lwr mutant embryos showing zen expression as visualized by RNA in situ hybridization. (C) Graph showing percent viability of dpp^hr27 mutant progeny from females that are either wild-type or heterozygous for the lwr¹¹⁸, lwr^4-3, or sumo^k06307 mutations. Viability is expressed as a percentage of the number of dpp^hr27 mutant progeny compared with those that inherit the wild-type chromosome paternally. No genetic interaction is observed when the lwr mutations are transmitted paternally (data not shown). (D) RNA in situ hybridization of Race expression in embryos from tub-GAL4; pUASp-sumo females, which results in sumo overexpression. Quantification is as described in A.