Morphogens are secreted signaling molecules that form concentration gradients and control
cell fate in developing tissues. During development, it is essential that morphogen range is
strictly regulated in order for correct cell type specification to occur. One of the best
characterized morphogens is Drosophila Decapentaplegic (Dpp), a BMP signaling molecule
that patterns the dorsal ectoderm of the embryo by activating the Mad and Medea (Med)
transcription factors. We demonstrate that there is a spatial and temporal expansion of the …

All the major components of the SUMO pathway are maternally expressed in the Drosophila
embryo (data not shown), including the essential E2-conjugating enzyme Ubc9. Ubc9 is
encoded by the lesswright (lwr, also called semushi) gene in flies, and embryos from
females carrying homozygous lwr118 mutant germline clones have greatly reduced lwr
mRNA (Epps and Tanda 1998). Therefore, we analyzed Dpp target gene expression in
lwr118 mutant embryos with reduced maternal and zygotic lwr activity (hereafter referred to …