sog and dpp exert opposing maternal functions to modify Toll signaling andpattern the dorsoventral axis of the Drosophila embryo

The short gastrulation (sog) and decapentaplegic (dpp) genes function antag onistically in the early Drosophila zygote to pattern the dorsoventral (DV) axis of the embryo. This interplay between sog and dpp determines the exte nt of the neuroectoderm and subdivides the dorsal ectoderm into two territo ries. Here, we present evidence that sog and dpp also play opposing roles d uring oogenesis in patterning the DV axis of the embryo. We show that mater nally produced Dpp increases levels of the I kappa B-related protein Cactus and reduces the magnitude of the nuclear concentration gradient of the NF kappa B-related Dorsal protein, and that Sog limits this effect. We present evidence suggesting that Dpp signaling increases Cactus levels by reducing a signal-independent component of Cactus degradation. Epistasis experiment s reveal that sog and dpp act downstream of, or in parallel to, the Ton rec eptor to reduce translocation of Dorsal protein into the nucleus, These res ults broaden the role previously defined for sog and dpp in establishing th e embryonic DV axis and reveal a novel form of crossregulation between the NF kappa B and TGF beta signaling pathways in pattern formation.