Gene expression in Am-Toll , Am-GB19066 , and Am-Dpp RNAi stage 4 embryos. (A) Am-zen stained control embryo, typical expression of Am-zen on the dorsal side of the embryo. (B) Knockdown of Am-GB19066 results in expansion of Am-zen expression. (C) Am-DppRNAi treated embryos, loss of Am-zen expression from the anterior of the embryo some weak mid-to-posterior expression remains (asterisks). (D) Am-TollRNAi embryo stained for Am-zen transcript results in mild expansion of Am-zen expression at the dorsal midline (indicated). (E) Control embryo stained for Am-twi expression. Am-twi is expressed along the ventral midline of the embryo. (F) Am-twi expression is lost in Am-Toll knockdown embryos (G) Am-DppRNAi embryos stained for Am-twi. Arrows show centrally located bands of expression running along the anterior-posterior axis. (H) Expression of Am-sna in control embryos. (I) Am-TollRNAi embryos displayed loss of Am-sna expression from the anterior-ventral through to the posterior third of the embryo. The remaining posterior domain of Am-sna expression is expanded dorsally. (J) Am-DppRNAi embryos stained for Am-sna. Staining is detected as a slightly broader ventral expression domain (indicated) compared to controls. (F-I) Schematic representation of the AP and DV patterning defects in dsRNA-knockdown embryos. All embryos are stage 4 embryos, oriented with anterior to the left and dorsal side up.