DPP is required to derepress Jupiter, Jar, and Zasp52 but cannot induce them ectopically. (A–F′) Control (A and B), tkv⁸ (C and D), and brk^M68, tkv⁸ (E and F) stage (S) 15 embryos marked for Jupiter::GFP (blue in A, C, and E; gray in A′, C′, and E′) Jar (green in A, C, and E; gray in A″, C″, and E″), phospho-Mad (pMad; red in in A, C, and E; gray in A‴, C‴, and E‴), Zasp52 (yellow in B, D, and F; gray in B′, D′, and F′), and E-Cadherin (magenta). The dashed lines delineate the midline. Accumulation of Jupiter::GFP, Jar, and Zasp52 at the LE is lost in tkv⁸ mutant embryos and restored in brk^M68, tkv⁸ embryos. (J and K) Prd-Gal4, UAS-tkv^ACT embryos marked for Jupiter::GFP (blue in G; gray in G′), Jar (green in G; gray in G″), phospho-Mad (red in G; gray in G‴), or Zasp52::GFP (yellow in H; gray in H′) and phospho-Mad (red). Ectopic activation of the DPP pathway does not lead to Jupiter, Jar, or Zasp52 accumulation (arrowheads). Bars, 10 µm.