Fig. 5. Division 14 mitotic domains are positioned relative to threshold levels of SMAD responses. Cephalic regions of embryos stained for Medea (A,C) or PMAD (B,D,E,F) (both green), and ToPro3 (red), dorsal views except C. ToPro3 DNA dye intensely stains highly condensed mitotic chromosomes. One of each paired domain is outlined in white. (A,B) The dorsal edges of mitotic domains ₁₄1 (1) and ₁₄5 (5) abut the lateral edges of the midline stripe of high-level SMAD response, either nuclear Medea (A) or PMAD (B). Mitotic domain ₁₄3 (3) has the same width as the stripe. (C-E) These domains retain their position relative to the altered stripe in embryos with altered dpp gene dosage. (C) Domains ₁₄1 and ₁₄5 still abut the narrow, weak Medea stripe in dpp^H46/+ embryos (1Xdpp). (D) Each pair of domains ₁₄1 and ₁₄5 is wider apart, but each domain still abuts the broad PMAD stripe in Dp(2;2)DTD48/Dp(2;2)DTD48 embryos (4Xdpp). Domain ₁₄3 fully spans the broader stripe. (E) Domains ₁₄1 and ₁₄5 fuse at the midline in dpp^H46/dpp^H46 embryos (dpp null), PMAD staining and ₁₄3 are lost. (F) PMAD staining is more intense in embryos expressing high levels of Medea from a transgene (ubi>Medea), but the mitotic domains still abut the stripe. Anterior is leftwards.

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