Fig. 4. Rescue of dpp expression levels following overexpression of Wg or Arm^act. Lateral view of stage 13 embryos stained by in situ hybridisation against decapentaplegic. dpp is expressed in the DME cells of wild-type embryos (A), and in one or two additional cells per segment ventrally localised, compare with the LE. In wg^– (B), expression levels are lower and dpp expression is often lost in the posterior DME cells. After ubiquitous overexpression of Wg (C) or Arm^act (D), dpp expression levels are restored to normal. Interestingly, although the overexpression is ubiquitous, the expression pattern in stage 13 embryos is not altered. (E) In wg>AS>Wg embryo, dpp expression levels are rescued, in contrast to wg>AS> Arm^act embryos (F), which show a weak expression of dpp similar to the levels observed in wg^– embryos.