Fig. 3. Signal transduction in dally dlp mutants expressing exogenous Wingless. (A) Lawn phenotype of an embryo lacking maternal and zygotic dally and dlp, as shown in Fig. 2E. (B) Naked cuticle is induced along the ventral region by expression of GFP-Wingless under the control of sim-gal4 in dally dlp-deficient embryos [as used by Desbordes and Sanson (Desbordes and Sanson, 2003)]. This shows that signal transduction can take place in the absence of the glypicans if sufficient Wingless expression is sustained.