Wnt6 is expressed in the maxillary palp anlage, and not wingless. (A-A’) Staining of control eye-antenna discs (A) with anti-wingless antibody (clone 4D4) gives a signal in the maxillary palp anlage (arrowhead) which is not visible in Wnt6KO discs (A’). (B) Wingless and Wnt6 do not induce expression of each other, detected by mRNA in situ hybridization. Expression of Wnt6 in the patched domain along the A/P boundary, perpendicular to the endogenous wingless and Wnt6 expression domains, does not ectopically induce wingless, and vice-versa. (C) Anti-wingless monoclonal antibody clone 4D4 cross-reacts with Wnt6 on immuno-blots. Lysates from control S2 cells or S2 cells transfected to express wingless or Wnt6 were probed with anti-wg antibody. The upper band is a non-specific band also present in untransfected S2 cells. (D-D’) In situ hybridization detecting wingless mRNA (D) and Wnt6 mRNA (D’) in eye-antenna discs reveals Wnt6 expression but not wingless expression in the maxillary palp anlage (arrow). Wnt6KO, Wnt6 knockout.