Fig. 1. Ectopic embryonic Wg transduction in a hypomorphic Apc2 mutant. (A) The Apc1 and Apc2 proteins. The conserved Armadillo repeat region (blue), ß-catenin-binding sites (purple) and Axin binding sites (green) are indicated. The position of the stop codon in Apc1Q8 and Apc2d40, as well as the epitope to which the anti-Apc2 sera was raised (black bar) are indicated. (B-E) Immunostaining of wild-type (B,D,E) and Apc2d40 maternal/zygotic mutant embryos (C) with the anti-Apc2 sera. (B,C) Embryos at similar stages obtained using the same confocal microscope settings. A dramatic reduction in Apc2 staining is found in the Apc2d40 mutant embryos. (F-H) Dark field images of cuticles of homozygous Apc2 mutant embryos from Apc2d40/Apc2d40 mothers and wild-type fathers (F), Apc2d40/Apc2d40 mothers and Apc2d40 /+ fathers (G), and Apc2d40/Df (w6) mothers and Df (w6)/+ fathers (H). Introducing a deficiency for Apc2 in the mothers and fathers results in an embryo that nearly completely lacks ventral epidermal denticles, and thus reveals the hypomorphic nature of the Apc2d40 mutation. (I-L) Immunostaining of heterozygous Apc2 embryos from Apc2d40/Apc2d40 mothers and wild-type fathers (I,K) or homozygous Apc2 mutant embryos from Apc2d40/Apc2d40 mothers and Apc2d40/+ fathers (J,L) with anti-Engrailed (red, I,J) or anti-Arm (green, K,L) antibodies. Apc2d40 maternal/zygotic mutants have an expansion of naked cuticle, and an expansion of Engrailed stripes, as well as a reduction in the striped accumulation of Arm protein, all consistent with the ectopic activation of Wg transduction.
