Fig. 2. Maternally expressed Cactus-lacZ fusion protein rescues Cactus function and exhibits dorsal group-dependent polar degradation. The Cactus-lacZ fusion protein was expressed in the female germline under the transcriptional control of the alpha-tubulin 67C promoter in cact011/ cact011 females, resulting in hatching embryos with normal DV polarity (B). cact011/ cact011 females normally produce ventralized embryos (A). Cactus-lacZ protein (visualized by enzymatic activity (C) or with anti-ß-galactosidase antibody (E)) exhibited a dorsal enrichment in the progeny of wild-type females (pipe/+, C) similar to that seen for endogenous Cactus protein (Bergmann et al., 1996). Cactus-lacZ protein exhibited a uniform distribution in the progeny of dorsal group mutant females (pipe/pipe, D). In this and all other figures embryos are positioned with dorsal side upwards, anterior towards the left and maternal genotypes are shown at top right. Similarly, in all panels, arrowheads identify ventral denticle bands, while FK indicates the position of Filzkörper.
