Fig. 6. The putative IB Kinase (IKK) target motif is dispensable for the spatially regulated degradation of Cactus-lacZ. Mutated derivatives of Cactus-lacZ in which serines 74 and 78 (A) or serines 74, 78, 82 and 83 (B) had been converted to alanine residues were expressed under maternal transcriptional control and their distributions determined by lacZ activity. Both proteins exhibited normal polarized distributions and were capable of restoring ventral pattern elements (D) to the otherwise dorsalized progeny of cact^BQ/cact^E10 females (C). Similarly, the mutated constructs were capable of restoring lateral and dorsal pattern elements (F) and the ability to hatch to the otherwise ventralized progeny of cact⁰¹¹/cact⁰¹¹ females (E).