Epithelial effects of Omb misexpression are not mediated by Sal. (A, A') Strong ectopic Omb has little effect on Sal expression. The arrowhead points to where the Gal4 30 expression domain  overlaps the wing pouch. (B, B') Complete loss of omb (in a l(1)ombD4clone, arrowhead) leads to strong reduction of Sal. (C) Incomplete elimination of omb function (in en>ombRNAi) only slightly decreases Sal expression. The arrowhead points to the posterior compartment, separated from the anterior compartment by a deep fold due to posterior reduction in Omb . (D-F) The phenotype of omb l-o-f clones (arrows) is elicited also outside the Sal domain. Cuticular manifestations of retraction and extrusion events were found anterior to L2 (D, E) and posterior to L5 (E).