Spatial discontinuity of Optomotor-blind expression in the Drosophila wing imaginal disc disrupts epithelial architecture and promotes cell sorting

Abstract Background Decapentaplegic (Dpp) is one of the best characterized morphogens, required for dorso-ventral patterning of the Drosophila embryo and for anterior-posterior (A/P) patterning of the wing imaginal disc. In the larval wing pouch, the Dpp target gene optomotor-blind (omb) is generally assumed to be expressed in a step function above a certain threshold of Dpp signaling activity. Results We show that the transcription factor Omb forms, in fact, a symmetrical gradient on both sides of the A/P compartment boundary. Disruptions of the Omb gradient lead to a re-organization of the epithelial cytoskeleton and to a retraction of cells toward the basal membrane suggesting that the O…