Fig. 5. Disruption of actin cytoskeleton and reduction in Arm and FASIII patterns along the apicobasal axis. (A-C) FITC-conjugated actin-phalloidin staining of wild-type (A), coroex11/coroex11 (B) and coroex6/coroex6 (C) wing discs. A' and A'' show disc in A at higher magnifications. Similarly B' and C' are higher magnification images of discs shown in B and C, respectively. Note moderate to severe disruption of fine network of the actin cytoskeleton in B and C, respectively. coroex6/coroex6 discs show a large number of darkly stained actin foci. Actin-phalloidin is normally localized to the apical surface of epithelial cells, which is reflected in higher intensity of staining at the DV boundary and at the presumptive hinge regions (A). In coroex6/coroex6 discs, such intense staining of actin-phalloidin is lost (C) suggesting loss of actin-phalloidin from the apical surface. (D,E) Wild-type (D) and coroex6/coroex6 (E) wing discs stained for Arm (green; D,E) and FASIII (red; D',E'). D'' and E'' are the merged images of D and D' and E and E', respectively. Note that in coroex6/coroex6 discs levels of both Arm and FASIII are very low and the staining is more diffused. (F-H) X-Z sections of wild-type (F), coroex11/coroex11 (G) and coroex6/coroex6 (H) wing discs stained for Arm (green) and FASIII (red). Note that normally Arm is apical and FASIII is basolateral. In wild-type wing discs both are expressed at very high levels. Both coroex11/coroex11 and coroex6/coroex6 show significant reduction in Arm and marginal reduction in FASIII staining indicating a possible defect in apicobasal polarity. In addition, cells are loosely arranged in coro- discs compared to wild-type disc, wherein cells are more compact. Normally coroex6/coroex6 discs show severe loss of FASIII and Arm staining (as shown in E) and general loss of cell and disc morphology (as shown in C). To ascertain specific effects of loss of coro on apicobasal polarity of wing discs, we have chosen those coroex6 wing discs, which show milder phenotype.