Fig. 7. Disorganization of actin filaments in vab-19 and genetic suppression in vab-19 sma-1 double mutants. Confocal images of F-actin distribution in wild-type and vab-19 embryo, visualized with fluorescently labeled phalloidin. In all panels, the bright longitudinal strips of phalloidin staining correspond to body wall muscles. (A-D) In the wild type, actin filaments form parallel bundles circumferentially around the embryo. In vab-19 embryos, actin bundles form normally at early elongation stage (E) but are more randomly oriented in later elongation (F-H) or missing from the apical surface of the epidermis (F). The disorganization of actin bundles is more obvious in regions where muscle is detached from epidermal cells (F). In sma-1(e30);vab-19(ju406) double mutants (I-K), actin bundles are less disorganized than in vab-19 single mutants. Scale bar, 10 µm.