Fig. 4

Dynamin is essential for maintaining EVL cell morphology and epithelial integrity. ((A)(C)) Phalloidin staining showing EVL cell morphology and F-Actin organization in untreated ((A) and (A′)), DMSO control treated ((B) and (B′)) and dynasore treated embryos ((C) and (C′)). Low magnification images in ((A)(C)) show actin organization in the EVL and yolk cell. Arrowhead in (C) shows that the actomyosin ring in the E-YSL is intact. Higher magnification projections in ((A′)(C′)) are taken from the animal pole. Representative XZ planes from the Z-stacks in ((A′)(C′)) are shown below each image. Arrowheads in (C′) indicate EVL cells that are protruding below the plane of the EVL. (D) Time-lapse imaging of an embryo expressing mGFP and treated with dynasore. Single planes taken from the sub-apical region of the EVL are shown. The red dot marks a cell tracked over a 32 min period. Arrows mark a transient gap formed between the membranes of adjacent cells and arrowheads show a cell from below the plane of the EVL which is incorporated into the EVL and subsequently basally extruded. These defects were never observed in control time-lapse images. ((E)(G)) Localization of ZO-1 in the EVL of untreated (E), DMSO control treated (F) and dynasore treated (G) embryos. ((H)(J)) Localization of P-ERM in the EVL of untreated ((H) and (H′)), DMSO control treated ((I) and (I′)) and dynasore treated ((J) and (J′)) embryos. Overlay with phalloidin staining is shown in ((H′)(I)). (K) An XZ plane taken from a time-lapse as in (D) showing an EVL cell (red dot) sending a protrusion into the underlying deep cells (arrowhead). Apical to the top. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)