Fig. 3. (A) Post sealing repair of wound-related damage to the cortical F-actin network. A Xenopus oocyte injected with fluorescent actin was wounded (circular profile) with a laser and then imaged at intervals of 3 minutes. An intensely labeled zone of F-actin assembly is seen around the wound site in the first panel and, in subsequent panels, is seen to contract, purse-string-style, restoring continuity to the cortical actin network. (B) Experimental analysis of the zone of actin polymerization indicates that it contains at its interface with the wound site a `contractile array' consisting of F-actin and myosin 2. Finger-like, polymerization-dependent protrusions of F-actin extend into the wound site and may facilitate final closure. (Micrographs and drawing courtesy of C. Mandato and W. Bement, University of Wisconsin.)