Immunoelectron microscopic localization of actin in migrating cells during planarian wound healing.

Wound repair in planarians is mainly characterized by two cell-migratory events involving the epidermis adjacent to the wound and its basement membrane. The first event is the migration of epidermal cells to cover the wound surface; the second one is the migration of newly differentiating replacement epidermal cells from the parenchyma to the epidermis. In addition to these events, migration of fixed parenchymal cells is observed during wound healing. All migrating cells were characterized by the presence of actin, as shown by the results obtained by means of indirect immunolocalization with fluorescent and electron microscopy. Migrating cells were heavily labeled with gold particles, which clustered at the level of cell-matrix and cell-cell contacts.