Epithelial fusions in the embryo.

Morphogenesis in the embryo involves the bending, folding and fusing of epithelial tissues to create the final complex shapes of the various organs and structures in the body. One essential process that occurs frequently during development is the drawing together and fusion of epithelial edges. Drosophila dorsal closure is perhaps the most genetically tractable of this type of movement, and several recent advances have revealed much about the signals regulating the dynamic actin cytoskeletal machineries that underlie the zippering-closed of this hole in the embryonic fly. It is now clear that there are intriguing parallels with more complex morphogenetic tissue movements in vertebrates.