Researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, came a step closer to understanding how cells close gaps not only during embryonic development but also during wound healing. Their study, published this week in the journal Cell, uncovers a fundamental misconception in the previous explanation for a developmental process called dorsal closure.
Scientists study dorsal closure, which occurs during the development of the fruit fly Drosophila melanogaster, to gain insights into wound healing in humans, as both processes involve closing a gap in the skin by stretching the surrounding epithelial cells over it.
Dorsal closure involves three entities: the cells that fill the gap, called amnioserosa cells, a cable of the protein actin which runs around the gap, and the epithelial cells that eventually stretch over and seal the gap. Until now, scientists believed dorsal closure started when some unknown signal made the amnioserosa cells and the actin cable contract. The actin cable would then act like the drawstring on a purse together with the gradually contracting amnioserosa cells, it would pull the epithelial cells together until the gap was closed. 