Kiehart and colleagues (page 471) used time-lapse and real-time imaging of a GFP-tagged fusion protein, along with a series of elegant biomechanical analyses, to determine the major types of forces acting on cell sheets during dorsal closure in Drosophila. In addition to illuminating this important aspect of fly biology, the experiments demonstrate a powerful new system for studying morphogenesis and wound healing.
Using a transgene encoding GFP fused to an actin-binding fragment from the fly moesin protein, the authors followed cell shape changes and tissue movements during dorsal closure. The team then used a laser to destroy small groups of cells in precise locations, observing the resulting changes in cell sheet morphology to determine the forces acting on the sheet. The results suggest that both purse string–like forces in the leading edge of the lateral epidermis and contractility...
