Understanding this seemingly arcane process is important because dorsal closure uses molecular and cellular mechanisms very similar to those involved in wound-healing as well as those that can go awry in humans to produce the spinal malformation spina bifida.
The researchers achievements were reported in an online article in the February 6, 2003, Sciencexpress -- and will appear in the April 4, 2003, print version of Science -- by an interdisciplinary Duke research team that includes biologists, physicists and a mathematician. It was this broad collaboration, said the scientists, that enabled them to refine the laser scalpel, to perform the microsurgery to dissect the fly tissue and to model the forces involved in key developmental machinery.
Dorsal closure is a good system for studying these processes because its tractable, said lead author Shane Hutson. We only have to deal with a few different kinds of cells that are arranged in a planar fashion.
According to Hutson -- a postdoctoral fellow in Dukes Free Electron Laser Laboratory (FELL) -- dorsal closure involves the interplay of forces among three kinds of tissues in the fly embryo, which is smaller than a grain of rice. The amnioserosa cells form an inner sheet of tissue involved in knitting the closure; the lateral epidermis is the tissue layer that ultimately forms the flys outer covering; and in between these two tissues is a group of leading edge cells that form a purse-string structure that somehow tightens to contribute to closure.