Complete canthi removal reveals that forces from the amnioserosa alone are sufficient to drive dorsal closure in Drosophila.
Bottom Line: Canthi maintain purse string curvature (necessary for their dorsalward forces), and zipping at the canthi shortens leading edges, ensuring a continuous epithelium at closure completion.Dissection of one or both canthi resulted in tissue recoil and flattening of each purse string.How the embryo coordinates multiple, large forces (each of which is orders of magnitude greater than the net force) during native closure and is also resilient to multiple perturbations are key extant questions.
Affiliation: Department of Biology, Duke University, Durham, NC 27708.Show MeSH
Related in: MedlinePlus
Mentions: To evaluate more quantitatively the effects of double canthus removal experiments, we characterized the effects of double canthus removal in greater detail when laser perturbation was performed midway through closure (Figure 3). The embryos were more precisely staged to improve reproducibility (see Materials and Methods and Discussion). We evaluated six embryos that were labeled with DE-cadherin-GFP and administered the laser protocol when the distance between the symmetry points of the leading edges (i.e., at the maximum dorsal opening) was 68 ± 1 μm, which is in the middle stage of closure. In each embryo, we selected six additional locations for height measurements—three on either side of the symmetry point (diagrammed in Figures 1C and 2C)—and plotted their heights over time (Figure 3B). The reproducibility of staged embryos is highlighted in Figure 3B, where the responses of all six embryos at a given position are shown on the same plot.
Affiliation: Department of Biology, Duke University, Durham, NC 27708.