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
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Mentions: As described earlier, we used laser surgery to dissect a single canthus from the dorsal opening (n = 8; Figure 5, E and E′) and then investigated the consequences for the behavior of amnioserosa cells. We compared the amnioserosa cells in the last image taken before the cut (∼30 s before) and the first image taken after the cut (∼1–2 min after; Figure 5, E and E′). For native, uncut embryos, we chose images that differ over the same time interval as that of cut embryos (Figure 5, F and F′).
Affiliation: Department of Biology, Duke University, Durham, NC 27708.