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: The most dramatic effect of the single-canthus cut was the displacement of centroids along the anterior–posterior axis away from the site of the cut (Figures 5, A and A′, and 6, A and A′). The centroids of cells closest to the dissected canthus were displaced the most. Moreover, the displacement of the centroids furthest from the cut (and nearest the intact canthus) appeared indistinguishable from that of unperturbed, native embryos. Indeed, we observed an inverse relationship between the displacement along the dorsal midline and the distance from the site of the cut that was well approximated by an exponential decay (Figure 6A; n = 8, R2 > 0.89). This exponential decay was consistently observed for all embryos we examined, regardless of the stage of closure.
Affiliation: Department of Biology, Duke University, Durham, NC 27708.