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: To evaluate quantitatively the area time series, we used Fourier methods to measure oscillation frequencies. The time series of apical cross-sectional area exhibit low- and high-frequency bands that correspond to ingression and reversible oscillations, respectively (Sokolow et al., 2012). The high-frequency band is due to the active forcing function along the perimeter of an amnioserosa cell. For each amnioserosa cell in each embryo, we estimated the high-frequency band and computed its discrete Fourier transform (DFT) during the first 30 min after dissection (Figure 8, D–D′′). We compared the periodicity of amnioserosa cells in regions both near and away from the removed canthus, as well as the periodicity of cells in cut versus uncut embryos.
Affiliation: Department of Biology, Duke University, Durham, NC 27708.