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Complete canthi removal reveals that forces from the amnioserosa alone are sufficient to drive dorsal closure in Drosophila.

Wells AR, Zou RS, Tulu US, Sokolow AC, Crawford JM, Edwards GS, Kiehart DP - Mol. Biol. Cell (2014)

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Duke University, Durham, NC 27708.

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Related in: MedlinePlus

Area plots of amnioserosa cells indicate no noticeable short-term change in area oscillations as a result of canthus removal. (A, B) Graphs of amnioserosa cell area over time in six single canthus removal embryos. The time of the first image after canthus removal is t = 0. (A) Plot of the areas of three cells closest to the laser cut (red) and three cells slightly farther away from the laser cut (blue). (Ai–Avi) Six different embryos. (B) Plot of cell area for the same six single cut embryos near the intact canthus (on the other side of the embryo). (C) Area plots of native embryos are qualitatively indistinguishable from the area plots in A and B. The “close to cut” and “away from cut” regions in native embryos refer to locations where a cut would have occurred had the embryo not been a control.
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Figure 7: Area plots of amnioserosa cells indicate no noticeable short-term change in area oscillations as a result of canthus removal. (A, B) Graphs of amnioserosa cell area over time in six single canthus removal embryos. The time of the first image after canthus removal is t = 0. (A) Plot of the areas of three cells closest to the laser cut (red) and three cells slightly farther away from the laser cut (blue). (Ai–Avi) Six different embryos. (B) Plot of cell area for the same six single cut embryos near the intact canthus (on the other side of the embryo). (C) Area plots of native embryos are qualitatively indistinguishable from the area plots in A and B. The “close to cut” and “away from cut” regions in native embryos refer to locations where a cut would have occurred had the embryo not been a control.

Mentions: We evaluated the oscillations in the apical cross section of the amnioserosa cells after canthus removal by tracking the change in area as a function of time with an automated cell segmentation program (see Materials and Methods and Supplemental Movie S6). The segmentation algorithm effectively tracked cell boundaries 30 min (after a 1– to 2-min delay) after laser dissection. Previous studies (Sokolow et al., 2012) observed that individual amnioserosa cell oscillations in unperturbed embryos range from 4 to 10 mHz, which correspond to a 1.7- to 4.2-min period. Thus the 30-min window we specified can capture at least seven full cell oscillations. We observed no remarkable quantitative differences in frequencies or amplitudes of the area oscillations in amnioserosa cells adjacent to the site of laser dissection, far from that site, or in native embryos. This observation was consistent for all cut and native embryos (Figure 7).


Complete canthi removal reveals that forces from the amnioserosa alone are sufficient to drive dorsal closure in Drosophila.

Wells AR, Zou RS, Tulu US, Sokolow AC, Crawford JM, Edwards GS, Kiehart DP - Mol. Biol. Cell (2014)

Area plots of amnioserosa cells indicate no noticeable short-term change in area oscillations as a result of canthus removal. (A, B) Graphs of amnioserosa cell area over time in six single canthus removal embryos. The time of the first image after canthus removal is t = 0. (A) Plot of the areas of three cells closest to the laser cut (red) and three cells slightly farther away from the laser cut (blue). (Ai–Avi) Six different embryos. (B) Plot of cell area for the same six single cut embryos near the intact canthus (on the other side of the embryo). (C) Area plots of native embryos are qualitatively indistinguishable from the area plots in A and B. The “close to cut” and “away from cut” regions in native embryos refer to locations where a cut would have occurred had the embryo not been a control.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 7: Area plots of amnioserosa cells indicate no noticeable short-term change in area oscillations as a result of canthus removal. (A, B) Graphs of amnioserosa cell area over time in six single canthus removal embryos. The time of the first image after canthus removal is t = 0. (A) Plot of the areas of three cells closest to the laser cut (red) and three cells slightly farther away from the laser cut (blue). (Ai–Avi) Six different embryos. (B) Plot of cell area for the same six single cut embryos near the intact canthus (on the other side of the embryo). (C) Area plots of native embryos are qualitatively indistinguishable from the area plots in A and B. The “close to cut” and “away from cut” regions in native embryos refer to locations where a cut would have occurred had the embryo not been a control.
Mentions: We evaluated the oscillations in the apical cross section of the amnioserosa cells after canthus removal by tracking the change in area as a function of time with an automated cell segmentation program (see Materials and Methods and Supplemental Movie S6). The segmentation algorithm effectively tracked cell boundaries 30 min (after a 1– to 2-min delay) after laser dissection. Previous studies (Sokolow et al., 2012) observed that individual amnioserosa cell oscillations in unperturbed embryos range from 4 to 10 mHz, which correspond to a 1.7- to 4.2-min period. Thus the 30-min window we specified can capture at least seven full cell oscillations. We observed no remarkable quantitative differences in frequencies or amplitudes of the area oscillations in amnioserosa cells adjacent to the site of laser dissection, far from that site, or in native embryos. This observation was consistent for all cut and native embryos (Figure 7).

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Duke University, Durham, NC 27708.

Show MeSH
Related in: MedlinePlus