Probing embryonic tissue mechanics with laser hole drilling

Ma, Xiaochen; Lynch, Holley E.; Scully, Peter C; Hutson, M. Shane

doi:10.1088/1478-3975/6/3/036004

Cited by 137 publications

(207 citation statements)

References 40 publications

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“…In support of this, laser-ablation experiments in AS cells have shown the presence of tensile stress at both cell-cell interfaces and cell centres (Ma et al, 2009). …”

Section: Research Articlementioning

confidence: 86%

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Cytoskeletal dynamics and supracellular organisation of cell shape fluctuations during dorsal closure

et al. 2010

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SUMMARYFluctuations in the shape of amnioserosa (AS) cells during Drosophila dorsal closure (DC) provide an ideal system with which to understand contractile epithelia, both in terms of the cellular mechanisms and how tissue behaviour emerges from the activity of individual cells. Using quantitative image analysis we show that apical shape fluctuations are driven by the medial cytoskeleton, with periodic foci of contractile myosin and actin travelling across cell apices. Shape changes were mostly anisotropic and neighbouring cells were often, but transiently, organised into strings with parallel deformations. During the early stages of DC, shape fluctuations with long cycle lengths produced no net tissue contraction. Cycle lengths shortened with the onset of net tissue contraction, followed by a damping of fluctuation amplitude. Eventually, fluctuations became undetectable as AS cells contracted rapidly. These transitions were accompanied by an increase in apical myosin, both at cell-cell junctions and medially, the latter ultimately forming a coherent, but still dynamic, sheet across cells. Mutants with increased myosin activity or actin polymerisation exhibited precocious cell contraction through changes in the subcellular localisation of myosin. thickveins mutant embryos, which exhibited defects in the actin cable at the leading edge, showed similar timings of fluctuation damping to the wild type, suggesting that damping is an autonomous property of the AS. Our results suggest that cell shape fluctuations are a property of cells with low and increasing levels of apical myosin, and that medial and junctional myosin populations combine to contract AS cell apices and drive DC.

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“…In support of this, laser-ablation experiments in AS cells have shown the presence of tensile stress at both cell-cell interfaces and cell centres (Ma et al, 2009). …”

Section: Research Articlementioning

confidence: 86%

“…Our results suggest that these changes result from an increase in both apical medial and junctional myosin levels. The overall increase in myosin levels and the formation of a continuous actin-myosin network could provide the molecular basis for the transition of the AS to a more solid tissue (Ma et al, 2009).…”

Section: Amnioserosa Contractionmentioning

confidence: 99%

Cytoskeletal dynamics and supracellular organisation of cell shape fluctuations during dorsal closure

et al. 2010

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“…[4][5][6][7][8]. However, morphogenetic processes typically encompass hundreds to thousands of cells, involve large deformations, and take minutes to hours, yet only a few attempts have been made to analyze the large-scale mechanical properties of epithelia (e.g., refs.…”

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confidence: 99%

Large-scale mechanical properties of Xenopus embryonic epithelium

Luu

David

Ninomiya

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Epithelia are planar tissues that undergo major morphogenetic movements during development. These movements must work in the context of the mechanical properties of epithelia. Surprisingly little is known about these mechanical properties at the time and length scales of morphogenetic processes. We show that at a time scale of hours, Xenopus gastrula ectodermal epithelium mimics an elastic solid when stretched isometrically; strikingly, its area increases twofold in the embryo by such pseudoelastic expansion. At the same time, the basal side of the epithelium behaves like a liquid and exhibits tissue surface tension that minimizes its exposed area. We measure epithelial stiffness (∼1 mN/m), surface tension (∼0.6 mJ/m 2 ), and epithelium-mesenchyme interfacial tensions and relate these to the folding of isolated epithelia and to the extent of epithelial spreading on various tissues. We propose that pseudoelasticity and tissue surface tension are main determinants of epithelial behavior at the scale of morphogenetic processes.

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“…Laser microsurgery experiments show that dorsal closure [see Figs. 1(A) and 1(B)] is driven by active cell shape changes in each tissue as described below (Kiehart et al, 2000;Hutson et al, 2003;Rodriguez-Diaz et al, 2008;Ma et al, 2009;Solon et al, 2009). The purse strings shorten, largely through contractions near the canthi [see below ], and cells of the lateral epidermis elongate toward the dorsal midline.…”

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confidence: 99%

“…At the same time, cells of the amnioserosa actively change shape anisotropically as their apical surfaces contract to help draw the lateral epidermal sheets together (Kiehart et al, 2000;Jacinto et al, 2002;Gorfinkiel et al, 2009;Solon et al, 2009). Recent experiments demonstrate that cell shape changes in the amnioserosa are contributed by forces produced near cell junctions and distributed over the apical cytoskeleton (Ma et al, 2009). In addition, our experimental observations indicate that the predominant cellular movement in this stage of dorsal closure occurs normal to the dorsal midline, so we also implement this observation as an assumption of the model (unpublished observations).…”

mentioning

confidence: 99%