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???displayArticle.abstract??? Blastopore closure in the amphibian embryo involves large scale tissue reorganization driven by physical forces. These forces are tuned to generate sustained blastopore closure throughout the course of gastrulation. We describe the mechanics of blastopore closure at multiple scales and in different regions around the blastopore by characterizing large scale tissue deformations, cell level shape change and subcellular F-actin organization and by measuring tissue force production and structural stiffness of the blastopore during gastrulation. We find that the embryo generates a ramping magnitude of force until it reaches a peak force on the order of 0.5μN. During this time course, the embryo also stiffens 1.5 fold. Strain rate mapping of the dorsal, ventral and lateral epithelial cells proximal to the blastopore reveals changing patterns of strain rate throughout closure. Cells dorsal to the blastopore, which are fated to become neural plateectoderm, are polarized and have straight boundaries. In contrast, cells lateral and ventral to the blastopore are less polarized and have tortuous cell boundaries. The F-actin network is organized differently in each region with the highest percentage of alignment occurring in the lateral region. Interestingly F-actin was consistently oriented toward the blastopore lip in dorsal and lateral cells, but oriented parallel to the lip in ventral regions. Cell shape and F-actin alignment analyses reveal different local mechanical environments in regions around the blastopore, which was reflected by the strain rate maps.
Barbee,
Shear stress-induced reorganization of the surface topography of living endothelial cells imaged by atomic force microscopy.
1994, Pubmed
Barbee,
Shear stress-induced reorganization of the surface topography of living endothelial cells imaged by atomic force microscopy.
1994,
Pubmed Beloussov,
The role of external tensions in differentiation of Xenopus laevis embryonic tissues.
1988,
Pubmed
,
Xenbase Blanchard,
Tissue tectonics: morphogenetic strain rates, cell shape change and intercalation.
2009,
Pubmed Burkel,
Versatile fluorescent probes for actin filaments based on the actin-binding domain of utrophin.
2007,
Pubmed
,
Xenbase Davidson,
Multi-scale mechanics from molecules to morphogenesis.
2009,
Pubmed Davidson,
Measuring mechanical properties of embryos and embryonic tissues.
2007,
Pubmed
,
Xenbase Davidson,
Embryo mechanics: balancing force production with elastic resistance during morphogenesis.
2011,
Pubmed Discher,
Tissue cells feel and respond to the stiffness of their substrate.
2005,
Pubmed Ewald,
Surface imaging microscopy, an automated method for visualizing whole embryo samples in three dimensions at high resolution.
2002,
Pubmed
,
Xenbase Gibson,
The emergence of geometric order in proliferating metazoan epithelia.
2006,
Pubmed Heisenberg,
Forces in tissue morphogenesis and patterning.
2013,
Pubmed Joshi,
Microscopy tools for quantifying developmental dynamics in Xenopus embryos.
2012,
Pubmed
,
Xenbase Keller,
Mechanisms of convergence and extension by cell intercalation.
2000,
Pubmed Keller,
Dynamic determinations: patterning the cell behaviours that close the amphibian blastopore.
2008,
Pubmed
,
Xenbase Keller,
How we are shaped: the biomechanics of gastrulation.
2003,
Pubmed
,
Xenbase Kim,
Investigating morphogenesis in Xenopus embryos: imaging strategies, processing, and analysis.
2013,
Pubmed
,
Xenbase Kim,
Punctuated actin contractions during convergent extension and their permissive regulation by the non-canonical Wnt-signaling pathway.
2011,
Pubmed
,
Xenbase Korukonda,
Visualizing the radial and circumferential strain distribution within vessel phantoms using synthetic-aperture ultrasound elastography.
2012,
Pubmed Lecuit,
Force generation, transmission, and integration during cell and tissue morphogenesis.
2011,
Pubmed Levental,
Soft biological materials and their impact on cell function.
2007,
Pubmed Majkut,
Heart-specific stiffening in early embryos parallels matrix and myosin expression to optimize beating.
2013,
Pubmed Mateus,
Endocytic and recycling endosomes modulate cell shape changes and tissue behaviour during morphogenesis in Drosophila.
2011,
Pubmed Moore,
The dorsal involuting marginal zone stiffens anisotropically during its convergent extension in the gastrula of Xenopus laevis.
1995,
Pubmed
,
Xenbase Moosmann,
X-ray phase-contrast in vivo microtomography probes new aspects of Xenopus gastrulation.
2013,
Pubmed
,
Xenbase Nusrat,
Rho protein regulates tight junctions and perijunctional actin organization in polarized epithelia.
1995,
Pubmed Orr,
Mechanisms of mechanotransduction.
2006,
Pubmed Pope,
Control of cell flattening and junctional remodeling during squamous epithelial morphogenesis in Drosophila.
2008,
Pubmed Rueden,
Visualization approaches for multidimensional biological image data.
2007,
Pubmed SELMAN,
The forces producing neural closure in amphibia.
1958,
Pubmed Solon,
Pulsed forces timed by a ratchet-like mechanism drive directed tissue movement during dorsal closure.
2009,
Pubmed Toyama,
Apoptotic force and tissue dynamics during Drosophila embryogenesis.
2008,
Pubmed Tyszka,
New tools for visualization and analysis of morphogenesis in spherical embryos.
2005,
Pubmed
,
Xenbase Varner,
Mechanics of head fold formation: investigating tissue-level forces during early development.
2010,
Pubmed von Dassow,
Surprisingly simple mechanical behavior of a complex embryonic tissue.
2010,
Pubmed
,
Xenbase Zhou,
Macroscopic stiffening of embryonic tissues via microtubules, RhoGEF and the assembly of contractile bundles of actomyosin.
2010,
Pubmed
,
Xenbase Zhou,
Actomyosin stiffens the vertebrate embryo during crucial stages of elongation and neural tube closure.
2009,
Pubmed
,
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