Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Development
2009 Feb 01;1364:677-88. doi: 10.1242/dev.026211.
Show Gene links
Show Anatomy links
Actomyosin stiffens the vertebrate embryo during crucial stages of elongation and neural tube closure.
Zhou J
,
Kim HY
,
Davidson LA
.
???displayArticle.abstract???
Physical forces drive the movement of tissues within the early embryo. Classical and modern approaches have been used to infer and, in rare cases, measure mechanical properties and the location and magnitude of forces within embryos. Elongation of the dorsal axis is a crucial event in early vertebrate development, yet the mechanics of dorsal tissues in driving embryonic elongation that later support neural tube closure and formation of the central nervous system is not known. Among vertebrates, amphibian embryos allow complex physical manipulation of embryonic tissues that are required to measure the mechanical properties of tissues. In this paper, we measure the stiffness of dorsal isolate explants of frog (Xenopus laevis) from gastrulation to neurulation and find dorsal tissues stiffen from less than 20 Pascal (Pa) to over 80 Pa. By iteratively removing tissues from these explants, we find paraxial somitic mesoderm is nearly twice as stiff as either the notochord or neural plate, and at least 10-fold stiffer than the endoderm. Stiffness measurements from explants with reduced fibronectin fibril assembly or disrupted actomyosin contractility suggest that it is the state of the actomyosin cell cortex rather than accumulating fibronectin that controls tissue stiffness in early amphibian embryos.
Fig. 3. Mechanics of paraxial-medial and paraxial-lateral tissues.(A) Schematic diagram of explants carrying complete sets of paraxial tissues (lateral-medial-medial-lateral or LMML) and those carrying only paraxial lateral tissues (lateral-lateral or LL) of the dorsal axis. (B) Fibronectin fibril localization in transverse sections of LMML and LL explants shows the location of paraxial mesoderm outlined by fibronectin. (C) A view of XmyoD expression through the endodermal face of explants reveals a distinct boundary between paraxial-medial (XmyoD expressing) and paraxial-lateral (non-expressing) tissues of control dorsal isolates and LMML explants. XmyoD is absent from most of the length of LL explants that can occasionally express a small `wedge' of XmyoD in their most posterior third (arrowhead). All explants are positioned so that anterior is at the top of the panel. (D) Frames and explant lengths over time from a single representative time-lapse (n=6) demonstrate that LMML and LL explants elongate to the same degree as control explants. (E) The stiffness of LL and MM isolates show that MM explants are significantly more stiff than LL explants. *P<0.05; **P<0.01.
Adams,
The mechanics of notochord elongation, straightening and stiffening in the embryo of Xenopus laevis.
1990, Pubmed,
Xenbase
Adams,
The mechanics of notochord elongation, straightening and stiffening in the embryo of Xenopus laevis.
1990,
Pubmed
,
Xenbase
Benink,
Concentric zones of active RhoA and Cdc42 around single cell wounds.
2005,
Pubmed
,
Xenbase
Colognato,
Form and function: the laminin family of heterotrimers.
2000,
Pubmed
Copp,
The genetic basis of mammalian neurulation.
2003,
Pubmed
Cramer,
Role of actin-filament disassembly in lamellipodium protrusion in motile cells revealed using the drug jasplakinolide.
1999,
Pubmed
Davidson,
Measuring mechanical properties of embryos and embryonic tissues.
2007,
Pubmed
,
Xenbase
Davidson,
Live imaging of cell protrusive activity, and extracellular matrix assembly and remodeling during morphogenesis in the frog, Xenopus laevis.
2008,
Pubmed
,
Xenbase
Davidson,
Measurements of mechanical properties of the blastula wall reveal which hypothesized mechanisms of primary invagination are physically plausible in the sea urchin Strongylocentrotus purpuratus.
1999,
Pubmed
Davidson,
Neural tube closure in Xenopus laevis involves medial migration, directed protrusive activity, cell intercalation and convergent extension.
1999,
Pubmed
,
Xenbase
Davidson,
Assembly and remodeling of the fibrillar fibronectin extracellular matrix during gastrulation and neurulation in Xenopus laevis.
2004,
Pubmed
,
Xenbase
Davidson,
Integrin alpha5beta1 and fibronectin regulate polarized cell protrusions required for Xenopus convergence and extension.
2006,
Pubmed
,
Xenbase
De Robertis,
Dorsal-ventral patterning and neural induction in Xenopus embryos.
2004,
Pubmed
,
Xenbase
Dent,
A whole-mount immunocytochemical analysis of the expression of the intermediate filament protein vimentin in Xenopus.
1989,
Pubmed
,
Xenbase
Elul,
Monopolar protrusive activity: a new morphogenic cell behavior in the neural plate dependent on vertical interactions with the mesoderm in Xenopus.
2000,
Pubmed
,
Xenbase
Engler,
Matrix elasticity directs stem cell lineage specification.
2006,
Pubmed
Ezin,
The presumptive floor plate (notoplate) induces behaviors associated with convergent extension in medial but not lateral neural plate cells of Xenopus.
2006,
Pubmed
,
Xenbase
Gardel,
Prestressed F-actin networks cross-linked by hinged filamins replicate mechanical properties of cells.
2006,
Pubmed
Georges,
Matrices with compliance comparable to that of brain tissue select neuronal over glial growth in mixed cortical cultures.
2006,
Pubmed
Hopwood,
MyoD expression in the forming somites is an early response to mesoderm induction in Xenopus embryos.
1989,
Pubmed
,
Xenbase
Jacobson,
Changes in the shape of the developing vertebrate nervous system analyzed experimentally, mathematically and by computer simulation.
1976,
Pubmed
Janmey,
Basic rheology for biologists.
2007,
Pubmed
Janmey,
Dealing with mechanics: mechanisms of force transduction in cells.
2004,
Pubmed
KITCHIN,
The effects of notochordectomy in Amblystoma mexicanum.
1949,
Pubmed
Keller,
The origin and morphogenesis of amphibian somites.
2000,
Pubmed
Keller,
Cell intercalation during notochord development in Xenopus laevis.
1989,
Pubmed
,
Xenbase
Kibar,
Toward understanding the genetic basis of neural tube defects.
2007,
Pubmed
Kinsey,
Fibrillin-1 microfibril deposition is dependent on fibronectin assembly.
2008,
Pubmed
Kofron,
Plakoglobin is required for maintenance of the cortical actin skeleton in early Xenopus embryos and for cdc42-mediated wound healing.
2002,
Pubmed
,
Xenbase
Lee,
Actomyosin contractility and microtubules drive apical constriction in Xenopus bottle cells.
2007,
Pubmed
,
Xenbase
Lee,
Temporal and spatial regulation of fibronectin in early Xenopus development.
1984,
Pubmed
,
Xenbase
Lee,
Wnt/Frizzled signaling controls C. elegans gastrulation by activating actomyosin contractility.
2006,
Pubmed
Luby-Phelps,
Cytoarchitecture and physical properties of cytoplasm: volume, viscosity, diffusion, intracellular surface area.
2000,
Pubmed
Maekawa,
Signaling from Rho to the actin cytoskeleton through protein kinases ROCK and LIM-kinase.
1999,
Pubmed
Malacinski,
Neural plate morphogenesis and axial stretching in "notochord-defective" Xenopus laevis embryos.
1981,
Pubmed
,
Xenbase
McBeath,
Cell shape, cytoskeletal tension, and RhoA regulate stem cell lineage commitment.
2004,
Pubmed
Moore,
The dorsal involuting marginal zone stiffens anisotropically during its convergent extension in the gastrula of Xenopus laevis.
1995,
Pubmed
,
Xenbase
Munro,
Polarized basolateral cell motility underlies invagination and convergent extension of the ascidian notochord.
2002,
Pubmed
Narumiya,
Use and properties of ROCK-specific inhibitor Y-27632.
2000,
Pubmed
Paszek,
Tensional homeostasis and the malignant phenotype.
2005,
Pubmed
Pollard,
Cellular motility driven by assembly and disassembly of actin filaments.
2003,
Pubmed
Shih,
Cell motility driving mediolateral intercalation in explants of Xenopus laevis.
1992,
Pubmed
,
Xenbase
Sivakumar,
New insights into extracellular matrix assembly and reorganization from dynamic imaging of extracellular matrix proteins in living osteoblasts.
2006,
Pubmed
Skoglund,
Xenopus fibrillin is expressed in the organizer and is the earliest component of matrix at the developing notochord-somite boundary.
2006,
Pubmed
,
Xenbase
Stamenović,
Effects of cytoskeletal prestress on cell rheological behavior.
2005,
Pubmed
Stemple,
Structure and function of the notochord: an essential organ for chordate development.
2005,
Pubmed
Stewart,
The anterior extent of dorsal development of the Xenopus embryonic axis depends on the quantity of organizer in the late blastula.
1990,
Pubmed
,
Xenbase
Talbot,
A homeobox gene essential for zebrafish notochord development.
1995,
Pubmed
,
Xenbase
Tao,
G-protein-coupled signals control cortical actin assembly by controlling cadherin expression in the early Xenopus embryo.
2007,
Pubmed
,
Xenbase
Wallingford,
Neural tube closure requires Dishevelled-dependent convergent extension of the midline.
2002,
Pubmed
,
Xenbase
Waters,
Cellular biomechanics in the lung.
2002,
Pubmed
Wedlich,
The distribution of fibronectin and laminin in the somitogenesis of Xenopus laevis.
1989,
Pubmed
,
Xenbase
Wilson,
Cell rearrangement during gastrulation of Xenopus: direct observation of cultured explants.
1991,
Pubmed
,
Xenbase
Wilson,
Cell rearrangement and segmentation in Xenopus: direct observation of cultured explants.
1989,
Pubmed
,
Xenbase
Yam,
Actin-myosin network reorganization breaks symmetry at the cell rear to spontaneously initiate polarized cell motility.
2007,
Pubmed
,
Xenbase
Ybot-Gonzalez,
Convergent extension, planar-cell-polarity signalling and initiation of mouse neural tube closure.
2007,
Pubmed
Youn,
Axial structure development in ultraviolet-irradiated (notochord-defective) amphibian embryos.
1981,
Pubmed
,
Xenbase
Zamir,
Material properties and residual stress in the stage 12 chick heart during cardiac looping.
2004,
Pubmed
Zamir,
On the effects of residual stress in microindentation tests of soft tissue structures.
2004,
Pubmed
von Dassow,
Natural variation in embryo mechanics: gastrulation in Xenopus laevis is highly robust to variation in tissue stiffness.
2009,
Pubmed
,
Xenbase
