scholarly journals Cooperation of polarized cell intercalations drives convergence and extension of presomitic mesoderm during zebrafish gastrulation

2008 ◽  
Vol 180 (1) ◽  
pp. 221-232 ◽  
Author(s):  
Chunyue Yin ◽  
Maria Kiskowski ◽  
Philippe-Alexandre Pouille ◽  
Emmanuel Farge ◽  
Lilianna Solnica-Krezel
Keyword(s):  
Wnt Signaling ◽  
Time Lapse ◽  
Presomitic Mesoderm ◽  
Mesodermal Cell ◽  
Cell Behaviors ◽  
Embryonic Tissues ◽  
Dorsal Mesoderm ◽  
Radial Cell ◽  
Convergence And Extension ◽  
Cell Layers

During vertebrate gastrulation, convergence and extension (C&E) movements narrow and lengthen the embryonic tissues, respectively. In zebrafish, regional differences of C&E movements have been observed; however, the underlying cell behaviors are poorly understood. Using time-lapse analyses and computational modeling, we demonstrate that C&E of the medial presomitic mesoderm is achieved by cooperation of planar and radial cell intercalations. Radial intercalations preferentially separate anterior and posterior neighbors to promote extension. In knypek;trilobite noncanonical Wnt mutants, the frequencies of cell intercalations are altered and the anteroposterior bias of radial intercalations is lost. This provides evidence for noncanonical Wnt signaling polarizing cell movements between different mesodermal cell layers. We further show using fluorescent fusion proteins that during dorsal mesoderm C&E, the noncanonical Wnt component Prickle localizes at the anterior cell edge, whereas Dishevelled is enriched posteriorly. Asymmetrical localization of Prickle and Dishevelled to the opposite cell edges in zebrafish gastrula parallels their distribution in fly, and suggests that noncanonical Wnt signaling defines distinct anterior and posterior cell properties to bias cell intercalations.

scholarly journals Essential roles of Gα12/13 signaling in distinct cell behaviors driving zebrafish convergence and extension gastrulation movements

2005 ◽  
Vol 169 (5) ◽  
pp. 777-787 ◽  
Author(s):  
Fang Lin ◽  
Diane S. Sepich ◽  
Songhai Chen ◽  
Jacek Topczewski ◽  
Chunyue Yin ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Cell Elongation ◽  
Dominant Negative ◽  
Embryonic Patterning ◽  
Mesodermal Cell ◽  
Cell Behaviors ◽  
Cellular Processes ◽  
Distinct Cell ◽  
Convergence And Extension ◽  
Modified Oligonucleotide

Gα12/13 have been implicated in numerous cellular processes, however, their roles in vertebrate gastrulation are largely unknown. Here, we show that during zebrafish gastrulation, suppression of both Gα12 and Gα13 signaling by overexpressing dominant negative proteins and application of antisense morpholino-modified oligonucleotide translation interference disrupted convergence and extension without changing embryonic patterning. Analyses of mesodermal cell behaviors revealed that Gα12/13 are required for cell elongation and efficient dorsalward migration during convergence independent of noncanonical Wnt signaling. Furthermore, Gα12/13 function cell-autonomously to mediate mediolateral cell elongation underlying intercalation during notochord extension, likely acting in parallel to noncanonical Wnt signaling. These findings provide the first evidence that Gα12 and Gα13 have overlapping and essential roles in distinct cell behaviors that drive vertebrate gastrulation.

Regulation of cell polarity, radial intercalation and epiboly inXenopus: novel roles for integrin and fibronectin

Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3635-3647 ◽  
Author(s):  
Mungo Marsden ◽  
Douglas W. DeSimone
Keyword(s):  
Cell Polarity ◽  
Time Lapse ◽  
Dominant Negative ◽  
Matrix Assembly ◽  
Cell Behaviors ◽  
Fibronectin Matrix ◽  
Cell Layers ◽  
Two Phases ◽  
Fibronectin Fibrils

Fibronectin (FN) is reported to be important for early morphogenetic movements in a variety of vertebrate embryos, but the cellular basis for this requirement is unclear. We have used confocal and digital time-lapse microscopy to analyze cell behaviors in Xenopus gastrulae injected with monoclonal antibodies directed against the central cell-binding domain of fibronectin. Among the defects observed is a disruption of fibronectin matrix assembly, resulting in a failure of radial intercalation movements, which are required for blastocoel roof thinning and epiboly. We identified two phases of FN-dependent cellular rearrangements in the blastocoel roof. The first involves maintenance of early roof thinning in the animal cap, and the second is required for the initiation of radial intercalation movements in the marginal zone. A novel explant system was used to establish that radial intercalation in the blastocoel roof requires integrin-dependent contact of deep cells with fibronectin. Deep cell adhesion to fibronectin is sufficient to initiate intercalation behavior in cell layers some distance from the substrate. Expression of a dominant-negative β1 integrin construct in embryos results in localized depletion of the fibronectin matrix and thickening of the blastocoel roof. Lack of fibronectin fibrils in vivo is correlated with blastocoel roof thickening and a loss of deep cell polarity. The integrin-dependent binding of deep cells to fibronectin is sufficient to drive membrane localization of Dishevelled-GFP, suggesting that a convergence of integrin and Wnt signaling pathways acts to regulate radial intercalation in Xenopus embryos.

scholarly journals Time Lapse Observation Based Modeling and Identification of Cell Behaviors in Angiogenic Sprout Development

2010 ◽  
Author(s):  
Levi B. Wood ◽  
Roger D. Kamm ◽  
H. Harry Asada
Keyword(s):  
Blood Vessel ◽  
Real Time ◽  
Time Lapse ◽  
Model Parameters ◽  
Cell Behaviors ◽  
The Matrix ◽  
The Individual ◽  
Sprout Formation ◽  
Cell Motion

This paper presents a method for deriving dynamic equations for Endothelial Cell (EC) motion and estimating parameters based on time lapse imagery of angiogenic sprout development. Angiogenesis is the process whereby a collection of endothelial cells sprout out from an existing blood vessel, degrade the surrounding scaffold and form a new blood vessel. Sprout formation requires that a collection of ECs all work together and coordinate their movements and behaviors. The process is initiated and guided by a collection of external growth factors. In addition, the individual cells communicate and respond to each other’s movements to behave in a coordinated fashion. The mechanics of cell coordination are extremely complex and include both chemical and mechanical communication between cells and between cells and the matrix. Despite the complexity of the physical system, with many variables that cannot be measured in real time, the ECs behave in a predictable manner based on just a few quantities that can be measured in real time. This work presents a methodology for constructing a set of simple stochastic equations for cell motion dependent only on quantities obtained from time lapse data observed from in vitro experiments. Model parameters are identified from time lapse data using a Maximum Likelihood Estimator.

scholarly journals Control of dynamic cell behaviors during angiogenesis and anastomosis by Rasip 1

2020 ◽  
Author(s):  
Minkyoung Lee ◽  
Charles Betz ◽  
Ilkka Paatero ◽  
Niels Schellinx ◽  
Jianmin Yin ◽  
...  
Keyword(s):  
Time Lapse ◽  
Tube Formation ◽  
Interacting Protein ◽  
Cell Behaviors ◽  
Sprouting Angiogenesis ◽  
Phenotype Analysis ◽  
Membrane Compartment ◽  
Dynamic Cell ◽  
Cellular Behaviors ◽  
And Function

AbstractOrgan morphogenesis is driven by a wealth of tightly orchestrated cellular behaviors, which ensure proper organ assembly and function. Many of these cell activities involve cell-cell interactions and remodeling of the F-actin cytoskeleton. Here, we analyze the requirement for Rasip1 (Ras-interacting protein 1), an endothelial-specific regulator of junctional dynamics, during blood vessel formation. Phenotype analysis of rasip1 mutants in zebrafish embryos reveal distinct requirements for Rasip1 during sprouting angiogenesis, vascular anastomosis and lumen formation. During angiogenic sprouting, Rasip1 is required for efficient cell pairing, which is essential for multicellular tube formation. High-resolution time-lapse analyses show that these cell pairing defects are caused by a destabilization of tricellular junctions suggesting that tri-cellular junctions may serve as a counterfort to tether sprouting endothelial cells during morphogenetic cell rearrangements. During anastomosis, Rasip1 is required to establish a stable apical membrane compartment; rasip1 mutants display ectopic, reticulated junctions and the apical compartment is frequently collapsed. Loss of Ccm1 and Heg1 function leads to junctional defects similar to those seen in rasip1 mutants. Analysis of radil-b single and rasip1/radil-b double mutants reveal distinct and overlapping functions of both proteins. While Rasip1 and Radil-b have similar functions during angiogenic sprouting, the junction formation during anastomosis may primarily depend on Rasip1.

scholarly journals Tet proteins influence the balance between neuroectodermal and mesodermal fate choice by inhibiting Wnt signaling

2016 ◽  
Vol 113 (51) ◽  
pp. E8267-E8276 ◽  
Author(s):  
Xiang Li ◽  
Xiaojing Yue ◽  
William A. Pastor ◽  
Lizhu Lin ◽  
Romain Georges ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Cell Fate ◽  
Transcriptional Activation ◽  
Ectopic Expression ◽  
Embryonic Stem ◽  
Mesodermal Cell ◽  
Cell Fate Decisions ◽  
Tet Proteins ◽  
Mesoderm Specification ◽  
Wnt Inhibitor

TET-family dioxygenases catalyze conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and oxidized methylcytosines in DNA. Here, we show that mouse embryonic stem cells (mESCs), either lacking Tet3 alone or with triple deficiency of Tet1/2/3, displayed impaired adoption of neural cell fate and concomitantly skewed toward cardiac mesodermal fate. Conversely, ectopic expression of Tet3 enhanced neural differentiation and limited cardiac mesoderm specification. Genome-wide analyses showed that Tet3 mediates cell-fate decisions by inhibiting Wnt signaling, partly through promoter demethylation and transcriptional activation of the Wnt inhibitor secreted frizzled-related protein 4 (Sfrp4). Tet1/2/3-deficient embryos (embryonic day 8.0–8.5) showed hyperactivated Wnt signaling, as well as aberrant differentiation of bipotent neuromesodermal progenitors (NMPs) into mesoderm at the expense of neuroectoderm. Our data demonstrate a key role for TET proteins in modulating Wnt signaling and establishing the proper balance between neural and mesodermal cell fate determination in mouse embryos and ESCs.

scholarly journals The patterning and functioning of protrusive activity during convergence and extension of the Xenopus organiser

Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 81-91 ◽  
Author(s):  
Ray Keller ◽  
John Shih ◽  
Carmen Domingo
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Marginal Zone ◽  
Tissue Differentiation ◽  
Tissue Interactions ◽  
Dorsal Mesoderm ◽  
Convergence And Extension ◽  
Early Gastrula ◽  
Ventral Explants ◽  
Anterior Posterior

We discuss the cellular basis and tissue interactions regulating convergence and extension of the vertebrate body axis in early embryogenesls of Xenopus. Convergence and extension occur in the dorsal mesoderm (prospective notochord and somite) and in the posterior nervous system (prospective hindbrain and spinal cord) by sequential cell intercalations. Several layers of cells intercalate to form a thinner, longer array (radial intercalation) and then cells intercalate in the mediolateral orientation to form a longer, narrower array (mediolateral intercalation). Fluorescence microscopy of labeled mesodermal cells in explants shows that protrusive activity is rapid and randomly directed until the midgastrula stage, when it slows and is restricted to the medial and lateral ends of the cells. This bipolar protrusive activity results in elongation, alignment and mediolateral intercalation of the cells. Mediolateral intercalation behavior (MIB) is expressed in an anterior-posterior and lateral-medial progression in the mesoderm. MIB is first expressed laterally in both somitic and notochordal mesoderm. From its lateral origins in each tissue, MIB progresses medially. If convergence does not bring the lateral boundaries of the tissues closer to the medial cells in the notochordal and somitic territories, these cells do not express MIB. Expression of tissue-specific markers follows and parallels the expression of MIB. These facts argue that MIB and some aspects of tissue differentiation are induced by signals emanating from the lateral boundaries of the tissue territories and that convergence must bring medial cells and boundaries closer together for these signals to be effective. Grafts of dorsal marginal zone epithelium to the ventral sides of other embryos, to ventral explants and to UV-ventralized embryos show that it has a role in organising convergence and extension, and dorsal tissue differentiation among deep mesodermal cells. Grafts of involuting marginal zone to animal cap tissue of the early gastrula shows that convergence and extension of the hindbrain-spinal cord are induced by planar signals from the involuting marginal zone.

Morphological polarity of intercalating deep mesodermal cells in the organzer of Xenopus laevis gastrulae

1989 ◽  
Vol 47 ◽  
pp. 840-841
Author(s):  
Ray Keller ◽  
John Shih ◽  
Paul Wilson
Keyword(s):  
Xenopus Laevis ◽  
Time Lapse ◽  
Light Level ◽  
Cell Labelling ◽  
Fluorescent Compound ◽  
Morphogenetic Movements ◽  
Tissue Interactions ◽  
Convergence And Extension ◽  
Morphological Polarity ◽  
Cell Intercalation

The dorsal lip of the blastopore constitutes the “organizer” of the amphibian body plan, both in terms of its tissue interactions and its morphogenetic movements of convergence and extension during gastrulation. This tissue autonomously narrows (converges) and lengthens (extends) during early development, functioning prominently in the morphogenetic movements of both gastrulation and neurulation Xenopus laevis. High resolution time-lapse recording of cell behavior in cultured explants and cell labelling studies have shown that the movements of convergence and extension are produced by radial intercalation of cells, in which several layers rearrange to produce fewer layers of greater area, and by mediolateral intercalation of cells, in which several rows of cells rearrange to produce a narrower, longer array. By labelling individual cells with the fluorescent compound, DiI, and making low light level recordings, we found that cells of the notochord intercalate mediolaterally using polarized protrusive activity at their internal medial or lateral ends. Thus polarized protrusive activity appears to play a major role in mediolateral cell intercalation after the boundary between the notochord and somites forms in the late gastrula stage.We examine further the morphology of the deep mesodermal cells with scanning electron microscopy at earlier stages, to search for morphological manifestations of a similar polarity of protrusive activity. The dorsal deep mesodermal cells of early gastrulae were exposed by rapidly pulling the. epithelial endoderm off the deep cells with forceps, in Danilchik's solution, and fixing the embryo within 15 seconds in 2% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.4) as described previously. The dorsal deep cells adjacent to the epithelium are elongate and aligned parallel to one another and to the circumference of the glastopore (Fig. 1). The medial and lateral ends bear broad, lamelliform protrusions (large pointers, Fig. 1, 2) whereas the anterior and posterior ends bear numerous small filiform protrusions (small pointers, Fig. 1, 2). This characteristic morphology is found only in the dorsal marginal zone, which undergoes convergence and extension by mediolateral intercalation.

Cell movements during epiboly and gastrulation in zebrafish

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 569-580 ◽  
Author(s):  
R.M. Warga ◽  
C.B. Kimmel
Keyword(s):  
Dorsal Side ◽  
Epithelial Layer ◽  
Convergent Extension ◽  
Blastula Stage ◽  
Cell Movements ◽  
Yolk Cell ◽  
Radial Cell ◽  
Convergence And Extension ◽  
Embryonic Ectoderm ◽  
Anterior Posterior

Beginning during the late blastula stage in zebrafish, cells located beneath a surface epithelial layer of the blastoderm undergo rearrangements that accompany major changes in shape of the embryo. We describe three distinctive kinds of cell rearrangements. (1) Radial cell intercalations during epiboly mix cells located deeply in the blastoderm among more superficial ones. These rearrangements thoroughly stir the positions of deep cells, as the blastoderm thins and spreads across the yolk cell. (2) Involution at or near the blastoderm margin occurs during gastrulation. This movement folds the blastoderm into two cellular layers, the epiblast and hypoblast, within a ring (the germ ring) around its entire circumference. Involuting cells move anteriorwards in the hypoblast relative to cells that remain in the epiblast; the movement shears the positions of cells that were neighbors before gastrulation. Involuting cells eventually form endoderm and mesoderm, in an anterior-posterior sequence according to the time of involution. The epiblast is equivalent to embryonic ectoderm. (3) Mediolateral cell intercalations in both the epiblast and hypoblast mediate convergence and extension movements towards the dorsal side of the gastrula. By this rearrangement, cells that were initially neighboring one another become dispersed along the anterior-posterior axis of the embryo. Epiboly, involution and convergent extension in zebrafish involve the same kinds of cellular rearrangements as in amphibians, and they occur during comparable stages of embryogenesis.

The behavior of chick gastrula mesodermal cells under the unidirectional tractive force parallel to the substrata

1995 ◽  
Vol 108 (2) ◽  
pp. 557-567 ◽  
Author(s):  
R. Toyoizumi ◽  
S. Takeuchi
Keyword(s):  
Cell Body ◽  
Magnetic Force ◽  
Single Cells ◽  
Attachment Site ◽  
Leading Edge ◽  
Time Lapse ◽  
Tractive Force ◽  
Citrate Buffer ◽  
Mesodermal Cell ◽  
Significance Level

Advancement of leading lamellae of a migratory cell inevitably causes a strain inside the cell body. We investigated the effect of the tension arisen inside a mesodermal cell on its behavior by pulling the cell body unidirectionally along the substratum. Chick gastrula mesodermal cells, known as highly migratory, were dissociated into single cells in sodium citrate buffer, conjugated with paramagnetic beads activated by tosyl-residue (4.5 microns in diameter) and seeded onto coverglasses coated with fibronectin. After the cells spread on the substratum and protruded cellular processes in all directions, they were exposed to a non-uniform magnetic field by a magnet. Thus the cells bearing the beads were pulled with a force in the order of 10(−10) N. The behavior of such cells was recorded with a time-lapse video taperecorder and assessed quantitatively. Shortly after the magnetic force was applied, the beads stuck to the cells were aligned in tandem along the line of magnetic force at the site for the magnet. Subsequently, they frequently came to extend their leading lamella precisely counter to the traction on the line of the beads. Observation with scanning electron microscope revealed that a large part of the beads attached to the cells were wrapped in the cell membrane. In this condition, the cells were stretched locally between the attachment site of the beads and adhesion plaques beneath the leading edge, which was formed in a direction away from the traction. It was proved statistically that such cells tended to locomote away from the magnet at the 0.1% significance level with Hotelling's T2-test. In contrast, the mesodermal cells free of the artificial traction in three kinds of control experiments did not show such a preference in the direction of locomotion. These results proved that migratory cells tended to move in the direction away from the tractive force parallel to the substratum, suggesting that advancement of a leading lamella is accelerated when it is stretched along the direction of projection by a mechanical force of sufficient strength. Implication of this finding to the mechanism of cell locomotion will be discussed.

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