Role of the extracellular matrix protein thrombospondin in the early development of the mouse embryo.

The distribution of the extracellular matrix protein thrombospondin (TSP) in cleavage to egg cylinder staged mouse embryos and its role in trophoblast outgrowth from cultured blastocysts were examined. TSP was present within the cytoplasm of unfertilized eggs; in fertilized one- to four-cell embryos; by the eight-cell stage, TSP was also densely deposited at cell-cell borders. In the blastocyst, although TSP was present in all three cell types; trophectoderm, endoderm, and inner cell mass (ICM), it was enriched in the ICM and at the surface of trophectoderm cells. Hatched blastocysts grown on matrix-coated coverslips formed extensive trophoblast outgrowths on TSP, grew slightly less avidly on laminin, or on a 140-kD fragment of TSP containing its COOH terminus and putative cell binding domains. There was little outgrowth on the NH2 terminus heparin-binding domain. Addition of anti-TSP antibodies (but not GRGDS) to blastocysts growing on TSP strikingly inhibited outgrowth. Consistent with its early appearance and presence in trophoblast cells during implantation, TSP may play an important role in the early events involved in mammalian embryogenesis.

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A novel H+ permeability dominating intracellular pH in the early mouse embryo

Development ◽

10.1242/dev.118.4.1353 ◽

1993 ◽

Vol 118 (4) ◽

pp. 1353-1361

Author(s):

J.M. Baltz ◽

J.D. Biggers ◽

C. Lechene

Keyword(s):

Plasma Membrane ◽

Intracellular Ph ◽

Inner Cell Mass ◽

Cell Mass ◽

Cell Types ◽

Preimplantation Embryos ◽

Developmentally Regulated ◽

Cell Stage ◽

K Concentration ◽

Early Mouse

Most cell types are relatively impermeant to H+ and are able to regulate their intracellular pH by means of plasma membrane proteins, which transport H+ or bicarbonate across the membrane in response to perturbations of intracellular pH. Mouse preimplantation embryos at the 2-cell stage, however, do not appear to possess specific pH-regulatory mechanisms for relieving acidosis. They are, instead, highly permeable to H+, so that the intracellular pH in the acid and neutral range is determined by the electrochemical equilibrium of H+ across the plasma membrane. When intracellular pH is perturbed, the rate of the ensuing H+ flux across the plasma membrane is determined by the H+ electrochemical gradient: its dependence on external K+ concentration indicates probable dependence on membrane potential and the rate depends on the H+ concentration gradient across the membrane. The large permeability at the 2-cell stage is absent or greatly diminished in the trophectoderm of blastocysts, but still present in the inner cell mass. Thus, the permeability to H+ appears to be developmentally regulated.

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Pericardin, aDrosophilatype IV collagen-like protein is involved in the morphogenesis and maintenance of the heart epithelium during dorsal ectoderm closure

Development ◽

10.1242/dev.129.13.3241 ◽

2002 ◽

Vol 129 (13) ◽

pp. 3241-3253 ◽

Cited By ~ 7

Author(s):

Aymeric Chartier ◽

Stéphane Zaffran ◽

Martine Astier ◽

Michel Sémériva ◽

Danielle Gratecos

Keyword(s):

Extracellular Matrix ◽

Matrix Protein ◽

Cell Types ◽

Tube Formation ◽

Extracellular Matrix Protein ◽

Heart Cells ◽

Dorsal Closure ◽

Heart Tube ◽

Pericardial Cells ◽

Dorsal Ectoderm

The steps that lead to the formation of a single primitive heart tube are highly conserved in vertebrate and invertebrate embryos. Concerted migration of the two lateral cardiogenic regions of the mesoderm and endoderm (or ectoderm in invertebrates) is required for their fusion at the midline of the embryo. Morphogenetic signals are involved in this process and the extracellular matrix has been proposed to serve as a link between the two layers of cells.Pericardin (Prc), a novel Drosophila extracellular matrix protein is a good candidate to participate in heart tube formation. The protein has the hallmarks of a type IV collagen α-chain and is mainly expressed in the pericardial cells at the onset of dorsal closure. As dorsal closure progresses, Pericardin expression becomes concentrated at the basal surface of the cardioblasts and around the pericardial cells, in close proximity to the dorsal ectoderm. Pericardin is absent from the lumen of the dorsal vessel.Genetic evidence suggests that Prc promotes the proper migration and alignment of heart cells. Df(3)vin6 embryos, as well as embryos in which prc has been silenced via RNAi, exhibit similar and significant defects in the formation of the heart epithelium. In these embryos, the heart epithelium appears disorganized during its migration to the dorsal midline. By the end of embryonic development, cardial and pericardial cells are misaligned such that small clusters of both cell types appear in the heart; these clusters of cells are associated with holes in the walls of the heart. A prc transgene can partially rescue each of these phenotypes, suggesting that prc regulates these events. Our results support, for the first time, the function of a collagen-like protein in the coordinated migration of dorsal ectoderm and heart cells.

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Self-assembling extracellular matrix proteins as materials for the condensation of silica nanostructures

RSC Advances ◽

10.1039/c6ra20911d ◽

2016 ◽

Vol 6 (97) ◽

pp. 95337-95341

Author(s):

Conor M. Gomes ◽

Leila F. Deravi

Keyword(s):

Extracellular Matrix ◽

Protein Binding ◽

Matrix Protein ◽

Matrix Proteins ◽

Extracellular Matrix Protein ◽

Binding Domains ◽

Synthetic Strategy ◽

Self Assembling ◽

Silica Nanostructures ◽

Biocomposite Material

A synthetic strategy is described to repurpose human extracellular matrix protein binding domains to catalyse the condensation of silica nanostructures in water for a seamlessly integrated biocomposite material.

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A role for the dystrophin-glycoprotein complex as a transmembrane linker between laminin and actin

The Journal of Cell Biology ◽

10.1083/jcb.122.4.809 ◽

1993 ◽

Vol 122 (4) ◽

pp. 809-823 ◽

Cited By ~ 913

Author(s):

JM Ervasti ◽

KP Campbell

Keyword(s):

Extracellular Matrix ◽

Matrix Protein ◽

Striated Muscle ◽

Extracellular Matrix Protein ◽

Dependent Manner ◽

Heparin Binding ◽

Glycoprotein Complex ◽

Dystrophin Glycoprotein Complex ◽

Dystrophin Glycoprotein ◽

Laminin Binding

The dystrophin-glycoprotein complex was tested for interaction with several components of the extracellular matrix as well as actin. The 156-kD dystrophin-associated glycoprotein (156-kD dystroglycan) specifically bound laminin in a calcium-dependent manner and was inhibited by NaCl (IC50 = 250 mM) but was not affected by 1,000-fold (wt/wt) excesses of lactose, IKVAV, or YIGSR peptides. Laminin binding was inhibited by heparin (IC50 = 100 micrograms/ml), suggesting that one of the heparin-binding domains of laminin is involved in binding dystroglycan while negatively charged oligosaccharide moieties on dystroglycan were found to be necessary for its laminin-binding activity. No interaction between any component of the dystrophin-glycoprotein complex and fibronectin, collagen I, collagen IV, entactin, or heparan sulfate proteoglycan was detected by 125I-protein overlay and/or extracellular matrix protein-Sepharose precipitation. In addition, laminin-Sepharose quantitatively precipitated purified dystrophin-glycoprotein complex, demonstrating that the laminin-binding site is accessible when dystroglycan is associated with the complex. Dystroglycan of nonmuscle tissues also bound laminin. However, the other proteins of the striated muscle dystrophin-glycoprotein complex appear to be absent, antigenically dissimilar or less tightly associated with dystroglycan in nonmuscle tissues. Finally, we show that the dystrophin-glycoprotein complex cosediments with F-actin but does not bind calcium or calmodulin. Our results support a role for the striated muscle dystrophin-glycoprotein complex in linking the actin-based cytoskeleton with the extracellular matrix. Furthermore, our results suggest that dystrophin and dystroglycan may play substantially different functional roles in nonmuscle tissues.

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The major laminin receptor of mouse embryonic stem cells is a novel isoform of the alpha 6 beta 1 integrin.

The Journal of Cell Biology ◽

10.1083/jcb.115.3.843 ◽

1991 ◽

Vol 115 (3) ◽

pp. 843-850 ◽

Cited By ~ 105

Author(s):

H M Cooper ◽

R N Tamura ◽

V Quaranta

Keyword(s):

Extracellular Matrix ◽

Matrix Protein ◽

Es Cells ◽

Embryonic Stem ◽

Cell Types ◽

Cytoplasmic Domain ◽

Laminin Receptor ◽

Extracellular Matrix Protein ◽

Cytoplasmic Domains ◽

Alternative Mrna Splicing

Laminin is the first extracellular matrix protein expressed in the developing mouse embryo. It is known to influence morphogenesis and affect cell migration and polarization. Several laminin receptors are included in the integrin family of extracellular matrix receptors. Ligand binding by integrin heterodimers results in signal transduction events controlling cell motility. We report that the major laminin receptor on murine embryonic stem (ES) cells is the integrin heterodimer alpha 6 beta 1, an important receptor for laminin in neurons, lymphocytes, macrophages, fibroblasts, platelets and other cell types. However, the cytoplasmic domain of the ES cell alpha 6 (alpha 6 B) differs totally from the reported cytoplasmic domain amino acid sequence of alpha 6 (alpha 6 A). Comparisons of alpha 6 cDNAs from ES cells and other cells suggest that the alpha 6 A and alpha 6 B cytoplasmic domains derive from alternative mRNA splicing. Anti-peptide antibodies to alpha 6 A are unreactive with ES cells, but react with mouse melanoma cells and embryonic fibroblasts. When ES cells are cultured under conditions that permit their differentiation, they become positive for alpha 6 A, concurrent with the morphologic appearance of differentiated cell types. Thus, expression of the alpha 6 B beta 1 laminin receptor may be favored in undifferentiated, totipotent cells, while the expression of alpha 6 A beta 1 receptor occurs in committed lineages. While the functions of integrin alpha chain cytoplasmic domains are not understood, it is possible that they contribute to transferring signals to the cell interior, e.g., by delivering cytoskeleton organizing signals in response to integrin engagement with extracellular matrix ligands. It is therefore reasonable to propose that the cellular responses to laminin may vary, according to what alpha subunit isoform (alpha 6 A or alpha 6 B) is expressed as part of the alpha 6 beta 1 laminin receptor. The switch from alpha 6 B to alpha 6 A, if confirmed in early embryos, could then be of striking potential relevance to the developmental role of laminin.

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Extracellular matrix fibronectin mediates an endothelial cell response to shear stress via the heparin-binding, matricryptic RWRPK sequence of FNIII1H

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00126.2016 ◽

2016 ◽

Vol 311 (4) ◽

pp. H1063-H1071 ◽

Cited By ~ 5

Author(s):

William Okech ◽

Keren M. Abberton ◽

Julia M. Kuebel ◽

Denise C. Hocking ◽

Ingrid H. Sarelius

Keyword(s):

Extracellular Matrix ◽

Shear Stress ◽

Matrix Protein ◽

Umbilical Vein ◽

Stress Fiber ◽

Stress Fibers ◽

Extracellular Matrix Protein ◽

Heparin Binding ◽

Flow Conditions ◽

Endothelial Cell Response

Endothelial cells (EC) respond to mechanical forces such as shear stress in a variety of ways, one of which is cytoskeletal realignment in the direction of flow. Our earlier studies implicated the extracellular matrix protein fibronectin in mechanosensory signaling to ECs in intact arterioles, via a signaling pathway dependent on the heparin-binding region of the first type III repeat of fibrillar fibronectin (FNIII1H). Here we test the hypothesis that FNIII1H is required for EC stress fiber realignment under flow. Human umbilical vein ECs (HUVECs) exposed to defined flow conditions were used as a well-characterized model of this stress fiber alignment response. Our results directly implicate FNIII1H in realignment of stress fibers in HUVECs and, importantly, show that the matricryptic heparin-binding RWRPK sequence located in FNIII1 is required for the response. Furthermore, we show that flow-mediated stress fiber realignment in ECs adhered via α5β1-integrin-specific ligands does not occur in the absence of FHIII1H, whereas, in contrast, αvβ3-integrin-mediated stress fiber realignment under flow does not require FNIII1H. Our findings thus indicate that there are two separate mechanosignaling pathways mediating the alignment of stress fibers after exposure of ECs to flow, one dependent on αvβ3-integrins and one dependent on FNIII1H. This study strongly supports the conclusion that the RWRPK region of FNIII1H may have broad capability as a mechanosensory signaling site.

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Identification of Fibronectin-Binding Proteins in Mycoplasma gallisepticum Strain R

Infection and Immunity ◽

10.1128/iai.74.3.1777-1785.2006 ◽

2006 ◽

Vol 74 (3) ◽

pp. 1777-1785 ◽

Cited By ~ 41

Author(s):

Meghan May ◽

Leka Papazisi ◽

Timothy S. Gorton ◽

Steven J. Geary

Keyword(s):

Matrix Protein ◽

Binding Proteins ◽

Mycoplasma Gallisepticum ◽

Peptide Sequencing ◽

Extracellular Matrix Protein ◽

Heparin Binding ◽

Heparin Binding Domain ◽

Fibronectin Binding ◽

Membrane Spanning

ABSTRACT We have determined that virulent Mycoplasma gallisepticum strain Rlow is capable of binding the extracellular matrix protein fibronectin. Fibronectin was found to be present in M. gallisepticum Rlow protein extracts by Western blotting and peptide sequencing. Mycoplasma gallisepticum Rhigh, the attenuated, high-passage derivative of Rlow, is deficient in this ability. MGA_1199, the M. gallisepticum homologue of the cytadherence-associated protein P65 from Mycoplasma pneumoniae, and MGA_0928, the M. gallisepticum homologue of the M. pneumoniae cytoskeletal protein HMW3, were identified as fibronectin-binding proteins. Peptides from the regions of MGA_1199 and MGA_0928 exhibiting the highest degree of homology with known fibronectin-binding proteins were shown to bind the gelatin/heparin-binding domain of fibronectin. MGA_1199 and MGA_0928 were shown to be absent and aberrant, respectively, in Rhigh, explaining its lack of fibronectin-binding capability. Consistent with its M. pneumoniae counterpart, MGA_1199 (renamed PlpA) was demonstrated to be surface exposed, despite a lack of classical membrane-spanning domains. Due to its demonstrated topology and the strength of interaction between its binding peptide and fibronectin, we propose that PlpA functions as a fibronectin-binding protein in vivo and may possess atypical transmembrane domains.

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Comparative Parallel Multi-Omics Analysis During the Induction of Pluripotent and Trophectoderm States

10.1101/2020.09.27.315259 ◽

2020 ◽

Author(s):

Mohammad Jaber ◽

Ahmed Radwan ◽

Netanel Loyfer ◽

Mufeed Abdeen ◽

Shulamit Sebban ◽

...

Keyword(s):

Stem Cells ◽

Inner Cell Mass ◽

Cell Mass ◽

Cell Types ◽

Chromatin Accessibility ◽

Early Embryo ◽

Cell Stage ◽

Omics Analysis ◽

Induced Pluripotent

Following fertilization, totipotent cells divide to generate two compartments in the early embryo: the inner cell mass (ICM) and trophectoderm (TE). It is only at the 32-64 -cell stage when a clear segregation between the two cell-types is observed, suggesting a ‘T’-shaped model of specification. Here, we examine whether the acquisition of these two states in vitro by nuclear reprogramming share similar dynamics/trajectories. We conducted a comparative parallel multi-omics analysis on cells undergoing reprogramming to Induced pluripotent stem cells (iPSCs) and induced trophoblast stem cells (TSCs), and examined their transcriptome, methylome, chromatin accessibility and activity and genomic stability. Our analysis revealed that cells undergoing reprogramming to pluripotency and TSC state exhibit specific trajectories from the onset of the process, suggesting ‘V’-shaped model. Using these analyses, not only we could describe in detail the various trajectories toward the two states, we also identified previously unknown stage-specific reprogramming markers as well as markers for faithful reprogramming and reprogramming blockers. Finally, we show that while the acquisition of the TSC state involves the silencing of embryonic programs by DNA methylation, during the acquisition of pluripotency these specific regions are initially open but then retain inactive by the elimination of the histone mark, H3K27ac.

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Use of F9 teratocarcinoma STEM cells to study cell-matrix interactions in the early mouse embryo

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123416 ◽

1992 ◽

Vol 50 (1) ◽

pp. 602-603

Author(s):

Marc Lenburg ◽

Rulang Jiang ◽

Lengya Cheng ◽

Laura Grabel

Keyword(s):

Mouse Embryo ◽

Inner Cell Mass ◽

Cell Mass ◽

Cell Types ◽

Embryoid Bodies ◽

F9 Cells ◽

Cell Matrix ◽

Matrix Interactions ◽

Cell Matrix Interactions ◽

F9 Teratocarcinoma

We are interested in defining the cell-cell and cell-matrix interactions that help direct the differentiation of extraembryonic endoderm in the peri-implantation mouse embryo. At the blastocyst stage the mouse embryo consists of an outer layer of trophectoderm surrounding the fluid-filled blastocoel cavity and an eccentrically located inner cell mass. On the free surface of the inner cell mass, facing the blastocoel cavity, a layer of primitive endoderm forms. Primitive endoderm then generates two distinct cell types; parietal endoderm (PE) which migrates along the inner surface of the trophectoderm and secretes large amounts of basement membrane components as well as tissue-type plasminogen activator (tPA), and visceral endoderm (VE), a columnar epithelial layer characterized by tight junctions, microvilli, and the synthesis and secretion of α-fetoprotein. As these events occur after implantation, we have turned to the F9 teratocarcinoma system as an in vitro model for examining the differentiation of these cell types. When F9 cells are treated in monolayer with retinoic acid plus cyclic-AMP, they differentiate into PE. In contrast, when F9 cells are treated in suspension with retinoic acid, they form embryoid bodies (EBs) which consist of an outer layer of VE and an inner core of undifferentiated stem cells. In addition, we have established that when VE containing embryoid bodies are plated on a fibronectin coated substrate, PE migrates onto the matrix and this interaction is inhibited by RGDS as well as antibodies directed against the β1 integrin subunit. This transition is accompanied by a significant increase in the level of tPA in the PE cells. Thus, the outgrowth system provides a spatially appropriate model for studying the differentiation and migration of PE from a VE precursor.

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