scholarly journals Regulated exocytosis and sequential construction of the extracellular matrix surrounding the sea urchin zygote

1997 ◽  
Vol 186 (1) ◽  
pp. 16-26 ◽  
Author(s):  
John C. Matese ◽  
Steven Black ◽  
David R. McClay
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Regulated Exocytosis

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

Transcription of the Spec 1-like gene of Lytechinus is selectively inhibited in response to disruption of the extracellular matrix

Development ◽  
1989 ◽  
Vol 106 (2) ◽  
pp. 355-365 ◽  
Author(s):  
G.M. Wessel ◽  
W. Zhang ◽  
C.R. Tomlinson ◽  
W.J. Lennarz ◽  
W.H. Klein
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Cdna Clone ◽  
Lytechinus Variegatus ◽  
Gene Products ◽  
Lytechinus Pictus ◽  
Collagenous Matrix ◽  
Cell Type Specific ◽  
Differential Gene ◽  
And Control

The influence of the extracellular matrix (ECM) on differential gene expression during sea urchin development was explored using cell-type-specific cDNA probes. The ECM of three species of sea urchin, Strongylocentrotus purpuratus, Lytechinus variegatus and Lytechinus pictus, was disrupted with the lathrytic agent beta-aminopropionitrile (BAPN), which inhibits collagen deposition in the ECM and arrests gastrulation (Wessel & McClay, Devl Biol. 121: 149, 1987). The levels of several mRNAs (Spec 1, Spec 2, CyIIa actin, CyIIIa actin and collagen in S. purpuratus, and metallothionine, ubiquitin and LpS3 in L. pictus and L. variegatus) were compared in BAPN-treated and control embryos. These mRNAs accumulated normally during BAPN treatment, even though the embryos did not gastrulate. To determine if the expression of any gene product is sensitive to ECM disruption, a differential cDNA screen compared poly (A+) RNA from BAPN-arrested and control embryos in Lytechinus. A cDNA clone was isolated from this screen that represented a 2.1 kb mRNA that did not accumulate during BAPN treatment. Removal of BAPN resulted in the accumulation of this transcript coincident with the onset of gastrulation. This cDNA clone encodes a L. variegatus homologue of LpS1, recently demonstrated to be an ancestral homologue of the aboral ectoderm-specific Spec 1-Spec 2 gene family in S. purpuratus. Nuclear run-on assays in L. pictus suggested that transcriptional activity of LpS1 was selectively inhibited by BAPN treatment. Thus, although the accumulation of many gene products occurred independently of the embryonic collagenous matrix, the accumulation of LpS1 and LvS1 appeared to be mediated by the ECM.

The sea urchin egg yolk granule is a storage compartment for HCL-32, an extracellular matrix protein

1998 ◽  
Vol 76 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Janice Mayne ◽  
John J Robinson
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Blot Analysis ◽  
Extracellular Matrix Protein ◽  
Yolk Granule ◽  
Cortical Granules ◽  
Yolk Granules ◽  
Storage Compartment ◽  
Protein Gel ◽  
Stage Of Development

We have utilized protein gel blot analysis and immunogold labelling to define the intracellular storage compartment for HCL-32, a 32-kDa protein component of the sea urchin embryonic extracellular matrices, the hyaline layer and basal lamina. Anti-HCL-32 antiserum specifically labelled yolk granules in unfertilized eggs. Cortical granules, mitochondria, sparse granules, and lipid vacuoles were not labelled. Label continued to be detected in the yolk granules through to the blastula stage of development. However, by the gastrula stage no labelling was detected in the yolk granules. In protein gel blot analysis HCL-32 was detected in yolk granules prepared from unfertilized eggs. These results clearly define the yolk granule as a storage compartment for HCL-32, an extracellular matrix protein.Key words: embryo, yolk granule, extracellular matrix.

Extracellular matrix of sea urchin and other marine invertebrate embryos

1989 ◽  
Vol 199 (1) ◽  
pp. 71-92 ◽  
Author(s):  
Evelyn Spiegel ◽  
Louisa Howard ◽  
Melvin Spiegel
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Marine Invertebrate

The hyaline layer in early development of the sea urchin: Cell-extracellular matrix interactions

1989 ◽  
Vol 47 ◽  
pp. 836-837
Author(s):  
David R. McClay ◽  
Mark C. Alliegro ◽  
Steven D Black
Keyword(s):  
Extracellular Matrix ◽  
Early Development ◽  
Sea Urchin ◽  
Protective Layer ◽  
Distinct Group ◽  
Cortical Granules ◽  
Matrix Interactions ◽  
Apical Vesicles ◽  
Double Label ◽  
Extracellular Matrix Interactions

The hyaline layer is released by the sea urchin zygote starting about 30 seconds after fertilization. This layer is elevated above the surface of the zygote where it serves as a protective layer, a barrier to polyspermy, and as an adhesive substrate for the early stages of development. We have been interested in learning how the hyaline layer is stored in the egg, how it is released after fertilization, and how it functions as an extracellular matrix during early development. The layer contains about fifteen abundant proteins plus a number of others that may be present or may contaminate preparations of the layer during isolation procedures. Our goal was to identify the major components of the hyaline membrane, to follow assembly of the structure after fertilization, and to identify molecules that are active as adhesive substrates for cells.Using double-label immunofluorescence and ultrastructural immunogold localization of polyclonal and monoclonal antibodies, the components of the hyaline layer have been localized to four vesicle classes in the unfertilized egg. Centrifugation studies on unfertilized eggs and double-label immunofluorescent studies have shown that the four classes each contain a distinct group of proteins. The four vesicles were followed through oogenesis to learn when proteins of each class were synthesized by the oocyte. Each of the four classes (cortical granules, basal lamina vesicles, apical vesicles and echinonectin vesicles) were synthesized, localized, and relocalized in the oocyte by unique spatial and temporal pathways.

A role for regulated secretion of apical extracellular matrix during epithelial invagination in the sea urchin

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 1049-1060 ◽  
Author(s):  
M.C. Lane ◽  
M.A. Koehl ◽  
F. Wilt ◽  
R. Keller
Keyword(s):  
Extracellular Matrix ◽  
Sea Urchin ◽  
Cytochalasin D ◽  
Tubular Structures ◽  
Purse String ◽  
Regulated Secretion ◽  
Optic Cup ◽  
Thermal Bending ◽  
Morphogenetic Event ◽  
Epithelial Sheet

Epithelial invagination, a basic morphogenetic process reiterated throughout embryonic development, generates tubular structures such as the neural tube, or pit-like structures such as the optic cup. The ‘purse-string’ hypothesis, which proposes that circumferential bands of actin microfilaments at the apical end of epithelial cells constrict to yield a curved epithelial sheet, has been widely invoked to explain invaginations during embryogenesis. We have reevaluated this hypothesis in two species of sea urchin by examining both natural invagination of the vegetal plate at the beginning of gastrulation and invagination induced precociously by Ca2+ ionophore. Neither type of invagination is prevented by cytochalasin D. In one species, treatment with A23187 three hours before the initiation of invagination resulted in the deposition of apical extracellular matrix at the vegetal plate, rather than invagination. This apical matrix contains chondroitin sulfate, as does the lumen of the archenteron in normal gastrulae. When the expansion of this secreted matrix was resisted by an agarose gel, the vegetal plate buckled inward, creating an archenteron that appeared 3–4 hours prematurely. Pretreatment with monensin, which blocks secretion, inhibits both Ca2+ ionophore-stimulated folding and natural invagination, demonstrating that secretion is probably required for this morphogenetic event. These results indicate that alternatives to the purse-string hypothesis must be considered, and that the directed deposition of extracellular matrix may be a key Ca(2+)-regulated event in some embryonic invaginations. A bending bilayer model for matrix-driven epithelial invagination is proposed in which the deposition of hygroscopic material into a complex, stratified extra-cellular matrix results in the folding of an epithelial sheet in a manner analagous to thermal bending in a bimetallic strip.

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