Stimulation of cortical actin polymerization in the sea urchin egg cortex by NH4Cl procaine and urethane: Elevation of cytoplasmic pH is not the common mechanism of action

1996 ◽  
Vol 35 (3) ◽  
pp. 210-224 ◽  
Author(s):  
David A. Begg ◽  
Gene K. Wong ◽  
Duncan H.R. Hoyle ◽  
Jay M. Baltz
Keyword(s):  
Sea Urchin ◽  
Mechanism Of Action ◽  
Actin Polymerization ◽  
Common Mechanism ◽  
Cytoplasmic Ph ◽  
Cortical Actin ◽  
Sea Urchin Egg ◽  
The Common ◽  
Egg Cortex ◽  
Stimulation Of

Wave of cortical actin polymerization in the sea urchin egg

1987 ◽  
Vol 7 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Shigenobu Yonemura ◽  
Issei Mabuchi
Keyword(s):  
Sea Urchin ◽  
Actin Polymerization ◽  
Cortical Actin ◽  
Sea Urchin Egg

scholarly journals The changes in structural organization of actin in the sea urchin egg cortex in response to hydrostatic pressure.

1983 ◽  
Vol 97 (6) ◽  
pp. 1795-1805 ◽  
Author(s):  
D A Begg ◽  
E D Salmon ◽  
H A Hyatt
Keyword(s):  
Hydrostatic Pressure ◽  
Sea Urchin ◽  
Actin Filament ◽  
Structural Organization ◽  
Cleavage Furrow ◽  
Cortical Actin ◽  
Cleavage Division ◽  
Sea Urchin Egg ◽  
Filament Bundles ◽  
Egg Cortex

We have used hydrostatic pressure to study the structural organization of actin in the sea urchin egg cortex and the role of cortical actin in early development. Pressurization of Arbacia punctulata eggs to 6,000 psi at the first cleavage division caused the regression of the cleavage furrow and the disappearance of actin filament bundles from the microvilli. Within 30 s to 1 min of decompression these bundles reformed and furrowing resumed. Pressurization of dividing eggs to 7,500 psi caused both the regression of the cleavage furrow and the complete loss of microvilli from the egg surface. Following release from this higher pressure, the eggs underwent extensive, uncoordinated surface contractions, but failed to cleave. The eggs gradually regained their spherical shape and cleaved directly into four cells at the second cleavage division. Microvilli reformed on the egg surface over a period of time corresponding to that required for the recovery of normal egg shape and stability. During the initial stages of their regrowth the microvilli contained a network of actin filaments that began to transform into bundles when the microvilli had reached approximately 2/3 of their final length. These results demonstrate that moderate levels of hydrostatic pressure cause the reversible disruption of cortical actin organization, and suggest that this network of actin stabilizes the egg surface and participates in the formation of the contractile ring during cytokinesis. The results also demonstrate that actin filament bundles are not required for the regrowth of microvilli after their removal by pressurization. Preliminary experiments demonstrate that F-actin is not depolymerized in vitro by pressures up to 10,000 psi and suggest that pressure may act indirectly in vivo, either by changing the intracellular ionic environment or by altering the interaction of actin binding proteins with actin.

scholarly journals pH regulates the polymerization of actin in the sea urchin egg cortex.

1979 ◽  
Vol 83 (1) ◽  
pp. 241-248 ◽  
Author(s):  
D A Begg ◽  
L I Rebhun
Keyword(s):  
Sea Urchin ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Filamentous Actin ◽  
Cortical Granules ◽  
Isolation Medium ◽  
Large Numbers ◽  
Sea Urchin Egg ◽  
Isolated Cortex ◽  
Egg Cortex

The state of actin in the isolated cortex of the unfertilized sea urchin egg can be controlled by experimentally manipulating the pH of the isolation medium. Cortices isolated at the pH of the unfertilized egg (6.5--6.7) do not contain filamentous actin, while those isolated at the pH of the fertilized egg (7.3--7.5) develop large numbers of microvilli which contain bundles of actin filaments. Cortices that are isolated at pH 6.5 and then transferred to isolation medium buffered at pH 7.5 also develop actin filaments. However, the filaments are not arranged in bundles and microvilli do not form. Although the cortical granules in cortices isolated at pH 6.5 discharge at a free Ca++ concentration of approximately 10 micrometer, actin polymerization is not induced by increasing the Ca++ concentration of the isolation medium. These results suggest that the increase in cytoplasmic pH which occurs following fertilization induces the polymerization of actin in the egg cortex.

Calcium-induced decrease in membrane fluidity of sea urchin egg cortex after fertilization

Nature ◽  
1980 ◽  
Vol 286 (5769) ◽  
pp. 185-186 ◽  
Author(s):  
Judith Campisi ◽  
Carl J. Scandella
Keyword(s):  
Membrane Fluidity ◽  
Sea Urchin ◽  
Sea Urchin Egg ◽  
Egg Cortex

scholarly journals A 45,000-mol-wt protein-actin complex from unfertilized sea urchin egg affects assembly properties of actin.

1984 ◽  
Vol 99 (3) ◽  
pp. 994-1001 ◽  
Author(s):  
H Hosoya ◽  
I Mabuchi
Keyword(s):  
Sea Urchin ◽  
Actin Filament ◽  
Actin Polymerization ◽  
Initial Rate ◽  
Gel Filtration ◽  
Molar Ratio ◽  
Capping Protein ◽  
Sea Urchin Egg ◽  
Rate Of Polymerization ◽  
Hemicentrotus Pulcherrimus

A one-to-one complex of a 45,000-mol-wt protein and actin was purified from unfertilized eggs of the sea urchin, Hemicentrotus pulcherrimus, by means of DNase l-Sepharose affinity and gel filtration column chromatographies. Effects of the complex on the polymerization of actin were studied by viscometry, spectrophotometry, and electron microscopy. The results are summarized as follows: (a) The initial rate of actin polymerization is inhibited at a very low molar ratio of the complex to actin. (b) Acceleration of the initial rate of polymerization occurs at a relatively high, but still substoichiometric, molar ratio of the complex to actin. (c) Annealing of F-actin fragments is inhibited by the complex. (d) The complex prevents actin filaments from depolymerizing. (e) Growth of the actin filament is inhibited at the barbed end. In all cases except b, a molar ratio of less than 1:100 of the 45,000-mol-wt protein-actin complex to actin is sufficient to produce these significant effects. These results indicate that the 45,000-mol-wt protein-actin complex from the sea urchin egg regulates the assembly of actin by binding to the barbed end (preferred end or rapidly growing end) of the actin filament. The 45,000-mol-wt protein-actin complex can thus be categorized as a capping protein.

scholarly journals STUDIES ON SULFHYDRYL GROUPS DURING CELL DIVISION OF SEA URCHIN EGG

1960 ◽  
Vol 8 (3) ◽  
pp. 603-607 ◽  
Author(s):  
Hikoichi Sakai
Keyword(s):  
Cell Division ◽  
Sea Urchin ◽  
Sulfhydryl Groups ◽  
Cell Stage ◽  
Sea Urchin Eggs ◽  
Maximum Value ◽  
Sea Urchin Egg ◽  
Egg Cortex

Masses of cortices of both unfertilized and fertilized sea urchin eggs can be isolated by crushing eggs in hypotonic MaCl2 (0.1 M) solution. The amount of cortical material in terms of protein-N increases steadily after fertilization until the monaster stage and thereafter remains almost constant until well into the two-cell stage. The amount of bound—SH per protein-N of the egg cortex also increases after fertilization, reaches a maximum value at the amphiaster stage and thereafter decreases rapidly as the cleavage of the cell proceeds.

scholarly journals Effects of Dithiothreitol on Fertilization and Early Development in Sea Urchin

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3573
Author(s):  
Nunzia Limatola ◽  
Jong Tai Chun ◽  
Sawsen Cherraben ◽  
Jean-Louis Schmitt ◽  
Jean-Marie Lehn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Early Development ◽  
Sea Urchin ◽  
Actin Filaments ◽  
Cortical Granule ◽  
Cortical Actin ◽  
Phenotypic Changes ◽  
Sea Urchin Egg ◽  
Cortical Granule Exocytosis

The vitelline layer (VL) of a sea urchin egg is an intricate meshwork of glycoproteins that intimately ensheathes the plasma membrane. During fertilization, the VL plays important roles. Firstly, the receptors for sperm reside on the VL. Secondly, following cortical granule exocytosis, the VL is elevated and transformed into the fertilization envelope (FE), owing to the assembly and crosslinking of the extruded materials. As these two crucial stages involve the VL, its alteration was expected to affect the fertilization process. In the present study, we addressed this question by mildly treating the eggs with a reducing agent, dithiothreitol (DTT). A brief pretreatment with DTT resulted in partial disruption of the VL, as judged by electron microscopy and by a novel fluorescent polyamine probe that selectively labelled the VL. The DTT-pretreated eggs did not elevate the FE but were mostly monospermic at fertilization. These eggs also manifested certain anomalies at fertilization: (i) compromised Ca2+ signaling, (ii) blocked translocation of cortical actin filaments, and (iii) impaired cleavage. Some of these phenotypic changes were reversed by restoring the DTT-exposed eggs in normal seawater prior to fertilization. Our findings suggest that the FE is not the decisive factor preventing polyspermy and that the integrity of the VL is nonetheless crucial to the egg’s fertilization response.

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