In vitro reactivation of anaphase B in isolated spindles of the sea urchin egg

1988 ◽  
Vol 10 (1-2) ◽  
pp. 197-209 ◽  
Author(s):  
Lionel I. Rebhun ◽  
Robert E. Palazzo
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Egg ◽  
Anaphase B

Using Caged Calcium to Study Sea Urchin Egg Cortical Granule Exocytosis in Vitro

Methods ◽  
1994 ◽  
Vol 6 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Nadeem I. Shafi ◽  
Steven S. Vogel ◽  
Joshua Zimmerberg
Keyword(s):  
Sea Urchin ◽  
Cortical Granule ◽  
Granule Exocytosis ◽  
Caged Calcium ◽  
Sea Urchin Egg ◽  
Cortical Granule Exocytosis

400-kV electron imaging of ice-embedded fascin-actin bundle

1994 ◽  
Vol 52 ◽  
pp. 110-111
Author(s):  
Joanita Jakana ◽  
Robert Edwards ◽  
Joseph Bryan ◽  
Michael F. Schmid ◽  
Wah Chiu
Keyword(s):  
Fusion Protein ◽  
Sea Urchin ◽  
Leading Edge ◽  
Female Sterility ◽  
E Coli ◽  
Sea Urchin Egg ◽  
Dose Condition ◽  
Neuron Growth ◽  
Electron Imaging

Fascin is a 55 kDa actin filament bundling protein first isolated from sea urchin egg actin gels by Kane. These gels consist of actin-fascin bundles cross linked by spectrin. Purified actin and fascin produce bundles when mixed in vitro, with an actin-fascin stoichiometry of 4.6 to 1 at saturation. Cloning of sea urchin fascin cDNA revealed homology to an uncharacterized Drosophila protein called singed. The singed phenotype, misshapen bristles and female sterility, canbe explained by a lack of actin bundles and Cant el al has shown recently that the singed gene product can bundle actin. Mammalian fascins have now been cloned from humans and mice. Murinefascin is highly expressed in brain; immunofluorescence reveals fascin localized to filopodia extending from the leading edge of hippocampal neuron growth cones.A soluble, active recombinant mouse fascin has been produced as a fusion protein with E. coli thioredoxin. When mixed with F-actin this fusion protein produces bundles with an actin-fascin ratio of approximately 4.1:1. The bundle was frozen in a thin layer of vitreous ice and examined at 400 kV in the JEOL 4000 electron microscope under low dose condition with a procedure previously described.

Degradation of sperm histones in vitro by cytoplasm of the sea urchin egg

1987 ◽  
Vol 20 (2-3) ◽  
pp. 125-136 ◽  
Author(s):  
Moshe Betzalel ◽  
Boaz Moav
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Egg

Characterisation and role of integrins during gametic interaction and egg activation

Zygote ◽  
1996 ◽  
Vol 4 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Céline de Nadai ◽  
Patrick Fenichel ◽  
Michèle Donzeau ◽  
David Epel ◽  
Brigitte Ciapa
Keyword(s):  
Sea Urchin ◽  
Cytoskeletal Proteins ◽  
Human Spermatozoa ◽  
Egg Activation ◽  
Western Blots ◽  
Sea Urchin Egg ◽  
Immunofluorescence Labelling ◽  
Β Chain

SummaryIt has recently been proposed that some of the processes induced by fertilisation in mammals may be mediated by integrins. By peforming immunofluorescence labelling and Western blots with antibodies directed against some of the α and β subunits of integrins, we show here the presence of some of these proteins in human and hamster oocytes. Among them, α2 and α5 were also present on in vitro preparations of sea urchin egg cortices. In addition, antibodies raised against these two proteins were the most effective at inhibiting attachment and fusion of human spermatozoa with hamster oocytes. We suggest that α2 and α5 integrin chains may be common mediators in adhesion-fusion mechanisms triggered by fertilisation. Using similar techniques, we show that eggs are rich three cytoskeletal proteins known to be linked to the β chain of integrins: talin, vinculin and α-actinin. Moreover, we found that talin and α-actinin were associated with proteins phosphorylated on tyrosine after fertilisation in sea urchin eggs. We suggest that integrins might be involved during fertilisation and trigger egg activation through cytoskeletal structures.

scholarly journals Induction of either contractile or structural actin-based gels in sea urchin egg cytoplasmic extract.

1980 ◽  
Vol 86 (3) ◽  
pp. 803-809 ◽  
Author(s):  
R E Kane
Keyword(s):  
Sea Urchin ◽  
Actin Polymerization ◽  
Cell Types ◽  
Soluble Form ◽  
Structural Protein ◽  
Simple Method ◽  
Egg Extract ◽  
Sea Urchin Egg ◽  
Amoeboid Motion

The gel formed by warming the 100,000 g supernate of isotonic extracts of sea urchin eggs to 40 degrees C is made up of actin and two additional proteins of mol wt of 58,000 and 220,000. Actin and 58,000 form a characteristic structural unit which has now been identified in the microvilli of the urchin egg and in the filopods of urchin coelomocytes. However, egg extract gels did not contract as those from other cell types do, and the aim of these experiments was to determine the reason for this lack of contraction. Although the extracts are dialyzed to a low ionic strength, myosin is present in soluble form and makes up approximately 1% of the protein of the extract. It becomes insoluble in the presence of high ATP concentrations at 0 degrees C, and the precipitate formed under these conditions consists almost entirely of myosin. This procedure provides a simple method of isolating relatively pure myosin without affecting other extract components and functions. Contraction will follow gelation in these extracts if the temperature and time of incubation used to induce actin polymerization are reduced to minimize myosin inactivation. At the optimal ATP and KCl concentration for contraction, the contracted material has an additional 250,000 component and contains very little 58,000. The conditions found to provide maximum gel yields favor the formation of the actin-58,000-220,000 structural gel, while reduced temperature and increase in KCl concentration results in a contractile gel whose composition is similar to those reported from amoeboid cell types. Both the structural protein cores found in the egg microvilli and a gel contraction related to the amoeboid motion which is seen in later urchin embryonic development can thus be induced in vitro in the same extract.

Nuclear Envelope Formation In Vitro: A Sea Urchin Egg Cell-Free System

2008 ◽  
pp. 207-223 ◽  
Author(s):  
Richard D. Byrne ◽  
Vanessa Zhendre ◽  
Banafshé Larijani ◽  
Dominic L. Poccia
Keyword(s):  
Nuclear Envelope ◽  
Sea Urchin ◽  
Egg Cell ◽  
Free System ◽  
Cell Free System ◽  
Sea Urchin Egg ◽  
Nuclear Envelope Formation

scholarly journals The part played by inositol trisphosphate and calcium in the propagation of the fertilization wave in sea urchin eggs.

1986 ◽  
Vol 103 (6) ◽  
pp. 2333-2342 ◽  
Author(s):  
K Swann ◽  
M Whitaker
Keyword(s):  
Sea Urchin ◽  
Calcium Ions ◽  
Calcium Concentration ◽  
Calcium Release ◽  
Inositol Trisphosphate ◽  
Lytechinus Pictus ◽  
Sea Urchin Egg ◽  
Sperm Entry ◽  
Fertilization Membrane

Sea urchin egg activation at fertilization is progressive, beginning at the point of sperm entry and moving across the egg with a velocity of 5 microns/s. This activation wave (Kacser, H., 1955, J. Exp. Biol., 32:451-467) has been suggested to be the result of a progressive release of calcium from a store within the egg cytoplasm (Jaffe, L. F., 1983, Dev. Biol., 99:265-276). The progressive release of calcium may be due to the production of inositol trisphosphate (InsP3), a second messenger. We show here that a wave of calcium release crosses the Lytechinus pictus egg; the peak of the wave travels with a velocity of 5 microns/s; microinjection of InsP3 causes the release of calcium within the egg; calcium release (as judged by fertilization envelope elevation) is abolished by prior injection of the calcium chelator EGTA; neomycin, an inhibitor of InsP3 production, does not prevent the release of calcium in response to InsP3 but does abolish the wave of calcium release; the egg cytoplasm rapidly buffers microinjected calcium; the calcium concentration required to cause fertilization membrane elevation when microinjected is very similar to that required to stimulate the production of InsP3 in vitro; and the progressive fertilization membrane elevation seen after microinjection of calcium buffers appears to be due to diffusion of the buffer across the egg cytoplasm rather than to the induction of the activation wave. We conclude that InsP3 diffuses through the egg cytoplasm much more readily than calcium ions and that calcium-stimulated production of InsP3 and InsP3-induced calcium release from an internal store can account for the progressive release of calcium at fertilization.

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