scholarly journals The soluble sperm factor that causes Ca2+ release from sea-urchin (Lytechinus pictus) egg homogenates also triggers Ca2+ oscillations after injection into mouse eggs

1999 ◽  
Vol 341 (1) ◽  
pp. 1-4 ◽  
Author(s):  
John PARRINGTON ◽  
Keith T. JONES ◽  
F. Anthony LAI ◽  
Karl SWANN
Keyword(s):  
Sea Urchin ◽  
Uncharacterized Protein ◽  
Lytechinus Pictus ◽  
Protein Factor ◽  
Chromatographic Columns ◽  
Sea Urchin Egg ◽  
Boar Sperm ◽  
Sperm Factor ◽  
Mammalian Eggs ◽  
Mouse Eggs

Cytosolic extracts of boar sperm contain a soluble phospholipase C (PLC) activity that induces Ca2+ release in sea-urchin (Lytechinus pictus) egg homogenates and an uncharacterized protein factor that causes Ca2+ oscillations when injected into mammalian eggs. In the present study we fractionated boar sperm extracts on three different FPLC chromatographic columns and found that the fractions that caused maximal Ca2+ release in sea-urchin egg homogenates were also the ones that triggered Ca2+ oscillations in mouse eggs. Our data suggests that the sperm factor which triggers Ca2+ oscillations in eggs contains a PLC and not the 33 kDa glucosamine deaminase previously suggested to be one its components.

scholarly journals Different Ca2+-releasing abilities of sperm extracts compared with tissue extracts and phospholipase C isoforms in sea urchin egg homogenate and mouse eggs

2000 ◽  
Vol 346 (3) ◽  
pp. 743-749 ◽  
Author(s):  
Keith T. JONES ◽  
Miho MATSUDA ◽  
John PARRINGTON ◽  
Matilda KATAN ◽  
Karl SWANN
Keyword(s):  
Phospholipase C ◽  
Sea Urchin ◽  
Tissue Extracts ◽  
Sea Urchin Egg ◽  
Boar Sperm ◽  
Specific Activities ◽  
Mammalian Eggs ◽  
Mouse Eggs

A soluble phospholipase C (PLC) from boar sperm generates InsP3 and hence causes Ca2+ release when added to sea urchin egg homogenate. This PLC activity is associated with the ability of sperm extracts to cause Ca2+ oscillations in mammalian eggs following fractionation. A sperm PLC may, therefore, be responsible for causing the observed Ca2+ oscillations at fertilization. In the present study we have further characterized this boar sperm PLC activity using sea urchin egg homogenate. Consistent with a sperm PLC acting on egg PtdIns(4,5)P2, the ability of sperm extracts to release Ca2+ was blocked by preincubation with the PLC inhibitor U73122 or by the addition of neomycin to the homogenate. The Ca2+-releasing activity was also detectable in sperm from other species and in whole testis extracts. However, activity was not observed in extracts from other tissues. Moreover recombinant PLCβ1, -γ1, -γ2, -∆1, all of which had higher specific activities than boar sperm extracts, were not able to release Ca2+ in the sea urchin egg homogenate. In addition these PLCs were not able to cause Ca2+ oscillations following microinjection into mouse eggs. These results imply that the sperm PLC possesses distinct properties that allow it to hydrolyse PtdIns(4,5)P2 in eggs.

scholarly journals Phospholipase C isoforms in mammalian spermatozoa: potential components of the sperm factor that causes Ca2+ release in eggs

Reproduction ◽  
2002 ◽  
pp. 31-39 ◽  
Author(s):  
J Parrington ◽  
ML Jones ◽  
R Tunwell ◽  
C Devader ◽  
M Katan ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Sea Urchin ◽  
Soluble Protein ◽  
Gel Filtration ◽  
Protein Factor ◽  
Sea Urchin Egg ◽  
Inositol 1,4,5 Trisphosphate ◽  
Sperm Factor ◽  
Mammalian Eggs ◽  
Mammalian Spermatozoa

Injection of a soluble protein factor from mammalian spermatozoa triggers Ca2+ oscillations in mammalian eggs similar to those seen at fertilization. This sperm factor also generates inositol 1,4,5-trisphosphate and causes Ca2+ release in sea urchin egg homogenates and frog eggs. Recent studies have indicated that the sperm factor may be an inositol-specific phospholipase C (PLC) activity. This study investigated whether any of the commonly known PLC isoforms are components of the sperm factor. PLCbeta, PLCgamma and PLCdelta isoforms were shown to be present in boar sperm extracts. However, upon column fractionation of sperm extracts, none of the PLC isoforms detected correlated with the ability to cause Ca2+ release in eggs. In addition to our previous work on recombinant PLCs, it was also shown that PLCdelta3, PLCdelta4 and its splice variant PLCdelta4 Alt1 fail to cause Ca2+ release. The recently discovered 255 kDa PLCepsilon isoform also appears unlikely to be a component of the sperm factor, as fractionation of sperm extracts on a gel filtration column demonstrated that the peak of Ca2+-releasing activity was associated with fractions of 30-70 kDa. These findings indicate that the sperm factor that triggers Ca2+ release in eggs does not appear to have a known PLC isoform as one of its components.

Ca(2+) oscillations induced by a cytosolic sperm protein factor are mediated by a maternal machinery that functions only once in mammalian eggs

Development ◽  
2000 ◽  
Vol 127 (5) ◽  
pp. 1141-1150 ◽  
Author(s):  
T.S. Tang ◽  
J.B. Dong ◽  
X.Y. Huang ◽  
F.Z. Sun
Keyword(s):  
Receptor Sensitivity ◽  
Present Evidence ◽  
Sperm Protein ◽  
Protein Factor ◽  
Bovine Sperm ◽  
Sperm Factor ◽  
Mammalian Eggs ◽  
Mouse Eggs ◽  
Fertilized Egg ◽  
Stimulation Of

At fertilization in mammals, the sperm activates the egg by inducing a series of oscillations in the intracellular free Ca(2+) concentration. There is evidence showing that this oscillatory event is triggered by a sperm-derived protein factor which diffuses into egg cytoplasm after gamete membrane fusion. At present the identity of this factor and its precise mechanism of action is unknown. Here, we studied the specificity of action of the sperm factor in triggering Ca(2+) oscillations in mammalian eggs. In doing so, we examined the patterns of Ca(2+) signaling in mouse eggs, zygotes, parthenogenetic eggs and maturing oocytes following the stimulation of bovine sperm extracts which contain the sperm factor. It is observed that the sperm factor could induce Ca(2+) oscillations in metaphase eggs, maturing oocytes and parthenogenetically activated eggs but not in the zygotes. We present evidence that Ca(2+) oscillations induced by the sperm factor require a maternal machinery. This machinery functions only once in mammalian oocytes and eggs, and is inactivated by sperm-derived components but not by parthenogenetic activation. In addition, it is found that neither InsP(3) receptor sensitivity to InsP(3) nor Ca(2+) pool size are the determinants that cause the fertilized egg to lose its ability to generate sperm-factor-induced Ca(2+) oscillations at metaphase. In conclusion, our study suggests that the orderly sequence of Ca(2+) oscillations in mammalian eggs at fertilization is critically dependent upon the presence of a functional maternal machinery that determines whether the sperm-factor-induced Ca(2+) oscillations can persist.

The Respiratory and Glycolytic Enzymes of Sea-Urchin Eggs

1954 ◽  
Vol 31 (2) ◽  
pp. 208-217
Author(s):  
MARTYNAS YČAS
Keyword(s):  
Cytochrome C ◽  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Lactic Dehydrogenase ◽  
Glycolytic Pathway ◽  
Endogenous Respiration ◽  
Centrifugal Field ◽  
Lytechinus Pictus ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg

1. Activity corresponding to phosphoglucomutase, phosphohexoisomerase, aldolase, triosephosphate dehydrogenase, enolase and lactic dehydrogenase has been demonstrated in homogenates prepared from unfertilized sea-urchin eggs (Strongylocentrotus purpuratus and Lytechinus pictus). 2. The presence of cytochromes a and b1 has been confirmed. These cytochromes sediment in a relatively low centrifugal field. 3. No cytochrome c could be demonstrated, although cytochrome c is both reduced and oxidized by homogenates, and addition of cytochrome c increases the endogenous respiration and oxidation of succinate. 4. These results support the view that the usual glycolytic pathway operates in the sea-urchin egg and is the principal route of oxidation of carbohydrate.

scholarly journals Organization of the sea urchin egg endoplasmic reticulum and its reorganization at fertilization.

1991 ◽  
Vol 114 (5) ◽  
pp. 929-940 ◽  
Author(s):  
M Terasaki ◽  
L A Jaffe
Keyword(s):  
Sea Urchin ◽  
Time Lapse ◽  
Sperm Nucleus ◽  
Temporal Organization ◽  
Calcium Wave ◽  
Zygote Nucleus ◽  
Lytechinus Pictus ◽  
Sea Urchin Egg ◽  
A Cell ◽  
Sperm Aster

The ER of eggs of the sea urchin Lytechinus pictus was stained by microinjecting a saturated solution of the fluorescent dicarbocyanine DiIC18(3) (DiI) in soybean oil; the dye spread from the oil drop into ER membranes throughout the egg but not into other organelles. Confocal microscopy revealed large cisternae extending throughout the interior of the egg and a tubular membrane network at the cortex. Since diffusion of DiI is confined to continuous bilayers, the spread of the dye supports the concept that the ER is a cell-wide, interconnected compartment. In time lapse observations, the internal cisternae were seen to be in continuous motion, while the cortical ER was stationary. After fertilization, the internal ER appeared to become more finely divided, beginning as a wave apparently coincident with the calcium wave and becoming most marked by 2-3 min. By 5-8 min the ER returned to an organization similar to that of the unfertilized egg. The cortical network also changed at fertilization; it became disrupted and eventually recovered. DiI labeling allowed continuous observations of the ER during pronuclear migration and mitosis. DiI-stained membranes accumulated in the region of the microtubule array surrounding the sperm nucleus and centriole (the sperm aster) as it migrated to the center of the egg; this accumulation persisted near the centrosomes and zygote nucleus throughout pronuclear fusion and the first two mitotic cycles. We have used a new method to observe the spatial and temporal organization of the ER in a living cell, and we have demonstrated a striking reorganization of the ER at fertilization.

Psammechinus miliaris egg homogenate as a model to investigate Ca2+-release mechanisms

1999 ◽  
Vol 79 (2) ◽  
pp. 323-326 ◽  
Author(s):  
Armando A. Genazzani ◽  
Heather L. Wilson ◽  
Antony Galione
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Lytechinus Pictus ◽  
Release Mechanisms ◽  
Psammechinus Miliaris ◽  
Sea Urchin Egg ◽  
Cyclic Adp Ribose ◽  
The Usa ◽  
Release Model ◽  
Convenient Model

The sea urchin egg has proved a reliable and robust system for measuring intracellular calcium release in response to three independent mechanisms: inositol 1,4,5 trisphosphate, cyclic ADP-ribose and the recently identified molecule, nicotinic acid adenine dinucleotide phosphate (NAADP). These calcium release mechanisms have been studied in homogenates of Lytechinus pictus and Spongylocentrotus purpuratus, which are two sea urchin species located off the west coast of the USA. A new calcium-release model from a species of sea urchin present off the coasts of Britain, Psammechinus miliaris is characterized and described. Although the Ca2+-release characteristics in this species do not differ from those of the other two sea urchin species, it may provide a more economical and convenient model for European scientists.

PLCζ: a sperm-specific trigger of Ca2+ oscillations in eggs and embryo development

Development ◽  
2002 ◽  
Vol 129 (15) ◽  
pp. 3533-3544 ◽  
Author(s):  
Christopher M. Saunders ◽  
Mark G. Larman ◽  
John Parrington ◽  
Llewellyn J. Cox ◽  
Jillian Royse ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Embryo Development ◽  
Specific Protein ◽  
Normal Embryo ◽  
Egg Activation ◽  
Sperm Factor ◽  
Mammalian Eggs ◽  
Mouse Eggs ◽  
Cytosolic Factor ◽  
Specific Trigger

Upon fertilisation by sperm, mammalian eggs are activated by a series of intracellular Ca2+ oscillations that are essential for embryo development. The mechanism by which sperm induces this complex signalling phenomenon is unknown. One proposal is that the sperm introduces an exclusive cytosolic factor into the egg that elicits serial Ca2+ release. The ‘sperm factor’ hypothesis has not been ratified because a sperm-specific protein that generates repetitive Ca2+ transients and egg activation has not been found. We identify a novel, sperm-specific phospholipase C, PLCζ, that triggers Ca2+ oscillations in mouse eggs indistinguishable from those at fertilisation. PLCζ removal from sperm extracts abolishes Ca2+ release in eggs. Moreover, the PLCζ content of a single sperm was sufficient to produce Ca2+ oscillations as well as normal embryo development to blastocyst. Our results are consistent with sperm PLCζ as the molecular trigger for development of a fertilised egg into an embryo.

scholarly journals Different Ca2+-releasing abilities of sperm extracts compared with tissue extracts and phospholipase C isoforms in sea urchin egg homogenate and mouse eggs

2000 ◽  
Vol 346 (3) ◽  
pp. 743 ◽  
Author(s):  
Keith T. JONES ◽  
Miho MATSUDA ◽  
John PARRINGTON ◽  
Matilda KATAN ◽  
Karl SWANN
Keyword(s):  
Phospholipase C ◽  
Sea Urchin ◽  
Tissue Extracts ◽  
Sea Urchin Egg ◽  
Mouse Eggs
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