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.

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 The cytosolic sperm factor that triggers Ca2+ oscillations and egg activation in mammals is a novel phospholipase C: PLCζ

Reproduction ◽  
2004 ◽  
Vol 127 (4) ◽  
pp. 431-439 ◽  
Author(s):  
K Swann ◽  
M G Larman ◽  
C M Saunders ◽  
F A Lai
Keyword(s):  
Membrane Fusion ◽  
Phospholipase C ◽  
Potential Role ◽  
Egg Activation ◽  
Specific Factor ◽  
Sperm Protein ◽  
Protein Factor ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Sperm Factor

When sperm activate eggs at fertilization the signal for activation involves increases in the intracellular free Ca2+concentration. In mammals the Ca2+changes at fertilization consist of intracellular Ca2+oscillations that are driven by the generation of inositol 1,4,5-trisphosphate (InsP3). It is not established how sperm trigger the increases in InsP3and Ca2+at fertilization. One theory suggests that sperm initiate signals to activate the egg by introducing a specific factor into the egg cytoplasm after membrane fusion. This theory has been mainly based upon the observation that injecting a cytosolic sperm protein factor into eggs can trigger the same pattern of Ca2+oscillations induced by the sperm. We have recently shown that this soluble sperm factor protein is a novel form of phospholipase C (PLC), and it is referred to as PLCζ(zeta). We describe the evidence that led to the identification of PLCζ and discuss the issues relating to its potential role in fertilization.

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 Fertilization-Induced Activation of Phospholipase C in the Sea Urchin Egg

1999 ◽  
Vol 215 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Brenda J. Rongish ◽  
Wenjun Wu ◽  
William H. Kinsey
Keyword(s):  
Phospholipase C ◽  
Sea Urchin ◽  
Sea Urchin Egg

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 Potential role of a sperm-derived phospholipase C in triggering the egg-activating Ca2+ signal at fertilization

Reproduction ◽  
2001 ◽  
pp. 839-846 ◽  
Author(s):  
K Swann ◽  
J Parrington ◽  
KT Jones
Keyword(s):  
Membrane Fusion ◽  
Phospholipase C ◽  
Potential Role ◽  
Egg Activation ◽  
Gamete Fusion ◽  
Inositol 1,4,5 Trisphosphate ◽  
Sperm Factor

An increase in intracellular Ca2+ at fertilization is the trigger for egg activation in all species that have been studied. Exactly how sperm-egg interaction leads to this Ca2+ increase has not been established. There is increasing support for the hypothesis that the spermatozoon introduces a Ca2+-releasing protein into the egg cytoplasm after gamete membrane fusion. This review discusses the merits of this 'sperm factor' hypothesis and presents evidence indicating that the sperm factor, at least in mammals, consists of a phospholipase C with distinctive properties. This evidence leads us to propose that, after gamete fusion, a sperm-derived phospholipase C causes production of inositol 1,4,5- trisphosphate, which then generates Ca2+ waves from within the egg cytoplasm.

scholarly journals Ca2+ release triggered by nicotinate adenine dinucleotide phosphate in intact sea urchin eggs

1995 ◽  
Vol 312 (3) ◽  
pp. 955-959 ◽  
Author(s):  
C M Perez-Terzic ◽  
E N Chini ◽  
S S Shen ◽  
T P Dousa ◽  
D E Clapham
Keyword(s):  
Sea Urchin ◽  
Specific Inhibitor ◽  
Intact Cells ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg ◽  
Cyclic Adp Ribose ◽  
Inositol 1,4,5 Trisphosphate ◽  
Dose Dependent Increase ◽  
Dose Dependent

Nicotinate adenine dinucleotide phosphate (NAADP) was recently identified [Lee and Aarhus (1995) J. Biol. Chem. 270, 2152-2157; Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] as a potent Ca(2+)-releasing agent in sea urchin egg homogenates. NAADP triggered Ca2+ release by a mechanism that was distinct from inositol 1,4,5-trisphosphate (InsP3)- and cyclic ADP-ribose (cADPR)-induced Ca2+ release. When NAADP was microinjected into intact sea urchin eggs it induced a dose-dependent increase in cytoplasmic free Ca2+ which was independent of the extracellular [Ca2+]. The Ca2+ waves elicited by microinjections of NAADP originated at the site of injection and swept across the cytosol. As previously found in sea urchin egg homogenates, NAADP-induced Ca2+ release in intact eggs was not blocked by heparin or by prior desensitization to InsP3 or cADPR. Thio-NADP, a specific inhibitor of the NAADP-induced Ca2+ release in sea urchin homogenates [Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] blocked NAADP (but not InsP3 or cADPR) injection-induced Ca2+ release in intact sea urchin eggs. Finally, fertilization of sea urchin eggs abrogated subsequent NAADP-induced Ca2+ release, suggesting that the NAADP-sensitive Ca2+ pool may participate in the fertilization response. This study demonstrates that NAADP acts as a selective Ca(2+)-releasing agonist in intact cells.

Sign in / Sign up

Export Citation Format

Share Document