Teleost fish spermatozoa contain a cytosolic protein factor that induces calcium release in sea urchin egg homogenates and triggers calcium oscillations when injected into mouse oocytes

2003 ◽  
Vol 305 (2) ◽  
pp. 299-304 ◽  
Author(s):  
Kevin Coward ◽  
Antonio Campos-Mendoza ◽  
Mark Larman ◽  
Olivia Hibbitt ◽  
Brendan McAndrew ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Teleost Fish ◽  
Calcium Release ◽  
Calcium Oscillations ◽  
Mouse Oocytes ◽  
Cytosolic Protein ◽  
Protein Factor ◽  
Sea Urchin Egg

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.

Spatiotemporal dynamics of intracellular [Ca2+]i oscillations during the growth and meiotic maturation of mouse oocytes

Development ◽  
1994 ◽  
Vol 120 (12) ◽  
pp. 3507-3517 ◽  
Author(s):  
J. Carroll ◽  
K. Swann ◽  
D. Whittingham ◽  
M. Whitaker
Keyword(s):  
Spatial Organization ◽  
Calcium Release ◽  
Calcium Oscillations ◽  
Meiotic Maturation ◽  
Similar Proportion ◽  
Calcium Waves ◽  
Apparent Difference ◽  
Immature Oocytes ◽  
Mouse Oocytes

Calcium oscillations occur during meiotic maturation of mouse oocytes. They also trigger activation at fertilization. We have monitored [Ca2+]i in oocytes at different stages of growth and maturation to examine how the calcium release mechanisms alter during oogenesis. Spontaneous calcium oscillations occur every 2–3 minutes in the majority of fully grown (but immature) mouse oocytes released from antral follicles and resuming meiosis. The oscillations last for 2–4 hours after release from the follicle and take the form of global synchronous [Ca2+]i increases throughout the cell. Rapid image acquisition or cooling the bath temperature from 28 degrees C to 16 degrees C did not reveal any wave-like spatial heterogeneity in the [Ca2+]i signal. Calcium appears to reach highest levels in the germinal vesicle but this apparent difference of [Ca2+] in nucleus and cytoplasm is an artifact of dye loading. Smaller, growing immature oocytes are less competent: about 40% are able to resume meiosis and a similar proportion of these oocytes show spontaneous calcium oscillations. [Ca2+]i transients are not seen in oocytes that do not resume meiosis spontaneously in vitro. Nonetheless, these oocytes are capable of [Ca2+]i oscillations since they show them in response to the addition of carbachol or thimerosal. To examine how the properties of calcium release change during meiotic maturation, a calcium-releasing factor from sperm was microinjected into fully grown immature and mature oocytes. The sperm-factor-induced oscillations were about two-fold larger and longer in mature oocytes compared to immature oocytes. Calcium waves travelling at 40–60 microns/second were generated in mature oocytes, but not in immature oocytes. In some mature oocytes, successive calcium waves had different sites of origin. The modifications in the size and spatial organization of calcium transients during oocyte maturation may be a necessary prerequisite for normal fertilization.

scholarly journals Cortical localization of a calcium release channel in sea urchin eggs.

1992 ◽  
Vol 116 (5) ◽  
pp. 1111-1121 ◽  
Author(s):  
S M McPherson ◽  
P S McPherson ◽  
L Mathews ◽  
K P Campbell ◽  
F J Longo
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Ryanodine Receptor ◽  
Sea Urchin ◽  
Calcium Release ◽  
Staining Pattern ◽  
Cortical Granule ◽  
Calcium Release Channel ◽  
Release Channel ◽  
Sea Urchin Eggs ◽  
Sea Urchin Egg

We have used an antibody against the ryanodine receptor/calcium release channel of skeletal muscle sarcoplasmic reticulum to localize a calcium release channel in sea urchin eggs. The calcium release channel is present in less than 20% of immature oocytes, where it does not demonstrate a specific cytoplasmic localization, while it is confined to the cortex of all mature eggs examined. This is in contrast to the cortical and subcortical localization of calsequestrin in mature and immature eggs. Immunolocalization of the calcium release channel reveals a cortical reticulum or honeycomb staining network that surrounds cortical granules and is associated with the plasma membrane. The network consists of some immunoreactive electron-dense material coating small vesicles and elongate cisternae of the endoplasmic reticulum. The fluorescent reticular staining pattern is lost when egg cortices are treated with agents known to affect sarcoplasmic reticulum calcium release and induce cortical granule exocytosis (ryanodine, calcium, A-23187, and caffeine). An approximately 380-kD protein of sea urchin egg cortices is identified by immunoblot analysis with the ryanodine receptor antibody. These results demonstrate: (a) the presence of a ryanodine-sensitive calcium release channel that is located within the sea urchin egg cortex; (b) an altered calcium release channel staining pattern as a result of treatments that initiate the cortical granule reaction; and (c) a spatial and functional dichotomy of the ER which may be important in serving different roles in the mobilization of calcium at fertilization.

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 Nicotinamide inhibits cyclic ADP-ribose-mediated calcium signalling in sea urchin eggs

1996 ◽  
Vol 319 (2) ◽  
pp. 613-617 ◽  
Author(s):  
Jaswinder K SETHI ◽  
Ruth M EMPSON ◽  
Antony GALIONE
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Calcium Signalling ◽  
Hydrolytic Activity ◽  
Calcium Release Channels ◽  
Adp Ribosyl Cyclase ◽  
Sea Urchin Egg ◽  
Cyclic Adp Ribose ◽  
Single Polypeptide ◽  
Hydrolysis Of

Cyclic ADP ribose (cADPR) is a potent Ca2+-releasing agent, and putative second messenger, the endogenous levels of which are tightly regulated by synthetic (ADP-ribosyl cyclases) and degradative (cADPR hydrolase) enzymes. These enzymes have been characterized in a number of mammalian and invertebrate tissues and their activities are often found on a single polypeptide. β-NAD+, cGMP and nitric oxide (NO) have been reported to mobilize Ca2+ in the sea urchin egg via the cADPR-mediated pathway. We now report that in sea urchin egg homogenates, nicotinamide inhibits the Ca2+-mobilizing action of β-NAD+, cGMP and NO, but has no effect on cADPR-induced Ca2+ release. Moreover, nicotinamide inhibits cGMP-induced regenerative Ca2+ waves in the intact sea urchin egg. By successfully separating the cADPR-metabolizing machinery from that which releases Ca2+, we have shown that nicotinamide inhibits cADPR-mediated Ca2+ signalling at the level of cADPR generation. Importantly, nicotinamide had no effect upon the hydrolysis of cADPR, and its selective action on cyclase activity was supported by its inhibition of purified Aplysia ADP-ribosyl cyclase, which does not exhibit detectable hydrolytic activity. The action of nicotinamide in blocking Ca2+ release by β-NAD+, cGMP and NO strongly suggests that these agents act as modulators of cADPR synthesis rather than to sensitize calcium release channels to cADPR.

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