scholarly journals Involvement of the Cytoskeleton in the Movement of Cortical Granules during Oocyte Maturation, and Cortical Granule Anchoring in Mouse Eggs

1998 ◽  
Vol 200 (1) ◽  
pp. 103-115 ◽  
Author(s):  
Stephanie A. Connors ◽  
Mito Kanatsu-Shinohara ◽  
Richard M. Schultz ◽  
Gregory S. Kopf
Keyword(s):  
Oocyte Maturation ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Mouse Eggs

The dynamics of plasma membrane PtdIns(4,5)P2 at fertilization of mouse eggs

2002 ◽  
Vol 115 (10) ◽  
pp. 2139-2149 ◽  
Author(s):  
Guillaume Halet ◽  
Richard Tunwell ◽  
Tamas Balla ◽  
Karl Swann ◽  
John Carroll
Keyword(s):  
Plasma Membrane ◽  
De Novo ◽  
Confocal Imaging ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Vegetal Cortex ◽  
Living Mouse ◽  
Cortical Granule Exocytosis ◽  
Phosphatidylinositol 4 ◽  
Mouse Eggs

A series of intracellular Ca2+ oscillations are responsible for triggering egg activation and cortical granule exocytosis at fertilization in mammals. These Ca2+ oscillations are generated by an increase in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], which results from the hydrolysis of phosphatidylinositol 4,5-bisphosphate[PtdIns(4,5)P2]. Using confocal imaging to simultaneously monitor Ca2+ and plasma membrane PtdIns(4,5)P2in single living mouse eggs we have sought to establish the relationship between the kinetics of PtdIns(4,5)P2 metabolism and the Ca2+ oscillations at fertilization. We report that there is no detectable net loss of plasma membrane PtdIns(4,5)P2either during the latent period or during the subsequent Ca2+oscillations. When phosphatidylinositol 4-kinase is inhibited with micromolar wortmannin a limited decrease in plasma membrane PtdIns(4,5)P2 is detected in half the eggs studied. Although we were unable to detect a widespread loss of PtdIns(4,5)P2, we found that fertilization triggers a net increase in plasma membrane PtdIns(4,5)P2 that is localized to the vegetal cortex. The fertilization-induced increase in PtdIns(4,5)P2 follows the increase in Ca2+, is blocked by Ca2+ buffers and can be mimicked, albeit with slower kinetics, by photoreleasing Ins(1,4,5)P3. Inhibition of Ca2+-dependent exocytosis of cortical granules, without interfering with Ca2+ transients, inhibits the PtdIns(4,5)P2 increase. The increase appears to be due to de novo synthesis since it is inhibited by micromolar wortmannin. Finally,there is no increase in PtdIns(4,5)P2 in immature oocytes that are not competent to extrude cortical granules. These studies suggest that fertilization does not deplete plasma membrane PtdIns(4,5)P2 and that one of the pathways for increasing PtdIns(4,5)P2 at fertilization is invoked by exocytosis of cortical granules.

Dynamics of cortical granule exocytosis at fertilization in living mouse eggs

1996 ◽  
Vol 270 (5) ◽  
pp. C1354-C1361 ◽  
Author(s):  
M. Tahara ◽  
K. Tasaka ◽  
N. Masumoto ◽  
A. Mammoto ◽  
Y. Ikebuchi ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cortical Granule ◽  
Free Calcium ◽  
Cortical Granules ◽  
Acetoxymethyl Ester ◽  
Living Mouse ◽  
Cortical Granule Exocytosis ◽  
Mouse Eggs

Sperm-egg fusion induces an intracellular free calcium concentration ([Ca2+]i) increase and exocytosis of cortical granules (CGs). Recently we used an impermeable fluorescent membrane probe, 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), to develop a method to evaluate the kinetics of exocytosis in single living cells. In this study we used digital imaging and confocal laser scanning microscopy to evaluate CG exocytosis in living mouse eggs with TMA-DPH. Time-related changes of CG exocytosis were estimated as the percent increase of TMA-DPH fluorescence. The increase of fluorescence in the egg started after sperm attachment, continued at an almost uniform rate, and ceased at 45-60 min. Whereas the [Ca2+]i increase at fertilization was transient or oscillatory, exocytosis was not always induced concomitantly with each [Ca2+]i peak. Next we used this method to determine some intracellular mediators of exocytosis in the egg. An intracellular calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, and a microfilament inhibitor, cytochalasin B, blocked sperm-induced exocytosis. A guanosine 5'-triphosphate-binding protein activator, AlF4-, induced exocytosis. These results suggest that [Ca2+]i, microfilament, and guanosine 5'-triphosphate-binding proteins may be involved in CG exocytosis. In conclusion, this method has significant advantages for studying exocytosis in living eggs.

359 MORPHOLOGIC AND BIOCHEMISTRY ALTERATIONS ON BOVINE OOCYTE MATURATION IN VITRO WITH NITRIC OXIDE AND ITS IMPACT ON EMBRYO DEVELOPMENT

2010 ◽  
Vol 22 (1) ◽  
pp. 336 ◽  
Author(s):  
K. S. Viana ◽  
M. C. C. Bussiere ◽  
C. S. Paes de Carvalho ◽  
B. L. Dias ◽  
M. R. Faes ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Plasma Membrane ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Control Group ◽  
Cortical Granule ◽  
Bovine Oocyte ◽  
Cortical Granules ◽  
Maturation In Vitro

The aim of this study was to evaluate morphologic and biochemistry alterations caused by the addition of sodium nitroprusside (SNP), a NO donor, on bovine oocyte maturation in vitro. Bovine ovaries were collected at a local abattoir. COC were cultured in TCM-199 with 10% FCS, 0.5 μg mL-1 FSH, 5.0 μg mL-1 LH, and antibiotics. Analysis of variance was conducted and the means were compared by t-test at a level of 5%. Experimental design: (1) evaluation of the oocyte plasma membrane viability and integrity using Annexin V/propidium iodide (PI) and Hoechst 33342/PI staining, respectively; (2) microtubule and microfilament organization, and migration of cortical granules by immunofluorescence; (3) oocyte glutathione content and concentration of NO3-/NO2-using the method of Griess (Ricart-Jane D et al. 2002 Nitric Oxide 6, 178-185) and (4) embryo development. In Experiment 1, the addition of 1 mM SNP caused cellular death in the majority of the oocytes [100%, AnnexinV/PI (+) and 80.7% Hoescht/IP (+)] differing from the control group and the 0.01 mM SNP (P < 0.05). In Experiment 2, the microtubule staining was observed in the cytoplasm in both control group and 0.01 mM SNP; however, the group treated with 1 mM of SNP exhibited clear defects in spindle and chromatin arrangements (P < 0.05). No alterations in microfilaments disposition was observed in the control group and 0.01 mM SNP. However, after the addition of 1 mM, the microfilaments arranged into clusters, and not below of the cortex. Oocytes treated with 1 mM SNP (68.2%) showed total cortical granule migration to the periphery of the ooplasm and were similar to the control group (72.2%) (P > 0.05). Nevertheless, in the group treated with 0.01 mM SNP the total cortical granule migration was greater (86.8%, P < 0.05). In Experiment 3, the glutathione content of oocytes cultured in the presence of 1 mM SNP was lower (4.4p mol) when compared to the control group (5.4p mol) and 0.01 mM SNP (5.5 pmol) (P > 0.05). The concentration of NO in the medium were similar to both control group (6.0 ± 3.0 μM) and treated with 0.01 mM SNP (15.8 ± 1.9 μM), however, the treatment with 1 mM SNP increased 10 times (59.9 ± 12.0 μM; P < 0.05) this concentration. In Experiment 4, cleavage rates and embryo development were similar for groups control and 0.01 mM SNP (P > 0.05). Even so, in the group treated with 0.01 mM there was a greater blastocyst cell number when compared to the control group (256.8 ± 52.5 and 196.9 ± 54.0, respectively-P < 0.05). These results indicate that: (1) the addition of 0.01 mM SNP increased the quality of the oocyte maturation, leading to a higher percentage of cortical granules migration and blastocyst cell numbers, in a different pathway from that of glutathione; (2) the addition of 1 mM of SNP caused a cytotoxic effect, leading to cellular death with loss of viability and integrity of plasma membrane, absence of nuclear maturation/organization of cytoskeleton and reduction of the glutathione content, although with no intervention in the migration of cortical granules.

Cortical granules of the sea urchin translocate early in oocyte maturation

Development ◽  
1997 ◽  
Vol 124 (9) ◽  
pp. 1845-1850
Author(s):  
L.K. Berg ◽  
G.M. Wessel
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Cortical Granule ◽  
Ionophore A23187 ◽  
Cortical Granules ◽  
Germinal Vesicle Breakdown

Cortical granules are secretory vesicles poised at the cortex of an egg that, upon stimulation by sperm contact at fertilization, secrete their contents. These contents modify the extracellular environment and block additional sperm from reaching the egg. The role of cortical granules in blocking polyspermy is conserved throughout much of phylogeny. In the sea urchin, cortical granules accumulate throughout the cytoplasm during oogenesis, but in mature eggs the cortical granules are attached to the plasma membrane, having translocated to the cortex at some earlier time. To study the process of cortical granule translocation to the cell surface we have devised a procedure for maturation of sea urchin oocytes in vitro. Using this procedure, we examined the rate of oocyte maturation by observing the movement and breakdown of the germinal vesicle, the formation of polar bodies and the formation of the egg pronucleus. We find that oocyte maturation takes approximately 9 hours in the species used here (Lytechinus variegatus), from the earliest indication of maturation (germinal vesicle movement) to formation of a distinct pronucleus. We then observed the translocation of cortical granules in these cells by immunolocalization using a monoclonal antibody to hyalin, a protein packaged specifically in cortical granules. We found that the translocation of cortical granules in in vitro-matured oocytes begins with the movement of the germinal vesicle to the oocyte cell surface, and is 50% complete 1 hour after germinal vesicle breakdown. In the in vitro-matured egg, 99% of the cortical granules are at the cortex, indistinguishable from translocation in oocytes that mature in vivo. We have also found that eggs that mature in vitro are functionally identical to eggs that mature in vivo by four criteria. (1) The matured cells undergo a selective turnover of mRNA encoding cortical granule contents. (2) The newly formed pronucleus begins transcription of histone messages. (3) Cortical granules that translocate in vitro are capable of exocytosis upon activation by the calcium ionophore, A23187. (4) The mature egg is fertilizable and undergoes normal cleavage and development. In vitro oocyte maturation enables us to examine the mechanism of cortical granule translocation and other processes that had previously only been observed in static sections of fixed ovaries.

scholarly journals Rab3A, a possible marker of cortical granules, participates in cortical granule exocytosis in mouse eggs

2016 ◽  
Vol 347 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Oscar Daniel Bello ◽  
Andrea Isabel Cappa ◽  
Matilde de Paola ◽  
María Natalia Zanetti ◽  
Mitsunori Fukuda ◽  
...  
Keyword(s):  
Cortical Granule ◽  
Cortical Granules ◽  
Granule Exocytosis ◽  
Cortical Granule Exocytosis ◽  
Mouse Eggs

Early Reactions of the Rodent Egg to Spermatozoon Penetration

1956 ◽  
Vol 33 (2) ◽  
pp. 358-365 ◽  
Author(s):  
C. R. AUSTIN ◽  
A. W. H. BRADEN
Keyword(s):  
Zona Pellucida ◽  
Cortical Granule ◽  
Perivitelline Space ◽  
Cortical Granules ◽  
Rats And Mice ◽  
Mouse Eggs

In the rat, mouse and hamster the spermatozoon passes rapidly through the thick, homogeneous zona pellucida surrounding the egg and the head almost immediately becomes attached to the surface of the inner cytoplasmic mass or vitellus. As a result of this attachment a block to polyspermy is developed in rat and mouse eggs. In the hamster a block is apparently not formed. It seems likely, therefore, that the disappearance of cortical granules in the hamster egg, also an outcome of contact with the spermatozoon head, could signal the release of an agent that is responsible, after crossing the perivitelline space, for bringing about the zona reaction, reducing the penetrability of the zona pellucida to spermatozoa. Data suggest that this mechanism exists also in rats and mice, although a cortical granule response has not been distinguished in these animals. Thus, attachment of the spermatozoon head to the vitellus probably elicits both the zona reaction and the block to polyspermy. These changes appear to be specific to spermatozoon penetration and to be initiated before the spermatozoon head passes through the surface of the vitellus and before the resumption of the second meiosis.

scholarly journals Compensatory endocytosis occurs after cortical granule exocytosis in mouse eggs

2019 ◽  
Vol 235 (5) ◽  
pp. 4351-4360
Author(s):  
Matías D. Gómez‐Elías ◽  
Rafael A. Fissore ◽  
Patricia S. Cuasnicú ◽  
Débora J. Cohen
Keyword(s):  
Cortical Granule ◽  
Granule Exocytosis ◽  
Cortical Granule Exocytosis ◽  
Mouse Eggs

scholarly journals OOCYTE DIFFERENTIATION IN THE SEA URCHIN, ARBACIA PUNCTULATA, WITH PARTICULAR REFERENCE TO THE ORIGIN OF CORTICAL GRANULES AND THEIR PARTICIPATION IN THE CORTICAL REACTION

1968 ◽  
Vol 37 (2) ◽  
pp. 514-539 ◽  
Author(s):  
Everett Anderson
Keyword(s):  
Sea Urchin ◽  
Golgi Complex ◽  
Morphological Evidence ◽  
Cortical Granule ◽  
Perivitelline Space ◽  
Unit Membrane ◽  
Cortical Granules ◽  
Arbacia Punctulata ◽  
Cortical Reaction ◽  
Oocyte Differentiation

This paper presents morphological evidence on the origin of cortical granules in the oocytes of Arbacia punctulata and other echinoderms. During oocyte differentiation, those Golgi complexes associated with the production of cortical granules are composed of numerous saccules with companion vesicles. Each element of the Golgi complex contains a rather dense homogeneous substance. The vesicular component of the Golgi complex is thought to be derived from the saccular member by a pinching-off process. The pinched-off vesicles are viewed as containers of the precursor(s) of the cortical granules. In time, they coalesce and form a mature cortical granule whose content is bounded by a unit membrane. Thus, it is asserted that the Golgi complex is involved in both the synthesis and concentration of precursors utilized in the construction of the cortical granule. Immediately after the egg is activated by the sperm the primary envelope becomes detached from the oolemma, thereby forming what we have called the activation calyx (see Discussion). Subsequent to the elaboration of the activation calyx, the contents of cortical granules are released (cortical reaction) into the perivitelline space. The discharge of the constituents of a cortical granule is accomplished by the union of its encompassing unit membrane, in several places, with the oolemma.

scholarly journals Poisson-distributed active fusion complexes underlie the control of the rate and extent of exocytosis by calcium.

1996 ◽  
Vol 134 (2) ◽  
pp. 329-338 ◽  
Author(s):  
S S Vogel ◽  
P S Blank ◽  
J Zimmerberg
Keyword(s):  
Poisson Process ◽  
Sea Urchin ◽  
Physiological Responses ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Granule Exocytosis ◽  
Calcium Dependence ◽  
Sea Urchin Egg ◽  
High Calcium ◽  
Cortical Granule Exocytosis

We have investigated the consequences of having multiple fusion complexes on exocytotic granules, and have identified a new principle for interpreting the calcium dependence of calcium-triggered exocytosis. Strikingly different physiological responses to calcium are expected when active fusion complexes are distributed between granules in a deterministic or probabilistic manner. We have modeled these differences, and compared them with the calcium dependence of sea urchin egg cortical granule exocytosis. From the calcium dependence of cortical granule exocytosis, and from the exposure time and concentration dependence of N-ethylmaleimide inhibition, we determined that cortical granules do have spare active fusion complexes that are randomly distributed as a Poisson process among the population of granules. At high calcium concentrations, docking sites have on average nine active fusion complexes.

Weak bases partially activate Xenopus eggs and permit changes in membrane conductance whilst inhibiting cortical granule exocytosis

1987 ◽  
Vol 87 (2) ◽  
pp. 205-220
Author(s):  
M. Charbonneau ◽  
D.J. Webb
Keyword(s):  
Polar Body ◽  
Membrane Conductance ◽  
Transient Increase ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Weak Base ◽  
Granule Exocytosis ◽  
Weak Bases ◽  
Prolonged Contact ◽  
Cortical Granule Exocytosis

At extracellular pH values close to their pKa values the weak bases, ammonia and procaine, elicited a series of events in non-activated Xenopus eggs, some of which resembled those normally occurring at fertilization. These included: (1) a transient increase in membrane conductance; (2) modification of the microvilli; (3) thickening of the cortical cytoplasm and displacement of the cortical granules; (4) pigment accumulation; (5) contractions and shape changes. However, these eggs did not undergo the cortical reaction nor emit the second polar body. Cortical granule exocytosis of inseminated or artificially stimulated eggs was inhibited if the eggs had been previously treated for 15 min with the weak base and subsequently rinsed. Multiple sperm-entry sites were exhibited by the inseminated eggs, suggesting polyspermy. However, such eggs did not cleave and although sperm had fused with the egg membrane, they were not incorporated. Nevertheless, a transient increase in membrane conductance was evoked, which was longer in duration and had a slightly different form from that normally accompanying fertilization. In these eggs cortical granules were intact but displaced away from the plasma membrane. Prolonged contact with the weak base rendered eggs totally unresponsive to sperm or artificial stimuli but eggs recovered when rinsed sufficiently. These effects of weak bases on unfertilized Xenopus eggs or during fertilization were completely absent at pH 7.4. Although changes in intracellular pH or Ca2+ may be involved in these phenomena, direct action by the weak base itself cannot be ruled out.

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