scholarly journals Ca2+cyt negatively regulates the initiation of oocyte maturation

2004 ◽  
Vol 165 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Lu Sun ◽  
Khaled Machaca
Keyword(s):  
Cell Cycle ◽  
Oocyte Maturation ◽  
Cell Cycle Progression ◽  
Germinal Vesicle ◽  
Germinal Vesicle Breakdown ◽  
Cycle Progression ◽  
Nuclear Maturation ◽  
Oocyte Meiosis ◽  
Kinase Cascade ◽  
Cell Cycle Machinery

Ca2+ is a ubiquitous intracellular messenger that is important for cell cycle progression. Genetic and biochemical evidence support a role for Ca2+ in mitosis. In contrast, there has been a long-standing debate as to whether Ca2+ signals are required for oocyte meiosis. Here, we show that cytoplasmic Ca2+ (Ca2+cyt) plays a dual role during Xenopus oocyte maturation. Ca2+ signals are dispensable for meiosis entry (germinal vesicle breakdown and chromosome condensation), but are required for the completion of meiosis I. Interestingly, in the absence of Ca2+cyt signals oocytes enter meiosis more rapidly due to faster activation of the MAPK-maturation promoting factor (MPF) kinase cascade. This Ca2+-dependent negative regulation of the cell cycle machinery (MAPK-MPF cascade) is due to Ca2+cyt acting downstream of protein kinase A but upstream of Mos (a MAPK kinase kinase). Therefore, high Ca2+cyt delays meiosis entry by negatively regulating the initiation of the MAPK-MPF cascade. These results show that Ca2+ modulates both the cell cycle machinery and nuclear maturation during meiosis.

Antioxidants Stimulate Germinal Vesicle Breakdown, But Inhibit Chromosome Formation And Spindle Assembly In Porcine Oocytes

2000 ◽  
Vol 6 (S2) ◽  
pp. 964-965
Author(s):  
Qing-Yuan Sun ◽  
Randall S. Prather ◽  
Heide Schatten
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Spindle Assembly ◽  
Mouse Oocyte ◽  
Germinal Vesicle Breakdown ◽  
Oocyte Meiosis ◽  
First Polar Body ◽  
Porcine Oocyte ◽  
Chromosome Formation

Mammalian oocytes are arrested at the diplotene stage of the first meiotic division. Release of oocytes from their follicles induces meiotic resumption characterized by germinal vesicle breakdown (GVBD), followed by the chromosome formation and metaphase I spindle organization and finally the extrusion the first polar body. Recently it was shown that cellpermeant antioxidants significantly inhibit spontaneous resumption of meiosis in mouse oocytes, which may indicate a role of oxygen radicals in oocyte maturation. The regulation of mouse oocyte meiosis resumption is different from that of large domestic animals in that GVBD is independent of Ca2+ and protein synthesis. The present study investigated the influence of two cell-permeant antioxidants, 2(3)-ter-butyl-4-hydroxyanisole (BHA) and nordihydroguaiaretic acid (NDGA), on porcine oocyte meiosis resumption, chromatin behavior and spindle assembly. Our findings revealed a different role of antioxidants in porcine oocyte meiosis resumption than in mouse oocyte maturation.

Involvement of catecholamines in the regulation of oocyte maturation in frogs

Zygote ◽  
2002 ◽  
Vol 10 (3) ◽  
pp. 271-281 ◽  
Author(s):  
Inés Ramos ◽  
Susana Cisint ◽  
Claudia A. Crespo ◽  
Marcela F. Medina ◽  
Silvia N. Fernández
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Significant Inhibition ◽  
Follicle Cells ◽  
Germinal Vesicle Breakdown ◽  
Nuclear Maturation ◽  
Dose Dependent ◽  
Metabolic Behaviour

The present study investigates the role of catecholamines in the regulation of Bufo arenarum oocyte maturation. The metabolic changes in the oxidation of carbohydrates and the meiotic resumption evinced by the germinal vesicle breakdown were used as indicators of cytoplasmic and nuclear maturation, respectively. The results obtained suggest that noradrenaline (norepinephrine) could be one of the factors responsible for the metabolic behaviour that characterises cytoplasmically immature oocytes. The use of adrenaline (epinephrine), on the other hand, induced a metabolic change which made oocytes cytoplasmically mature. The effect of both catecholamines, which was dose-dependent, was observed in ovarian oocytes (surrounded by follicle cells) as well as in coelomic oocytes (free from follicle cells), suggesting the presence of adrenergic receptors in the gamete. The results obtained using adrenergic agonists and antagonists suggest that the effect of adrenaline would be due to an interaction with β2-receptors. Although catecholamines have an influence on the determination of the stage of cytoplasmic maturation of the oocytes, they do not affect nuclear maturation by themselves. Nevertheless, pretreatment of follicles with adrenaline caused a significant inhibition in progesterone-induced nuclear maturation even though this effect was markedly weaker when using noradrenaline.

scholarly journals Regulation of cyclin D1 expression and cell cycle progression by mitogen-activated protein kinase cascade

1999 ◽  
Vol 56 (4) ◽  
pp. 1258-1261 ◽  
Author(s):  
Yoshio Terada ◽  
Seiji Inoshita ◽  
Osamu Nakashima ◽  
Michio Kuwahara ◽  
Sei Sasaki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Mitogen Activated Protein Kinase ◽  
Cycle Progression ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

scholarly journals Rac and Cdc42 Induce Actin Polymerization and G1 Cell Cycle Progression Independently of p65PAK and the JNK/SAPK MAP Kinase Cascade

Cell ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 519-529 ◽  
Author(s):  
Nathalie Lamarche ◽  
Nicolas Tapon ◽  
Lisa Stowers ◽  
Peter D Burbelo ◽  
Pontus Aspenström ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Map Kinase ◽  
Cell Cycle Progression ◽  
Actin Polymerization ◽  
Cycle Progression ◽  
Map Kinase Cascade ◽  
Kinase Cascade

scholarly journals Ras links growth factor signaling to the cell cycle machinery via regulation of cyclin D1 and the Cdk inhibitor p27KIP1.

1997 ◽  
Vol 17 (7) ◽  
pp. 3850-3857 ◽  
Author(s):  
H Aktas ◽  
H Cai ◽  
G M Cooper
Keyword(s):  
Cell Cycle ◽  
Growth Factor ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Constitutive Expression ◽  
Ras Signaling ◽  
Cdk Inhibitor ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
Cell Cycle Machinery

Activation of growth factor receptors by ligand binding initiates a cascade of events leading to cell growth and division. Progression through the cell cycle is controlled by cyclin-dependent protein kinases (Cdks), but the mechanisms that link growth factor signaling to the cell cycle machinery have not been established. We report here that Ras proteins play a key role in integrating mitogenic signals with cell cycle progression through G1. Ras is required for cell cycle progression and activation of both Cdk2 and Cdk4 until approximately 2 h before the G1/S transition, corresponding to the restriction point. Analysis of Cdk-cyclin complexes indicates that Ras signaling is required both for induction of cyclin D1 and for downregulation of the Cdk inhibitor p27KIP1. Constitutive expression of cyclin D1 circumvents the requirement for Ras signaling in cell proliferation, indicating that regulation of cyclin D1 is a critical target of the Ras signaling cascade.

scholarly journals Induction of maturation-promoting factor during Xenopus oocyte maturation uncouples Ca2+ store depletion from store-operated Ca2+ entry

2002 ◽  
Vol 156 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Khaled Machaca ◽  
Shirley Haun
Keyword(s):  
Oocyte Maturation ◽  
Xenopus Oocyte ◽  
Medical Science ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Egg Activation ◽  
Germinal Vesicle Breakdown ◽  
Store Depletion ◽  
Oocyte Meiosis ◽  
Maturation Promoting Factor

Department of Physiology and Biophysics, University of Arkansas Medical Science, Little Rock, AR 72205 During oocyte maturation, eggs acquire the ability to generate specialized Ca2+ signals in response to sperm entry. Such Ca2+ signals are crucial for egg activation and the initiation of embryonic development. We examined the regulation during Xenopus oocyte maturation of store-operated Ca2+ entry (SOCE), an important Ca2+ influx pathway in oocytes and other nonexcitable cells. We have previously shown that SOCE inactivates during Xenopus oocyte meiosis. SOCE inactivation may be important in preventing premature egg activation. In this study, we investigated the correlation between SOCE inactivation and the Mos–mitogen-activated protein kinase (MAPK)–maturation-promoting factor (MPF) kinase cascade, which drives Xenopus oocyte maturation. SOCE inactivation at germinal vesicle breakdown coincides with an increase in the levels of MAPK and MPF. By differentially inducing Mos, MAPK, and MPF, we demonstrate that the activation of MPF is necessary for SOCE inactivation during oocyte maturation. In contrast, sustained high levels of Mos kinase and the MAPK cascade have no effect on SOCE activation. We further show that preactivated SOCE is not inactivated by MPF, suggesting that MPF does not block Ca2+ influx through SOCE channels, but rather inhibits coupling between store depletion and SOCE activation.

scholarly journals Nek9 regulates spindle organization and cell cycle progression during mouse oocyte meiosis and its location in early embryo mitosis

Cell Cycle ◽  
2012 ◽  
Vol 11 (23) ◽  
pp. 4366-4377 ◽  
Author(s):  
Shang-Wu Yang ◽  
Chen Gao ◽  
Lei Chen ◽  
Ya-Li Song ◽  
Jin-Liang Zhu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Early Embryo ◽  
Mouse Oocyte ◽  
Cycle Progression ◽  
Oocyte Meiosis

scholarly journals Pervasive 3′-UTR Isoform Switches During Mouse Oocyte Maturation

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuanlin He ◽  
Qiuzhen Chen ◽  
Jing Zhang ◽  
Jing Yu ◽  
Meng Xia ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Germinal Vesicle ◽  
Differentially Expressed ◽  
Sequencing Data ◽  
Germinal Vesicle Breakdown ◽  
Oocyte Meiosis ◽  
Gene Level ◽  
Individual Mouse

Oocyte maturation is the foundation for developing healthy individuals of mammals. Upon germinal vesicle breakdown, oocyte meiosis resumes and the synthesis of new transcripts ceases. To quantitatively profile the transcriptomic dynamics after meiotic resumption throughout the oocyte maturation, we generated transcriptome sequencing data with individual mouse oocytes at three main developmental stages: germinal vesicle (GV), metaphase I (MI), and metaphase II (MII). When clustering the sequenced oocytes, results showed that isoform-level expression analysis outperformed gene-level analysis, indicating isoform expression provided extra information that was useful in distinguishing oocyte stages. Comparing transcriptomes of the oocytes at the GV stage and the MII stage, in addition to identification of differentially expressed genes (DEGs), we detected many differentially expressed transcripts (DETs), some of which came from genes that were not identified as DEGs. When breaking down the isoform-level changes into alternative RNA processing events, we found the main source of isoform composition changes was the alternative usage of polyadenylation sites. With detailed analysis focusing on the alternative usage of 3′-UTR isoforms, we identified, out of 3,810 tested genes, 512 (13.7%) exhibiting significant switches of 3′-UTR isoforms during the process of moues oocyte maturation. Altogether, our data and analyses suggest the importance of examining isoform abundance changes during oocyte maturation, and further investigation of the pervasive 3′-UTR isoform switches in the transition may deepen our understanding on the molecular mechanisms underlying mammalian early development.

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