scholarly journals Effects of puberty and gonadotropins on the molecular events controlling meiotic resumption of mouse oocytes

Reproduction ◽  
2010 ◽  
Vol 139 (6) ◽  
pp. 959-969 ◽  
Author(s):  
Dong Han ◽  
Xin-Yan Cao ◽  
Hui-Li Wang ◽  
Jing-Jing Li ◽  
Yan-Bo Wang ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Meiotic Progression ◽  
Adult Mice ◽  
Molecular Events ◽  
Control Oocyte ◽  
Cytoplasmic Maturation ◽  
Equine Chorionic Gonadotropin ◽  
First Time ◽  
Kinase A

Although studies suggest that the low competence of oocytes from prepubertal animals is due to their insufficient cytoplasmic maturation and that FSH improves oocyte maturation possibly by retarding meiotic progression and allowing more time for cytoplasmic maturation, the mechanisms by which puberty and gonadotropins regulate meiotic progression require additional detailed studies. For the first time, we observed that while meiotic progression was significantly slower, the maturation-promoting factor (MPF) activity of oocytes was significantly higher in prepubertal than in adult mice. To resolve this contradiction, we specified the molecules regulating the MPF activity and their localization during oocyte maturation in prepubertal and adult mice primed with or without gonadotropins. Our tests using corresponding enzyme regulators suggested that while activities of protein kinase A were unaffected, the activity of adenylate cyclase (ADCY) and phosphodiesterase increased while cell division cycle 2 homolog A (CDC2A) decreased significantly after puberty. While most of the adult oocytes had CDC2A protein concentrated in the germinal vesicle (GV) region, the majority of prepubertal oocytes showed no nuclear concentration of CDC2A. Maximally priming mice with equine chorionic gonadotropin brought the above parameters of prepubertal oocytes close to those in adult oocytes. Together, the results suggest that puberty and gonadotropin control oocyte meiotic progression mainly by regulating the ADCY activity and the concentration of the activated MPF toward the GV region.

Action of actinomycin and puromycin upon frog oocyte maturation

Development ◽  
1966 ◽  
Vol 16 (1) ◽  
pp. 183-195
Author(s):  
T. A. Dettlaff
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Cell Types ◽  
Follicle Cells ◽  
Oocyte Nucleus ◽  
Frog Oocyte ◽  
Cytoplasmic Maturation ◽  
Gonadotropic Hormones ◽  
Cerebratulus Lacteus

In amphibians, as well as in other vertebrates, occytes start to mature under the action of hypophyseal gonadotropic hormones. (In this paper the term ‘maturation’ implies the transformation into ripe eggs of oocytes that have finished growing.) In the course of maturation the oocytes themselves and the follicle cells surrounding them undergo changes; the changes of these two cell types are not causally connected, their coincidence in time is easily broken in unfavourable conditions (Wright, 1945; Tchou-Su & Wang Yu-lan, 1958). As shown earlier (Dettlaff, Nikitina & Stroeva, 1964), hypophyseal gonadotropic hormones affect amphibian oocytes through the oocyte nucleus, the germinal vesicle. As a result of their action the nuclear sap of the germinal vesicle acquires the ability to induce cytoplasmic maturation (the property revealed by Delage on the oocytes of Asterias glacialis, 1899, 1901, and by Wilson on those of Cerebratulus lacteus, 1903).

5-HT causes an increase in cAMP that stimulates, rather than inhibits, oocyte maturation in marine nemertean worms

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1415-1427
Author(s):  
S.A. Stricker ◽  
T.L. Smythe
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
Mitogen Activated Protein Kinases ◽  
Mitogen Activated Protein ◽  
Important Regulator ◽  
First Time ◽  
Intracellular Pathway ◽  
Cerebratulus Lacteus

In the nemertean worms Cerebratulus lacteus and Micrura alaskensis, 5-HT (=5-hydroxytryptamine, or serotonin) causes prophase-arrested oocytes to mature and complete germinal vesicle breakdown (GVBD). To identify the intracellular pathway that mediates 5-HT stimulation, follicle-free oocytes of nemerteans were assessed for GVBD rates in the presence or absence of 5-HT after being treated with various modulators of cAMP, a well known transducer of 5-HT signaling and an important regulator of hormone-induced maturation in general. Unlike in many animals where high levels of intra-oocytic cAMP block maturation, treatment of follicle-free nemertean oocytes with agents that elevate cAMP (8-bromo-cAMP, forskolin or inhibitors of phosphodiesterases) triggered GVBD in the absence of added 5-HT. Similarly, 5-HT caused a substantial cAMP increase prior to GVBD in nemertean oocytes that had been pre-injected with a cAMP fluorosensor. Such a rise in cAMP seemed to involve G-protein-mediated signaling and protein kinase A (PKA) stimulation, based on the inhibition of 5-HT-induced GVBD by specific antagonists of these transduction steps. Although the downstream targets of activated PKA remain unknown, neither the synthesis of new proteins nor the activation of MAPKs (mitogen-activated protein kinases) appeared to be required for GVBD after 5-HT stimulation. Alternatively, pre-incubation in roscovitine, an inhibitor of maturation-promoting factor (MPF), prevented GVBD, indicating that maturing oocytes eventually need to elevate their MPF levels, as has been documented for other animals. Collectively, this study demonstrates for the first time that 5-HT can cause immature oocytes to undergo an increase in cAMP that stimulates, rather than inhibits, meiotic maturation. The possible relationship between such a form of oocyte maturation and that observed in other animals is discussed.

scholarly journals Apelin (APLN) regulates progesterone secretion and oocyte maturation in bovine ovarian cells

Reproduction ◽  
2017 ◽  
Vol 153 (5) ◽  
pp. 589-603 ◽  
Author(s):  
J Roche ◽  
C Ramé ◽  
M Reverchon ◽  
N Mellouk ◽  
A Rak ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Oocyte Maturation ◽  
Granulosa Cells ◽  
Germinal Vesicle ◽  
Meiotic Progression ◽  
Ovarian Cells ◽  
Progesterone Secretion ◽  
Maturation Medium ◽  
G Protein Coupled

APLN and its G-protein coupled receptor APLNR are expressed in the bovine ovary. However their role in granulosa cells and oocytes is unknown. Here, we studied their expression in bovine ovarian cells and investigated their regulation in cultured luteinizing granulosa cells in response to IGF1 and FSH. We determined the effect and the molecular mechanism of APLN (isoforms 17 and 13) on bovine granulosa cell progesterone secretion and on oocyte maturation. By RT-qPCR and immunoblot, we showed that the expression of both APLN and APLNR in granulosa and oocytes significantly increased with ovarian follicles size whereas it was similar in theca interstitial cells.In vitro, in unstimulated luteinizing bovine granulosa cells and in response to IGF1 (10−8 M) but not to FSH (10−8 M), we observed that APLN (-17 and -13) (10−9 M) increased progesterone production; this was abolished in response to the APLNR antagonist ML221. These latter effects were dependent on the MAPK ERK1/2 kinase. Furthermore, we showed that APLN (-17 and -13) (10−9 M) increased cell proliferation through AKT signaling. Conversely, the addition of APLN-13 and APLN-17 toin vitromaturation medium containing IGF1 (10−8 M) but not FSH (10−8 M) arrested most oocytes at the germinal vesicle stage, which was associated with a decrease in progesterone secretion, an inhibition in MAPK ERK1/2 phosphorylation and an increase in PRKA phosphorylation in oocytes. Thus, APLN can increase progesterone secretion and cell proliferation in bovine luteinizing granulosa cellsin vitro, while it blocks meiotic progression at the germinal vesicle stage during bovine oocytein vitromaturation.

Effects of vitrification of cumulus-enclosed porcine oocytes at the germinal vesicle stage on cumulus expansion, nuclear progression and cytoplasmic maturation

2017 ◽  
Vol 29 (12) ◽  
pp. 2419 ◽  
Author(s):  
Ruth Appeltant ◽  
Tamás Somfai ◽  
Elisa C. S. Santos ◽  
Thanh Quang Dang-Nguyen ◽  
Takashi Nagai ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Germinal Vesicle ◽  
Developmental Competence ◽  
Nuclear Morphology ◽  
Cumulus Expansion ◽  
Nuclear Maturation ◽  
Meiotic Progression ◽  
Oocyte Aging ◽  
Cytoplasmic Maturation ◽  
And Control

Although offspring have been produced from porcine oocytes vitrified at the germinal vesicle (GV) stage, the rate of embryo development remains low. In the present study, nuclear morphology and progression, cumulus expansion, transzonal projections (TZPs), ATP and glutathione (GSH) levels were compared between vitrified cumulus–oocyte complexes (COCs) and control COCs (no cryoprotectant treatment and no cooling), as well as a toxicity control (no cooling). Vitrification was performed with 17.5% (v/v) ethylene glycol and 17.5% (v/v) propylene glycol. Vitrification at the GV stage caused premature meiotic progression, reflected by earlier GV breakdown and untimely attainment of the MII stage. However, cytoplasmic maturation, investigated by measurement of ATP and GSH levels, as well as cumulus expansion, proceeded normally despite detectable damage to TZPs in vitrified COCs. Moreover, treatment with cryoprotectants caused fragmentation of nucleolus precursor bodies and morphological changes in F-actin from which oocytes were able to recover during subsequent IVM culture. Reduced developmental competence may be explained by premature nuclear maturation leading to oocyte aging, although other mechanisms, such as initiation of apoptosis and reduction of cytoplasmic mRNA, can also be considered. Further research will be required to clarify the presence and effects of these phenomena during the vitrification of immature COCs.

PLCz-induced Ca2+ oscillations are enhanced after germinal vesicle breakdown during mouse oocyte maturation

2016 ◽  
Author(s):  
Jessica Sanders ◽  
Ethan Bateson ◽  
Yuansong Yu ◽  
Michail Nomikos ◽  
Antony Lai ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Mouse Oocyte ◽  
Germinal Vesicle Breakdown

scholarly journals In Vitro Oocyte Maturation and Ovulation in Rainbow Trout (Salmo gairdneri), Northern Pike (Esox lucius), and Goldfish (Carassius auratus)

1976 ◽  
Vol 33 (4) ◽  
pp. 974-988 ◽  
Author(s):  
Bernard Jalabert
Keyword(s):  
Oocyte Maturation ◽  
Sensu Stricto ◽  
Salmo Gairdneri ◽  
Follicular Maturation ◽  
Goldfish Carassius Auratus ◽  
Control Oocyte ◽  
Follicle Maturation ◽  
Ovulatory Process ◽  
Matured Oocyte

The endocrine processes which control oocyte maturation (resumption of meiosis) and ovulation have been studied in vitro in the trout Salmo gairdneri. Follicular maturation is ultimately under the control of a pituitary gonadotropin which induces the follicle to synthesize specific steroids; these steroids act in turn directly on the oocyte to promote maturation. The systematic study of the in vitro efficiency of various steroids have shown that 17α-hydroxy-20β-dihydroprogesterone plays a preferential role in initiating maturation; this steroid has a high affinity for a plasma protein system. The efficiency of this steroid, similarly to the efficiency of the gonadotropin, can be modulated by other circulating steroids. The precise chronology of some events of follicle maturation have been defined using inhibitors of protein and RNA synthesis.The ovulatory process (sensu stricto: expulsion of matured oocyte from the follicular envelopes) has been experimentally dissociated from oocyte maturation, and some mediators likely to act on ovulation have been identified.These data permit the consideration of novel means of intervention at the ovarian level to synchronize maturation and ovulation in fish, in order to give new tools for progress in aquaculture.

scholarly journals Cytoplasmic dynein participates in meiotic checkpoint inactivation in mouse oocytes by transporting cytoplasmic mitotic arrest-deficient (Mad) proteins from kinetochores to spindle poles

Reproduction ◽  
2007 ◽  
Vol 133 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Dong Zhang ◽  
Shen Yin ◽  
Man-Xi Jiang ◽  
Wei Ma ◽  
Yi Hou ◽  
...  
Keyword(s):  
Spindle Checkpoint ◽  
Germinal Vesicle ◽  
Cytoplasmic Dynein ◽  
Mitotic Arrest ◽  
Checkpoint Proteins ◽  
Meiotic Progression ◽  
Spindle Poles ◽  
Anaphase Onset ◽  
Oocyte Meiosis ◽  
And Function

The present study was designed to investigate the localization and function of cytoplasmic dynein (dynein) during mouse oocyte meiosis and its relationship with two major spindle checkpoint proteins, mitotic arrest-deficient (Mad) 1 and Mad2. Oocytes at various stages during the first meiosis were fixed and immunostained for dynein, Mad1, Mad2, kinetochores, microtubules, and chromosomes. Some oocytes were treated with nocodazole before examination. Anti-dynein antibody was injected into the oocytes at germinal vesicle (GV) stage before the examination of its effects on meiotic progression or Mad1 and Mad2 localization. Results showed that dynein was present in the oocytes at various stages from GV to metaphase II and the locations of Mad1 and Mad2 were associated with dynein’s movement. Both Mad1 and Mad2 had two existing states: one existed in the cytoplasm (cytoplasmic Mad1 or cytoplasmic Mad2), which did not bind to kinetochores, while the other bound to kinetochores (kinetochore Mad1 or kinetochore Mad2). The equilibrium between the two states varied during meiosis and/or in response to the changes of the connection between microtubules and kinetochores. Cytoplasmic Mad1 and Mad2 recruited to chromosomes when the connection between microtubules and chromosomes was destroyed. Inhibition of dynein interferes with cytoplasmic Mad1 and Mad2 transportation from chromosomes to spindle poles, thus inhibits checkpoint silence and delays anaphase onset. These results indicate that dynein may play a role in spindle checkpoint inactivation.

scholarly journals Requirement of mosXe protein kinase for meiotic maturation of Xenopus oocytes induced by a cdc2 mutant lacking regulatory phosphorylation sites.

1992 ◽  
Vol 12 (7) ◽  
pp. 3192-3203 ◽  
Author(s):  
K M Pickham ◽  
A N Meyer ◽  
J Li ◽  
D J Donoghue
Keyword(s):  
Protein Kinase ◽  
Oocyte Maturation ◽  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Phosphorylation Sites ◽  
Germinal Vesicle Breakdown ◽  
Regulatory Phosphorylation

The p34cdc2 protein kinase is a component of maturation-promoting factor, the master regulator of the cell cycle in all eukaryotes. The activity of p34cdc2 is itself tightly regulated by phosphorylation and dephosphorylation. Predicted regulatory phosphorylation sites of Xenopus p34cdc2 were mutated in vitro, and in vitro-transcribed RNAs were injected into Xenopus oocytes. The cdc2 single mutants Thr-14----Ala and Tyr-15----Phe did not induce germinal vesicle breakdown (BVBD) upon microinjection into oocytes. In contrast, the cdc2 double mutant Ala-14/Phe-15 did induce GVBD. Both the Ala-14 and Ala-14/Phe-15p34cdc2 mutants were shown to coimmunoprecipitate cyclin B1 and to phosphorylate histone H1 in immune complex kinase assays. Microinjection of antisense oligonucleotides to c-mosXe was used to demonstrate the role of mos protein synthesis in the induction of GVBD by the Ala-14/Phe-15 cdc2 mutant. Thr-161 was also mutated. p34cdc2 single mutants Ala-161 and Glu-161 and triple mutants Ala-14/Phe-15/Ala-161 and Ala-14/Phe-15/Glu-161 failed to induce GVBD in oocytes and showed a decreased binding to cyclin B1 in coimmunoprecipitations. Each of the cdc2 mutants was also assayed by coinjection with cyclin B1 or c-mosXe RNA into oocytes. Several of the cdc2 mutants were found to affect the kinetics of cyclin B1 and/or mos-induced GVBD upon coinjection, although none affected the rate of progesterone-induced maturation. We demonstrate here the significance of Thr-14, Tyr-15, and Thr-161 of p34cdc2 in Xenopus oocyte maturation. In addition, these results suggest a regulatory role for mosXe in induction of oocyte maturation by the cdc2 mutant Ala-14/Phe-15.

Behavioral neurotoxicity in adolescent and adult mice exposed to fenproporex during pregnancy

2005 ◽  
Vol 24 (8) ◽  
pp. 403-408 ◽  
Author(s):  
C Q Moreira ◽  
M JSS Faria ◽  
E G Moreira
Keyword(s):  
Forced Swimming Test ◽  
Tail Suspension Test ◽  
Stereotyped Behavior ◽  
Dopaminergic Transmission ◽  
Adult Mice ◽  
Gestational Exposure ◽  
Behavioral Toxicity ◽  
Anorectic Drugs ◽  
Swimming Test ◽  
First Time

We investigated the effects of gestational exposure to fenproporex, one of the most used anorectic drugs in Brazil, on the behavior of adolescent and adult pups (30 and 60 days of age, respectively). Pregnant Swiss mice were treated daily, by gavage, with 15 mg/kg of fenproporex chloride or water during the whole gestational period. Male pups were submitted to open-field, forced swimming test, tail suspension test and fenproporexinduced stereotyped behavior. The results demonstrated that gestational exposure to fenproporex induces antidepressant-like effect and decreases fenproporexinduced stereotyped behavior in both adolescent and adult pups. Moreover, fenproporex-exposed adolescent pups tended (P–0.06) to be more active than control pups. Our data show, for the first time, that gestational exposure to fenproporex leads to long-lasting behavioral toxicity in male mice characteristic of altered dopaminergic transmission.

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