scholarly journals Wee1B, Myt1, and Cdc25 function in distinct compartments of the mouse oocyte to control meiotic resumption

2010 ◽  
Vol 188 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Jeong Su Oh ◽  
Seung Jin Han ◽  
Marco Conti
Keyword(s):  
Cell Cycle ◽  
Germinal Vesicle ◽  
Mouse Oocyte ◽  
Cyclin B ◽  
Down Regulation ◽  
Meiotic Arrest ◽  
Long Period ◽  
Prophase I ◽  
Subcellular Compartments ◽  
Maturation Promoting Factor

After a long period of quiescence at dictyate prophase I, termed the germinal vesicle (GV) stage, mammalian oocytes reenter meiosis by activating the Cdc2–cyclin B complex (maturation-promoting factor [MPF]). The activity of MPF is regulated by Wee1/Myt1 kinases and Cdc25 phosphatases. In this study, we demonstrate that the sequestration of components that regulate MPF activity in distinct subcellular compartments is essential for their function during meiosis. Down-regulation of either Wee1B or Myt1 causes partial meiotic resumption, and oocytes reenter the cell cycle only when both proteins are down-regulated. Shortly before GV breakdown (GVBD), Cdc25B is translocated from the cytoplasm to the nucleus, whereas Wee1B is exported from the nucleus to the cytoplasm. These movements are regulated by PKA inactivation and MPF activation, respectively. Mislocalized Wee1B or Myt1 is not able to maintain meiotic arrest. Thus, cooperation of Wee1B, Myt1, and Cdc25 is required to maintain meiotic arrest and relocation of these components before GVBD is necessary for meiotic reentry.

scholarly journals YWHA (14-3-3) protein isoforms and their interactions with CDC25B phosphatase in mouse oogenesis and oocyte maturation

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Alaa A. Eisa ◽  
Santanu De ◽  
Ariana Detwiler ◽  
Eva Gilker ◽  
Alexander C. Ignatious ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Oocyte Maturation ◽  
Messenger Rna ◽  
Germinal Vesicle ◽  
Protein Isoforms ◽  
Cell Cycle Protein ◽  
Meiotic Arrest ◽  
Germinal Vesicle Breakdown ◽  
Prophase I ◽  
Mouse Oocytes

Abstract Background Immature mammalian oocytes are held arrested at prophase I of meiosis by an inhibitory phosphorylation of cyclin-dependent kinase 1 (CDK1). Release from this meiotic arrest and germinal vesicle breakdown is dependent on dephosphorylation of CDK1 by the protein, cell cycle division 25B (CDC25B). Evidence suggests that phosphorylated CDC25B is bound to YWHA (14-3-3) proteins in the cytoplasm of immature oocytes and is thus maintained in an inactive form. The importance of YWHA in meiosis demands additional studies. Results Messenger RNA for multiple isoforms of the YWHA protein family was detected in mouse oocytes and eggs. All seven mammalian YWHA isoforms previously reported to be expressed in mouse oocytes, were found to interact with CDC25B as evidenced by in situ proximity ligation assays. Interaction of YWHAH with CDC25B was indicated by Förster Resonance Energy Transfer (FRET) microscopy. Intracytoplasmic microinjection of oocytes with R18, a known, synthetic, non-isoform-specific, YWHA-blocking peptide promoted germinal vesicle breakdown. This suggests that inhibiting the interactions between YWHA proteins and their binding partners releases the oocyte from meiotic arrest. Microinjection of isoform-specific, translation-blocking morpholino oligonucleotides to knockdown or downregulate YWHA protein synthesis in oocytes suggested a role for a specific YWHA isoform in maintaining the meiotic arrest. More definitively however, and in contrast to the knockdown experiments, oocyte-specific and global deletion of two isoforms of YWHA, YWHAH (14-3-3 eta) or YWHAE (14-3-3 epsilon) indicated that the complete absence of either or both isoforms does not alter oocyte development and release from the meiotic prophase I arrest. Conclusions Multiple isoforms of the YWHA protein are expressed in mouse oocytes and eggs and interact with the cell cycle protein CDC25B, but YWHAH and YWHAE isoforms are not essential for normal mouse oocyte maturation, fertilization and early embryonic development.

Molecular Mechanisms of Prophase I Meiotic Arrest Maintenance and Meiotic Resumption in Mammalian Oocytes

2018 ◽  
Vol 26 (11) ◽  
pp. 1519-1537
Author(s):  
Maxim Filatov ◽  
Yulia Khramova ◽  
Maria Semenova
Keyword(s):  
In Vitro Maturation ◽  
Molecular Mechanisms ◽  
Germinal Vesicle ◽  
Follicular Cells ◽  
Meiotic Arrest ◽  
Germinal Vesicle Breakdown ◽  
Prophase I ◽  
The Stability ◽  
Multiple Molecules

Mechanisms of meiotic prophase I arrest maintenance (germinal vesicle [GV] stage) and meiotic resumption (germinal vesicle breakdown [GVBD] stage) in mammalian oocytes seem to be very complicated. These processes are regulated via multiple molecular cascades at transcriptional, translational, and posttranslational levels, and many of them are interrelated. There are many molecular cascades of meiosis maintaining and meiotic resumption in oocyte which are orchestrated by multiple molecules produced by pituitary gland and follicular cells. Furthermore, many of these molecular cascades are duplicated, thus ensuring the stability of the entire system. Understanding mechanisms of oocyte maturation is essential to assess the oocyte status, develop effective protocols of oocyte in vitro maturation, and design novel contraceptive drugs. Mechanisms of meiotic arrest maintenance at prophase I and meiotic resumption in mammalian oocytes are covered in the present article.

scholarly journals Activities of maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) are not required for the global histone deacetylation observed after germinal vesicle breakdown (GVBD) in porcine oocytes

Reproduction ◽  
2006 ◽  
Vol 131 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Tsutomu Endo ◽  
Kunihiko Naito ◽  
Sachi Kume ◽  
Yukio Nishimura ◽  
Koji Kashima ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Protein Kinase ◽  
Germinal Vesicle ◽  
Histone Deacetylation ◽  
Mitogen Activated Protein Kinase ◽  
Germinal Vesicle Breakdown ◽  
Immature Oocytes ◽  
Mitogen Activated Protein ◽  
Maturation Promoting Factor

The acetylation of nuclear core histone has been suggested to work as an epigenetic mark for transmitting gene expression patterns to daughter cells. Global histone deacetylations, presumably involved in the reprogramming of the gene expression, have been observed after germinal vesicle breakdown (GVBD) in a cell cycle-dependent manner during meiotic maturation of mouse and porcine oocytes, although the regulation mechanism of histone deacetylation has not been studied well. In the present study, we examined the involvement of a crucial cell-cycle-regulator, maturation-promoting factor (MPF), and a meiosis-related kinase, mitogen-activated protein kinase (MAPK), in the global histone deacetylation during porcine oocyte maturation. In order to know whether the activities of MPF and MAPK were required, or the breakdown of GV membrane was sufficient, for the global histone deacetylation observed after GVBD, we artificially destroyed the GV membrane of the porcine immature oocytes. The artificial GV destruction (AGVD) induced histone deacetylation without the activation of MPF and MAPK. This deacetylation after AGVD was not affected by an MPF inhibitor, roscovitine, or an inhibitor of protein synthesis, cycloheximide, but was completely prevented by an inhibitor of histone deactylases (HDACs), trichostatine A. HDAC1 was present in the GV of the immature oocytes and localized on chromosomes after GVBD and AGVD. These results suggest that the MPF and MAPK activities were dispensable and the breakdown of the GV membrane was sufficient for the global histone deacetylation, which was catalyzed by HDAC activity

scholarly journals Two Distinct Mechanisms Control the Accumulation of Cyclin B1 and Mos inXenopusOocytes in Response to Progesterone

1999 ◽  
Vol 10 (10) ◽  
pp. 3279-3288 ◽  
Author(s):  
Marie Frank-Vaillant ◽  
Catherine Jessus ◽  
René Ozon ◽  
James L. Maller ◽  
Olivier Haccard
Keyword(s):  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Cyclin B ◽  
Meiotic Maturation ◽  
Dependent Protein Kinase ◽  
Germinal Vesicle Breakdown ◽  
Dependent Protein ◽  
Factor Transfer ◽  
Necessary And Sufficient ◽  
Maturation Promoting Factor

Progesterone-induced meiotic maturation of Xenopusoocytes requires the synthesis of new proteins, such as Mos and cyclin B. Synthesis of Mos is thought to be necessary and sufficient for meiotic maturation; however, it has recently been proposed that newly synthesized proteins binding to p34cdc2could be involved in a signaling pathway that triggers the activation of maturation-promoting factor. We focused our attention on cyclin B proteins because they are synthesized in response to progesterone, they bind to p34cdc2, and their microinjection into resting oocytes induces meiotic maturation. We investigated cyclin B accumulation in response to progesterone in the absence of maturation-promoting factor–induced feedback. We report here that the cdk inhibitor p21cip1, when microinjected into immatureXenopus oocytes, blocks germinal vesicle breakdown induced by progesterone, by maturation-promoting factor transfer, or by injection of okadaic acid. After microinjection of p21cip1, progesterone fails to induce the activation of MAPK or p34cdc2, and Mos does not accumulate. In contrast, the level of cyclin B1 increases normally in a manner dependent on down-regulation of cAMP-dependent protein kinase but independent of cap-ribose methylation of mRNA.

scholarly journals Amphibian oocyte maturation induced by extracts of Physarum polycephalum in mitosis.

1988 ◽  
Vol 106 (5) ◽  
pp. 1445-1452 ◽  
Author(s):  
R C Adlakha ◽  
G L Shipley ◽  
J Y Zhao ◽  
K B Jones ◽  
D A Wright ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hela Cells ◽  
Physarum Polycephalum ◽  
Germinal Vesicle ◽  
Slime Mold ◽  
G1 Phase ◽  
Affinity Column ◽  
Factor Activity ◽  
Germinal Vesicle Breakdown ◽  
Maturation Promoting Factor

The orderly progression of eukaryotic cells from interphase to mitosis requires the close coordination of various nuclear and cytoplasmic events. Studies from our laboratory and others on animal cells indicate that two activities, one present mainly in mitotic cells and the other exclusively in G1-phase cells, play a pivotal role in the regulation of initiation and completion of mitosis, respectively. The purpose of this study was to investigate whether these activities are expressed in the slime mold Physarum polycephalum in which all the nuclei traverse the cell cycle in natural synchrony. Extracts were prepared from plasmodia in various phases of the cell cycle and tested for their ability to induce germinal vesicle breakdown and chromosome condensation after microinjection into Xenopus laevis oocytes. We found that extract of cells at 10-20 min before metaphase consistently induced germinal vesicle breakdown in oocytes. Preliminary characterization, including purification on a DNA-cellulose affinity column, indicated that the mitotic factors from Physarum were functionally very similar to HeLa mitotic factors. We also identified a number of mitosis-specific antigens in extracts from Physarum plasmodia, similar to those of HeLa cells, using the mitosis-specific monoclonal antibodies MPM-2 and MPM-7. Interestingly, we also observed an activity in Physarum at 45 min after metaphase (i.e., in early S phase since it has no G1) that is usually present in HeLa cells only during the G1 phase of the cell cycle. These are the first studies to show that maturation-promoting factor activity is present in Physarum during mitosis and is replaced by the G1 factor (or anti-maturation-promoting factor) activity in a postmitotic stage. A comparative study of these factors in this slime mold and in mammalian cells would be extremely valuable in further understanding their function in the regulation of eukaryotic cell cycle and their evolutionary relationship to one another.

scholarly journals Meiotic induction by Xenopus cyclin B is accelerated by coexpression with mosXe.

1991 ◽  
Vol 11 (3) ◽  
pp. 1713-1717 ◽  
Author(s):  
R S Freeman ◽  
S M Ballantyne ◽  
D J Donoghue
Keyword(s):  
Xenopus Laevis ◽  
Antisense Oligonucleotide ◽  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Cyclin B ◽  
Germinal Vesicle Breakdown ◽  
The Relationship ◽  
Maturation Promoting Factor

We have investigated the relationship between Xenopus laevis c-mos (mosXe) and the cyclin B component of maturation-promoting factor. Microinjection of Xenopus oocytes with in vitro-synthesized RNAs encoding Xenopus cyclin B1 or cyclin B2 induces the progression of meiosis, characterized by germinal vesicle breakdown (GVBD). By preinjecting oocytes with a mosXe-specific antisense oligonucleotide, we show that GVBD induced by cyclin B does not require expression of the mosXe protein. GVBD induced by cyclin B proceeds significantly faster than GVBD induced by progesterone or MosXe. However, coinjection of RNAs encoding cyclin B1 or cyclin B2 with mosXe RNA results in a 2.5- to 3-fold acceleration in GVBD relative to that induced by cyclin B alone. This acceleration of GVBD does not correlate with changes in the level of cyclin B1 and cyclin B2 phosphorylation.

scholarly journals SGK regulates pH increase and cyclin B-Cdk1 activation to resume meiosis in starfish ovarian oocytes

2018 ◽  
Author(s):  
Enako Hosoda ◽  
Daisaku Hiraoka ◽  
Noritaka Hirohashi ◽  
Saki Omi ◽  
Takeo Kishimoto ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Germinal Vesicle ◽  
Cyclin B ◽  
Biological Processes ◽  
Large Nucleus ◽  
Germinal Vesicle Breakdown ◽  
Ph Increase ◽  
Hormonal Stimulus ◽  
And Function ◽  
Cell Cycle Machinery

AbstractTight regulation of intracellular pH (pHi) is essential for biological processes. Fully-grown oocytes, having a large nucleus called the germinal vesicle, arrest at meiotic prophase-I. Upon hormonal stimulus, oocytes resume meiosis to acquire fertilizability. At this time, pHi increases through Na+/H+ exchanger activity. However, regulation and function of this change remains obscure. Here we show that in starfish oocytes, serum- and glucocorticoid-regulated kinase (SGK) is activated by the PI3K/TORC2/PDK1 signaling after hormonal stimulus, and is required for the pHi increase and cyclin B–Cdk1 activation. Furthermore, when we clamped pHi at 6.7, corresponding to the pHi of unstimulated ovarian oocytes, hormonal stimulus normally induced cyclin B–Cdk1 activation; thereafter, oocytes initiated germinal vesicle breakdown (GVBD), but failed to complete it. Thus, SGK-dependent pHi increase is likely prerequisite for completion of GVBD in ovarian oocytes. We propose a model that SGK drives meiotic resumption through concomitant regulation of pHi and the cell-cycle machinery.

scholarly journals Germinal vesicle material drives meiotic cell cycle of mouse oocyte through the 3′UTR-dependent control of cyclin B1 synthesis

2006 ◽  
Vol 292 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Steffen Hoffmann ◽  
Chizuko Tsurumi ◽  
Jacek Z. Kubiak ◽  
Zbigniew Polanski
Keyword(s):  
Cell Cycle ◽  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Mouse Oocyte ◽  
Meiotic Cell
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