Analysis of the mechanism(s) of metaphase I arrest in maturing mouse oocytes

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 925-933 ◽  
Author(s):  
A. Hampl ◽  
J.J. Eppig
Keyword(s):  
Oocyte Maturation ◽  
Kinase Activity ◽  
Regulatory Protein ◽  
Cyclin B ◽  
Meiotic Maturation ◽  
Prophase I ◽  
Mouse Oocytes ◽  
Metaphase I

Fully grown mouse oocytes are normally competent to progress from prophase I to metaphase II without interruption. However, growing mouse oocytes initially become only partially competent to undergo meiotic maturation. Meiotic maturation in these oocytes does not progress beyond metaphase I. In contrast to the oocytes of most strains of mice, most oocytes of strain LT/Sv mice become arrested at metaphase I even when they are fully grown. The initiation of oocyte maturation is correlated with an increase in p34cdc2 kinase activity that continues to rise until metaphase I. The transition into anaphase I is normally correlated with a decrease in p34cdc2 kinase activity. This study demonstrated that metaphase I arrest in both partially competent growing oocytes and fully grown LT/Sv oocytes is correlated with a sustained elevation of p34cdc2 kinase activity. In fact, p34cdc2 activity continued to increase during the time when activity normally decreased. In normally maturing oocytes, some, but not all, of the cyclin B, the regulatory protein associated with p34cdc2, became degraded in oocytes that entered anaphase I. In contrast, the amount of cyclin B present in the metaphase I-arrested oocytes continued to increase at the time when it was being degraded in normal oocytes progressing to metaphase II. These results suggest that the progression of meiosis is arrested at metaphase I in both groups of oocytes because of continued p34cdc2 kinase activity sustained, at least in part, by restricted degradation of cyclin B.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of chromosome condensation during meiotic maturation induces parthenogenetic development of mouse oocytes

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 97-103 ◽  
Author(s):  
H.J. Clarke ◽  
J. Rossant ◽  
Y. Masui
Keyword(s):  
Protein Synthesis ◽  
Blastocyst Stage ◽  
Chromosome Condensation ◽  
Meiotic Maturation ◽  
Dibutyryl Cyclic Amp ◽  
Developmental Arrest ◽  
Mouse Oocytes ◽  
Parthenogenetic Development ◽  
No Activation ◽  
Metaphase I

Mouse oocytes at metaphase I were treated with puromycin, which caused the chromosomes to become decondensed within an interphase nucleus. When the oocytes were allowed to resume protein synthesis, they returned to metaphase within 8–10 h and neither synthesized DNA nor cleaved, indicating that they had not been parthenogenetically activated by the puromycin treatment. However, when dibutyryl cyclic AMP was added to the medium after protein synthesis resumed, the oocytes remained in interphase. These oocytes maintained in interphase began DNA synthesis beginning 20 h after puromycin withdrawal, even though no activation stimulus had been given to them. After transfer to the oviducts of foster mothers, the oocytes could develop to the blastocyst stage. These results indicate that oocytes whose chromosomes were decondensed by puromycin treatment at metaphase I could begin parthenogenetic development in the absence of an activating stimulus, provided that they were prevented from returning to metaphase. In contrast, when the puromycin-treated oocytes were allowed to return to metaphase, they became developmentally arrested at the end of maturation. This suggests that the mechanism responsible for the developmental arrest of mature oocytes at metaphase II depends on cytoplasmic conditions that cause chromosome condensation to the metaphase state.

scholarly journals Tyrosine phosphorylation and activation of homologous protein kinases during oocyte maturation and mitogenic activation of fibroblasts.

1991 ◽  
Vol 11 (5) ◽  
pp. 2517-2528 ◽  
Author(s):  
J Posada ◽  
J Sanghera ◽  
S Pelech ◽  
R Aebersold ◽  
J A Cooper
Keyword(s):  
Cell Cycle ◽  
Map Kinase ◽  
Tyrosine Phosphorylation ◽  
Oocyte Maturation ◽  
Mammalian Cells ◽  
Map Kinases ◽  
Kinase Activity ◽  
Mitotic Cell ◽  
Meiotic Maturation ◽  
Sea Star

Meiotic maturation of Xenopus and sea star oocytes involves the activation of a number of protein-serine/threonine kinase activities, including a myelin basic protein (MBP) kinase. A 44-kDa MBP kinase (p44mpk) purified from mature sea star oocytes is shown here to be phosphorylated at tyrosine. Antiserum to purified sea star p44mpk was used to identify antigenically related proteins in Xenopus oocytes. Two tyrosine-phosphorylated 42-kDa proteins (p42) were detected with this antiserum in Xenopus eggs. Xenopus p42 chromatographs with MBP kinase activity on a Mono Q ion-exchange column. Tyrosine phosphorylation of Xenopus p42 approximately parallels MBP kinase activity during meiotic maturation. These results suggest that related MBP kinases are activated during meiotic maturation of Xenopus and sea star oocytes. Previous studies have suggested that Xenopus p42 is related to the mitogen-activated protein (MAP) kinases of culture mammalian cells. We have cloned a MAP kinase relative from a Xenopus ovary cDNA library and demonstrate that this clone encodes the Xenopus p42 that is tyrosine phosphorylated during oocyte maturation. Comparison of the sequences of Xenopus p42 and a rat MAP kinase (ERK1) and peptide sequences from sea star p44mpk indicates that these proteins are close relatives. The family members appear to be tyrosine phosphorylated, and activated, in different contexts, with the murine MAP kinase active during the transition from quiescence to the G1 stage of the mitotic cell cycle and the sea star and Xenopus kinases being active during M phase of the meiotic cell cycle.

scholarly journals Phosphatidylinositol 3-kinase activity is important for progesterone-induced Xenopus oocyte maturation.

1993 ◽  
Vol 13 (11) ◽  
pp. 6661-6666 ◽  
Author(s):  
A J Muslin ◽  
A Klippel ◽  
L T Williams
Keyword(s):  
Oocyte Maturation ◽  
Kinase Activity ◽  
Sh2 Domain ◽  
Pi3 Kinase ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Phosphatidylinositol 3

In somatic cells, phosphatidylinositol 3-kinase (PI3 kinase) is a critical intermediary in growth factor-induced mitogenesis. We have examined the role of this enzyme in meiotic maturation of Xenopus laevis oocytes. PI3 kinase activity was present in immunoprecipitates of the p85 subunit of PI3 kinase from immature oocytes and markedly increased following progesterone stimulation. Injection of bacterially expressed protein corresponding to the C-terminal SH2 domain of p85 (SH2-C) inhibited progesterone-induced PI3 kinase activation and meiotic maturation. Injection of protein corresponding to the N-terminal SH2 domain or the SH3 domain of p85 did not inhibit PI3 kinase activation or maturation. SH2-C did not inhibit oocyte maturation induced by c-mos RNA injection. In addition, radiolabelled SH2-C was used to probe oocyte lysates, revealing that a novel 200-kDa protein bound to SH2-C. This protein may be an important mediator of progesterone-induced lipid metabolism in oocytes.

Activation of p90rsk during meiotic maturation and first mitosis in mouse oocytes and eggs: MAP kinase-independent and -dependent activation

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1957-1964 ◽  
Author(s):  
P. Kalab ◽  
J.Z. Kubiak ◽  
M.H. Verlhac ◽  
W.H. Colledge ◽  
B. Maro
Keyword(s):  
Kinase Activity ◽  
Polar Body ◽  
Ribosomal Subunit ◽  
Germinal Vesicle ◽  
Maximum Level ◽  
Meiotic Maturation ◽  
S6 Kinase ◽  
Mouse Oocytes ◽  
M Phase ◽  
Second Polar Body

Mitogen-activated protein kinases (MAPK) become activated during the meiotic maturation of oocytes from many species; however, their molecular targets remain unknown. This led us to characterize the activation of the ribosomal subunit S6 kinase of Mr 82 X 10(3) - 92 X 10(3) (p90rsk; a major substrate of MAPK in somatic cells) in maturing mouse oocytes and during the first cell cycle of the mouse embryo. We assessed the phosphorylation state of p90rsk by examining the electrophoretic mobility shifts on immunoblots and measured the kinase activity of immunoprecipitated p90rsk on a S6-derived peptide. Germinal vesicle stage (GV) oocytes contained a doublet of Mr 82 × 10(3) and 84 × 10(3) with a low S6 peptide kinase activity (12% of the maximum level found in metaphase II oocytes). A band of Mr 86 × 10(3) was first observed 30 minutes after GV breakdown (GVBD) and became prominent within 2 to 3 hours. MAPK was not phosphorylated 1 hour after GVBD, when the p90rsk-specific S6 kinase activity reached 37 % of the M II level. 2 hours after GVBD, MAPK became phosphorylated and p90rsk kinase activity reached 86% of the maximum level. The p90rsk band of Mr 88 × 10(3), present in mature M II oocytes when S6 peptide kinase activity is maximum, appeared when MAPK phosphorylation was nearly complete (2.5 hours after GVBD). In activated eggs, the dephosphorylation of p90rsk to Mr 86 X 10(3) starts about 1 hour after the onset of pronuclei formation and continues very slowly until the beginning of mitosis, when the doublet of Mr 82 X 10(3) and 84 X 10(3) reappears. A role for a M-phase activated kinase (like p34cdc2) in p90rsk activation was suggested by the reappearance of the Mr 86 X 10(3) band during first mitosis and in 1-cell embryos arrested in M phase by nocodazole. The requirement of MAPK for the full activation of p90rsk during meiosis was demonstrated by the absence of the fully active Mr 88 X 10(3) band in maturing c-mos −/− oocytes, where MAPK is not activated. The inhibition of kinase activity in activated eggs by 6-DMAP after second polar body extrusion provided evidence that both MAPK- and p90rsk-specific phosphatases are activated at approximately the same time prior to pronuclei formation.

scholarly journals Spindle assembly in the absence of chromosomes in mouse oocytes

Reproduction ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 731-738 ◽  
Author(s):  
Ji-Wen Yang ◽  
Zi-Li Lei ◽  
Yi-Liang Miao ◽  
Jun-Cheng Huang ◽  
Li-Hong Shi ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Spindle Assembly ◽  
Meiotic Maturation ◽  
Bipolar Spindle ◽  
Microtubule Organizing Centers ◽  
Mouse Oocytes ◽  
Inactive Form ◽  
Different Shapes ◽  
Metaphase I

This study was carried out to investigate the contributions of chromosomes to spindle assembly in mouse oocytes. We generated two groups of cytoplasts (holo- and hemi-cytoplasts) by enucleation of germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) oocytes using micromanipulation technology. After in vitro culture for 18 h, spindles with different shapes (bi-, mono-, or multipolar) formed in most of these cytoplasts except in hemi-GV cytoplasts. Two or more spindles were observed in most of holo-GV, holo-MI, and holo-MII cytoplasts (76.1, 77.0, and 83.7% respectively). However, the proportions of hemi-MI and hemi-MII cytoplasts with multiple sets of spindles decreased to 17.6 and 20.7% respectively. A single bipolar spindle was observed in each sham-operated oocyte generated by removing different volumes of cytoplasm from the oocytes and keeping nuclei intact. Localization of γ-tubulin showed that microtubule organizing centers (MTOCs) were dispersed at each pole of the multiple sets of spindles formed in holo-cytoplasts. However, most of the MTOCs aggregated at the two poles of the bipolar spindle in sham-operated oocytes. Our results demonstrate that chromosomes are not essential for initiating spindle assembly but for directing distinct MTOCs to aggregate to form a bipolar spindle. Some factors of undetermined nature may pre-exist in an inactive form in GV-stage ooplasm, serving as initiators of spindle assembly upon their activation. Moreover, GV materials released into the cytoplasm may facilitate spindle assembly in normal meiotic maturation.

Immunofluorescent anti-tubulin staining of spindles during meiotic maturation of mouse oocytes in vitro

1978 ◽  
Vol 29 (1) ◽  
pp. 171-188
Author(s):  
P.M. Wassarman ◽  
K. Fujiwara
Keyword(s):  
Polar Body ◽  
Immunofluorescent Staining ◽  
Meiotic Maturation ◽  
Cytoplasmic Bridge ◽  
Specific Staining ◽  
Mouse Oocytes ◽  
Maturation In Vitro ◽  
Reproducible Manner ◽  
Metaphase I

Immunofluorescent anti-tubulin staining has been used to follow nuclear progression from dictyate to metaphase II during meiotic maturation of mouse oocytes in vitro. Antibody directed against tubulin isolated from sea-urchin eggs decorates the metaphase I and metaphase II spindles, as well as the cytoplasmic bridge, midbody, and polar body of the maturing mouse oocytes. Changes in the tubulin-specific staining pattern during meiotic maturation in vitro take place in a highly reproducible manner. Oocytes exposed continuously to cytochalasin B arrest at metaphase I and display a spindle which by immunofluorescent staining is virtually indistinguishable from the spindle of untreated oocytes.

Tamoxifen-induced alterations in meiotic maturation and cytogenetic abnormalities in mouse oocytes and 1-cell zygotes

Zygote ◽  
2001 ◽  
Vol 9 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Steve N. London ◽  
John B. Mailhes
Keyword(s):  
Calcium Antagonist ◽  
Tamoxifen Treatment ◽  
Meiotic Maturation ◽  
Oral Gavage ◽  
Camp Phosphodiesterase ◽  
Cytogenetic Abnormalities ◽  
Female Mice ◽  
Mouse Oocytes ◽  
Oocyte Meiotic Maturation ◽  
Metaphase I

Alterations in the rate of oocyte meiotic maturation (OM) and the timing of the metaphase-anaphase transition may predispose oocytes to premature centromere separation (PCS) and aneuploidy. Tamoxifen has the potential for perturbing the rate of OM since it can function as a calcium antagonist by binding to calmodulin and inhibiting the formation of a calcium-calmodulin complex which is needed for activating calmodulin-dependent cAMP phosphodiesterase and initiating OM. The objective of this study was to test the hypothesis that tamoxifen alters the rate of OM and predisposes oocytes to PCS and aneuploidy. Different does of tamoxifen were administered by oral gavage to female mice preovulation. Metaphase II oocyte and 1-cell zygote chromosomes were C-banded and cytogenetically analysed. Tamoxifen treatment resulted in a modest, but significant (p < 0.05), increase in oocytes with PCS. Similar frequencies of hyperploidy and oocytes with unpaired, single chromatids (SC) were found. Metaphase I, diploid and premature anaphase (PA) oocytes were not detected. Hyperploidy, polyploidy, PCS, PA and SC were not detected in zygotes. These data indicate that the levels of tamoxifen-induced PCS found in mouse oocytes did not predispose zygotes to aneuploidy. Tamoxifen did, however, reduce the proportion of females exhibiting oestrus.

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.

Sign in / Sign up

Export Citation Format

Share Document