scholarly journals Biphasic Activation of Aurora-A Kinase during the Meiosis I- Meiosis II Transition in Xenopus Oocytes

2003 ◽  
Vol 23 (5) ◽  
pp. 1703-1716 ◽  
Author(s):  
Chunqi Ma ◽  
Cathy Cummings ◽  
X. Johné Liu
Keyword(s):  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Apparent Paradox ◽  
Germinal Vesicle Breakdown ◽  
Mitogen Activated Protein ◽  
Mrna Polyadenylation ◽  
Polyadenylation Factor ◽  
Meiosis I

ABSTRACT Xenopus Aurora-A (also known as Eg2) is a member of the Aurora family of mitotic serine/threonine kinases. In Xenopus oocytes, Aurora-A phosphorylates and activates a cytoplasmic mRNA polyadenylation factor (CPEB) and therefore plays a pivotal role in MOS translation. However, hyperphosphorylation and activation of Aurora-A appear to be dependent on maturation-promoting factor (MPF) activation. To resolve this apparent paradox, we generated a constitutively activated Aurora-A by engineering a myristylation signal at its N terminus. Injection of Myr-Aurora-A mRNA induced germinal vesicle breakdown (GVBD) with the concomitant activation of MOS, mitogen-activated protein kinase, and MPF. Myr-Aurora-A-injected oocytes, however, appeared to arrest in meiosis I with high MPF activity and highly condensed, metaphase-like chromosomes but no organized microtubule spindles. No degradation of CPEB or cyclin B2 was observed following GVBD in Myr-Aurora-A-injected oocytes. In the presence of progesterone, the endogenous Aurora-A became hyperphosphorylated and activated at the time of MPF activation. Following GVBD, Aurora-A was gradually dephosphorylated and inactivated before it was hyperphosphorylated and activated again. This biphasic pattern of Aurora-A activation mirrored that of MPF activation and hence may explain meiosis I arrest by the constitutively activated Myr-Aurora-A.

scholarly journals Identification of Factors Regulating Poly(A) Tail Synthesis and Maturation

2004 ◽  
Vol 24 (10) ◽  
pp. 4196-4206 ◽  
Author(s):  
David A. Mangus ◽  
Mandy M. Smith ◽  
Jennifer M. McSweeney ◽  
Allan Jacobson
Keyword(s):  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Genes Encoding ◽  
Mitogen Activated Protein ◽  
Regulatory Complex ◽  
Cleavage And Polyadenylation ◽  
Mrna Polyadenylation ◽  
Two Hybrid ◽  
Polyadenylation Factor

ABSTRACT Posttranscriptional maturation of the 3′ end of eukaryotic pre-mRNAs occurs as a three-step pathway involving site-specific cleavage, polymerization of a poly(A) tail, and trimming of the newly synthesized tail to its mature length. While most of the factors essential for catalyzing these reactions have been identified, those that regulate them remain to be characterized. Previously, we demonstrated that the yeast protein Pbp1p associates with poly(A)-binding protein (Pab1p) and controls the extent of mRNA polyadenylation. To further elucidate the function of Pbp1p, we conducted a two-hybrid screen to identify factors with which it interacts. Five genes encoding putative Pbp1p-interacting proteins were identified, including (i) FIR1/PIP1 and UFD1/PIP3, genes encoding factors previously implicated in mRNA 3′-end processing; (ii) PBP1 itself, confirming directed two-hybrid results and suggesting that Pbp1p can multimerize; (iii) DIG1, encoding a mitogen-activated protein kinase-associated protein; and (iv) PBP4 (YDL053C), a previously uncharacterized gene. In vitro polyadenylation reactions utilizing extracts derived from fir1Δ and pbp1Δ cells and from cells lacking the Fir1p interactor, Ref2p, demonstrated that Pbp1p, Fir1p, and Ref2p are all required for the formation of a normal-length poly(A) tail on precleaved CYC1 pre-mRNA. Kinetic analyses of the respective polyadenylation reactions indicated that Pbp1p is a negative regulator of poly(A) nuclease (PAN) activity and that Fir1p and Ref2p are, respectively, a positive regulator and a negative regulator of poly(A) synthesis. We suggest a model in which these three factors and Ufd1p are part of a regulatory complex that exploits Pab1p to link cleavage and polyadenylation factors of CFIA and CFIB (cleavage factors IA and IB) to the polyadenylation factors of CPF (cleavage and polyadenylation factor).

scholarly journals Cyclic Adenosine 3′,5′-Monophosphate-Dependent Activation of Mitogen-Activated Protein Kinase in Cumulus Cells Is Essential for Germinal Vesicle Breakdown of Porcine Cumulus-Enclosed Oocytes

Endocrinology ◽  
2005 ◽  
Vol 146 (10) ◽  
pp. 4437-4444 ◽  
Author(s):  
Cheng-Guang Liang ◽  
Li-Jun Huo ◽  
Zhi-Sheng Zhong ◽  
Da-Yuan Chen ◽  
Heide Schatten ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Germinal Vesicle ◽  
Cumulus Cells ◽  
Mitogen Activated Protein Kinase ◽  
Pde4 Inhibitor ◽  
Germinal Vesicle Breakdown ◽  
Germinal Vesicles ◽  
Mitogen Activated Protein ◽  
Culture Models ◽  
Cell Type Specific

MAPK plays an important role during meiotic maturation in mammalian oocytes, whereas the necessity of MAPK during meiotic resumption in porcine oocytes is still controversial. Here, by applying the method of ultracentrifugation to move the opaque lipid droplets to the edge of the oocyte, therefore allowing clear visualization of porcine germinal vesicles, oocytes just before germinal vesicle breakdown (GVBD) and those that had just undergone GVBD were selected for the assay of MAPK activation. Our results showed that phosphorylation of MAPK in oocytes occurred after GVBD in all three different culture models: spontaneous maturation model, inhibition-induction maturation model, and normal maturation model. Moreover, we found that activation of MAPK in cumulus cells but not in oocytes was essential for GVBD in cumulus-enclosed oocytes. Then the cross-talk between cAMP and MAPK in cumulus cells was investigated by using cell-type-specific phosphodiesterase (PDE) isoenzyme inhibitors. Our results showed that PDE3 subtype existed in oocytes, whereas PDE4 subtype existed in cumulus cells. PDE3 inhibitor prevented meiotic resumption of oocytes, whereas PDE4 inhibitor enhanced the ability of FSH or forskolin to activate MAPK in cumulus cells. We propose that increased cAMP resulting from inhibition of PDE3 in oocytes blocks GVBD, whereas increased cAMP resulting from inhibition of PDE4 activates MAPK pathway in cumulus cells, which is essential for GVBD induction.

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 Requirement for Raf and MAP kinase function during the meiotic maturation of Xenopus oocytes

1993 ◽  
Vol 122 (3) ◽  
pp. 645-652 ◽  
Author(s):  
JR Fabian ◽  
DK Morrison ◽  
IO Daar
Keyword(s):  
Tyrosine Kinase ◽  
Electrophoretic Mobility ◽  
Receptor Tyrosine Kinase ◽  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Mobility Shift ◽  
Germinal Vesicle Breakdown ◽  
Mapk Activation ◽  
Mitogen Activated Protein

The role of Raf and MAPK (mitogen-activated protein kinase) during the maturation of Xenopus oocytes was investigated. Treatment of oocytes with progesterone resulted in a shift in the electrophoretic mobility of Raf at the onset of germinal vesicle breakdown (GVBD), which was coincident with the activation of MAPK. Expression of a kinase-defective mutant of the human Raf-1 protein (KD-RAF) inhibited progesterone-mediated MAPK activation. MAPK activation was also inhibited by KD-Raf in oocytes expressing signal transducers of the receptor tyrosine kinase (RTK) pathway, including an activated tyrosine kinase (Tpr-Met), a receptor tyrosine kinase (EGFr), and Ha-RasV12. KD-RAF completely inhibited GVBD induced by the RTK pathway. In contrast, KD-RAF did not inhibit GVBD and the progression to Meiosis II in progesterone-treated oocytes. Injection of Mos-specific antisense oligodeoxyribonucleotides inhibited MAPK activation in response to progesterone and Tpr-Met, but failed to inhibit these events in oocytes expressing an oncogenic deletion mutant of Raf-1 (delta N'Raf). Injection of antisense oligodeoxyribonucleotides to Mos also reduced the progesterone- and Tpr-Met-induced electrophoretic mobility shift of Xenopus Raf. These results demonstrate that RTKs and progesterone participate in distinct yet overlapping signaling pathways resulting in the activation of maturation or M-phase promoting factor (MPF). Maturation induced by the RTK pathway requires activation of Raf and MAPK, while progesterone-induced maturation does not. Furthermore, the activation of MAPK in oocytes appears to require the expression of Mos.

scholarly journals Nucleus, Cytoskeleton, and Mitogen-Activated Protein Kinase p38 Dynamics during In Vitro Maturation of Porcine Oocytes

Animals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 163
Author(s):  
Payungsuk Intawicha ◽  
Li-Kuang Tsai ◽  
Shih-Ying Yen ◽  
Neng-Wen Lo ◽  
Jyh-Cherng Ju
Keyword(s):  
Oocyte Maturation ◽  
Mammalian Cells ◽  
In Vitro Maturation ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
Mitogen Activated Protein ◽  
Porcine Oocyte

The mitogen-activated kinase (MAPK) p38, a member of the MAPK subfamily, is conserved in all mammalian cells and plays important roles in response to various physiologic cues, including mitogens and heat shock. In the present study, MAPK p38 protein expression in porcine oocytes was analyzed during in vitro maturation (IVM) by Western blotting and immunocytochemistry. The levels of p-p38 or activated p38 and p38 expression were at the lowest in the germinal vesicle (GV) stage oocyte, gradually rising at the germinal vesicle breakdown (GVBD) and then reaching a plateau throughout the IVM culture (p < 0.05). Similarly, the expression level of total p38 was also lower in the GV oocyte than in the oocyte of other meiotic stages and uprising after GVBD and remained high until the metaphase III (MII) stage (p < 0.05). In the GV stage, phosphorylated p38 (p-p38) was initially detectable in the ooplasm and subsequently became clear around the nucleus and localized in the ooplasm at GVBD (18 h post-culture). During the metaphase I (MI) and metaphase II (MII) stages, p-p38 was evenly distributed throughout the ooplasm after IVM for 30 or 42 h. We found that the subcellular localization increased in p-p38 expression throughout oocyte maturation (p < 0.05) and that dynamic reorganization of the cytoskeleton, including microfilaments and microtubules, was progressively changed during the course of meiotic maturation which was likely to be associated with the activation or networking of p38 with other proteins in supporting oocyte development. In conclusion, the alteration of p38 activation is essential for the regulation of porcine oocyte maturation, accompanied by the progressive reorganization and redistribution of the cytoskeleton and MAPK p38, respectively, in the ooplasm.

Involvement of microRNA-335-5p in cytoskeleton dynamics in mouse oocytes

2013 ◽  
Vol 25 (4) ◽  
pp. 691 ◽  
Author(s):  
Xiang-Shun Cui ◽  
Shao-Chen Sun ◽  
Yong-Kook Kang ◽  
Nam-Hyung Kim
Keyword(s):  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Germinal Vesicle Breakdown ◽  
Oocyte Meiosis ◽  
Extracellular Signal ◽  
Multiple Processes ◽  
Mitogen Activated Protein ◽  
Actin Nucleator ◽  
Cytoskeleton Dynamics ◽  
Multiple Poles

MicroRNA is a short RNA molecule expressed in eukaryotic cells that is involved in multiple processes, including translational repression, target degradation and gene silencing. However, its specific role(s) in these processes remains largely unknown, especially in terms of germ cell development. The present study identified a microRNA, namely miR-335-5p, that is involved in mouse oocyte meiosis. MiR-335-5p was highly expressed in oocytes, but levels decreased markedly shortly after fertilisation. Microinjection of miR-335-5p or its inhibitor into oocytes resulted in a higher proportion of 2-cell-like MII oocytes and oocytes at the germinal vesicle breakdown and/or MI stage, indicating failure of asymmetric oocyte division. This may be due to regulation of actin because perturbation of miR-335-5p resulted in reduced expression of actin nucleator Daam1, a member of the Formin family. Moreover, injection of miR-335-5p or its inhibitor resulted in aberrant spindle morphology, namely an elongated spindle and multiple poles spindle. After injection of oocytes, levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) decreased, suggesting that miR-335-5p may regulate spindle formation via the mitogen-activated protein kinase pathway. Overexpression and inhibition of miR-335-5p had no effect on embryo development. Together, the results of the present study indicate that miR-335-5p is a novel regulator expressed in oocytes that is involved in cytoskeleton dynamics.

scholarly journals Activation of mitogen-activated protein kinase during meiotic maturation in porcine oocytes

Zygote ◽  
1995 ◽  
Vol 3 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Maki Inoue ◽  
Kunihiko Naito ◽  
Fugaku Aoki ◽  
Yutaka Toyoda ◽  
Eimei Sato
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Kinase Activity ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body ◽  
Mitogen Activated Protein

SummaryTo investigate the involvement of mitogen-activated protein kinase(MAP kinase) in meiotic maturation of porcine oocytes, we assayed MAP kinase activity using basic protein(MBP) as a substrate. MAP kinase activity was low during the germinal vesicle stage, 0–20 h of culture. An abrupt increase was observed at metaphase I(30 h of culture), and activity remained significantly higher than that at 0 h until 50 h of culture, with a transient slight decrease at the time of first polar body extrusion (40 h). Detection of the kinase activity by an in-gel phosphorylation assay confirmed that the 42 and 44 kDa MAP kinases were significantly activated in 45 h cultured oocytes but not in 0 h oocytes, and just slightly in 20 h oocytes. In immunoblotting, however, the 42 and 44 kDa bands were detected in 0, 20 and 45 h cultured oocytes. Furthermore, the signal strength of the two bands did not change during the period of culture, but shifted up to 45 h, indicating that the activation of MAP kinase depended not on the synthesis but on the phosphorylation of this enzyme. These results suggest that the activation of MAP kinase is involved in the regulation of meiotic maturation of porcine oocytes, and especially in the regulation after germinal vesicle breakdown.

Mitogen-activated protein kinase phosphorylation patterns in pig oocytes and cumulus cells during gonadotrophin-induced resumption of meiosis in vitro

Zygote ◽  
2007 ◽  
Vol 15 (2) ◽  
pp. 139-147 ◽  
Author(s):  
S. Ebeling ◽  
C. Schuon ◽  
B. Meinecke
Keyword(s):  
Protein Kinase ◽  
Germinal Vesicle ◽  
Cumulus Cells ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Germinal Vesicle Breakdown ◽  
Mapk Phosphorylation ◽  
Rapid Action ◽  
Mitogen Activated Protein

SummaryThe present study investigated the phosphorylation pattern of mitogen-activated protein kinase (MAPK) in cumulus–oocyte complexes (COCs) during spontaneous and FSH/LH-induced in vitro maturation (IVM). Both isoforms of MAPK were unphosphorylated in oocytes recovered immediately after liberation from follicles and became phosphorylated following 25 h incubation, corresponding to the time of germinal vesicle breakdown (GVBD). In contrast, MAPK was already phosphorylated in minimal amounts in cumulus cells at the time of liberation from follicles and phosphorylation of MAPK increased after 0.5 h incubation. Supplementation of medium with gonadotrophins intensified phosphorylation at 0.5 h incubation, demonstrating the early and rapid action of FSH/LH on MAPK phosphorylation. Phosphorylation of MAPK in cumulus cells peaked after 21 h of incubation, whereas MAPK was almost completely dephosphorylated at the end of incubation (45 h). During subsequent incubation in the absence of added gonadotrophins, between 5 and 10 h exposure to FSH/LH-supplemented medium was required to induce resumption of meiosis in COCs. Phosphorylation of MAPK in oocytes was prevented by the MEK inhibitor U0126, but the inhibitor reduced phosphorylation of MAPK in cumulus cells only during the first 2 h of IVM. The data support the hypothesis that two different MAPK phosphorylation events occurred following gonadotrophin stimulation, one in cumulus cells and the other in oocytes. In cumulus cells, FSH/LH induced early and rapid U0126-insensitive phosphorylation of MAPK, whereas U0126-susceptible MAPK phosphorylation took place in the oocyte itself around the time of GVBD.

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