scholarly journals Dynamic Changes of pStat3 are Involved in Meiotic Spindle Assembly in Mouse Oocytes

2020 ◽  
Author(s):  
Seiki Haraguchi ◽  
Mitsumi Ikeda ◽  
Satoshi Akagi ◽  
Yuji Hirao
Keyword(s):  
Oocyte Maturation ◽  
Spindle Assembly ◽  
Meiotic Spindle ◽  
Dual Function ◽  
Dependent Manner ◽  
Vitro Fertilization ◽  
Spindle Poles ◽  
Activation Of Transcription ◽  
Transcription 3

The signal transducer and activator of transcription 3 (Stat3) is activated in response to the phosphorylation of Y705 (pStat3) and has the dual function of signal transduction and activation of transcription. Our previous study suggested that pStat3 is functional during oocyte maturation when transcription is silenced. Therefore, we speculated that pStat3 may have another function. Immunocytochemical analysis revealed that pStat3 emerges at the microtubule asters and spindle and then localizes at the spindle poles concomitant with a Pericentrin during mouse oocyte maturation. When we examined conditionally knocked out Stat3−/− oocytes, we detected Stat3 and pStat3 proteins. The localization of the pStat3 was the same as that of Stat3+/+ oocytes, and the oocyte maturation proceeded normally, suggesting that pStat3 was still functioning. The oocytes were treated either with the Stat3 specific inhibitors, Stattic and BP-1-102, or anti-pStat3 antibody injection. This caused significant abnormal spindle assembly and chromosome mis-location in a dose-dependent manner, in which the pStat3 was either negative or localized improperly. Moreover, development of pre-implantation stage embryos derived from inhibitor-treated oocytes was also hampered significantly after in vitro fertilization. These findings indicate a novel function of pStat3 involved in spindle assembly.

scholarly journals Dynamic Changes in pStat3 Are Involved in Meiotic Spindle Assembly in Mouse Oocytes

2020 ◽  
Vol 21 (4) ◽  
pp. 1220
Author(s):  
Seiki Haraguchi ◽  
Mitsumi Ikeda ◽  
Satoshi Akagi ◽  
Yuji Hirao
Keyword(s):  
Oocyte Maturation ◽  
Spindle Assembly ◽  
Meiotic Spindle ◽  
Dual Function ◽  
Dependent Manner ◽  
Vitro Fertilization ◽  
Mouse Oocytes ◽  
Spindle Poles ◽  
Transcription 3

The signal transducer and activator of transcription 3 (Stat3) is activated upon phosphorylation at Y705 (pStat3) and serves the dual function of signal transduction and transcription activation. Our previous study suggested that pStat3 is functional during oocyte maturation when transcription is silenced. Therefore, we speculated that pStat3 serves other functions. Immunocytochemical analysis revealed that pStat3 emerges at microtubule asters and spindle and is subsequently localized at the spindle poles along with pericentrin during mouse oocyte maturation. Both Stat3 and pStat3 proteins were detected in conditionally knocked out Stat3−/− mouse oocytes. pStat3 localization was the same in Stat3+/+ and Stat3−/− oocytes, and oocyte maturation proceeded normally, suggesting that pStat3 was still functional. Furthermore, the treatment of oocytes with the Stat3-specific inhibitors stattic and BP-1-102 or anti-pStat3 antibody led to significantly abnormal spindle assembly and chromosome mislocation in a dose-dependent manner, and pStat3 was either absent or improperly localized in these oocytes. Moreover, the development of pre-implantation stage embryos derived from inhibitor-treated oocytes was significantly hampered following in vitro fertilization. These findings indicate a novel function of pStat3 in spindle assembly.

scholarly journals Differentiation of Cytoplasmic and Meiotic Spindle Assembly MCAK Functions by Aurora B-dependent Phosphorylation

2004 ◽  
Vol 15 (6) ◽  
pp. 2895-2906 ◽  
Author(s):  
Ryoma Ohi ◽  
Tanuj Sapra ◽  
Jonathan Howard ◽  
Timothy J. Mitchison
Keyword(s):  
Chromosome Segregation ◽  
Spindle Assembly ◽  
Microtubule Dynamics ◽  
Meiotic Spindle ◽  
Aurora B ◽  
Dependent Manner ◽  
Dynamic Nature ◽  
Spindle Microtubule ◽  
Bipolar Spindles

The KinI kinesin MCAK is a microtubule depolymerase important for governing spindle microtubule dynamics during chromosome segregation. The dynamic nature of spindle assembly and chromosome-microtubule interactions suggest that mechanisms must exist that modulate the activity of MCAK, both spatially and temporally. In Xenopus extracts, MCAK associates with and is stimulated by the inner centromere protein ICIS. The inner centromere kinase Aurora B also interacts with ICIS and MCAK raising the possibility that Aurora B may regulate MCAK activity as well. Herein, we demonstrate that recombinant Aurora B-INCENP inhibits Xenopus MCAK activity in vitro in a phosphorylation-dependent manner. Substituting endogenous MCAK in Xenopus extracts with the alanine mutant XMCAK-4A, which is resistant to inhibition by Aurora B-INCENP, led to assembly of mono-astral and monopolar structures instead of bipolar spindles. The size of these structures and extent of tubulin polymerization in XMCAK-4A extracts indicate that XM-CAK-4A is not defective for microtubule dynamics regulation throughout the cytoplasm. We further demonstrate that the ability of XMCAK-4A to localize to inner centromeres is abolished. Our results show that MCAK regulation of cytoplasmic and spindle-associated microtubules can be differentiated by Aurora B-dependent phosphorylation, and they further demonstrate that this regulation is required for bipolar meiotic spindle assembly.

scholarly journals The Differential Metabolomes in Cumulus and Mural Granulosa Cells from Human Preovulatory Follicles

2021 ◽  
Author(s):  
Er-Meng Gao ◽  
Bongkoch Turathum ◽  
Ling Wang ◽  
Di Zhang ◽  
Yu-Bing Liu ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Granulosa Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Cumulus Cells ◽  
Cholesterol Transport ◽  
Vitro Fertilization ◽  
Expression Of Genes ◽  
Preovulatory Follicles ◽  
Morphological Differences

AbstractThis study evaluated the differences in metabolites between cumulus cells (CCs) and mural granulosa cells (MGCs) from human preovulatory follicles to understand the mechanism of oocyte maturation involving CCs and MGCs. CCs and MGCs were collected from women who were undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. The differences in morphology were determined by immunofluorescence. The metabolomics of CCs and MGCs was measured by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) followed by quantitative polymerase chain reaction (qPCR) and western blot analysis to further confirm the genes and proteins involved in oocyte maturation. CCs and MGCs were cultured for 48 h in vitro, and the medium was collected for detection of hormone levels. There were minor morphological differences between CCs and MGCs. LC-MS/MS analysis showed that there were differences in 101 metabolites between CCs and MGCs: 7 metabolites were upregulated in CCs, and 94 metabolites were upregulated in MGCs. The metabolites related to cholesterol transport and estradiol production were enriched in CCs, while metabolites related to antiapoptosis were enriched in MGCs. The expression of genes and proteins involved in cholesterol transport (ABCA1, LDLR, and SCARB1) and estradiol production (SULT2B1 and CYP19A1) was significantly higher in CCs, and the expression of genes and proteins involved in antiapoptosis (CRLS1, LPCAT3, and PLA2G4A) was significantly higher in MGCs. The level of estrogen in CCs was significantly higher than that in MGCs, while the progesterone level showed no significant differences. There are differences between the metabolomes of CCs and MGCs. These differences may be involved in the regulation of oocyte maturation.

Parthenogenesis and cytoskeletal organization in ageing mouse eggs

Development ◽  
1986 ◽  
Vol 95 (1) ◽  
pp. 131-145
Author(s):  
Michelle Webb ◽  
Sarah K. Howlett ◽  
Bernard Maro
Keyword(s):  
Critical Concentration ◽  
Metaphase Plate ◽  
Meiotic Spindle ◽  
Cytoskeletal Organization ◽  
Spindle Poles ◽  
Different Types ◽  
Mouse Egg ◽  
Parthenogenetic Embryos

The cytoskeletal organization of the mouse egg changes during ageing in vivo and in vitro. The earliest change observed is the disappearance of the microfilament-rich area overlying the meiotic spindle. This is followed by the migration of the spindle towards the centre of the egg. Finally the spindle breaks down and the chromosomes are no longer organized on a metaphase plate. This spindle disruption may result from changes in the microtubule nucleating material found at the spindle poles and from an increase in the critical concentration for tubulin polymerization. It is possible to correlate the changes in the cytoskeletal organization of the egg occurring during ageing with the different types of parthenogenetic embryos obtained after ethanol activation. These observations strengthen the hypothesis that the actin-rich cortical area that overlies the meiotic spindle forms a domain to which the meiotic cleavage furrow is restricted and provides some insights into the mechanisms by which different types of parthenogenetic embryos are generated.

scholarly journals Perfluorononanoic acid impedes mouse oocyte maturation by inducing mitochondrial dysfunction and oxidative stress

2021 ◽  
Author(s):  
Xiaofei Jiao ◽  
Ning Liu ◽  
Yiding Xu ◽  
Huanyu Qiao
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Oocyte Maturation ◽  
Early Stage ◽  
Spindle Assembly ◽  
Mouse Oocyte ◽  
Toxic Effects ◽  
Germinal Vesicle Breakdown ◽  
Maturation In Vitro

Perfluorononanoic acid (PFNA), a member of PFAS, is frequently detected in human blood and tissues, even in follicular fluid of women. The exposure of PFNA, but not PFOA and PFOS, is positively correlated with miscarriage and increased time to pregnancy. Toxicological studies indicated that PFNA exposure is associated with immunotoxicity, hepatotoxicity, developmental toxicity, and reproductive toxicity in animals. However, there is little information regarding the toxic effects of PFNA on oocyte maturation. In this study, we investigated the toxic effects of PFNA exposure on mouse oocyte maturation in vitro. Our results showed that 600 μM PFNA significantly inhibited germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) in mouse oocytes. Our further study revealed that PFNA induced abnormal metaphase I (MI) spindle assembly, evidenced by malformed spindles and mislocalization of p-ERK1/2 in PFNA-treated oocytes. We also found that PFNA induced abnormal mitochondrial distribution and increased mitochondrial membrane potential. Consequently, PFNA increased reactive oxygen species (ROS) levels, leading to oxidative stress, DNA damage, and eventually early-stage apoptosis in oocytes. In addition, after 14 h culture, PFNA disrupted the formation of metaphase II (MII) spindle in most PFNA-treated oocytes with polar bodies. Collectively, our results indicate that PFNA interferes with oocyte maturation in vitro via disrupting spindle assembly, damaging mitochondrial functions, and inducing oxidative stress, DNA damage, and early-stage apoptosis.

Asynchrony between human cumulus-corona cell complex and oocyte maturation after human menopausal gonadotropin treatment for in vitro fertilization

1984 ◽  
Vol 42 (3) ◽  
pp. 366-372 ◽  
Author(s):  
Neri Laufer ◽  
Basil C. Tarlatzis ◽  
Alan H. DeCherney ◽  
Joyce T. Masters ◽  
Florence P. Haseltine ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Oocyte Maturation ◽  
Cell Complex ◽  
Human Menopausal Gonadotropin ◽  
Vitro Fertilization
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