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Qing-yuan Sun - One of the best experts on this subject based on the ideXlab platform.
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absence of mitochondrial dna methylation in mouse oocyte maturation aging and Early Embryo development
Biochemical and Biophysical Research Communications, 2019Co-Authors: Lihua Fan, Zhen-bo Wang, Ying-chun Ouyang, Yi Hou, Heide Schatten, Tiegang Meng, Mingzhe Dong, Qing-yuan SunAbstract:Mitochondrial DNA (mtDNA) is important for oxidative phosphorylation; dysfunctions can play a role in many mitochondrial diseases and can also affect the aging of cells and individuals. DNA methylation is an important epigenetic modification that plays a critical role in regulating gene expression. While recent studies have revealed the existence of mtDNA methylation there are still controversies about mtDNA methylation due to the special structure of mtDNA. Mitochondria and DNA methylation are both essential for regulating oocyte maturation and Early Embryo development, but whether mtDNA methylation changes during this process is unknown. By employing bisulfite sequencing, we found that in the process of mouse oocyte maturation, postovulatory oocyte aging, and Early Embryo development, all analyzed mitochondrial genes, including 16S-CpGI, DCR, ND6, 12S, and ATP8, lacked 5'mC. Thus, mtDNA methylation does not occur in the oocyte and Early Embryo.
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geminin deletion in mouse oocytes results in impaired Embryo development and reduced fertility
Molecular Biology of the Cell, 2016Co-Authors: Fei Lin, Zhen-bo Wang, Heide Schatten, Tiegang Meng, Lin Huang, Zhongwei Wang, Zongzhe Jiang, Qing-yuan SunAbstract:Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and Early Embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, Early Embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs Early Embryo development.
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translocation of active mitochondria during pig oocyte maturation fertilization and Early Embryo development in vitro
Reproduction, 2001Co-Authors: Qing-yuan Sun, Liangxue Lai, K W Park, Ryan A Cabot, Heetae Cheong, B N Day, Randall S Prather, Heide SchattenAbstract:The distribution of active mitochondria during pig oocyte maturation, fertilization and Early Embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of Early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and Early Embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.
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cytoplasmic changes in relation to nuclear maturation and Early Embryo developmental potential of porcine oocytes effects of gonadotropins cumulus cells follicular size and protein synthesis inhibition
Molecular Reproduction and Development, 2001Co-Authors: Qing-yuan Sun, Liangxue Lai, Randall S Prather, Aaron Bonk, Heide SchattenAbstract:Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and Early Embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen-activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule-free domain (CGFD) and an actin-thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole-treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin-thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as Embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and Embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B1, phosphorylate MAP kinase and translocate CGs, but their maturation and Embryo developmental ability were limited. Removal of cumulus cells from small follicle-derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation. Mol. Reprod. Dev. 59:192–198, 2001. © 2001 Wiley-Liss, Inc.
Heide Schatten - One of the best experts on this subject based on the ideXlab platform.
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absence of mitochondrial dna methylation in mouse oocyte maturation aging and Early Embryo development
Biochemical and Biophysical Research Communications, 2019Co-Authors: Lihua Fan, Zhen-bo Wang, Ying-chun Ouyang, Yi Hou, Heide Schatten, Tiegang Meng, Mingzhe Dong, Qing-yuan SunAbstract:Mitochondrial DNA (mtDNA) is important for oxidative phosphorylation; dysfunctions can play a role in many mitochondrial diseases and can also affect the aging of cells and individuals. DNA methylation is an important epigenetic modification that plays a critical role in regulating gene expression. While recent studies have revealed the existence of mtDNA methylation there are still controversies about mtDNA methylation due to the special structure of mtDNA. Mitochondria and DNA methylation are both essential for regulating oocyte maturation and Early Embryo development, but whether mtDNA methylation changes during this process is unknown. By employing bisulfite sequencing, we found that in the process of mouse oocyte maturation, postovulatory oocyte aging, and Early Embryo development, all analyzed mitochondrial genes, including 16S-CpGI, DCR, ND6, 12S, and ATP8, lacked 5'mC. Thus, mtDNA methylation does not occur in the oocyte and Early Embryo.
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geminin deletion in mouse oocytes results in impaired Embryo development and reduced fertility
Molecular Biology of the Cell, 2016Co-Authors: Fei Lin, Zhen-bo Wang, Heide Schatten, Tiegang Meng, Lin Huang, Zhongwei Wang, Zongzhe Jiang, Qing-yuan SunAbstract:Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and Early Embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, Early Embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs Early Embryo development.
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translocation of active mitochondria during pig oocyte maturation fertilization and Early Embryo development in vitro
Reproduction, 2001Co-Authors: Qing-yuan Sun, Liangxue Lai, K W Park, Ryan A Cabot, Heetae Cheong, B N Day, Randall S Prather, Heide SchattenAbstract:The distribution of active mitochondria during pig oocyte maturation, fertilization and Early Embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of Early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and Early Embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.
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cytoplasmic changes in relation to nuclear maturation and Early Embryo developmental potential of porcine oocytes effects of gonadotropins cumulus cells follicular size and protein synthesis inhibition
Molecular Reproduction and Development, 2001Co-Authors: Qing-yuan Sun, Liangxue Lai, Randall S Prather, Aaron Bonk, Heide SchattenAbstract:Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and Early Embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen-activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule-free domain (CGFD) and an actin-thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole-treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin-thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as Embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and Embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B1, phosphorylate MAP kinase and translocate CGs, but their maturation and Embryo developmental ability were limited. Removal of cumulus cells from small follicle-derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation. Mol. Reprod. Dev. 59:192–198, 2001. © 2001 Wiley-Liss, Inc.
Shaochen Sun - One of the best experts on this subject based on the ideXlab platform.
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inhibition of rac1 gtpase activity affects porcine oocyte maturation and Early Embryo development
Scientific Reports, 2016Co-Authors: Sijing Song, Qiaochu Wang, Nam-hyung Kim, Xiang-shun Cui, Ruxia Jia, Shaochen SunAbstract:Mammalian oocyte asymmetric division relies on the eccentric positioning of the spindle, resulting in the polar body formation. Small signaling G protein Rac1 is a member of GTPases, which regulates a diverse array of cellular events, including the control of cell growth, cytoskeletal reorganization, and the activation of protein kinases. However, effects of Rac1 on the porcine oocyte maturation and Early Embryo development are not fully understood. In present study we investigated the role of Rac1 in oocyte maturation and Embryo cleavage. We first found that Rac1 localized at the cortex of the porcine oocytes, and disrupting the Rac1 activities by treating with NSC 23766 led to the failure of polar body emission. In addition, a majority of treated oocytes exhibited abnormal spindle morphology, indicating that Rac1 may involve into porcine oocyte spindle formation. This might be due to the regulation of Rac1 on MAPK, since p-MAPK expression decreased after NSC 23766 treatments. Moreover, we found that the position of most meiotic spindles in treated oocytes were away from the cortex, indicating the roles of Rac1 on meiotic spindle positioning. Our results also showed that inhibition of Rac1 activity caused the failure of Early Embryo development. Therefore, our study showed the critical roles of Rac1 GTPase on porcine oocyte maturation and Early Embryo cleavage.
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small gtpase rhoa regulates cytoskeleton dynamics during porcine oocyte maturation and Early Embryo development
Cell Cycle, 2014Co-Authors: Yu Zhang, Xing Duan, Nam-hyung Kim, Xiang-shun Cui, Rui Cao, Honglin Liu, Rong Rui, Shaochen SunAbstract:Mammalian oocyte maturation is distinguished by asymmetric division that is regulated primarily by cytoskeleton, including microtubules and microfilaments. Small Rho GTPase RhoA is a key regulator of cytoskeletal organization which regulates cell polarity, migration, and division. In this study, we investigated the roles of RhoA in mammalian oocyte meiosis and Early Embryo cleavage. (1) Disrupting RhoA activity or knock down the expression of RhoA caused the failure of polar body emission. This may have been due to decreased actin assembly and subsequent spindle migration defects. The involvement of RhoA in this process may have been though its regulation of actin nucleators ROCK, p-Cofilin, and ARP2 expression. (2) In addition, spindle morphology was also disrupted and p-MAPK expression decreased in RhoA inhibited or RhoA KD oocytes, which indicated that RhoA also regulated MAPK phosphorylation for spindle formation. (3) Porcine Embryo development was also suppressed by inhibiting RhoA activity. Two nucl...
Cheng-guang Liang - One of the best experts on this subject based on the ideXlab platform.
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cytoskeleton associated protein 5 and clathrin heavy chain binding regulates spindle assembly in mouse oocytes
Oncotarget, 2017Co-Authors: Cheng-jie Zhou, Zhe Han, Donghui Wang, Xiangwei Kong, Zhizhong Yun, Cheng-guang LiangAbstract:Mammalian oocyte meiotic maturation is the precondition of Early Embryo development. Lots of microtubules (MT)-associated proteins participate in oocyte maturation process. Cytoskeleton-associated protein 5 (CKAP5) is a member of the XMAP215 family that regulates microtubule dynamics during mitosis. However, its role in meiosis has not been fully studied. Here, we investigated the function of CKAP5 in mouse oocyte meiotic maturation and Early Embryo development. Western blot showed that CKAP5 expression increased from GVBD, maintaining at high level at metaphase, and decreased after late 1-cell stage. Confocal microscopy showed there is no specific accumulation of CKAP5 at interphase (GV, PN or 2-cell stage). However, once cells enter into meiotic or mitotic division, CKAP5 was localized at the whole spindle apparatus. Treatment of oocytes with the tubulin-disturbing reagents nocodazole (induces MTs depolymerization) or taxol (prevents MTs depolymerization) did not affect CKAP5 expression but led to a rearrangement of CKAP5. Further, knock-down of CKAP5 resulted in a failure of first polar body extrusion, serious defects in spindle assembly, and failure of chromosome alignment. Loss of CKAP5 also decreased Early Embryo development potential. Furthermore, co-immunoprecipitation showed that CKAP5 bound to clathrin heavy chain 1 (CLTC). Taken together, our results demonstrate that CKAP5 is important in oocyte maturation and Early Embryo development, and CKAP5 might work together with CLTC in mouse oocyte maturation.
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Casein kinase 1 alpha regulates chromosome congression and separation during mouse oocyte meiotic maturation and Early Embryo development.
Public Library of Science (PLoS), 2024Co-Authors: Lu Wang, Cheng-jie Zhou, Hong-xia Zhou, Ran Sun, Jie Zhao, Jiang-peng Shen, Cheng-guang LiangAbstract:Casein kinase I alpha (CK1α) is a member of serine/threonine protein kinase, generally present in all eukaryotes. In mammals, CK1α regulates the transition from interphase to metaphase in mitosis. However, little is known about its role in meiosis. Here we examined Ck1α mRNA and protein expression, as well as its subcellular localization in mouse oocytes from germinal vesicle to the late 1-cell stage. Our results showed that the expression level of CK1α was increased in metaphase. Immunostaining results showed that CK1α colocalized with condensed chromosomes during oocyte meiotic maturation and Early Embryo development. We used the loss-of-function approach by employing CK1α specific morpholino injection to block the function of CK1α. This functional blocking leads to failure of polar body 1 (PB1) extrusion, chromosome misalignment and MII plate incrassation. We further found that D4476, a specific and efficient CK1 inhibitor, decreased the rate of PB1 extrusion. Moreover, D4476 resulted in giant polar body extrusion, oocyte pro-MI arrest, chromosome congression failure and impairment of Embryo developmental potential. In addition, we employed pyrvinium pamoate (PP), an allosteric activator of CK1α, to enhance CK1α activity in oocytes. Supplementation of PP induced oocyte meiotic maturation failure, severe congression abnormalities and misalignment of chromosomes. Taken together, our study for the first time demonstrates that CK1α is required for chromosome alignment and segregation during oocyte meiotic maturation and Early Embryo development
Rong Rui - One of the best experts on this subject based on the ideXlab platform.
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small gtpase rhoa regulates cytoskeleton dynamics during porcine oocyte maturation and Early Embryo development
Cell Cycle, 2014Co-Authors: Yu Zhang, Xing Duan, Nam-hyung Kim, Xiang-shun Cui, Rui Cao, Honglin Liu, Rong Rui, Shaochen SunAbstract:Mammalian oocyte maturation is distinguished by asymmetric division that is regulated primarily by cytoskeleton, including microtubules and microfilaments. Small Rho GTPase RhoA is a key regulator of cytoskeletal organization which regulates cell polarity, migration, and division. In this study, we investigated the roles of RhoA in mammalian oocyte meiosis and Early Embryo cleavage. (1) Disrupting RhoA activity or knock down the expression of RhoA caused the failure of polar body emission. This may have been due to decreased actin assembly and subsequent spindle migration defects. The involvement of RhoA in this process may have been though its regulation of actin nucleators ROCK, p-Cofilin, and ARP2 expression. (2) In addition, spindle morphology was also disrupted and p-MAPK expression decreased in RhoA inhibited or RhoA KD oocytes, which indicated that RhoA also regulated MAPK phosphorylation for spindle formation. (3) Porcine Embryo development was also suppressed by inhibiting RhoA activity. Two nucl...
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kif20a regulates porcine oocyte maturation and Early Embryo development
PLOS ONE, 2014Co-Authors: Yu Zhang, Jun Liu, Xu Peng, Chengcheng Zhu, Jun Han, Jia Luo, Rong RuiAbstract:KIF20A (Kinesin-like family member 20A), also called mitotic kinesin-like proteins 2 (MKLP2), is a mammalian mitotic kinesin-like motor protein of the Kinesin superfamily proteins (KIFs), which was originally involved in Golgi apparatus dynamics and thought to essential for cell cycle regulation during successful cytokinesis. In the present study, we investigated whether KIF20A has roles on porcine oocyte meiotic maturation and subsequent Early Embryo development. By immunofluorescence staining, KIF20A was found to exhibit a dynamic localization pattern during meiosis. KIF20A was restricted to centromeres after germinal vesicle breakdown (GVBD), transferred to the midbody at telophase I (TI), and again associated with centromeres at metaphase II (MII). Inhibition of endogenous KIF20A via a specific inhibitor, Paprotrain, resulted in failure of polar body extrusion. Further cell cycle analysis showed that the percentage of oocytes that arrested at Early metaphase I (MI) stage increased after KIF20A activity inhibition; however, the proportion of oocytes at anaphase/telophase I (ATI) and MII stages decreased significantly. Our results also showed that KIF20A inhibition did not affect spindle morphology. In addition, KIF20A was localized at the nucleus of Early Embryos, and KIF20A inhibition resulted in failure of Early parthenogenetic Embryo development. These results demonstrated that KIF20A is critical for porcine oocyte meiotic maturation and subsequent Early Embryo development.
