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oocyte meiosis

Dejun Xu, Lin Wu, Xiaohan Jiang, Li Yang, Jianyong Cheng, Huali Chen, Rongmao Hua, Guoxia Geng, Lulu Yang, Qingwang Li
SIRT2, a member of the sirtuin family, has been recently shown to exert important effects on mitosis and/or metabolism. However, its roles in oocyte maturation have not been fully clarified. In this study, SIRT2, located in the cytoplasm and nucleus, was found in abundance in the meiotic stage, and its expression gradually decreased until the blastocyst stage. Treatment with SIRT2 inhibitors resulted in the prevention of oocyte maturation and the formation of poor-quality oocytes. By performing confocal scanning and quantitative analysis, the results showed that SIRT2 inhibition induced prominent defects in spindle/chromosome morphology, and led to the hyperacetylation of α-tubulin and H4K16...
March 18, 2019: International Journal of Molecular Sciences
Rodrigo G Barros, Paula F Lima, Ana Caroline S Soares, Lorena Sanches, Christopher A Price, José Buratini
PURPOSE: We first assessed regulation of FGF2 expression in cumulus cells by FSH and oocyte-secreted factors during in vitro maturation (IVM). Then, we tested the hypothesis that FGF2 regulates meiotic progression, cumulus expansion, and apoptosis in cumulus-oocyte complexes (COC) undergoing IVM. METHODS: In vitro maturation of bovine COC was utilized as a model to assess regulation of FGF2 expression by FSH and oocyte-secreted factors (via microsurgical removal of the oocyte), as well as effects of graded doses of FGF2 on meiotic progression, degree of cumulus expansion, dissociation of cumulus cells, and cumulus cells apoptosis...
March 18, 2019: Journal of Assisted Reproduction and Genetics
Zubing Cao, Tengteng Xu, Xu Tong, Dandan Zhang, Chengxue Liu, Yiqing Wang, Di Gao, Lei Luo, Ling Zhang, Yunsheng Li, Yunhai Zhang
HASPIN kinase-catalyzed phosphorylation of histone H3 on threonine 3 (H3T3p) directs the activity and localization of chromosomal passenger complex (CPC) and spindle assembly checkpoint (SAC) to regulate chromosome condensation and segregation in both mitosis and meiosis. However, the function of HASPIN kinase in the meiotic maturation of porcine oocytes is not yet known. Here, we found that HASPIN mRNA is constantly expressed in porcine oocyte maturation and subsequent early embryo development. H3T3p is highly enriched on chromosomes at germinal vesicle breakdown (GVBD) stage and thereafter maintains a low level in progression through metaphase I (MI) to metaphase II (MII)...
March 1, 2019: Reproduction: the Official Journal of the Society for the Study of Fertility
Hanna Achache, Lévana Laurent, Yaël Hecker-Mimoun, Hasan Ishtayeh, Yisrael Rappaport, Eitan Kroizer, Monica P Colaiácovo, Yonatan B Tzur
During meiosis, a series of evolutionarily conserved events allow for reductional chromosome division, which is required for sexual reproduction. Although individual meiotic processes have been extensively studied, we currently know far less about how meiosis is regulated and coordinated. In the C. elegans gonad, MAPK signalling drives oogenesis while undergoing spatial activation and deactivation waves. However, it is currently unclear how MAPK activation is governed and how it facilitates the progression of oogenesis...
March 13, 2019: Genetics
Hieu Nguyen, W Steven Ward, Nicholas James
The Origin Replication Complex (ORC), which is a multi-subunit protein complex composed of six proteins ORC1-6, is essential for initiating licensing at DNA replication origins. We have previously reported that ORC4 has an alternative function wherein it forms a cage surrounding the extruded chromatin in female meiosis and is required for polar body extrusion (PBE). As this is a highly unexpected finding for protein that normally binds DNA, we tested whether ORC4 can actually form larger, higher order structures, which would be necessary to form a cage-like structure...
March 13, 2019: Methods and Applications in Fluorescence
Yang Xiang, Chun Wu, Jiang Wu, Weili Quan, Chao Cheng, Jian Zhou, Li Chen, Lixin Xiang, Fengjie Li, Kebin Zhang, Qian Ran, Yi Zhang, Zhongjun Li
BACKGROUND: Bone marrow stromal cells (BMSCs) are extensively used in regeneration therapy and cytology experiments simulate how BMSCs respond to radiation. Due to the small number and the heterogeneity of primary isolated BMSCs, extensive in vitro expansion is usually required before application, which affects the cellular characteristics and gene expression of BMSCs. However, whether the radiation response of BMSCs changes during in vitro expansion is unclear. METHODS: In this study, BMSCs were passaged in vitro and irradiated at passage 6 (P6) and passage 10 (P10)...
March 8, 2019: Stem Cell Research & Therapy
Monika Fluks, Katarzyna Szczepanska, Takao Ishikawa, Anna Maria Ajduk
In fully grown ovarian follicles both transcriptionally active (NSN) and inactive (SN) oocytes are present. NSN oocytes have been shown to display lower developmental potential. It is possible that oocytes that have not completed transcription before meiosis resumption accumulate less RNA and proteins required for their further development, including those responsible for regulation of Ca2+ homeostasis. Oscillations of the cytoplasmic concentration of free Ca2+ ions ([Ca2+]i) are triggered in oocytes by a fertilizing spermatozoon and are crucial for inducing and regulating further embryonic development...
February 1, 2019: Reproduction: the Official Journal of the Society for the Study of Fertility
Zhenzhen Lu, Chengtu Zhang, Chengquan Han, Quanli An, Yuyao Cheng, Yongzhong Chen, Ru Meng, Yong Zhang, Jianmin Su
Bis(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer in polyvinyl chloride (PVC) plastics. Humans and animals are widely and continuously exposed to DEHP, especially with respect to diet, which is associated with reproductive diseases. Nevertheless, the effects and underlying mechanisms of DEHP exposure on oocytes in vivo remain ambiguous. In this study, we found that oral administration of DEHP (40 μg/kg body weight per day for 14 days) markedly reduced the maturation and fertilization of oocytes in vivo...
March 12, 2019: Journal of Agricultural and Food Chemistry
Yuewen Qi, Haowen Qi, Zeyuan Liu, Peiyuan He, Bingqing Li
Colorectal cancer (CRC) is the third most prevalent cancer in the world. Although great progress has been made, the specific molecular mechanism remains unclear. This study aimed to explore the differentially expressed genes (DEGs) and underlying mechanisms of CRC using bioinformatics analysis. In this study, we identified a total of 1353 DEGs in the database of GSE113513, including 715 up- and 638 downregulated genes. Gene ontology analysis results showed that upregulated DEGs were significantly enriched in cell division, cell proliferation, and DNA replication...
February 27, 2019: Journal of Computational Biology: a Journal of Computational Molecular Cell Biology
Xin Yu Yang, Zhen Wei Jia
The surge of luteinizing hormone (LH) in preovulatory ovarian follicles triggers the resumption of meiosis in oocytes and induces the proliferation of surrounding cumulus granulosa cells. It is believed that LH receptors are expressed in the mural granulosa cells, but not the oocytes and the surrounding cumulus cells, suggesting that the LH signaling is mediated by factors produced by the granulosa cells. However, the mechanism underlying oocyte maturation induced by LH before ovulation has been controversial...
February 20, 2019: Yi Chuan, Hereditas
Zhen-Zhen Jia, Jing-Wen Zhang, Di Zhou, Ding-Qi Xu, Xi-Zeng Feng
Pyrethroid insecticides are commonly used as insecticides and considered to be less toxic to mammals, but may still impair the reproduction of animals and humans. The aim of this research was to evaluate the tendency of deltamethrin induced oxidative stress and its effects on meiosis, apoptosis and autophagy of mouse oocytes in vitro maturation after deltamethrin exposure. Especially, the maturation rate of oocytes decreased significantly after 14 h exposure of deltamethrin in concentration-dependent manners, which was manifested as abnormal spindle morphology and DNA double strand breaks...
February 15, 2019: Chemosphere
Luhan T Zhou, Raquel Romar, Mary Ellen Pavone, Cristina Soriano-Úbeda, John Zhang, Chad Slawson, Francesca E Duncan
Meiotic maturation and fertilization are metabolically demanding processes, and thus the mammalian oocyte is highly susceptible to changes in nutrient availability. O-GlcNAcylation-the addition of a single sugar residue (O-linked β-N-acetylglucosamine) on proteins-is a posttranslational modification that acts as a cellular nutrient sensor and likely modulates the function of oocyte proteins. O-GlcNAcylation is mediated by O-GlcNAc transferase (OGT), which adds O-GlcNAc onto proteins, and O-GlcNAcase (OGA), which removes it...
February 21, 2019: Molecular Reproduction and Development
Kara Turner, Colleen Lynch, Hannah Rouse, Vimal Vasu, Darren K Griffin
Reproductive ageing in women, particularly after the age of 35, is associated with an exponential increase in the proportion of chromosomally abnormal oocytes produced. Several hypotheses have attempted to explain this observation, including the 'limited oocyte pool' hypothesis and the 'two-hit' hypothesis, the latter explaining that a depletion in oocyte quality with age results from the multiple opportune stages for errors to occur in meiosis. Recently however, the telomere theory of reproductive ageing in women has been proposed...
February 16, 2019: Cells
Sandra Soto-Heras, Maria-Teresa Paramio, Jeremy G Thompson
In vitro embryo production depends on oocyte competence, which is acquired during folliculogenesis, involving cytoplasmic and nuclear processes. In vitro maturation (IVM) induces spontaneous resumption of meiosis, preventing full competence acquisition. The incorporation of a pre-IVM phase with supplementation with C-type natriuretic peptide (CNP) and 3-Isobutyl-1-methylxanthine (IBMX) was used with the aim of improving developmental competence of cattle oocytes. In a preliminary experiment, COCs were cultured with increasing CNP concentrations and nuclear stage assessment was performed...
March 2019: Animal Reproduction Science
Robert O Gilbert
Diseases of postpartum dairy cows impair reproductive processes, resulting in prolonged anestrus, reduced conception, and increased pregnancy attrition, regardless of whether the initial disease precedes insemination (even by many weeks), occurs close to insemination, or follows fertilization. Bacteria and their products activate pattern recognition receptors that respond to pathogen-associated molecular patterns (PAMP). These receptors include toll-like receptors (TLR), nucleotide-binding oligomerization domain (NOD)-like receptors and others, and their activation culminates in upregulation of proinflammatory cytokines such as IL-1β, IL-18, and tumor necrosis factor-α...
February 13, 2019: Journal of Dairy Science
Yufei Li, Leyun Wang, Linlin Zhang, Zhengquan He, Guihai Feng, Hao Sun, Jiaqiang Wang, Zhikun Li, Chao Liu, Jiabao Han, Junjie Mao, Pengcheng Li, Xuewei Yuan, Liyuan Jiang, Ying Zhang, Qi Zhou, Wei Li
Meiosis with a single round of DNA replication and two successive rounds of chromosome segregation requires specific cyclins associated with cyclin-dependent kinases (CDKs) to ensure its fidelity. But how cyclins control the distinctive meiosis is still largely unknown. In this study, we explored the role of cyclin B3 in female meiosis by generating Ccnb3 mutant mice via CRISPR/Cas9. Ccnb3 mutant oocytes characteristically arrested at metaphase I (MetI) with normal spindle assembly and lacked enough anaphase-promoting complex/cyclosome (APC/C) activity, which is spindle assembly checkpoint (SAC) independent, to initiate anaphase I (AnaI)...
February 15, 2019: Journal of Cell Biology
Nara Shin, Luciann Cuenca, Rajendiran Karthikraj, Kurunthachalam Kannan, Monica P Colaiácovo
Chemicals that are highly prevalent in our environment, such as phthalates and pesticides, have been linked to problems associated with reproductive health. However, rapid assessment of their impact on reproductive health and understanding how they cause such deleterious effects, remain challenging due to their fast-growing numbers and the limitations of various current toxicity assessment model systems. Here, we performed a high-throughput screen in C. elegans to identify chemicals inducing aneuploidy as a result of impaired germline function...
February 2019: PLoS Genetics
Islam M Saadeldin, Ayman Abdel-Aziz Swelum, Mona Elsafadi, Amer Mahmood, Syed Hilal Yaqoob, Musaad Alfayez, Abdullah N Alowaimer
All-trans retinoic acid (RA) is a metabolite of vitamin A and has pleiotropic actions on many different biological processes, including cell growth and differentiation, and is involved in different aspects of fertility and developmental biology. In the current study, we investigated the effects of RA on camel (Camelus dromedarius) cumulus-oocyte complex in vitro maturation (IVM). IVM medium was supplemented with 0, 10, 20, and 40 µM RA. Application of 20 µM RA significantly reduced the proportion of degenerated oocytes and significantly improved oocyte meiosis and first polar body extrusion compared to the control and other experimental groups...
February 14, 2019: Journal of Reproduction and Development
Ahmed Gad, Lucie Nemcova, Matej Murin, Jiri Kanka, Jozef Laurincik, Michal Benc, Lazo Pendovski, Radek Prochazka
Oocyte developmental competence is acquired during folliculogenesis and regulated by complex molecular mechanisms. Several molecules are involved in these mechanisms, including microRNAs (miRNAs) that are essential for oocyte-specific processes throughout the development. The objective of this study was to identify the expression profile of miRNAs in porcine oocytes derived from follicles of different sizes using RNA deep sequencing. Oocytes were aspirated from large (LO; 3-6 mm) or small (SO; 1.5-1.9 mm) follicles and tested for developmental competence and chromatin configurations...
February 13, 2019: Molecular Reproduction and Development
Mark D Levasseur, Christopher Thomas, Owen R Davies, Jonathan M G Higgins, Suzanne Madgwick
Successful mitosis requires that cyclin B1:CDK1 kinase activity remains high until chromosomes are correctly aligned on the mitotic spindle. It has therefore been unclear why, in mammalian oocyte meiosis, cyclin B1 destruction begins before chromosome alignment is complete. Here, we resolve this paradox and show that mouse oocytes exploit an imbalance in the ratio of cyclin B1 to CDK1 to control CDK1 activity; early cyclin B1 destruction reflects the loss of an excess of non-CDK1-bound cyclin B1 in late prometaphase, while CDK1-bound cyclin B1 is destroyed only during metaphase...
March 11, 2019: Developmental Cell
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