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oocyte meiosis

Xin-Jun Wu, Peter Thomas, Yong Zhu
Recent investigations suggest progestin receptor membrane component 1 (PGRMC1) associates with and transports a wide range of molecules such as heme, cytochromes P450, steroids with 21 carbons, membrane progestin receptor alpha (mPRα/Paqr7), epidermal growth factor receptor (EGFR), and insulin receptor. It is difficult to discriminate the true functions of PGRMC1 from the functions of its associated molecules using biochemical and pharmacological approaches. To determine the physiological function(s) of PGRMC1, we generated global knockouts for pgrmc1 ( pgrmc1 -/- ) in zebrafish...
2018: Frontiers in Endocrinology
Jeong-Woo Choi, Wenjun Zhou, Zheng-Wen Nie, Ying-Jie Niu, Kyung-Tae Shin, Xiang-Shun Cui
Spindlin 1 (SPIN1), which contains Tudor-like domains, regulates maternal transcripts via interaction with a messenger RNA (mRNA)-binding protein. SPIN1 is involved in tumorigenesis in somatic cells and is highly expressed in cancer cells. Nevertheless, the role of SPIN1 in porcine oocyte maturation remains totally unknown. To explore the function of SPIN1 in porcine oocyte maturation, knockdown, and overexpression techniques were used. SPIN1 mRNA was identified in maternal stages ranging from GV to MII. SPIN1 was localized in the cytoplasm and to chromosomes during meiosis...
October 14, 2018: Journal of Cellular Physiology
Bong-Seok Song, Pil-Soo Jeong, Jong-Hee Lee, Moon-Hyung Lee, Hae-Jun Yang, Seon-A Choi, Hwal-Yong Lee, Seung-Bin Yoon, Young-Ho Park, Kang-Jin Jeong, Young-Hyun Kim, Yeung Bae Jin, Ji-Su Kim, Bo-Woong Sim, Jae-Won Huh, Sang-Rae Lee, Deog-Bon Koo, Kyu-Tae Chang, Sun-Uk Kim
Successful production of transgenic pigs requires oocytes with a high developmental competence. However, cumulus-oocyte complexes (COCs) obtained from antral follicles have a heterogeneous morphology. COCs can be classified into one of two classes: class I, with five or more layers of cumulus cells; and class II, with one or two layers of cumulus cells. Activator [e.g., epidermal growth factor (EGF)] or inhibitors (e.g., wortmannin and U0126) are added to modulate kinases in oocytes during meiosis. In the present study, we investigated the effects of kinase modulation on nuclear and cytoplasmic maturation in COCs...
2018: PloS One
Bettina P Mihalas, Elizabeth G Bromfield, Jessie M Sutherland, Geoffry N De Iuliis, Eileen A McLaughlin, R John Aitken, Brett Nixon
An increase in oxidative protein damage is a leading contributor to age-associated decline in oocyte quality. By removing such damaged proteins, the proteasome plays an essential role in maintaining the fidelity of oocyte meiosis. In this study, we established that decreased proteasome activity in naturally aged, germinal vesicle (GV) mouse oocytes positively correlates with increased protein modification by the lipid aldehyde 4-hydroxynonenal (4-HNE). Further, attenuation of proteasome activity in GV oocytes of young animals was accompanied by an increase in 4-HNE-modified proteins, including α-tubulin, thereby contributing to a reduction in tubulin polymerization, microtubule stability, and integrity of oocyte meiosis...
October 10, 2018: Journal of Biological Chemistry
Luigia Santella, Nunzia Limatola, Filip Vasilev, Jong Tai Chun
Starfish and sea urchin are excellent models to study the mechanisms that regulate oocyte maturation and egg activation. Hormonal stimulation of starfish oocytes and their following interaction with spermatozoa induce rapid changes of F-actin and Ca2+ increases which are prerequisites for normal fertilization and development. Fully grown oocytes isolated from the gonads of starfish contain a large nucleus (∼60-70 μm) (termed germinal vesicle, GV), which is arrested at the first prophase of meiosis. If inseminated, these immature oocytes are penetrated by additional spermatozoa...
October 6, 2018: Biochemical and Biophysical Research Communications
Zhen-Nan Pan, Yujie Lu, Feng Tang, Meng-Hao Pan, Xiang Wan, Mei Lan, Yu Zhang, Shao-Chen Sun
Actin filaments are widely involved in multiple cellular processes in oocyte meiosis, such as spindle migration and polar body extrusion. The actin nucleators like Arp2/3 complex and formins are the most recognized molecules for actin assembly in oocytes. In the present study, we report that the vesicle trafficking factor, RAB8A GTPase, is a new regulator critical for actin assembly in meiosis. Our results showed that RAB8A was localized at both the spindle periphery and cortex in mouse oocytes, which was similar to the localization patterns of actin filaments...
October 3, 2018: Biology of Reproduction
Li Zhu, Suresh K Kandasamy, Susan E Liao, Ryuya Fukunaga
Post-transcriptional regulation of gene expression plays an essential role during oocyte maturation. Here we report that Drosophila MARF1 (Meiosis Regulator And mRNA Stability Factor 1), which consists of one RNA-recognition motif and six tandem LOTUS domains with unknown molecular function, is essential for oocyte maturation. When tethered to a reporter mRNA, MARF1 post-transcriptionally silences reporter expression by shortening reporter mRNA poly-A tail length and thereby reducing reporter protein level...
October 2, 2018: Nature Communications
Zhe Wei, Jessica Greaney, Chenxi Zhou, Hayden A Homer
Female meiotic divisions are extremely asymmetric, producing large oocytes and small polar bodies (PBs). In mouse oocytes, the spindle relocates to the cortex before anaphase of meiosis I (MI). It is presumed that by displacing the future midzone, pre-anaphase spindle repositioning alone ensures asymmetry. But how subsequent anaphase events might contribute to asymmetric PB extrusion (PBE) is unknown. Here, we find that inactivation of cyclin-dependent kinase 1 (Cdk1) induces anaphase and simultaneously triggers cytoplasmic formin-mediated F-actin polymerisation that propels the spindle into the cortex causing it to protrude while anaphase progresses...
October 2, 2018: Nature Communications
Xin Tang, Yicong Xu, Lin Lu, Yang Jiao, Jianjun Liu, Linlin Wang, Hongbo Zhao
Purpose: Cervical cancer (CC) is one of the most common malignant tumors among women. The present study aimed at integrating two expression profile datasets to identify critical genes and potential drugs in CC. Materials and methods: Expression profiles, GSE7803 and GSE9750, were integrated using bioinformatics methods, including differentially expressed genes analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and protein-protein interaction (PPI) network construction...
2018: Cancer Management and Research
Esra Gozde Kosebent, Fatma Uysal, Saffet Ozturk
Telomeres are repetitive non-coding DNA sequences located at the end of chromosomes in eukaryotic cells. Their most important function is to protect chromosome ends from being recognized as DNA damage. They are also implicated in meiosis and synapse formation. The length of telomeres inevitably shortens at the end of each round of DNA replication and, also, as a consequence of the exposure to oxidative stress and/or genotoxic agents. The enzyme telomerase contributes to telomere lengthening. It has been reported that telomerase is exclusively expressed in germ cells, granulosa cells, early embryos, stem cells, and various types of cancerous cells...
September 28, 2018: Journal of Reproduction and Development
Huanyu Qiao, H B D Prasada Rao, Yan Yun, Sumit Sandhu, Jared H Fong, Manali Sapre, Michael Nguyen, Addy Tham, Benjamin W Van, Tiffany Y H Chng, Amy Lee, Neil Hunter
Oocyte quality control culls eggs with defects in meiosis. In mouse, oocyte death can be triggered by defects in chromosome synapsis and recombination, which involve repair of DNA double-strand breaks (DSBs) between homologous chromosomes. We show that RNF212, a SUMO ligase required for crossing over, also mediates oocyte quality control. Both physiological apoptosis and wholesale oocyte elimination in meiotic mutants require RNF212. RNF212 sensitizes oocytes to DSB-induced apoptosis within a narrow window as chromosomes desynapse and cells transition into quiescence...
September 12, 2018: Molecular Cell
Yongdong Peng, Li Chang, Yaqi Wang, Ruining Wang, Lulu Hu, Ziya Zhao, Liying Geng, Zhengzhu Liu, Yuanfang Gong, Jingshi Li, Xianglong Li, Chuansheng Zhang
Bashang long-tail chickens are an indigenous breed with dual purpose in China (meat and eggs) but have low egg laying performance. To improve the low egg laying performance, a genome-wide analysis of mRNAs and long noncoding RNAs (lncRNAs) from Bashang long-tail chickens and Hy-Line brown layers was performed. A total of 16,354 mRNAs and 8691 lncRNAs were obtained from ovarian follicles. Between the breeds, 160 mRNAs and 550 lncRNAs were found to be significantly differentially expressed. Integrated network analysis suggested some differentially expressed genes were involved in ovarian follicular development through oocyte meiosis, progesterone-mediated oocyte maturation, and the cell cycle...
September 27, 2018: Genomics
Tobias L Lenz, Nina Hafer, Irene E Samonte, Sarah E Yeates, Manfred Milinski
Females choose specific mates in order to produce fitter offspring. However, several factors interfere with females' control over fertilization of their eggs, including sneaker males and phenotypically unpredictable allele segregation during meiosis. Mate choice at the individual level thus provides only a poor approximation for obtaining the best genetic match. Consequently, postcopulatory sperm selection by female oocytes has been proposed as a mechanism to achieve complementary combinations of parental haplotypes...
September 24, 2018: Evolution; International Journal of Organic Evolution
So-Youn Kim, Takeshi Kurita
The immature oocytes within primordial follicles are arrested at Prophase I of meiosis and remain dormant until awakened by an increase in intracellular levels of phosphatidylinositol (3,4,5)-trisphosphate (PIP3). Oocyte PIP3 level is determined by the balance between the activity of phosphoinositide 3-kinase (PI3K) and phosphatase and tensin homologue (PTEN). When this balance favours PI3K, PIP3 levels elevate and trigger the cascade of PI3K/protein kinase B (AKT)/the mammalian target of rapamycin (mTOR) pathway, leading to activation of primordial follicles...
June 2018: European Medical Journal. Reproductive Health
Poulomi Nath, Sudipta Maitra
Nitric oxide (NO, nitrogen monoxide), a short-lived, free radical carrying an unpaired electron, is one of the smallest molecules synthesized in the biological system. In addition to its role in angiogenesis, neuronal function and inflammatory response, NO has wide-spread significance in regulation of ovarian function in vertebrates. Based on tissue-specific expression, three different nitric oxide synthase (NOS) isoforms, neuronal (nNOS) or NOS1, inducible (iNOS) or NOS2 and endothelial (eNOS) or NOS3 have been identified...
September 19, 2018: General and Comparative Endocrinology
Anirban Ray, Tiffany Rene Oliver, Pinku Halder, Upamanyu Pal, Sumantra Sarkar, Supratim Dutta, Sujay Ghosh
Consanguineous marriage was examined as a risk factor for Down syndrome birth. We genotyped Down syndrome family trios using short tandem repeat markers on 21q-to interpret the parental and meiotic stage of origin of errors as well as to record recombination profile along long arm of chromosome 21. We then compared nonconsanguineous (N = 811) group with-the consanguineous (N =157) marriages. We report for the first time that consanguineous marriage is associated with an increased risk for nondisjunction of chromosome 21 in oocytes-during the second meiotic division...
September 21, 2018: American Journal of Medical Genetics. Part A
Susanne Huber, Martin Fieder
There is an ongoing debate why a trait like human menopause should have evolved. Adaptive explanations explain menopause with fitness benefits of ceasing reproduction, whereas non-adaptive explanations view it as an epiphenomenon. Here we present data in support of non-adaptive explanations of menopause suggesting a maximum shelf-life of oocytes. By analyzing the association between lifespan and age at reproductive senescence across 49 mammal species, we find that the positive association levels off in long lived species, indicating that the age at reproductive senescence has an upper limit...
September 20, 2018: Scientific Reports
Marketa Koncicka, Anna Tetkova, Denisa Jansova, Edgar Del Llano, Lenka Gahurova, Jana Kracmarova, Sarka Prokesova, Tomas Masek, Martin Pospisek, Alexander W Bruce, Michal Kubelka, Andrej Susor
The rate of chromosome segregation errors that emerge during meiosis I in the mammalian female germ line are known to increase with maternal age; however, little is known about the underlying molecular mechanism. The objective of this study was to analyze meiotic progression of mouse oocytes in relation to maternal age. Using the mouse as a model system, we analyzed the timing of nuclear envelope breakdown and the morphology of the nuclear lamina of oocytes obtained from young (2 months old) and aged females (12 months old)...
September 19, 2018: International Journal of Molecular Sciences
Zhangying Jennie Chen, Kaitlin M Hitt, Hyebin H Roh, Cynthia Salas, Jessica Hornick, Francesca E Duncan
Mature eggs ovulated from the ovary are arrested in metaphase II and are characterized by a prominent meiotic spindle. The spindle is the cellular machinery responsible for properly segregating chromosomes in both mitosis and meiosis. Microtubules are the main components of the spindle and are composed of heterodimers of α- and β-tubulin organized in protofilaments. Post-translational modification-such as acetylation, phosphorylation, and glycylation-of tubulin regulates its function. Acetylation adds an acetyl group to lysine-40 residues on α-heterodimers, promoting spindle stability through regulating microtubule architecture and integrity...
September 14, 2018: Molecular Reproduction and Development
Stefanie Redemann, Ina Lantzsch, Norbert Lindow, Steffen Prohaska, Martin Srayko, Thomas Müller-Reichert
In oocytes of many organisms, meiotic spindles form in the absence of centrosomes [1-5]. Such female meiotic spindles have a pointed appearance in metaphase with microtubules focused at acentrosomal spindle poles. At anaphase, the microtubules of acentrosomal spindles then transition to an inter-chromosomal array, while the spindle poles disappear. This transition is currently not understood. Previous studies have focused on this inter-chromosomal microtubule array and proposed a pushing model to drive chromosome segregation [6, 7]...
September 24, 2018: Current Biology: CB
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