scholarly journals Regulation of mitochondrial DNA accumulation during oocyte growth and meiotic maturation in the mouse

Reproduction ◽  
2012 ◽  
Vol 144 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Enas Mahrous ◽  
Qin Yang ◽  
Hugh J Clarke
Keyword(s):  
Granulosa Cells ◽  
Oocyte Quality ◽  
Meiotic Maturation ◽  
Mt Dna ◽  
Oocyte Growth ◽  
Α Subunit ◽  
Insufficient Amount ◽  
Mtdna Replication ◽  
Replication Factors

Oocytes accumulate an enormous quantity of mitochondrial (mt) DNA, and an insufficient amount of mtDNA may underlie some cases of poor oocyte quality leading to infertility. Little is known, however, about the mechanisms that govern the timing and regulation of mtDNA accumulation during oogenesis. We report, through analysis of the mtDNA content of individual oocytes of the mouse, that mtDNA accumulates steadily during oocyte growth to reach a value of ∼175 000 copies per cell. MtDNA content ceases to increase once oocytes reach full size and remains unchanged during meiotic maturation. To test whether mtDNA accumulation depends on oocyte growth, we inhibited growth in vitro in two ways – by exposing complexes comprising partially grown oocytes enclosed by granulosa cells to a chemical inhibitor of the phosphatidylinositol-3-kinase signaling pathway and by removing the surrounding granulosa cells from partially grown oocytes. Under both conditions, the oocytes fail to grow, but mtDNA accumulation is unaffected, indicating that the two processes can be mechanistically uncoupled. Quantitative analysis of the mRNAs encoding proteins required for mtDNA replication revealed that Polg (Polga) (polymerase-γ, α-subunit), Polg2 (Polgb), and Tfam (transcription factor A, mitochondrial) increase during oocyte growth but then decrease after fully grown oocytes become transcriptionally silent as indicated by the non-surrounded nucleolus-to-surrounded nucleolus transition. Thus, there is a correlation between the decline in the quantity of mRNAs encoding mtDNA replication factors in fully grown oocytes and the arrest of mtDNA accumulation in these cells, suggesting that the two events may be causally linked.

scholarly journals The Function of Cumulus Cells in Oocyte Growth and Maturation and in Subsequent Ovulation and Fertilization

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2292
Author(s):  
Bongkoch Turathum ◽  
Er-Meng Gao ◽  
Ri-Cheng Chian
Keyword(s):  
Granulosa Cells ◽  
Follicular Development ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Early Embryo ◽  
Developmental Competence ◽  
Meiotic Maturation ◽  
Supporting Cells ◽  
Oocyte Growth ◽  
Oocyte Meiotic Maturation

Cumulus cells (CCs) originating from undifferentiated granulosa cells (GCs) differentiate in mural granulosa cells (MGCs) and CCs during antrum formation in the follicle by the distribution of location. CCs are supporting cells of the oocyte that protect the oocyte from the microenvironment, which helps oocyte growth and maturation in the follicles. Bi-directional communications between an oocyte and CCs are necessary for the oocyte for the acquisition of maturation and early embryonic developmental competence following fertilization. Follicle-stimulation hormone (FSH) and luteinizing hormone (LH) surges lead to the synthesis of an extracellular matrix in CCs, and CCs undergo expansion to assist meiotic resumption of the oocyte. The function of CCs is involved in the completion of oocyte meiotic maturation and ovulation, fertilization, and subsequent early embryo development. Therefore, understanding the function of CCs during follicular development may be helpful for predicting oocyte quality and subsequent embryonic development competence, as well as pregnancy outcomes in the field of reproductive medicine and assisted reproductive technology (ART) for infertility treatment.

Differential cytolocalization of prosomes in axolotl during oogenesis and meiotic maturation

1988 ◽  
Vol 90 (4) ◽  
pp. 543-553 ◽  
Author(s):  
J. Gautier ◽  
J.K. Pal ◽  
M.F. Grossi de Sa ◽  
J.C. Beetschen ◽  
K. Scherrer
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Germinal Vesicle ◽  
Immunoblot Analysis ◽  
Ambystoma Mexicanum ◽  
Meiotic Maturation ◽  
Crescent Formation ◽  
Oocyte Growth ◽  
Oocyte Cytoplasm

The prosomes, a novel type of small RNA-protein complex previously characterized in avian and mammalian cells, were isolated from axolotl (Ambystoma mexicanum) oocytes and identified by sedimentation analysis and protein composition. The prosomal nature of these particles was further ascertained by immunoblot analysis with anti-duck prosome monoclonal antibodies. By in vitro [35S]methionine labelling, de novo synthesis of prosomal proteins could be detected neither during oogenesis nor meiotic maturation. The results obtained by both indirect immunofluorescence and immunoblot analyses demonstrated a dramatic change in the localization of prosomal antigens during oocyte development. They were initially detected in the oocyte cytoplasm, during oocyte growth. At the end of vitellogenesis (stages V-VI), they entered the nucleus (germinal vesicle) and were accumulated there to the highest concentration. During oocyte maturation, after nuclear envelope breakdown, prosomal antigens were found to be localized again in the cytoplasm, until fertilization. No specific localization of prosomal antigens in mature oocytes, unfertilized and fertilized eggs was observed within the oocyte cytoplasm in relation to the cytoplasmic rearrangements leading to grey crescent formation.

scholarly journals Inhibition of oocyte growth factors in vivo modulates ovarian folliculogenesis in neonatal and immature mice

Reproduction ◽  
2010 ◽  
Vol 139 (3) ◽  
pp. 587-598 ◽  
Author(s):  
Samu Myllymaa ◽  
Arja Pasternack ◽  
David G Mottershead ◽  
Matti Poutanen ◽  
Minna M Pulkki ◽  
...  
Keyword(s):  
Growth Factors ◽  
Granulosa Cells ◽  
Microscopic Analysis ◽  
Corpora Lutea ◽  
Electron Microscopic ◽  
Oocyte Growth ◽  
Long Term Study ◽  
Ovarian Folliculogenesis

Growth differentiation factor-9 (GDF9) and bone morphogenetic protein-15 (BMP15) are among the key regulators transmitting the signaling between the oocyte and the surrounding granulosa cells. Previously, it has been shown that a recombinant BMP type II receptor ectodomain–Fc fusion protein (BMPR2ecd–Fc) is able to inhibit the actions of GDF9 and BMP15 in vitro. Here, we have produced bioactive BMPR2ecd–Fc, which was injected i.p. into neonatal mice. Early folliculogenesis was first studied by injecting mice five times with various doses of BMPR2ecd–Fc during the postnatal days 4–12. Folliculogenesis was affected dose dependently, as evidenced by a decreased mitogenesis of granulosa cells of the growing follicles. Furthermore, we also noticed a decrease in the number of secondary and tertiary follicles as well as an increase in the oocyte size. Electron microscopic analysis revealed that the ultrastructure of the granulosa cells of the primary follicles was not affected by the BMPR2ecd–Fc treatment. A second study was conducted to investigate whether a longer treatment with 12 injections during postnatal days 4–28 would inhibit folliculogenesis. Similar effects were observed in the two studies on the early follicular developmental stages. However, in the long-term study, later stages of folliculogenesis were not blocked but rather increased numbers of antral follicles, preovulatory follicles, and corpora lutea were found. We conclude that BMPR2ecd–Fc is a potent modulator of ovarian folliculogenesis in vivo, and thus, is a valuable tool for studying the physiology and downstream effects of oocyte-derived growth factors in vivo.

Addition of granulosa cell mass to the culture medium of oocytes derived from early antral follicles increases oocyte growth, ATP content, and acetylation of H4K12

Zygote ◽  
2016 ◽  
Vol 24 (6) ◽  
pp. 848-856 ◽  
Author(s):  
Miyako Sugiyama ◽  
Mei Sumiya ◽  
Koumei Shirasuna ◽  
Takehito Kuwayama ◽  
Hisataka Iwata
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Culture Medium ◽  
Cell Mass ◽  
Fertilization Rate ◽  
Atp Content ◽  
Oocyte Growth ◽  
Acetylation Level ◽  
Antral Follicles

SummaryThe main aim of the present study was to examine the hypothesis that an increase in the number of granulosa cells surrounding developing bovine oocytes results in both high ATP levels and an increase in the acetylation level of H4K12 in oocytes grown in vitro. Oocyte–granulosa cell complexes (OGCs) were collected from early antral follicles (EAFs, 0.4–0.7 mm in diameter), and individually cultured on 96-well plates with or without additional granulosa cell mass that had been prepared from other OGCs. After 16 days of culture, we examined: (i) the rate of antrum formation of the OGCs; (ii) the diameter, maturation, and fertilization rate of the oocytes; and (iii) the ATP content and acetylation level of H4K12 in the oocytes grown in vitro. Granulosa cell mass added to the culture medium contributed to the development of OGCs with a higher rate of antrum formation and oocyte growth. Furthermore, the addition of granulosa cells increased the ATP content and acetylation level of H4K12 in oocytes grown in vitro compared with those developed without addition of granulosa cells. In addition, there was a positive correlation between the ATP content in oocytes grown in vitro and the number of granulosa cells in the corresponding OGCs. The results suggest that granulosa cells play a role not only in the development of OGCs and the growth of oocytes, but also in the determination of ATP content and the acetylation of H4K12 in the oocytes developed in vitro.

scholarly journals Aspects of cytoplasmic maturation of bovine oocytes: Interplay between mapk, mRNA-cap binding complex and cytoplasmic mRNA metabolism in regulation of translation

2003 ◽  
Vol 19 (3-4) ◽  
pp. 1-8 ◽  
Author(s):  
Tatjana Smiljakovic ◽  
Melo Sterza ◽  
M. Kubelka ◽  
Z. Vohnikova ◽  
W. Tomek
Keyword(s):  
Binding Protein ◽  
Germinal Vesicle ◽  
Initiation Factor ◽  
Meiotic Maturation ◽  
Detailed Knowledge ◽  
Germinal Vesicle Breakdown ◽  
Oocyte Growth ◽  
Stage Of Development ◽  
Bovine Oocytes

Bovine oocytes are arrested in the germinal vesicle stage (GV stage)and mature spontaneously when they are removed from their follicles and transferred to a suitable culture medium. This process, known as meiotic maturation is characterized among others, by germinal vesicle breakdown followed by metaphase I (MI) stage and further development to metaphase II (MII), where they become arrested again. During GVBD to MI transition, the overall protein synthesis reaches the highest level and it rapidly declines in MII. We have previously shown that transcription completely declines during meiotic maturation. Therefore we suppose that gene expression is exclusively regulated on translational level at this stage of development. This means that mRNAs, which were stored in repressed form during oocyte growth, were actively translated during meiotic maturation. Therefore we have investigated specific regulators of translation, namely the eukaryotic initiation factor of translation eIF4E (cap binding protein) and a specific repressor of eIF4E function, the 4E-binding protein 4E-BP1. Furthermore, we have elucidated pathways, which lead to eIF4E and 4E-BP1 phosphorylation by using specific M-phase kinase inhibitors, and we compare these results with transcription and cytoplasmic polyadenylation events during the course of meiotic maturation. The detailed knowledge of such regulatory processes can help to improve in vitro bio-techniques and to estimate the risk of these techniques.

A co-culture system with preantral follicular granulosa cells in vitro induces meiotic maturation of immature oocytes

2011 ◽  
Vol 135 (5) ◽  
pp. 513-522 ◽  
Author(s):  
Zhanbiao Li ◽  
Pan Zhang ◽  
Zhipeng Zhang ◽  
Bo Pan ◽  
Huhe Chao ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Culture System ◽  
Meiotic Maturation ◽  
Immature Oocytes

scholarly journals Contrasting Effects of in Vitro Fertilization and Nuclear Transfer on the Expression of mtDNA Replication Factors

Genetics ◽  
2007 ◽  
Vol 176 (3) ◽  
pp. 1511-1526 ◽  
Author(s):  
Emma J. Bowles ◽  
Joon-Hee Lee ◽  
Ramiro Alberio ◽  
Rhiannon E. I. Lloyd ◽  
Dov Stekel ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Nuclear Transfer ◽  
Vitro Fertilization ◽  
Mtdna Replication ◽  
Replication Factors

Immunisation against inhibin enhances follicular development, oocyte maturation and superovulatory response in water buffaloes

2011 ◽  
Vol 23 (6) ◽  
pp. 788 ◽  
Author(s):  
D. R. Li ◽  
G. S. Qin ◽  
Y. M. Wei ◽  
F. H. Lu ◽  
Q. S. Huang ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Oocyte Quality ◽  
Control Group ◽  
High Group ◽  
Α Subunit ◽  
And Control

This study was carried out to test the feasibility of enhancing embryo production in vivo and in vitro by immunoneutralisation against inhibin or follistatin. In Experiment 1, multi-parity buffaloes were assigned into three groups: High group (n = 8), which received one primary (2 mg) and two booster (1 mg) vaccinations (28-day intervals) with a recombinant inhibin α subunit in 1 mL of white oil adjuvant; Low group (n = 8), which received half that dose; and Control group (n = 7), which received only adjuvant. Immunisation against inhibin stimulated development of ovarian follicles. Following superovulation and artificial insemination, inhibin-immunised buffaloes had more developing follicles than the Control buffaloes. The average number of embryos and unfertilised ova (4.5 ± 0.6, n = 6) in the High group was higher (P < 0.05) than in the Control group (2.8 ± 0.6, n = 5) and was intermediate (4.1 ± 0.7, n = 7) in the Low group. The pooled number of transferable embryos of the High and Low groups (3.2 ± 0.5, n = 13) was also higher (P < 0.05) than that (1.6 ± 0.7, n = 5) of the controls. The immunised groups also had higher plasma concentrations of activin, oestradiol and progesterone. In Experiment 2, the addition of anti-inhibin or anti-follistatin antibodies into buffalo oocyte IVM maturation medium significantly improved oocyte maturation and cleavage rates following parthenogenic activation. Treatment with anti-follistatin antibody also doubled the blastocyst yield from activated embryos. These results demonstrated that immunisation against inhibin stimulated follicular development, enhanced oocyte quality and maturation competence, yielded more and better embryos both in vivo and in vitro.

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