Influence of oocyte collection technique on initial chromatin configuration, meiotic competence, and male pronucleus formation after intracytoplasmic sperm injection (ICSI) of equine oocytes

2001 ◽  
Vol 60 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Maria Elena Dell'Aquila ◽  
Mary Masterson ◽  
Filippo Maritato ◽  
Katrin Hinrichs
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Male Pronucleus ◽  
Oocyte Collection ◽  
Chromatin Configuration ◽  
Meiotic Competence

scholarly journals Meiotic Competence of Equine Oocytes and Pronucleus Formation after Intracytoplasmic Sperm Injection (ICSI) as Related to Granulosa Cell Apoptosis1

2003 ◽  
Vol 68 (6) ◽  
pp. 2065-2072 ◽  
Author(s):  
Maria Elena Dell'Aquila ◽  
Maria Albrizio ◽  
Filippo Maritato ◽  
Paolo Minoia ◽  
Katrin Hinrichs
Keyword(s):  
Granulosa Cell ◽  
Intracytoplasmic Sperm Injection ◽  
Meiotic Competence

scholarly journals A prematuration approach to equine IVM: considering cumulus morphology, seasonality, follicle of origin, gap junction coupling and large-scale chromatin configuration in the germinal vesicle

2019 ◽  
Vol 31 (12) ◽  
pp. 1793 ◽  
Author(s):  
Valentina Lodde ◽  
Silvia Colleoni ◽  
Irene Tessaro ◽  
Davide Corbani ◽  
Giovanna Lazzari ◽  
...  
Keyword(s):  
Gap Junction ◽  
Embryo Development ◽  
Large Scale ◽  
Germinal Vesicle ◽  
Culture Conditions ◽  
Developmental Competence ◽  
Morphological Criteria ◽  
Chromatin Configuration ◽  
Follicle Size ◽  
Meiotic Competence

Several studies report that a two-step culture where mammalian oocytes are first kept under meiosis-arresting conditions (prematuration) followed by IVM is beneficial to embryo development. The most promising results were obtained by stratifying the oocyte population using morphological criteria and allocating them to different culture conditions to best meet their metabolic needs. In this study, horse oocytes were characterised to identify subpopulations that may benefit from prematuration. We investigated gap-junction (GJ) coupling, large-scale chromatin configuration and meiotic competence in compact and expanded cumulus–oocyte complexes (COCs) according to follicle size (<1, 1–2, >2cm) and season. Then we tested the effect of cilostamide-based prematuration in compact COCs collected from follicles <1 and 1–2cm in diameter on embryo development. Meiotic competence was not affected by prematuration, whereas COCs from follicles 1–2cm in diameter yielded embryos with a higher number of cells per blastocyst than oocytes that underwent direct IVM (P<0.01, unpaired Mann–Whitney test), suggesting improved developmental competence. Oocytes collected from follicles <1cm in diameter were not affected by prematuration. This study represents an extensive characterisation of the functional properties of immature horse oocytes and is the first report of the effects of cilostamide-based prematuration in horse oocyte IVM on embryo development.

scholarly journals The position of the germinal vesicle and the chromatin organization together provide a marker of the developmental competence of mouse antral oocytes

Reproduction ◽  
2009 ◽  
Vol 138 (4) ◽  
pp. 639-643 ◽  
Author(s):  
Michele Bellone ◽  
Maurizio Zuccotti ◽  
Carlo Alberto Redi ◽  
Silvia Garagna
Keyword(s):  
Germinal Vesicle ◽  
Chromatin Organization ◽  
Developmental Competence ◽  
Cell Stage ◽  
Morphological Marker ◽  
Good Marker ◽  
Chromatin Configuration ◽  
Meiotic Competence

Based on their chromatin organization, antral oocytes can be classified into two classes, namely surrounded nucleolus (SN, chromatin forms a ring around the nucleolus), and not surrounded nucleolus (NSN, chromatin has a diffuse pattern). Oocytes of both classes are capable of meiotic resumption, but while SN oocytes, following fertilization, develop to term, NSN oocytes never develop beyond the two-cell stage. A recent study has shown that the position of the germinal vesicle (GV) can be used as a morphological marker predictive of oocyte meiotic competence, i.e. oocytes with a central GV have a higher meiotic competence than oocytes with an eccentric GV. In the present study, we have associated both markers with the aim of identifying, with more accuracy, the oocytes' developmental competence. Following their isolation, antral oocytes were classified on the basis of both SN and NSN chromatin configuration and their GV position, matured to metaphase II and fertilized in vitro. We demonstrated that the position of the GV is a good marker to predict the oocytes' developmental competence, but only when associated with the observation of the chromatin organization.

scholarly journals Association between p34cdc2 levels and meiotic arrest in pig oocytes during early growth

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Yuji Hirao ◽  
Youki Tsuji ◽  
Takashi Miyano ◽  
Akira Okano ◽  
Masashi Miyake ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Early Growth ◽  
Catalytic Subunit ◽  
The Other ◽  
Antral Follicles ◽  
Stages Of Growth ◽  
Mean Diameter ◽  
M Phase ◽  
Chromatin Configuration ◽  
Meiotic Competence

SummaryThe molecules involved in determining meiotic competence were determined in porcine oocytes isolated from preantral and antral follicles of different sizes. Oocytes isolated from preantral follicles had a mean diameter of 78 μm, contained diffuse filamentous chromatin in the germinal vesicle and were incapable of progressing from the G2 to the M phase of the cycle even after 72 h in culture. Oocytes from early antral follicles had a mean diameter of 105 μm, showed a filamentous chromatin configuration and about half resumed meiosis but arrested at metaphase I (MI) when cultured. Oocytes from mid-antral (3–4 mm) and large antral follicles (5–6 mm) had mean oocyte diameters of 115 and 119 μm respectively, contained condensed chromatin around the nucleolus and progressed to metaphase II (MII) in 48% and 93% of instances respectively. Analysis of p34cdc2, the catalytic subunit of maturation promoting factor (MPF), by immunoblotting indicates that the inability of small (78 μm) oocytes to resume meiosis is due, at least in part, to inadequate levels of the catalytic subunit of MPF. On the other hand, the inability of intermediate-sized (105 μm) oocytes from antral follicles to complete the first meiotic division by progressing beyond MI appears not to be limited by levels of p34cdc2, which are maximal by this stage. We postulate that an inadequacy of molecules other than p34cdc2 limits progression of MI to MII; the acquisition of these molecules during the final stages of growth may be correlated with the formation of the perinucleolar chromatin rim in the germinal vesicle.

scholarly journals Oocyte Meiotic Competence in the Domestic Cat Model: Novel Roles for Nuclear Proteins BRD2 and NPM1

2021 ◽  
Vol 9 ◽  
Author(s):  
Daniela R. Chavez ◽  
Pei-Chih Lee ◽  
Pierre Comizzoli
Keyword(s):  
Embryo Development ◽  
Germinal Vesicle ◽  
Domestic Cat ◽  
Nuclear Proteins ◽  
Protein Levels ◽  
Nuclear Factors ◽  
Chromatin Configuration ◽  
Mammalian Female ◽  
Adult Cat ◽  
Meiotic Competence

To participate in fertilization and embryo development, oocytes stored within the mammalian female ovary must resume meiosis as they are arrested in meiotic prophase I. This ability to resume meiosis, known as meiotic competence, requires the tight regulation of cellular metabolism and chromatin configuration. Previously, we identified nuclear proteins associated with the transition from the pre-antral to the antral follicular stage, the time at which oocytes gain meiotic competence. In this study, the objective was to specifically investigate three candidate nuclear factors: bromodomain containing protein 2 (BRD2), nucleophosmin 1 (NPM1), and asparaginase-like 1 (ASRGL1). Although these three factors have been implicated with folliculogenesis or reproductive pathologies, their requirement during oocyte maturation is unproven in any system. Experiments were conducted using different stages of oocytes isolated from adult cat ovaries. The presence of candidate factors in developing oocytes was confirmed by immunostaining. While BRD2 and ASRGL1 protein increased between pre-antral and the antral stages, changes in NPM1 protein levels between stages were not observed. Using protein inhibition experiments, we found that most BRD2 or NPM1-inhibited oocytes were incapable of participating in fertilization or embryo development. Further exploration revealed that inhibition of BRD2 and NPM-1 in cumulus-oocyte-complexes prevented oocytes from maturing to the metaphase II stage. Rather, they remained at the germinal vesicle stage or arrested shortly after meiotic resumption. We therefore have identified novel factors playing critical roles in domestic cat oocyte meiotic competence. The identification of these factors will contribute to improvement of domestic cat assisted reproduction and could serve as biomarkers of meiotically competent oocytes in other species.

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