Mouse eggs arrest at metaphase II following ovulation and are only triggered to complete meiosis when fertilized. Sperm break the cell-cycle arrest by a long-lasting series of Ca2+ spikes that lead to an activation of the anaphase-promoting complex/cyclosome. The signal transduction pathway is not fully resolved but both protein kinase C (PKC) and calmodulin-dependent protein kinase II (CamKII)...

Mammalian oocytes are arrested at prophase I of meiosis, and resume meiosis prior to ovulation. Coordination of meiotic arrest and resumption is partly dependent on the post-transcriptional regulation of maternal transcripts. Here, we report that, SPINDLIN1 (SPIN1), a maternal protein containing Tudor-like domains, interacts with a known mRNA-binding protein SERBP1, and is involved in regulatin...

Oocyte meiotic resumption is triggered by the ovulatory gonadotropin surge; in cattle, angiotensin II (AngII) and prostaglandins (PG) are key mediators of this gonadotropin-induced event. Here, we tested the hypothesis that progesterone (P(4)) is also involved in oocyte meiotic resumption induced by the gonadotropin surge. In Experiment I, P(4) induced nuclear maturation in a dose-dependent man...

Since the pig is not only an important farm animal, but also a model animal for biomedical applications, the development of reproductive technologies in this species has been very important. In vitro oocyte maturation and fertilization (IVM-IVF) are basic techniques for a number of oocyte- or embryo-related technologies. The practical aspects for pig oocyte IVM-IVF have been reviewed, while the...

Female meiotic divisions are extremely asymmetric, giving rise to a large oocyte and small degenerating polar bodies, keeping the maternal stores for further embryo development. This asymmetry is achieved via off-center positioning of the division spindle. Mouse oocytes have developed a formin-2-dependent actin-based spindle positioning mechanism that allows the meiotic spindle to migrate towar...

Background: Maternal mRNA degradation is a selective process that occurs in waves corresponding to important developmental transitions such as resumption of meiosis, fertilization and zygotic genome activation. It has been demonstrated that the number, position, and combination of 3 UTR cis-acting elements interacting with trans-acting protein factors regulate translation and mRNA stability. Ou...

introduction: dehp [di(2-ethylhexyl) phthalate)] is widely used in plastic industry and some reproductive toxicity has been shown with it. so, this study was designed to evaluate dehp effects on resumption of meiosis and in vitro maturation of mouse oocytes as well as development of embryos resulted from them. material and methods: mice of 4-6 weeks old were administered daily doses of 50, 100,...

Cell cycle progression in mammals involves multiple cyclin-dependent kinases (Cdks). Mice lacking Cdk2, Cdk3, Cdk4 or Cdk6 are viable, however, because Cdk1 can compensate for their loss by forming active complexes with A-, B-, Eand D-type cyclins in a stepwise manner. Thus, these Cdks are not essential for the mammalian cell cycle. In contrast, homozygous deletion of Cdk1 causes early embryoni...

The aim of this study was to evaluate the suitability of a commercial kit for bovine embryo vitrification for cryopreserving cat oocytes and to evaluate comparatively the effects of its use with slow freezing procedure on cryotolerance in terms of morphology and oocyte resumption of meiosis. Germinal vesicle stage oocytes isolated from cat ovaries were either vitrified (n = 72) using a vitrific...