Cell cycle transitions spanning meiotic maturation of the Xenopus oocyte and early embryogenesis are tightly regulated at the level of stored inactive maternal mRNA. We investigated here the translational control of cyclin E1, required for metaphase II arrest of the unfertilised egg and the initiation of S phase in the early embryo. We show that the cyclin E1 mRNA is regulated by both cytoplasm...

Background: In vitro maturation (IVM) of oocytes reduces the costs and averts the side-effects of gonadotropin stimulation for in vitro fertilization (IVF). Reliable IVM is an intellectual, scientific and clinical challenge with a number of potential applications. Objective: The effect of hCG was evaluated on the timing and regulation of in vitro ovulation for the Syrian mice oocytes in the pre...

Heat shock may affect different aspects of oocyte maturation and its subsequent development to the blastocyst stage. A series of in vitro experiments was performed to determine whether physiologically heat shock (41°C) disrupts the progression of the ovine oocytes through meiosis, activation and blastocyst formation. Cumulus-oocyte complexes (COCs) were aspirated from 2-6-mm follicles and cultu...

The oocyte maturation includes nuclear maturation and cytoplasmic maturation before fertilization. Moreover, the oocyte nucleus, the cytoplasm and other cell organelles occur changes, zona pellucida (ZP) synchronously undergoes biochemical and structural modifications in the final maturation phase of oocyte prior to fertilization (ZP maturation). It is reported that ZP modifications, such as gl...

Immature oocytes become fertilisable eggs through a process called meiotic maturation, which is often induced by specific hormones. Oocyte maturation involves the activation of various signal transduction pathways that converge to activate maturation-promoting factor (MPF); this is a key activity that catalyses entry into M-phase of meiosis I and meiosis II. Whereas the function of MPF in promo...

The inhibitor CEP-33779 is a specific selective inhibitor of JAK2. In most somatic cells, JAK2 plays essential roles in cellular signal transduction and in the regulation of cell cycle. Little is known regarding the effects of JAK2 on mammalian oocyte maturation. In the present study, we investigated the effects of CEP-33779 on mouse oocytes meiosis and possible mechanisms of JAK2 during mouse ...

The present studies have been undertaken to investigate the interactions that occur between the nucleus and cytoplasm of ovine oocytes at various stages during meiotic maturation. We report that the nucleus of ovine fully grown dictyate stage oocytes can be efficiently removed by a microsurgical enucleation procedure. It is demonstrated that between the initiation of maturation and germinal ves...

In mitosis, Borealin is a member of the chromosomal passenger complex (CPC), which plays interaction roles with INCENP and survivin in the complex. Its roles in mammalian meiosis are unknown. Here, we report the expression, localization, and function of Borealin and its relation with survivin in mouse oocyte meiosis. Borealin expression was gradually increased from GV stage to MII. Immunofluore...

The objective was to examine potential roles of glucose and pyruvate in nuclear and cytoplasmic maturation of porcine oocytes. Oocyte-cumulus complexes (OCC), derived from 3 to 6mm follicles, were cultured in a chemically defined medium (pyruvate-free mNCSU37-PVA), with or without 5.55 mM glucose, during in vitro maturation (IVM); in the absence of glucose, germinal vesicle breakdown (GVBD) and...