Stag3, a meiosis-specific subunit of cohesin complex, has been demonstrated to function in both male and female reproductive systems in mammals. However, its roles during oocyte meiotic maturation have not been fully defined. In the present study, we report that Stag3 uniquely accumulates on the spindle apparatus and colocalizes with microtubule fibers during mouse oocyte meiotic maturation. De...

OBJECTIVE To evaluate the influence of ovarian follicular dominance on the outcome of oocyte in-vitro maturation. METHODS This retrospective cohort study included 21 patients with polycystic ovaries or polycystic ovary syndrome (Rotterdam criteria, 2004) subjected to 24 invitro maturation (IVM) cycles between October 2015 and January 2017. Patients undergoing IVM received minimal gonadotropin...

The molecular underpinnings of the oocyte-to-embryo transition are poorly understood. Here we show that two protein tyrosine phosphatase-like (PTPL) family proteins, EGG-4 and EGG-5, are required for key events of the oocyte-to-embryo transition in Caenorhabditis elegans. The predicted EGG-4 and EGG-5 amino acid sequences are 99% identical and their functions are redundant. In embryos lacking E...

Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) induces Ca2+ oscillations and waves in Xenopus laevis oocytes. Microsomes from oocytes exhibit high-affinity binding for Ins(1,4,5)P3, and demonstrate Ins(1,4,5)P3-induced Ca2+ release. The Ins(1,4,5)P3 receptor (InsP3R) was purified from oocyte microsomes as a large tetrameric complex and shown to have a monomer molecular mass of 256 kDa, compared wi...

In vitro embryo production is the cornerstone of infertility treatment in human and is increasingly used in cattle to propagate high genetic merit animals. To increase its efficiency, many different approaches have been tested all of which stem from the concepts of oocyte quality and developmental competence. Presented here are recently reported findings and perspectives related to bovine oocyt...

Meiotic maturation of mammalian oocytes is a precisely orchestrated and complex process. Dimethyl sulfoxide (DMSO), a widely used solvent, drug, and cryoprotectant, is capable of disturbing asymmetric cytokinesis of oocyte meiosis in mice. However, in pigs, DMSO's effect on oocyte meiosis still remains unknown. We aimed to evaluate if DMSO treatment will affect porcine oocyte meiosis and the un...

BACKGROUND The complex relationship between oocyte morphology, specific follicular fluid metabolites, gene expression in cumulus granulosa cells, and oocyte competence toward fertilization and embryo development still needs further clarification. METHODS Forty-six oocytes retrieved from the largest pre-ovulatory follicle of patients undergoing intra-cytoplasmic sperm injection (ICSI) were con...

We have measured the levels of cyclin mRNAs and polypeptides during oogenesis, progesterone-induced oocyte maturation, and immediately after egg activation in the frog, Xenopus laevis. The mRNA for each cyclin is present at a constant level of approximately 5 x 10(7) molecules per oocyte from the earliest stages of oogenesis until after fertilization. The levels of polypeptides show more comple...

The anterior-posterior axis of C. elegans is defined by the asymmetric division of the one-cell zygote, and this is controlled by the PAR proteins, including PAR-3 and PAR-6, which form a complex at the anterior of the cell, and PAR-1, which localizes at the posterior [1-4]. PAR-1 plays a similar role in axis formation in Drosophila: the protein localizes to the posterior of the oocyte and is n...

Many RNAs involved in determination of the oocyte, specification of embryonic axes, and establishment of germ cells in Drosophila are localized asymmetrically within the developing egg or syncytial embryo. Here I review the current state of knowledge about the cis-acting sequences involved in RNA targeting, RNA binding proteins; gene activities implicated in localizing specific RNAs, and the ro...