Inhibiting oocyte aging is important not only for healthy reproduction but also for the success of assisted reproduction techniques. Although our previous studies showed that cumulus cells accelerated aging of mouse oocytes, the underlying mechanism is unknown. The objective of this paper was to study the effects of pyruvate and cumulus cells on mouse oocyte aging. Freshly ovulated mouse cumulu...

In the present study, we discovered that mouse oocyte maturation was inhibited by simulated microgravity via disturbing spindle organization. We cultured mouse oocytes under microgravity condition simulated by NASA's rotary cell culture system, examined the maturation rate and observed the spindle morphology (organization of cytoskeleton) during the mouse oocytes meiotic maturation. While the r...

Spindle sizes are different in diverse species and cell types. In frogs, the meiotic spindle size is positively correlated with the egg cell volume. Across species, relatively small mouse oocytes (70-80 μm) have a relatively large spindle while larger pig oocytes (about 120 μm) have a considerably smaller spindle. In this study we investigated whether species-specific oocyte spindle size was de...

Background: Oocyte maturation is usually defined as the period of progression from the first to the second meiotic arrest and involves coordinated nuclear and cytoplasmic modification. Ca2+ signals are known as important regulators of oocyte maturation. Extracellular Ca2+ is important for first polar body formation, normal meiosis kinetics, and for preserving the chromosome and spindle configur...

A sperm-specific phospholipase C-zeta (PLCζ) is believed to play an essential role in oocyte activation during mammalian fertilization. Sperm PLCζ has been shown to trigger a prolonged series of repetitive Ca(2+) transients or oscillations in oocytes that precede activation. This remarkable intracellular Ca(2+) signalling phenomenon is a distinctive characteristic observed during in vitro ferti...

The mammalian zona pellucida is an extracellular matrix that surrounds growing oocytes, ovulated eggs and early embryos. The mouse zona is composed of three sulfated glycoproteins: ZP1, ZP2 and ZP3. Each is critically involved in fertilization, the postfertilization block to polyspermy and protection of the preimplantation embryo. We have previously isolated cDNAs encoding mouse ZP2 and ZP3 and...

Undifferentiated mouse embryonal carcinoma (EC) cells are capable of transactivating the adenovirus EIIa promoter in the absence of its normal transactivator, E1A protein, suggesting that EC cells contain an E1A-like activity. In an effort to identify where this activity appears during normal mouse development, mouse oocytes and preimplantation embryos were injected with plasmids containing the...

Background: Cryopreservation of oocytes is an effective technology in assisted reproductive technology. Although successful vitrification of gametes has been reported in several mammalian species, the survival is generally low. The aim of this study was to investigate the effects of fibroblast growth factor (FGF) and hepatocyte growth factor (HGF) on preantral follicle development after vitrifi...

BACKGROUND: Although chromosome missegregation during oocyte maturation (OM) is a significant contributor to human morbidity and mortality, very little is known about the causes and mechanisms of aneuploidy. Several investigators have proposed that temporal perturbations during OM predispose oocytes to aberrant chromosome segregation. One approach for testing this proposal is to temporarily inh...

In order to measure the content of beta- and gamma-actin mRNA in mouse oocytes and ovulated eggs, Northern and slot blots were hybridized to complementary RNA probes transcribed from mouse isotype-specific cDNA sequences. The blots included samples of isotype-specific sense strand RNA standards prepared from the same cDNA sequences. Total actin mRNA content was estimated to be 40 fg per preovul...