Okadaic acid (OA)-induced germinal vesicle breakdown (GVBD) and localization of protein phosphatase-1 (PP1) in oocyte nuclei are suggestive of PP1's role in regulating oocyte GVBD. To explore this possibility, we microinjected protein phosphatase (PP) inhibitors OA, anti-PP1 antibody (anti-PP1), PP1 inhibitor I2, and anti-PP2A antibody (anti-PP2A) into nuclei of roscovitine (ROSC)-arrested mous...

JMY is a transcriptional co-factor of p53. Latest work has revealed that JMY is also an actin nucleation factor that regulates new filament assembly and activates Arp2/3 complex in somatic cells; however, roles of JMY in mouse oocyte are unknown. Here we showed the expression and functions of JMY during mouse oocyte meiotic maturation. JMY mRNA is expressed largely from germinal vesicle to meta...

1. Methylxanthines (IBMX, caffeine, theophylline), which are known inhibitors of c-AMP phosphodiesterase inhibited reversibly progesterone-induced maturation of Xenopus oocyte. 2. The time course of protein phosphorylation during maturation stimulated by progesterone was analysed in Xenopus oocyte : protein phosphorylation increased around germinal vesicle breakdown (GVBD). No quantitative chan...

In oocytes of the newt Pleurodeles waltl, the maternal nuclear protein PwA33 occurs on the lampbrush chromosomes and in some nucleoplasmic particles of the germinal vesicle. PwA33 is a modular protein and we used site-directed mutagenesis to alter the sequences encoding two metal-binding regions, the C3HC4 (or RING finger) and B-box motifs. Several mutant clones were generated and their synthet...

This review compiles present knowledge of the structure and molecular composition of the enigmatic cytoplasmic organelles called accessory nuclei. Most typically, they are found in the perinuclear cytoplasm in oocytes of insects and several other invertebrates. Accessory nuclei originate by budding of the oocyte nucleus (germinal vesicle) and are surrounded by an envelope identical to the nucle...

Mitochondria (mt) have been reported to be closely related to the maturation of mammalian oocytes, but their function in oocyte maturation has not been elucidated. In this study, we examined the kinetics of mt and chromatin configuration during in vitro maturation of mouse oocytes to clarify the relationship between oocyte maturation and mitochondrial distribution morphologically. Oocytes were ...

The present study was undertaken to explore the regulatory mechanisms for meiotic resumption of pig cumulus-oocyte complexes (COCs) by assessing the nuclear status of oocytes, the degree of gap junction cell-to-cell communication and cumulus expansion after culture of various numbers of COCs in 10 microl droplets of medium for 24 h. Gap junction communication was examined by confocal laser scan...

A STUDY of nucleo-cytoplasmic interactions in pre-embryonic development, at maturation stages in particular, is of great interest. During this period ooplasmic segregation takes place, specific properties of the cortex arise, and the cytoplasm obtains information from the oocyte nucleus which promotes the development of the embryo during all the changes related to fertilization, cleavage and bl...

There is massive destruction of transcripts during the maturation of mouse oocytes. The objective of this project was to identify and characterize the transcripts that are degraded versus those that are stable during the transcriptionally silent germinal vesicle (GV)-stage to metaphase II (MII)-stage transition using a microarray approach. A system for oocyte transcript amplification using both...

Oocyte cryopreservation is a promising technology that could benefit women undergoing assisted reproduction. Most studies examining the effects of cryopreservation on fertilization and developmental competence have been done using metaphase II-stage oocytes, while fewer studies have focused on freezing oocytes at the germinal vesicle (GV) stage, followed by in vitro maturation. Herein, we exami...