In freshly isolated fully grown pig oocytes at the germinal vesicle (GV) stage, the cytoplasmic microtubules are arranged in a meshwork. This microtubule arrangement is also maintained during the initial phases of meiotic maturation in vitro. A perinuclear array of microtubules is formed immediately before germinal vesicle breakdown (GVBD). Short-term treatment of oocytes with taxol when oocyte...

The growth of vertebrate oocyte stops temporarily at the late diplotene stage of 1 meiotic cell division and stays at that stage until puberty. Before ovulation, the arrest is resumed and enters the 2 meiotic phase and stops again at the metaphase until fertilization. The arrest is mediated by the constant flow of cAMP, which is generated by activated adenylyl cyclase. This state is manifested ...

The efflux of glycerol-(3)H from mature R. pipiens oocytes was studied by extractive analysis and by quantitative radioautography using techniques suitable for diffusible solutes. Extractive analysis was used to determine the total cellular concentration of tracer, and radioautography, regional intracellular concentrations, at equilibrium and as a function of efflux time, t(E). The efflux was r...

Meiotic maturation of oocytes requires a variety of ATP-dependent reactions, such as germinal vesicle breakdown, spindle formation, and rearrangement of plasma membrane structure, which is required for fertilization. Mitochondria are accordingly expected be localized to subcellular sites of energy utilization. Although microtubule-dependent cellular traffic for mitochondria has been studied ext...

Mammalian oocytes synthesize and secrete a zona pellucida that surrounds the growing oocytes, ovulated eggs and preimplantation embryos. The extracellular zona matrix is composed of three glycoproteins (ZP1, ZP2, ZP3) that are involved in folliculogenesis, species-specific fertilization, and passage of the early embryo down the oviduct. We have established a mouse line in which Zp3 has been ina...

Fertilized mouse eggs regulate their size principally by accumulating glycine as an intracellular osmolyte using the GLYT1 (SLC6A9) transporter, a mechanism of cell volume homeostasis apparently unique to early embryos before the morula stage. However, nothing was known of cell volume regulation in oocytes before fertilization. We show here that GLYT1 is quiescent in mouse germinal-vesicle-stag...

Cortical granules are secretory vesicles formed in the eggs of most animals and are essential for the prevention of polyspermy in these organisms. We have studied the biogenesis of cortical granules in sea urchin oocytes by identifying cDNA clones that encode proteins targeted selectively to the cortical granules. These cDNA clones were identified by an immunoscreen of a cDNA library using anti...

Effects of the neutralization of endogenous progesterone with rabbit antiserum to progesterone (anti-progesterone) on germinal vesicle breakdown of ova in follicles of small (less than 125 micrometers), intermediate (125-250 micrometers) and large (greater than 250 micrometers) diameter were examined by a quantitative histological technique. Immature rats were treated with 5 IU pregnant mare's ...

This study was aimed at elucidating the fate of three important nuclear envelope components - lamins B and A/C and nucleoporin Nup160, during meiotic maturation of mouse oocytes. These proteins were localized by epifluorescence and confocal microscopy using specific antibodies in oocytes at different stages from prophase I (germinal vesicle) to metaphase II. In immature germinal vesicle oocytes...

OBJECTIVE Retinoids are recognized as important regulators of cell differention and tissue function. Previous studies, performed both in vivo and in vitro, indicate that retinoids influence several reproductive events. In this study, we investigated the effect of all-trans retinoic acid (t-RA) on maturation and fertilization rate of immature oocytes (germinal vesicle). MATERIALS AND METHODS G...