During the first meiotic cell division of the Xenopus oocyte, a transient microtubule network appears at the basal part of the disintegrating nucleus. In order to know if this structure plays a role in the formation of the first meiotic spindle, we have studied the actions of Ca2+ ions and taxol during the whole maturation process. We now report that when the free cytosolic Ca2+ concentration i...

The germinal vesicle (GV) of follicle-enclosed oocytes in mice remains arrested at the dictyate state of meiosis. Upon releasing the oocytes from the follicles, the meiotic process resumes, leading to dissolution of the GV, suggesting that factors in the follicular constituents sustain the meiotic arrest of oocytes. Vasoactive intestinal peptide (VIP) was demonstrated in the ovary and found to ...

ATP-binding cassette E1 (ABCE1) is a member of the ATP-binding cassette transporters and essential for diverse biological events regulating abroad range of biological functions including viral infection, cell proliferation, anti-apoptosis, translation initiation and ribosome biogenesis. Here, we discovered that Abce1 also plays indispensable roles in mouse oocyte meiotic progression. In the pre...

In the brachiopod Terebratalia transversa, each ovarian follicle consists of (i) a prophase-arrested oocyte with an enlarged nucleus (= the germinal vesicle, or GV), and (ii) a surrounding sheath of follicle cells that attach to the oocyte by means of junctional complexes. Within about 80 min after removing a follicle from the ovary, the follicular sheath undergoes a microfilament-mediated retr...

To study the time- and temperature-dependent survival of ovarian oocytes collected from postmortem carcass, ICR mice were killed and placed for different periods (0, 1, 2, 4, 6, 8 and 10 h) at different temperatures (25°C, 4°C and 37°C). After preservation, oocyte morphology, germinal vesicle (GV) oocyte number, oocyte meiotic maturation percentage, mitochondrial distribution and intracellular ...

The distribution of annulate lamellae, electron-dense masses, rough endoplasmic reticulum, and Golgi complexes in longitudinal sections of newt oocytes at several stages of progesterone-induced maturation was recorded with an electron microscope equipped with a drawing device. Annulate lamellae in full-grown oocytes occur in close contact with electron-dense masses and the nuclear envelope and ...

By using the whole cell voltage-clamp technique, we studied changes in plasma membrane permeability at different meiotic stages of bovine oocytes. Follicular oocytes were matured in vitro and activated by Ca(2+) ionophore. Oocytes at germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), metaphase II (MII), and meiosis exit were used for electrophysiological recording. By c...

Oocyte nuclear proteins of Xenopus are distributed into the cytoplasm of the maturing egg after germinal vesicle breakdown. Later they are found in all cell nuclei of the embryo. At early stages of development, different nuclear proteins behave differently. A class of 'early shifting' antigens is accumulated by pronuclei and cleavage nuclei, whereas others appear to be excluded from the nuclei ...

In the present study, the response of Nili Ravi buffalo oocytes to recombinant human follicle stimulating hormone (rhFSH) (Organon) on meiotic maturation in vitro was examined. Oocytes were matured in vitro in medium containing either 0 or 0.05 IU/ ml rhFSH and the stage of nuclear maturation recorded after 24 hours. The percentage of oocytes in the control group undergoing germinal vesicle bre...