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 ...

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...

ING3 (inhibitor of growth family, member 3) is a subunit of the nucleosome acetyltransferase of histone 4 (NuA4) complex, which activates gene expression. ING3, which contains a plant homeodomain (PHD) motif that can bind to trimethylated lysine 4 on histone H3 (H3K4me3), is ubiquitously expressed in mammalian tissues and governs transcriptional regulation, cell cycle control, and apoptosis via...

Most organisms modulate their reproductive activity responding to day length by the nocturnal release of melatonin by the pineal gland. This hormone is also responsible for synchronizing reproduction with specific external environment stimuli in order to optimize reproductive success.The aim of this study was to establish the effect of melatonin on zebrafish reproduction.Adult females were dail...

Phospholipase D2 (PLD2) is involved in cytoskeletal reorganization, cell migration, cell cycle progression, transcriptional control and vesicle trafficking. There is no evidence about PLD2 function in oocytes during meiosis. Herein, we analyzed PLD2 expression and its relationship with spindle formation and positioning in mouse oocyte meiosis. High protein level of PLD2 was revealed in oocytes ...

Extracts from mitotic HeLa cells, when injected into fully grown Xenopus laevis oocytes, exhibit maturation-promoting activity (MPA) indicated by germinal vesicle breakdown (GVBD) and chromosome condensation. Recently, we observed that the MPA of mitotic cell extracts is neutralized by the inhibitors of mitotic factors (IMF) in HeLa cells, which are activated at telophase and remain active thro...

Stage VI Xenopus oocytes are suspended at the G2/M transition of meiosis I, and represent an excellent system for the identification and examination of cell cycle regulatory proteins. Essential cell cycle regulators such as MAPK, cyclins and mos have the ability to induce oocyte maturation, causing the resumption of the cell cycle from its arrested state. We have identified the product of a nov...

Resumption of meiosis was inhibited in mouse oocyte cumulus complexes (OCC) co-cultured with pig membrane granulosa (PMG). After 3 and 6 h of co-culture these oocytes possessed an intact nuclear envelope and their nucleolar surface was associated with granules approximately 80 nm in diameter. Preincubation of OCCs for 30, 45, 60 or 90 min followed by co-culture with PMG for 2 h of either OCCs o...

KIF20A (Kinesin-like family member 20A), also called mitotic kinesin-like proteins 2 (MKLP2), is a mammalian mitotic kinesin-like motor protein of the Kinesin superfamily proteins (KIFs), which was originally involved in Golgi apparatus dynamics and thought to essential for cell cycle regulation during successful cytokinesis. In the present study, we investigated whether KIF20A has roles on por...

Histological examination of gonadotrophin stimulated Macaca fascicularis ovaries removed at mid-follicular phase showed that germinal vesicles (GV) could exhibit different configurations in follicles greater than 1000 microns in diameter. We describe 3 types of nuclear organization called GV1 (dispersed and filamentous chromatin), GV2 (clumped and filamentous chromatin) and GV3 (perinucleolar c...