Cyclic AMP (cAMP) plays a critical role in oocyte meiotic maturation. However, the source of cAMP surge prior to maturation and the direction of gap junction-dependent cAMP movement are unclear. In this study, inhibition of gap junctional communication (GJC) using carbenoxolone (3.5 h) induced meiotic resumption in ~90% of follicle-enclosed oocytes (FEOs). The concentration of cAMP in a single ...

BACKGROUND The first clues to the process of gamete activation date back to nearly 60 years ago. The mutual activation of gametes is a crucial event during fertilization. In the testis and ovaries, spermatozoa and oocytes are in a state of meiotic and metabolic quiescence and require reciprocal signals in order to undergo functional changes that lead to competence for fertilization. First, the ...

The Drosophila anterior-posterior (AP) axis is specified at mid-oogenesis when Par-1 kinase recruited to the posterior cortex of oocyte, where it polarises microtubule cytoskeleton define determinants, bicoid and oskar mRNAs localise. This polarity established in response an unknown signal from follicle cells, but how this occurs unclear. Here we show that myosin chaperone, Unc-45 Non-Muscle My...

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...

The origin of most ovarian tumors is undefined. Here, we report development of a novel mouse model in which conditional inactivation of the tumor suppressor gene Rb1 in oocytes leads to the formation of ovarian teratomas (OTs). While parthenogenetically activated ooctyes are a known source of OT in some mutant mouse models, enhanced parthenogenetic propensity in vitro was not observed for Rb1-d...

Fully grown mammalian oocytes are arrested at the first meiotic prophase until a surge of gonadotrophin at the mid-cycle. The actions of gonadotrophins, follicle stimulating hormone (FSH) and luteinizing hormone (LH), on oocyte meiotic resumption are believed to be mediated in large part through increasing the production of cyclic adenosine 3',5'-monophosphate and subsequent activation of mitog...

In oogenesis, meiosis must be highly regulated to ensure that growth of the oocyte and chromosomal segregation are coordinated properly. To do this, meiosis arrests at two points to permit oocyte differentiation and coordination with fertilization. In Drosophila, the first arrest in prophase I is released by oocyte maturation, and the second arrest in metaphase I is released by egg activation. ...