oskar mRNA localization at the oocyte posterior pole is essential for correct patterning of the Drosophila embryo. Here we show at the ultrastructural level that endogenous oskar ribonucleoprotein complexes (RNPs) assemble sequentially with initial recruitment of Hrp48 and the exon junction complex (EJC) to oskar transcripts in the nurse cell nuclei, and subsequent recruitment of Staufen and mi...

The oocyte is the only cell in Drosophila that goes through meiosis with meiotic recombination, but several germ cells in a 16-cell cyst enter meiosis and form synaptonemal complexes (SC) before one cell is selected to become the oocyte. Using an antibody that recognises a component of the SC or the synapsed chromosomes, we have analysed how meiosis becomes restricted to one cell, in relation t...

Oocytes in primordial ("resting") follicles in adult human ovaries contain a complex paranuclear structure identified by light microscopists as Balbiani's vitelline body. By electron microscopy this structure is composed of a mass of mitochondria with associated endoplasmic reticulum, multiple compound aggregates which form a ring around the cytocentrum, and a single stack or coil of annulate l...

Drosophila pole (germ) plasm contains germline and abdominal determinants. Its assembly begins with the localization and translation of oskar (osk) RNA at the oocyte posterior, to which the pole plasm must be restricted for proper embryonic development. Osk stimulates endocytosis, which in turn promotes actin remodeling to form long F-actin projections at the oocyte posterior pole. Although the...

Oocyte maturation is critical for successful fertilization and pregnancy. The mechanism underlying the control of this complex process remain relatively unknown, and even more so the specific mechanism through which oocytes acquire competentce to restrain apoptosis and resume meiosis. Insulin-like Growth Factor 1 (IGF-1) is a growth factor that had been frequently used in inducing oocyte matura...

BACKGROUND Successful transition from oocyte to zygote depends on the timely degradation of oocyte proteins to prepare for embryonic development. In C. elegans, degradation of the oocyte protein MEI-1 depends on MBK-2, a kinase that phosphorylates MEI-1 shortly after fertilization during the second meiotic division. RESULTS Here we report that precise timing of MEI-1 phosphorylation depends o...

Abdomen and germ cell development of Drosophila melanogaster embryo requires proper localization of oskar mRNA to the posterior pole of the developing oocyte. oskar mRNA localization depends on complex cell biological events like cell-cell communication, dynamic rearrangement of the microtubule network, and function of the actin cytoskeleton of the oocyte. To investigate the cellular mechanisms...

The cumulus-oocyte complex (COC) is an oocyte surrounded by specialized granulosa cells, called cumulus cells. cells surrounding the ensure healthy and embryo development. maturity of COCs at retrieval may be used as indicator to predict outcome assisted reproductive technology (ART). Segmenting a preliminary step in many image processing pipelines evaluate maturity. However, acquiring well-ann...

The ability of an oocyte to successfully mature is highly dependent on intrafollicular conditions, including the size and structure of the follicle. Here we present a mathematical model of oxygen transport in the antral follicle. We relate mean oxygen concentration in follicular fluid of bovine follicles to the concentration in the immediate vicinity of the cumulus-oocyte complex (COC). The mod...