BACKGROUND Current outcome results with embryos derived from thawed MII human oocyes are significantly lower than with embryos cryopreserved at the pronuclear stage. Here, we investigated whether freezing-thawing was associated with changes in oocyte mitochondrial polarity (DeltaPsim) that could influence competence by altering ATP levels or the ability of the cytoplasm to regulate intracellula...

Cell fate is often determined by the intracellular localization of RNAs and proteins. In Drosophila oocytes, oskar (osk) RNA localization and the subsequent Osk synthesis at the posterior pole direct the assembly of the pole plasm, where factors for the germline and abdomen formation accumulate. osk RNA produces two isoforms, long and short Osk, which have distinct functions in pole plasm assem...

Germ cells may be specified through the localization of germ line determinants to specific cells in early embryogenesis, or by inductive signals from neighboring cells to germ cell precursors in later embryogenesis. Such determinants can be produced and localized during or after oogenesis, either autonomously by oocytes or by associated nutritive cells. In Drosophila, each oocyte is connected t...

Although it is known that the establishment of polarity during Drosophila oogenesis is initiated by signalling from the oocyte to the overlying follicle cells, much less is understood about the role of specific follicular subpopulations. One powerful approach for addressing this question, toxigenic cell ablation of specific subpopulations, has not previously been applicable to studying follicul...

Collective cell movement is a mechanism for invasion identified in many developmental events. Examples include the movement of lateral-line neurons in Zebrafish, cells in the inner blastocyst, and metastasis of epithelial tumors [1]. One key model to study collective migration is the movement of border cell clusters in Drosophila. Drosophila egg chambers contain 15 nurse cells and a single oocy...

Oocyte maturation in rodents is characterized by a dramatic reorganization of the endoplasmic reticulum (ER) and an increase in the ability of an oocyte to release Ca(2+) in response to fertilization or inositol 1,4,5-trisphosphate (IP(3)). We examined if human oocytes undergo similar changes during cytoplasmic meiotic maturation both in vivo and in vitro. Immature, germinal vesicle (GV)-stage ...

Asymmetric mRNA localization is an effective mechanism for establishing cellular and developmental polarity. Posterior localization of oskar in the Drosophila oocyte targets the synthesis of Oskar to the posterior, where Oskar initiates the assembly of the germ plasm. In addition to harboring germline determinants, the germ plasm is required for localization and translation of the abdominal det...

The E2F family of transcription factors contributes to cell cycle control by regulating the transcription of DNA replication factors. Functional 'E2F' is a DNA-binding heterodimer composed of E2F and DP proteins. Drosophila contains two E2F genes (dE2F, dE2F2) and one DP gene (dDP). Mutation of either dE2F or dDP eliminates G(1)-S transcription of known replication factors during embryogenesis ...

The establishment of dorsoventral polarity in the Drosophila oocyte and future embryo is dependent on the efficient transport of K10 mRNA from nurse cells into the oocyte. To investigate the cis-requirements of K10 mRNA transport, we used a transgenic fly assay to analyze the expression patterns of a series of K10 deletion variants. Such studies identify a 44 nucleotide sequence within the K10 ...

Subcellular localization of gene products and cell migration are both critical for pattern formation during development. The bullwinkle gene is required in Drosophila for disparate aspects of these processes. In females mutant at the bullwinkle locus, the follicle cells that synthesize the dorsal eggshell filaments do not migrate properly, creating short, broad structures. Mosaic analyses demon...