In the Drosophila ovary, the Bicaudal-D (Bic-D) gene is required for the differentiation of one of 16 interconnected cystocyte sister cells into an oocyte. A new class of Bic-Dnull alleles reveals a novel requirement for Bic-D for zygotic viability. In the germ line, the null mutations show that developmental processes that take place in germarial region 1, even those that create asymmetry, are...

Vasa, a DEAD box mRNA helicase similar to eIF4A, is involved in pole plasm assembly in the Drosophila oocyte and appears to regulate translation of oskar and nanos mRNAs. However, several vasa alleles exhibit a wide range of early oogenesis phenotypes. Here we report a detailed analysis of Vasa function during early oogenesis using novel as well as previously identified hypomorphic vasa alleles...

Filamentous actin or F-actin is a major component of stress fibers and involved in cellular architecture. Its dynamic rearrangement supports not only cellular morphology but also intracellular signal transduction that regulate cell-cell or cell-extracellular matrix interactions, cell motility, and proliferation. Several lines of evidence demonstrate that, in several organisms, oocyte cortical c...

During Drosophila oogenesis, localization of the transforming growth factor alpha (TGFalpha)-like signaling molecule Gurken to the oocyte membrane is required for polarity establishment of the egg and embryo. To test Gurken domain functions, full-length and truncated forms of Gurken were expressed ectopically using the UAS/Gal4 expression system, or in the germline using the endogenous promoter...

The directed traffic of membrane proteins to the cell surface is crucial for many developmental events. We describe the role of Sec5, a member of the exocyst complex, in directed membrane traffic in the Drosophila oocyte. During oogenesis, we find that Sec5 localization undergoes dynamic changes, correlating with the sites at which it is required for the traffic of membrane proteins. Germline c...

Pattern formation along the dorsal-ventral axis of the developing Drosophila embryo depends upon two sequentially acting signal transduction cascades functioning in the ovarian egg chamber and in the egg, respectively (Ray and Schüpbach, 1996; Morisato and Anderson, 1995). In the egg chamber, spatially restricted activation of the Drosophila EGF receptor homolog, Torpedo, leads to the establish...

In Drosophila, the formation of the embryonic axes is initiated by Gurken, a transforming growth factor alpha signal from the oocyte to the posterior follicle cells, and an unknown polarising signal back to the oocyte. We report that Drosophila Merlin is specifically required only within the posterior follicle cells to initiate axis formation. Merlin mutants show defects in nuclear migration an...

JMY is a transcriptional co-factor of p53. Latest work has revealed that JMY is also an actin nucleation factor that regulates new filament assembly and activates Arp2/3 complex in somatic cells; however, roles of JMY in mouse oocyte are unknown. Here we showed the expression and functions of JMY during mouse oocyte meiotic maturation. JMY mRNA is expressed largely from germinal vesicle to meta...

We describe a mutant, maelstrom, that disrupts a previously unobserved step in mRNA localization within the early oocyte, distinct from nurse-cell-to-oocyte RNA transport. Mutations in maelstrom disturb the localization of mRNAs for Gurken (a ligand for the Drosophila Egf receptor), Oskar and Bicoid at the posterior of the developing (stage 3-6) oocyte. maelstrom mutants display phenotypes dete...