Polarization of the microtubule cytoskeleton during early oogenesis is required to specify the posterior of the Drosophila oocyte, which is essential for asymmetric mRNA localization during mid-oogenesis and for embryonic axis specification. The posterior determinant oskar mRNA is translationally silent until mid-oogenesis. We show that mutations in armitage and three components of the RNAi pat...

Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line. Here we provide evidence supporting the influence of these gut bacteria on the germ line of Drosophila melanogaster. Removal of the gut bacteria represses oogenesis, expedites maternal-to-zygoti...

We have identified a new member of the posterior group of genes, which we call pipsqueak. We show that pipsqueak acts after the establishment of the oskar posterior anchor but before the localization of vasa protein during oogenesis. Characterization of multiple alleles at the pipsqueak locus shows that pipsqueak, like vasa, is required for early stages of oogenesis, including but not limited t...

In full-grown Xenopus oocytes, cell-cycle regulators and an inactive form of maturation/M phase promoting factor (pre-MPF) are stored ready to bring about a specific cell cycle for oocyte maturation. We examined the expression pattern of these cell-cycle regulators as well as pre-MPF formation during oogenesis. Cdc2 and Cyclin B2 were already present in stage I oocytes and pre-MPF formation was...

Genetic experiments suggest that polarization of the oocyte is linked directly to the initial cell fate determination that singles out the oocyte from its 15 sister cells. Specification of oocyte cell fate as well as establishment and maintenance of a polarized microtubule network within the Drosophila oocyte require the activity of the egalitarian (egl) and BicaudalD (BicD) genes. We have isol...

Zygentoma and Microcoryphia, which used to be combined in one order Thysanura, are Apterygota most closely related to Pterygota. As histological and ultrastructural studies have shown, both Zygentoma and Microcoryphia have panoistic ovaries (Bitsch, 1980a, b; Bitsch and Bitsch, 1982). Vitellogenesis, of heterosynthetic or mixed type with heterosynthetic kind dominating, is typical of these inse...

The Notch gene in Drosophila encodes a transmembrane protein with homology to EGF that, in a variety of tissues, appears to mediate cell interactions necessary for cell fate choices. Here we demonstrate that oogenesis and spermatogenesis depend on Notch. We examine the phenotypes of the temperature-sensitive Notch allele, Nts1, and, using a monoclonal antibody, determine the cellular and subcel...

In many animals, the bipolar spindle of the first zygotic division is established after the contribution of centrioles by the sperm at fertilization. To avoid the formation of a multipolar spindle in the zygote, centrosomes are eliminated during oogenesis in most organisms, although the mechanism of this selective elimination is poorly understood. We show that cki-2, a Caenorhabditis elegans cy...

Recent advances shed light on the cellular processes that cooperate during oogenesis to produce a fully patterned egg, containing all the maternal information required for embryonic development. Progress has been made in defining the early steps in oocyte specification and it has been shown that progression of oogenesis is controlled by a meiotic checkpoint and requires active maintenance of th...