Many of the genes that control pattern formation in Drosophila encode mRNAs that are localized to discrete regions of the oocyte during oogenesis. While such localization is generally assumed to be important for the pattern-forming activities of these genes, this has been rigorously demonstrated in only a few cases. Here we address the role of mRNA localization for the dorsoventral patterning g...

Spire is a WH2 domain-containing actin nucleator essential for establishing an actin mesh during oogenesis. In vitro, in addition to nucleating filaments, Spire can sever them and sequester actin monomers. Understanding how Spire is capable of these disparate functions and which are physiologically relevant is an important goal. To study severing, we examined the effect of Drosophila Spire on p...

Drosophila oogenesis provides a useful system to study signal transduction pathways and their interactions. Through clonal analysis, we found that brinker (brk), a repressor of Dpp signaling, plays an important role in the Drosophila ovary, where its function is essential for dorsal appendage formation. In the absence of brk, operculum fates are specified at the expense of dorsal appendage fate...

The zinc-finger protein Nanos and the RNA-binding protein Pumilio act together to repress the translation of maternal hunchback RNA in the posterior of the Drosophila embryo, thereby allowing abdomen formation. nanos RNA is localized to the posterior pole during oogenesis and the posteriorly synthesized Nanos protein is sequestered into the germ cells as they form in the embryo. This maternally...

We have isolated nine gain-of-function (gf) alleles of the sex-determination gene fem-3 as suppressors of feminizing mutations in fem-1 and fem-2. The wild-type fem-3 gene is needed for spermatogenesis in XX self-fertilizing hermaphrodites and for male development in both soma and germ line of XO animals. Loss-of-function alleles of fem-3 transform XX and XO animals into females (spermless herm...

Caenorhabditis elegans hermaphrodites make first sperm, then oocytes. By contrast, animals homozygous for any of six loss-of-function mutations in the gene mog-1 (for masculinization of the germ line) make sperm continuously and do not switch into oogenesis. Therefore, in mog-1 mutants, germ cells that normally would become oocytes are transformed into sperm. By contrast, somatic sexual fates a...

Establishment of anterior-posterior and dorsal-ventral polarity within the Drosophila egg chamber requires signaling between the germline and the somatic cells of the ovary. The gene gurken (grk) encodes a TGFalpha-like protein that is localized within the developing oocyte and is thought to locally activate torpedo/Egfr (top/Egfr), the Drosophila homolog of the EGF receptor, which is expressed...

Mitochondrial (mt)DNA is strictly maternally inherited in mammals; new mutations thus segregate along maternal lineages without the benefit of homologous recombination with mtDNA of paternal origin. Despite the high mtDNA copy number (approximately 100000 or more) in mature oocytes, and despite the relatively small number of cell divisions during oogenesis, mtDNA sequence variants segregate rap...

Whether or not oocyte regeneration occurs in adult life has been the subject of much debate. In this study, we have traced germ-cell lineages over the life spans of three genetically modified mouse models and provide direct evidence that oogenesis does not originate from any germline stem cells (GSCs) in adult mice. By selective ablation of all existing oocytes in a Gdf9-Cre;iDTR mouse model, w...

After fertilization, the development of a zygote depends upon both gene products synthesized by its maternal parent and gene products synthesized by the zygote itself. To analyze genetically the relative contributions of these two sources of gene products, several laboratories have been isolating two classes of mutants of Drosophila melanogaster: maternal-effect lethals and zygotic lethals. Thi...