The translational repressor Cup is required for germ cell development in Drosophila.

In Drosophila, germ cell formation depends on inherited maternal factors localized in the posterior pole region of oocytes and early embryos, known as germ plasm. Here, we report that heterozygous cup mutant ovaries and embryos have reduced levels of Staufen (Stau), Oskar (Osk) and Vasa (Vas) proteins at the posterior pole. Moreover, we demonstrate that Cup interacts with Osk and Vas to ensure anchoring and/or maintenance of germ plasm particles at the posterior pole of oocytes and early embryos.

Diminution of eIF4E activity suppresses parkin mutant phenotypes.

Mutations in the human parkin (PARK2) gene cause autosomal recessive-juvenile Parkinson's disease (AR-JP). In Drosophila melanogaster, mutant parkin alleles display a broad range of phenotypic alterations, including female infertility. Here we report that reducing the level of eukaryotic translation initiation factor 4E (eIF4E) activity specifically rescues the female sterile phenotypes associated with the parkin(P23) mutant allele.

The impact on microtubule network of a bracovirus IkappaB-like protein.

Polydnavirus-encoded IkappaB-like proteins are similar to insect and mammalian IkappaB, and an immunosuppressive function in the host cells has been inferred to these proteins. Here we show that the expression of one of these IkappaB-like viral genes, the TnBVank1, in the Drosophila germline affects the localization of gurken, bicoid, and oskar mRNAs whose gene products are relevant for proper embryonic patterning. The altered localization of these mRNAs is suggestive of general defects in the intracellular, microtubule-based, trafficking routes.

Aphidius ervi teratocytes release an extracellular enolase.

We report the cloning of a gene and the characterization of the encoded protein, which is released by the teratocytes of the parasitoid Aphidius ervi in the haemocoel of the host aphid Acyrthosiphon pisum. The studied protein was identified by LC-MS/MS, and the gathered information used for isolating the full length cDNA. The corresponding gene was made of 3 exons and 2 introns, and was highly expressed in the adult wasps and in parasitized hosts.

The molecular chaperone Hsp90 is a component of the cap-binding complex and interacts with the translational repressor Cup during Drosophila oogenesis.

In metazoa, the spatio-temporal translation of diverse mRNAs is essential to guarantee proper oocyte maturation and early embryogenesis. The eukaryotic translation initiation factor 4E (eIF4E), which binds the 5' cap structure of eukaryotic mRNAs, associates with either stimulatory or inhibitory factors to modulate protein synthesis. In order to identify novel factors that might act at the translational level during Drosophila oogenesis, we have undertaken a functional proteomic approach and isolated the product of the Hsp83 gene, the evolutionarily conserved chaperone Hsp90, as a specific component of the cap-binding complex.

The translational repressor Cup associates with the adaptor protein Miranda and the mRNA carrier Staufen at multiple time-points during Drosophila oogenesis.

In Drosophila melanogaster, Cup acts as a translational regulator during oocyte maturation and early embryogenesis. In this report, we show that Cup associates with Miranda, an adaptor protein involved in localization of specific mRNA complexes in both neuroblasts and oocytes. miranda and cup also interact genetically, since reducing miranda activity worsens the oogenesis defects associated with different cup mutant alleles.

dSTAM expression pattern during wild type and mutant egg chamber development in D. melanogaster.

STAM (signal-transducing adaptor molecule) is a protein highly conserved from yeast to mammals. In Drosophila melanogaster the basic molecular architecture of the protein is comprised of a N-terminal VHS domain, an ubiquitin-interacting motif and a central Src homology-3 domain. In this paper we examine the expression pattern of the stam gene and the localisation of the STAM protein during D.

A gamma-glutamyl transpeptidase of Aphidius ervi venom induces apoptosis in the ovaries of host aphids.

Parasitism by the endophagous braconid Aphidius ervi (Hymenoptera, Braconidae) has a negative impact on the reproductive activity of its host, Acyrthosiphon pisum (Homoptera, Aphididae). The host castration is induced by the parasitoid venom and is reproduced by the injection of chromatographic fractions highly enriched with two proteins, of 18 (p18) and 36 kDa (p36) in size, respectively. Here we demonstrate that these bioactive proteins trigger apoptosis of the cells in the germaria and ovariole sheath of the host aphid.

nup154 genetically interacts with cup and plays a cell-type-specific function during Drosophila melanogaster egg-chamber development.

Nucleoporin Nup154 is a Drosophila component of the nuclear pore complex (NPC), evolutionarily conserved from yeast to humans. While functional studies carried out in both yeast and metazoan cells indicated that Nup154 homologs are key elements of the NPC framework, the striking phenotypic specificity displayed by nup154 hypomorphic mutant alleles suggested that Nup154 might play additional roles in the context of the NPC. Actually, genetic analyses demonstrated that mutant nurse-cell nuclei do not undergo a normal chromosome dispersal process, uncovering an essential requirement for nup154 gene function during oogenesis.

Functional dissection of the Drosophila Kallmann's syndrome protein DmKal-1.

Background: Anosmin-1, the protein implicated in the X-linked Kallmann's syndrome, plays a role in axon outgrowth and branching but also in epithelial morphogenesis. The molecular mechanism of its action is, however, widely unknown. Anosmin-1 is an extracellular protein which contains a cysteine-rich region, a whey acidic protein (WAP) domain homologous to some serine protease inhibitors, and four fibronectin-like type III (FnIII) repeats.

Embryonic expression pattern of the Drosophila Kallmann syndrome gene kal-1.

The role of kal-1, the gene responsible for the X chromosome-linked form of Kallmann syndrome, is not well definite. In Drosophila, the kal-1 gene encodes a putative protein with the characteristic kal-1 topology but with only two Fibronectin-like type III (FnIII) domains. We studied the embryonic expression pattern of kal-1 using whole mount in situ hybridization.

Oogenesis in Drosophila melanogaster: a model system for studying cell differentiation and development.

Drosophila oogenesis is a complex developmental process involving the coordinated differentiation of germ line and somatic cells. Correct execution and timing of cell fate specification and patterning events is achieved during this process by the integration of different cell-cell signalling pathways, eventually leading to the generation of positional information inside the oocyte, that is instrumental for the establishment of embryonic polarity. The large body of data accumulated at both cellular and molecular levels in the last decade clearly demonstrated how Drosophila oogenesis is a genetically tractable system particularly suited for the investigation of key developmental biology questions.