Project description:We conducted a genome-wide expression analysis of wild-type males using three cell populations isolated from mitotic, meiotic and post-meiotic phases of spermatogenesis in Drosophila melanogaster. Our approach was to directly isolate testis regions enriched with RNAs from each of the three specific germline phases. We used microarrays to detail the global gene expression profile in spermatogenesis and identified up- and down-regulated genes between two different spermatogenic phases in pairwise comparisons
Project description:We conducted a genome-wide expression analysis of wild-type males using three cell populations isolated from mitotic, meiotic and post-meiotic phases of spermatogenesis in Drosophila melanogaster. Our approach was to directly isolate testis regions enriched with RNAs from each of the three specific germline phases. We used microarrays to detail the global gene expression profile in spermatogenesis and identified up- and down-regulated genes between two different spermatogenic phases in pairwise comparisons Experiment Overall Design: Cell types present at various stages of spermatogenesis are generally located in a gradient along the proximal-distal axis of the testis, however most are not exclusively restricted to any one geographic region. Cells enriched for mitotic, meiotic and post-meiotic phases were obtained by dissection of apical, proximal and distal regions of the testis, respectively
Project description:Spermiogenesis in Drosophila melanogaster is a highly conserved process and essential for male fertility. In this haploid phase of spermatogenesis, motile sperm are assembled from round cells, flagella are assembled, and needle-shaped nuclei with highly compacted genomes are formed. We aimed at identifying proteins relevant for the maturation phase from spermatids to sperm. As transcription takes place mainly in spermatocytes, and transcripts with relevance for post-meiotic sperm development are translationally repressed for days, we comparatively analysed the prote-ome of larval testes (stages before meiotic divisions), of testes of 1–2-day-old pupae (meiotic and early spermatid stages) and adult flies (late spermatids and sperm). We identified 6677 pro-teins, with 422 solely detected in larval testes, 623 in pupal testes and 634 in adult testes. We analysed a few so far uncharacterized proteins with repect to stage specific expression and im-portance for male fertility. For example, Mst84B (gene CG1988), a very basic cysteine- and lysine-rich nuclear protein, was present in the phase of transition from a histone-based to a pro-tamine-based chromatin structure. CG6332 encodes d-Theg, which is related to the mouse tHEG and human THEG proteins. Mutants of d-Theg lacked sperm in the seminal vesicles and were sterile. The identification of numerous predicted proteins underscores the high potential of pro-teome analysis for future analyses of spermatogenesis.
Project description:Nucleus is a highly structured organelle and contains many functional compartments. While the structural basis for this complex spatial organization of compartments is unknown, a major component of this organization is likely to be the non-chromatin scaffolding called nuclear matrix (NuMat). Experimental evidence over the past decades indicates that most of the nuclear functions are at least transiently associated with the NuMat although the components of NuMat itself are poorly known. Here, we report NuMat proteome analysis from Drosophila melanogaster embryos and discuss its links with nuclear architecture and functions. In the NuMat proteome, we find structural proteins, chaperones related, DNA/RNA binding, chromatin remodeling and transcription factors. This complexity of NuMat proteome is an indicator of its structural and functional significance. Comparison of the 2D profile of NuMat proteome from different developmental stages of Drosophila embryos shows that less than half of the NuMat proteome is constant and rest of the proteins are stage specific dynamic components. This NuMat dynamics suggests a possible functional link between NuMat and the embryonic development. Finally, we also show that a subset of NuMat proteins remain associated with the mitotic chromosomes implicating their role in mitosis and possibly the epigenetic cellular memory. NuMat proteome analysis provides tools and opens up ways to understand nuclear organization and function.
Project description:Drosophila melanogaster is a validated eukaryotic model for immunity-concerned studies in the post-genomic era. In the present study we performed oral experimental infection of D. melanogaster with Pseudomonas aeruginosa (strain ATCC27853). By using a whole genome microarray approach, we intended to identify significant alterations in the expression profile of relevant genes amenable to qualify as new models for the investigation of specific host-parasite interactions.