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:A method for the long-term maintenance of germ-free flies was established using aseptic isolators. The methodology effectively and reliably yields large numbers of germ-free flies in homogeneous cultures. Germ-free flies exhibited increased lifespan (only female flies) and decreased egg production, markedly reduced fat storage, less midday sleep, and enhanced aggressiveness (male flies). Fructilactobacillus—a species of fly intestinal microbes—was re-colonized in germ-free flies, and these gnotobiotic flies were successfully maintained for numerous generations. The proteome of those flies were analyzed.
