Transcriptional profiling of Drosophila melanogaster heads from experimentally-evolved populations
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ABSTRACT: We used RNA sequencing to examine the transcriptomes of male and female heads from experimentally-evolved D. melanogaster populations after 117 generations of mating system manipulation in order to examine the pattern of evolution in sex-biased genes. Examined head transcriptomes of 3 monogamous populations and 3 polygamous populations, both males and females, for 12 total samples.
Project description:Investigation of gene expression level changes in evolved polygamous and monogamous populations of Drosophila melanogaster. The populations investigated are described in Hollis et al. 2011. Populations with elevated mutation load do not benefit from the operation of sexual selection. Journal of Evolutionary Biology 24: 1918-1926. A study using total RNA extracted from male and female virgin 4-day old Drosophila melanogaster and then transcriptionally profiled with 12x135k Nimblegen arrays. Also, transcriptional profiling of male and female heads from the same populations using Illumina RNA-Seq.
Project description:By combining an experimental evolution approach with genomic techniques, we investigated the effects of seminal fluid on female gene expression. In our study, we experimentally manipulated the mating system in replicate populations of D. melanogaster, by removing post-copulatory sexual selection, with the aim of testing differences in short term post-mating reaction of females evolved under different mating strategies. We show that monogamous females suffer decreased fecundity, regardless of the type of male they were mated with, and that their post-mating gene expression profiles differ significantly from promiscuous females, involving 1141 transcripts (9% of the genes tested). These transcripts are active in several tissues, mainly ovaries, neural tissues, midgut and spermathecae, and are involved in metabolic processes, reproduction and signaling pathways. Our results provide a list of candidate genes responsible for the decrease in female fecundity in the absence of post-copulatory sexual selection, and demonstrate how the female post-mating response can evolve under different mating systems over relatively short time frames. From an LHM base population, we created 8 replicate populations and maintained them under experimental evolution: 4 populations were allowed to mate only once every generation (monogamy), and the other 4 were kept under the standard mating protocol (promiscuous). After 46 generations, we crossed males and females within the same population and with individuals of the opposite treatment. Mated female flies were frozen 6 h after mating and RNA extracted. Two biological replicates per cross per population (2x2x8=32 samples).
Project description:We used RNA-seq to investigate gene expression variation in Malpighian tubules, which have a function analogous to that of human kidneys. In order to characterize population differentiation, we sequenced the Malpighian tubule transcriptomes of flies derived from two populations, one from sub-Saharan Africa (Zimbabwe) and one from Europe (the Netherlands). Males and females were examined separately. Overall, we found a high amount of differential expression between sexes (2,308 genes) and populations (2,474 genes). Although most of the differentially expressed genes were consistent between sexes and populations, there were 615 genes showed sex-biased expression in only one population and 557 genes showed population-biased expression in only one sex. mRNA expression profiles of Drosophila melanogaster Malpighian tubules from adult males and females from a European and an African population (2 biological replicates per sex and population)
Project description:Cancer represents a complex family of diseases, characterized by the uncontrolled malignant growth of a particular cell type and by metastatic dissemination of these transformed cells to secondary sites. The hallmark tumor features emerge as a result of aberrant cellular signaling and pathological gene expression driven by cooperating genetic lesions. Being the convergence points of signaling pathways, transcription factors play crucial roles in cancer. Here, we define a transcription factor network that triggers an abnormal gene expression program promoting malignancy of clonal tumors, generated in Drosophila imaginal disc epithelium by overexpressing oncogenic Ras (RasV12) in a background lacking the tumor suppressor gene scribble (scrib1). We show that the nuclear receptor Ftz-F1 and the ETS-domain transcription factor Ets21c are upregulated in the rasV12scrib1 tumors in response to activated Jun-N-terminal kinase (JNK) signaling. Depletion of either Ftz-F1 or Ets21c improves viability of Drosophila larvae suffering from tumors, and this effect can be further enhanced by simultaneous removal of the Jun-dimerizing partner Fos. We identified Fos as a key mediator of JNK-induced differentiation defects and further show that Ftz-F1 and Fos are required for tumor invasiveness. However, only Ets21c can efficiently substitute for JNK and cooperate with RasV12 to induce invasive tumors that recapitulate hallmarks of malignant rasV12scrib1 tumors including elevated matrix metalloprotease (MMP1) and insulin-like peptide 8 (Dilp8) expression. In conclusion, our study provides functional evidence for a network of cooperating transcription factor that dictates target gene expression and promotes tumor phenotypes in response to aberrant JNK signaling. 20 samples analyzed, 4 control samples
Project description:see Super Series Summary We treated Drosophila S2-DRSC cells for 1, 2, 4 and 20 h with 10 µM JQ1 and compared their gene expression to DMSO-treated control cells (1 and 20 h).
Project description:Background: The question of how cells re-establish gene expression states after cell division is still poorly understood. Genetic and molecular analyses have indicated that Trithorax group (TrxG) proteins are critical for the long-term maintenance of active gene expression states in many organisms. A generally accepted model suggests that TrxG proteins contribute to maintenance of transcription by protecting genes from inappropriate Polycomb group (PcG)-mediated silencing, instead of directly promoting transcription. Results: Here we report a physical and functional interaction in Drosophila between two members of the TrxG, the histone methyltransferase ASH1 and the bromodomain and extraterminal family protein FSH. We investigated this interface at the genome level, uncovering a widespread colocalization of both proteins at promoters and PcG-bound intergenic elements. Our integrative analysis of chromatin maps and gene expression profiles revealed that the observed ASH1-FSH binding pattern at promoters is a hallmark of active genes. Inhibition of FSH-binding to chromatin resulted in global down-regulation of transcription. In addition, we found that genes displaying marks of robust PcG-mediated repression also have ASH1 and FSH bound to their promoters. Conclusions: Our data strongly favor a global coactivator function of ASH1 and FSH during transcription, as opposed to the notion that TrxG proteins impede inappropriate PcG-mediated silencing, but are dispensable elsewhere. Instead, our results suggest that PcG repression needs to overcome the transcription-promoting function of ASH1 and FSH in order to silence genes. Refer to individual Series
Project description:We compare fore- and mid-brain transcriptomes of reproductive males in monogamous and non-monogamous species pairs of Peromyscus mice, Microtus voles, parid songbirds, dendrobatid frogs, and Xenotilapia species of cichlid fishes. Our study provides evidence of a universal transcriptomic mechanism underlying the evolution of monogamy in vertebrates.
Project description:The ability to cope with infection by a parasite is one of the major challenges for any host species and is a major driver of evolution. Parasite pressure differs between habitats. It is thought to be higher in tropical regions compared to temporal ones. We infected Drosophila melanogaster from two tropical (Malaysia and Zimbabwe) and two temperate populations (the Netherlands and North Carolina) with the generalist entomopathogenic fungus Beauveria bassiana to examine if adaptation to local parasite pressures led to differences in resistance. Contrary to previous findings we observed increased survival in temperate populations. This, however, is not due to increased resistance to infection per se, but rather the consequence of a higher general vigor of the temperate populations. We also assessed transcriptional response to infection within these flies eight and 24 hours after infection. Only few genes were induced at the earlier time point, most of which are involved in detoxification. In contrast, we identified more than 4,000 genes that changed their expression state after 24 hours. This response was generally conserved over all populations with only few genes being uniquely regulated in the temperate populations. We furthermore found that the American population was transcriptionally highly diverged from all other populations concerning basal levels of gene expression. This was particularly true for stress and immune response genes, which might be the genetic basis for their elevated vigor. mRNA profiles of whole Drosophila melanogaster adult males from an African, American, Asian and European population after infection with Beauveria bassiana. Samples include uninfected controls, 8h after infection and 24h after infection. 3 biological replicates each (2 in the case of American controls).