Background: Changes in gene regulation are thought to be crucial for the adaptation of organisms to their environment. Transcriptome analyses can be used to identify candidate genes for ecological adaptation, but can be complicated by variation in gene expression between tissues, sexes, or individuals. Here we use high-throughput RNA sequencing of a single Drosophila melanogaster tissue to detect brain-specific differences in gene expression between the sexes and between two populations, one from the ancestral species range in sub-Saharan Africa and one from the recently colonized species range in Europe. Results: Relatively few genes (<100) displayed sexually dimorphic expression in the brain, but there was an enrichment of sex-biased genes, especially male-biased genes, on the X chromosome. Over 340 genes differed in brain expression between flies from the African and European populations, with the between-population divergence being highly correlated between males and females. The differentially expressed genes include those involved in stress response, olfaction, and detoxification. Expression differences were associated with transposable element insertions at two genes implicated in insecticide resistance (Cyp6g1 and CHKov1). Conclusions: Analysis of the brain transcriptome revealed many genes differing in expression between populations that were not detected in previous studies using whole flies. There was little evidence for sex-specific regulatory adaptation in the brain, as most expression differences between populations were observed in both males and females. The enrichment of genes with sexually dimorphic expression on the X chromosome is consistent with dosage compensation mechanisms affecting sex-biased expression in somatic tissues. Overall design: mRNA profiles of Drosophila melanogaster brains from adult males and females from a European and an African population (2 biological replicates each)
Population and sex differences in Drosophila melanogaster brain gene expression.
Sex, Subject
View SamplesTranscriptome analysis may provide means to investigate the underlying genetic causes of shared and divergent phenotypes in different populations and help to identify potential targets of adaptive evolution. Applying RNA sequencing to whole male Drosophila melanogaster from the ancestral tropical African environment and a very recently colonized cold-temperate European environment at both standard laboratory conditions and following a cold shock, we seek to uncover the transcriptional basis of cold adaptation. In both the ancestral and the derived populations, the predominant characteristic of the cold shock response is the swift and massive upregulation of heat shock proteins and other chaperones. Although we find ~30% of the genome to be differentially expressed following a cold shock, only relatively few genes (n=26) are up- or down-regulated in a population-specific way. Intriguingly, 24 of these 26 genes show a greater degree of differential expression in the African population. Likewise, there is an excess of genes with particularly strong cold-induced changes in expression in Africa on a genome-wide scale. The analysis of the transcriptional cold shock response most prominently reveals an upregulation of components of a general stress response, which is conserved over many taxa and triggered by a plethora of stressors. Despite the overall response being fairly similar in both populations, there is a definite excess of genes with a strong cold-induced fold-change in Africa. This is consistent with a detrimental deregulation or an overshooting stress response. Thus, the canalization of European gene expression might be responsible for the increased cold tolerance of European flies. Overall design: mRNA profiles of whole Drosophila melanogaster adult males from a Africa (4 lines) and Europe (4 lines) during a 7h cold shock experiment. Samples include room temperature controls, 3.5h into the cold shock, 15 minutes after recovery and 90 minutes after recovery. 2 biological replicates each.
Canalization of gene expression is a major signature of regulatory cold adaptation in temperate Drosophila melanogaster.
Sex, Subject
View SamplesThe 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. Overall design: 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).
Survival Rate and Transcriptional Response upon Infection with the Generalist Parasite Beauveria bassiana in a World-Wide Sample of Drosophila melanogaster.
Sex, Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A unique H2A histone variant occupies the transcriptional start site of active genes.
Sex, Age, Specimen part
View SamplesChromatin performs numerous functions during cellular differentiation, and therefore it must be capable of adopting a multitude of different structures. How these various structures are established is poorly understood, but we propose that specific histone H2A variants will have a key role in remodelling chromatin during differentiation. Structurally, we show here that the gain of just a single acidic amino acid residue has generated a new mouse H2A.Bbd-like histone variant, H2A.Lap1, and that when incorporated into nucleosomal arrays imparts on them unique biophysical properties that are distinct from arrays containing either H2A or human H2A.Bbd. Functionally, we identify H2A.Lap1 as a novel chromatin component of active genes that are expressed during spermatogenesis, and in combination with H2A.Z create a unique chromatin landscape at the start site of transcription. During round spermatid differentiation, H2A.Lap1 dramatically loads onto the inactive X chromosome enabling a subset of its genes to be transcriptionally activated.
A unique H2A histone variant occupies the transcriptional start site of active genes.
Sex, Age, Specimen part
View SamplesThe aim of the experiment is provide a reference dataset for placing wheat grain transcriptome experiments in a developmental context. RNA was isolated from whole grain tissue of replicate wheat cv. Hereward plants at 6, 8, 10, 12, 14, 17, 21, 28, 35 and 42 days after anthesis (daa). Also supplied are array data for grain sampled at 14, 21 and 28 daa under control, hot, dry and hot&dry conditions to illustrate the importance of developmental context in interpretation.
Transcriptome analysis of grain development in hexaploid wheat.
Age, Specimen part, Time
View SamplesWe investigated the differential regulation patterns of type I anti-CD20 monoclonal antibody (mAb) rituximab and type II obinutuzumab on a transcriptional level. Using a panel of MCL cell lines, we determined the effects of obinutuzumab and rituximab as monotherapies as well as in combination on cell viability and proliferation.
Differential regulation patterns of the anti-CD20 antibodies obinutuzumab and rituximab in mantle cell lymphoma.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Histone H2A.Z inheritance during the cell cycle and its impact on promoter organization and dynamics.
Specimen part, Cell line
View SamplesComparison of gene expression profiles between neuroblastoma samples and Ewing family tumor samples. RNA from native tumor samples was processed for DNA-microarray analysis using Affymetrix HG-U133A microarrays. Primary image analysis was performed using MAS 5.0 and data were scaled to an target intesity of 500.
DNA microarrays reveal relationship of Ewing family tumors to both endothelial and fetal neural crest-derived cells and define novel targets.
No sample metadata fields
View SamplesWhile it has been clearly established that well positioned H2A.Z-containing nucleosomes flank the nucleosome depleted region (NDR) at the transcriptional start site (TSS) of active mammalian genes 1,2, how this chromatin-based information is transmitted through the cell cycle is unknown. We show here that in trophoblast stem (TS) cells, the level of H2A.Z at promoters decreases during S phase coinciding with homotypic (H2A.Z/H2A.Z) nucleosomes flanking the TSS becoming heterotypic (H2A.Z/H2A). Surprisingly, these nucleosomes remain heterotypic at M phase. At the TSS, we identify an unstable heterotypic H2A.Z-containing nucleosome in G1 which, strikingly, is lost following DNA replication. These dynamic changes in H2A.Z at the TSS mirror a global expansion of the NDR at S and M which, unexpectedly, is unrelated to transcriptional activity. Coincident with the loss of H2A.Z at promoters, it is targeted to the centromere when mitosis begins.
Histone H2A.Z inheritance during the cell cycle and its impact on promoter organization and dynamics.
Specimen part, Cell line
View Samples