Drosophila melanogaster
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA319893 | ENA |
REPOSITORIES: ENA
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Project description:The circadian clock is an evolutionarily conserved mechanism that drives rhythmic expression of downstream genes. The core circadian clock drives the expression of clock-controlled genes either directly or indirectly, which in turn play critical roles in carrying out many rhythmic physiological processes. Nevertheless, the molecular mechanisms by which clock output genes orchestrate rhythmic signals from the brain to peripheral tissues are largely unknown. Here we explored the role of one rhythmic gene, Achilles, in regulating the rhythmic transcriptome in fly heads. Achilles is a clock-controlled gene in Drosophila that encodes a putative RNA-binding protein. Achilles expression is not detectable in core clock neurons using in-situ hybridization, although its expression is found in neurons throughout the fly brain. Together, these observations argue against a role for Achilles in regulating the core clock. To assess its impact on circadian mRNA rhythms, we performed RNA sequencing (RNAseq) to compare the rhythmic transcriptomes of control flies and those with diminished Achilles expression in all neurons. Consistent with previous observations, we observe dramatic upregulation of immune response genes upon knock-down of Achilles. Furthermore, a subset of circadian mRNAs lose their rhythmicity in Achilles knock-down flies, suggesting that a subset of the rhythmic transcriptome is regulated either directly or indirectly by Achilles. These Achilles-mediated rhythms include many genes involved in immune function and neuronal signaling such as Prosap, Nemy and Jhl-21. Comparison of RNAseq data from control flies reveal that only 42.7% of clock-controlled genes in the fly brain are rhythmic in both males and females. As mRNA rhythms of core clock genes are largely invariant between the sexes, this observation suggests that sex-specific mechanisms are an important, and heretofore under-appreciated, regulator of the rhythmic transcriptome.
2018-12-31 | GSE120100 | GEO
Project description:Circadian clocks coordinate time-of-day specific metabolic and physiological processes to maximize performance and fitness. In addition to light, which is considered the strongest time cue to entrain animal circadian clocks, metabolic input has emerged as an important signal for clock modulation and entrainment, especially in peripheral clocks. Circadian clock proteins have been to be substrates of O-GlcNAcylation, a nutrient sensitive post-translational modification (PTM), and the interplay between clock protein O-GlcNAcylation and other PTMs, like phosphorylation, is expected to facilitate the regulation of circadian physiology by metabolic signals. Here, we used mass spectrometry proteomics to identify PTMs on PERIOD, the key biochemical timer of the Drosophila clock, over the circadian cycle.
2017-11-23 | MSV000081736 | MassIVE
Project description:The intestinal microbiota has been identified as an environmental factor that markedly impacts energy storage and body fat accumulation, yet the underlying mechanisms remain unclear. Here we show that the microbiota regulates body composition through the circadian transcription factor NFIL3. Nfil3 transcription oscillates diurnally in intestinal epithelial cells and the amplitude of the circadian oscillation is controlled by the microbiota through type 3 innate lymphoid cells (ILC3), STAT3, and the epithelial cell circadian clock. NFIL3 controls expression of a circadian lipid metabolic program and regulates lipid absorption and export in intestinal epithelial cells. These findings provide mechanistic insight into how the intestinal microbiota regulates body composition and establish NFIL3 as an essential molecular link among the microbiota, the circadian clock, and host metabolism.
2017-09-26 | GSE100339 | GEO
Project description:Circadian rhythms are daily oscillations in metabolism and physiology and are generated by the circadian clock. In fruit fly Drosophila, the circadian clock is generated by a transcription-translation feedback loop in which the positive arm components Clock and Cycle activate the expression of the Period and Timeless genes of negative arm, as well as other circadian clock-regulated genes. After being retained in the cytoplasm, the Period and Timeless proteins then migrate to the nucleus to inhibit the Clock/Cycle transactivity by protein-protein interactions (PPIs). The endogenous circadian clock is synchronized with the geological (solar) clock via photoreceptors. Drosophila Cryptochrome protein functions as a circadian photoreceptor. In the early morning, exposure of Cryptochrome to light causes a conformational change in it which results in the formation of new PPIs. Light-activated Cryptochrome interacts with the core clock protein Timeless and the E3 ubiquitin ligase-substrate adaptor protein Jetlag, which results in the ubiquitylation of Timeless by Jetlag-E3 ligase complex and then degradation of Timeless within minutes by proteasome system. Rapid degradation of Timeless and then its partner protein Period, because of its instability in the absence of Timeless, relieves the inhibition on the Clock/Cycle transcription factors suddenly. Therefore, Clock/Cycle-driven expression of circadian clock-regulated genes are induced again, which is the restart of the circadian oscillation or the resetting of the clock. Following Timeless degradation, Cryptochrome is also degraded so the photoreceptor mechanism does not start a new resetting signal until all the required factors are re-synthesized in a circadian manner. Light-dependent degradation of Drosophila Cryptochrome can be observed in Drosophila S2 cell line in culture. In this project, we aimed at finding the interactome of Cryptochrome protein in Drosophila S2 cell line under light and in the dark using proximity labeling method. Because of the fast kinetics of Cryptochrome degradation, we chose the enzymes that can saturate in less than one hour. TurboID (TID) and APEX2 enzymes label proteins with biotin in the proximity even though they work with different mechanisms. They were fused to Cryptochrome protein, and proximity labeling was performed in the dark or under light. We have identified novel light-dependent or -independent interactors of Drosophila Cryptochrome and confirmed some of them using classical coimmunoprecipitation technique.
2024-02-05 | PXD038052 | Pride
Project description:Though it is well established that immunological functions of CD4+ T cells are time of day-dependent, the underlying molecular mechanisms remain largely obscure. To address the question whether T cells themselves harbor a functional clock driving circadian rhythms of immune function, we analyzed clock gene expression and immune responses of CD4+ T cells purified from blood of healthy subjects at different time points throughout the day. Circadian clock function as well as immune function was further analyzed in cultivated T cells and circadian clock reporter systems. We found robust rhythms of clock gene expression as well as, after stimulation, of IFN-g production and CD40L expression in both freshly isolated and in cultured CD4+ T cells. Moreover, circadian luciferase reporter activities in CD4+ T cells and in thymic sections from PER2::LUCIFERASE reporter mice suggest that endogenous T cell clock rhythms are self-sustained under constant culture conditions. Microarray analysis of stimulated CD4+ T cell cultures revealed a rhythmic regulation of the NF-kB pathway as a candidate mechanism regulating circadian immune responses. Collectively, these data demonstrate for the first time that CD4+ T cell responses are regulated by an intrinsic cellular circadian oscillator capable of driving rhythmic adaptive immune responses in vitro and in vivo. The study is designed with 3 biological replicates from three different time points.
2012-04-30 | E-GEOD-29583 | biostudies-arrayexpress
Project description:CWO binding sites were genome-widely searched with Drosophila genome tiling array. Abstract: The Drosophila circadian clock consists of integrated autoregulatory feedback loops, making the clock difficult to elucidate without comprehensively identifying the network components in vivo. Previous studies have adopted genome-wide screening for clock-controlled genes using high-density oligonucleotide arrays that identified hundreds of clock-controlled genes. In an attempt to identify the core clock genes among these candidates, we applied genome-wide functional screening using an RNAi system in vivo. Here we report the identification of novel clock gene candidates including clockwork orange (cwo), a transcriptional repressor belonging to the basic helix-loop-helix-ORANGE family. cwo is rhythmically expressed and directly regulated by CLK-CYC through canonical E-box sequences. A genome-wide search for its target genes using the Drosophila genome tilling array revealed that cwo forms its own negative feedback loop and directly suppresses the expression of other clock genes through the E-box sequence. Furthermore, this negative transcriptional feedback loop contributes to sustaining a high-amplitude circadian oscillation in vivo. Based on these results, we propose that the competition between cyclic CLK-CYC activity and the adjustable threshold imposed by CWO keeps E-box-mediated transcription within the controllable range of its activity, thereby rendering a Drosophila circadian clock capable of generating high-amplitude oscillation. Keywords: ChIP-chip
2007-04-24 | GSE7569 | GEO
Project description:The peripheral circadian oscillator plays an essential role in synchronizing local physiology to operate in a circadian manner via regulation of the expression of clock-controlled genes. In the murine uterus, the endometrial stromal cells undergo proliferation and differentiation into decidual cells in response to ovarian steroids and blastocyst implantation at the early stage of pregnancy. The circadian clock genes are attenuated in the decidualizing cells only 2 days after implantation. The present study aimed to evaluate the circadian rhythms of clock genes and clock-controlled genes expressed in the rat uterus endometrial stromal cells (UESCs) during the stage of implantation. The real-time monitoring system of Per2 promoter activity was employed to precisely evaluate the generation of circadian rhythms in the UESCs prepared from transgenic rats constructed with mouse Per2 promoter-destabilized luciferase reporter gene (Per2-dLuc). During monitoring Per2-dLuc oscillation after synchronization with dexamethasone, total RNA was isolated from the cultured UESCs at four-time points (6-h interval) in the first to second phases and cDNA was synthesized. cRNA was synthesized from the double strand cDNA and hybridized on a DNA microarray. RT-qPCR was performed to confirm the expression of core clock genes revealed by DNA microarray analysis. Several clock genes such as Bmal1, Rev-erbα, and Per2 displayed significant rhythms. Of 12,252 genes showing significantly expression, 7,235 genes displayed significant alterations (p < 0.05). These genes were related to growth factors, transcription factors, receptors, channels, and enzymes. Some candidates as clock-controlled genes were evaluated by using RNA interference to Bmal1 mRNA. Down-regulation of Igf1 gene expression was observed by Bmal1 silencing, whereas the expression of Inhβa, Fas, and Caspase3 were significantly increased. These results indicate that clock-controlled genes are up- or down-regulated in rat UESCs during the stage of decidualization. DNA microarray analysis coupled with RNA interference will be helpful to understand the physiological roles of some oscillating genes in blastocyst implantation and placenta formation. The circadian clock positively or negatively regulates the expression of clock-controlled genes, including growth factors and apoptosis-related factors. To search the clock-controlled genes expressed during the period of implantation, we analyzed the clock genes and clock-controlled genes expressed in cultured uterus endometrial stromal cells prepared from pregnant rats at the stage of implantation using DNA microarray technology. We used transgenic rats constructed with mouse Per2 promoter-destabilized luciferase (Per2-dLuc) reporter gene to precisely adjust the time of gene expression. In addition, several genes of significantly expressed genes including growth factor genes and apoptosis-related genes were analyzed using RNA interference to Bmal1 mRNA whether these were controlled under circadian clockwork.
2013-07-23 | E-GEOD-49080 | biostudies-arrayexpress
Project description:Using high throughput sequencing of Drosophila head RNA, a small set of miRNAs that undergo robust circadian oscillations in levels were discovered. We concentrated on a cluster of six miRNAs, mir-959-964, all of which peak at about ZT12 or lights-off. The data indicate that the cluster pri-miRNA is transcribed under bona fide circadian transcriptional control and that all 6 mature miRNAs have short half-lives, a requirement for oscillating. Manipulation of food intake dramatically affects the levels and timing of cluster miRNA transcription with no more than minor effects on the core circadian oscillator. This indicates that the central clock regulates feeding, which in turn regulates proper levels and cycling of the cluster miRNAs. Viable Gal4 knock-in as well as cluster knock-out and over-expression strains were used to localize cluster miRNA expression as well as explore their functions. The adult head fat body is a major site of expression, and feeding behavior, innate immunity, metabolism, and perhaps stress responses are under cluster miRNA regulation. The feeding behavior results indicate that there is a feedback circuit between feeding time and cluster miRNA function as well as a surprising role of post-transcriptional regulation in these behaviors and physiology. Six samples of small RNA libraries (RNA size 19 to 29 nucleotides long) were prepared from Drosophila heads, each collected at one circadian time point during a light-dark cycle (ZT0, ZT4, ZT8, ZT12, ZT16, ZT20).
2012-11-02 | E-GEOD-40943 | biostudies-arrayexpress
Project description:Circadian expression profiling of purified clock neurons in adult Drosophila
| PRJNA127387 | ENA
Project description:Circadian biology regulates inflammatory responses in mice via the clock protein REVERBα, resulting in altered mortality and morbidity. The influence of this immune-modulation pathway in humans is unclear, but may affect outcomes after transplant. We sought to determine whether the circadian clock affects primary graft dysfunction after lung transplantation, and the role of the clock protein REVERBα. In this study we investigated the action of a synthetic REVERB ligand, (GSK4112) in human monocyte-derived macrophages.
2019-05-13 | E-MTAB-6478 | biostudies-arrayexpress