Genome-wide features of neuroendocrine regulation in Drosophila by the basic helix-loop-helix transcription factor DIMMED
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ABSTRACT: Neuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The DIMM basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMMM-bM-^@M-^Ys activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile. By this combined approach, we showed that DIMM binds to conserved E-boxes in enhancers of 212 genes whose expression is enriched in DIMM-expressing NE cells. DIMM binds preferentially to certain E-boxes within first introns of specific gene isoforms. Statistical machine learning revealed that flanking regions of putative DIMM binding sites contribute to its DNA binding specificity. DIMMM-bM-^@M-^Ys transcriptional repertoire features at least 20 LDCV constituents. In addition, DIMM notably targets the pro-secretory transcription factor, CREB-A, but significantly, DIMM does not target any neuropeptide genes. DIMM therefore prescribes the scale of secretory activity in NE neurons, by a systematic control of the regulated secretory pathway at steps that are both proximal and distal. DIMM::MYC ChIP-chip (c929>DIMM::MYC/tubGAL80ts) and control (c929>tubGAL80ts): 2 replicates each, input and IP samples. Total of 8 arrays
Project description:We used AGO-APP, a novel approach to purify Argonaute-bound miRNAs directly from cells and tissues in vivo, to isolate actively inhibiting miRNAs from different neural cell populations in the larval Drosophila central nervous system. This new experimental approach allows to establish cell specific micro-RNA profile with no need to cell sorting.
Project description:The goal of the RNA-Seq experiment was to identify novel target genes of the Decapentaplegic (Dpp) signalling pathway in the early Drosophila embryo. This was thus achieved by identifying genes that were differentially expressed in response to ectopic Dpp signalling (over-expression of Thickviens (Tkv)) in comparison to the control samples.
Project description:The IRE1a-XBP1 pathway, a conserved adaptive response to the unfolded protein response, is indispensable for development of the secretory cells. It maintains endoplasmic reticulum homeostasis by enhancing protein folding and the secretory capacity of the cells. Here, we used a modified ChIP-seq protocol (ChIPmentation) to investigate the genome-wide binding events of the transcription factor XBP1 in differentiated mouse Th2 cells.
Project description:Cell competition promotes the elimination of weaker cells from a growing population. Here we investigate how cells of Drosophila wing imaginal discs distinguish “winners” from “losers” during cell competition. Using genomic and functional assays we have identified Maxwell`s Demon (Mwd), a cell membrane protein conserved in multicellular animals. Our results suggest that the membrane protein Mwd is a dedicated component of the cell competition response that is required and sufficient to label cells as “winners” or “losers”. In Drosophila, the mwd locus produces three isoforms, mwdubi, mwdLose-A and mwdLose-B. Basal levels of mwdubi are constantly produced. During competition the mwdLose isoforms are upregulated in prospective loser cells. Cell-cell comparison of relative mwdLose and mwdubi levels ultimately determine which cell undergoes apoptosis. This “extracellular code” may constitute an ancient mechanism to terminate competitive conflicts among cells. Two samples have been analysed: tub>dmyc>Gal4 transgene cells (competitor) and tub>cd2>Gal4 control cells (non competitor) at different time points (0, 12, 24 and 48 hours). Each experiment was replicated 6 times, three of them by dye swap.
Project description:RNA-seq was performed to confirm the effect of dMyc overexpression or RNAi repression on conserved Myc targets in the Drosophila wing disc.
Project description:RNAseq of dissected adult fat body after DSX isoform is switched using temperature inducible alleles or constructs. Biological duplicates were sequenced for each genotype at each condition.
Project description:RNAseq of dissected adult ovary and testis after DSX isoform is switched using temperature inducible alleles or constructs. Biological duplicates were sequenced for each genotype at each condition.
Project description:The inner nuclear envelope (NE) proteins interact with the nuclear lamina and participate in the architectural compartmentalization of chromosomes. The association of NE proteins with DNA contributes to the spatial rearrangement of chromosomes and their gene expression. Sun1 is an inner nuclear membrane (INM) protein that locates to telomeres and anchors chromosome movement in the prophase of meiosis. Here, we have created Sun1-/- mice and found that these mice are born and grow normally but are reproductively infertile. Detailed molecular analyses showed that Sun1-/- P14 testes are repressed for the expression of reproductive genes and have no detectable piRNA. These findings raise a heretofore unrecognized role of Sun1 in the selective gene expression of coding and non-coding RNAs needed for gemetogenesis. Total RNA was isolated from E14.5 mouse embryonic fibroblasts (MEFs) and and day 9 and 14 mouse whole testes. cDNA samples from paired (same parents) wt (Cy3-labled) and Sun1-/- (Cy5-labled) mice were mixed and hybridized.
Project description:The integrity of the nuclear envelope (NE) is essential to maintain the structural stability of the nucleus. Rupture of the NE has been frequently observed in cancer cells, especially in the context of mechanical challenges, such as physical confinement and migration. However, spontaneous NE rupture events have also been described, without any obvious physical challenges to the cell. The molecular mechanism(s) of these spontaneous NE rupture events remain to be explored. Here, we show that DNA damage and subsequent ATR activation can lead to NE rupture. Upon DNA damage, Lamin A/C is phosphorylated in an ATR-dependent manner, leading to changes in lamina assembly and, ultimately, NE rupture. In addition, we show that cancer cells with intrinsic DNA repair defects undergo frequent events of DNA damage-induced NE rupture, which renders them extremely sensitive to further NE perturbations. Exploiting this NE vulnerability could provide a new angle to complement traditional, DNA damage-based chemotherapy.
Project description:ChIP-seq study analysing adult Drosophila melanogaster head, glial, neuronal and fat body, as well as embryonic RNA pol II and H2A.v binding by employing the GAL4-UAS system to generate GFP-fusion proteins and ChIP-seq