The mitochondrial matrix is unique in that it must integrate folding and assembly of proteins derived from nuclear and mitochondrial genomes. In C. elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial matrix-localized ornithine trans-carbamylase (OTC) induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here, we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response involved widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing due to transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3. This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt. Overall design: triplicate experiment of 2 conditions (untreated, GTPP treatment)
Mitochondrial unfolded protein response controls matrix pre-RNA processing and translation.
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View SamplesGranulomas are immune cell aggregates formed in response to persistent inflammatory stimuli. Granuloma macrophage subsets are diverse and carry varying copy numbers of their genomic information. The molecular programs that control the differentiation of such macrophage populations in response to a chronic stimulus, though critical for disease outcome, have not been defined. In this study, we performed scRNA-Seq experiments to gain insights into the transcriptional regulation of polyploid macrophage differentiation in response to chronically persistent inflammatory stimuli. Overall design: scRNA-Seq was performed on FACS-sorted 2c and >4c DNA content polyploid macrophages after six days of bacterial lipoprotein, FSL-1 treatment of bone marrow-derived macrophage precursors. 2c DNA content macrophages treated with M-CSF alone were used as controls. CEL-Seq2 protocol was used for single cell sequencing (Hashimshony et al. 2016).
DNA Damage Signaling Instructs Polyploid Macrophage Fate in Granulomas.
Specimen part, Cell line, Subject
View SamplesThe objective of this experiment was to test the effect, at a transcrptomic level, of lymphotoxin-beta receptor activation in HBV-infected differentiated HepaRG cells
Specific and nonhepatotoxic degradation of nuclear hepatitis B virus cccDNA.
No sample metadata fields
View SamplesThe zebrafish heart remarkably regenerates after a severe ventricular damage followed by inflammation, fibrotic tissue deposition and removal concomitant with cardiac muscle replacement. We have investigated the role of the endocardium in this regeneration process. 3D-whole mount imaging in injured hearts revealed that GFP-labelled endocardial cells in ET33mi-60A transgenic fish become rapidly activated and highly proliferative at 3 days post cryoinjury (dpci). Endocardial cells extensively expand within the injury site and organize to form a coherent structure at 9 dpci that persists throughout the regeneration process. Upon injury, endocardial cells strongly up-regulate the Notch pathway ligand delta like4 (dll4) and the Notch receptors notch1b, notch2 and notch3. Expression profiling showed that Notch signalling inhibition affects endocardial gene expression and genes related to extracellular matrix remodelling and inflammation. Gain- and loss-of-function experiments revealed that Notch is required for the organization of the endocardium, attenuation of the inflammatory response and cardiomyocyte proliferation. These results demonstrate a novel structural and signalling role for the endocardium during heart regeneration. Overall design: RNA was extracted from apical tip of heart ventricles 72h after cryoinjured adult zebrafish heart treated with DMSO (Controls) or RO gamma secretase inhibitor at 24 and 48h post injury.
Notch signalling restricts inflammation and <i>serpine1</i> expression in the dynamic endocardium of the regenerating zebrafish heart.
No sample metadata fields
View SamplesEffects of loss-of-function of AtMIKC* MADS-box genes on the mature Arabidopsis pollen transcriptome.
MADS-complexes regulate transcriptome dynamics during pollen maturation.
Age, Specimen part
View SamplesWe use the Tlr2 mutant of zebrafish embryos model to study the transcriptome response to Mycobacterium marinum infection. We injected M.marinum into the caudal vein at 28 hours post fertilization and took samples at 4 days post infection. Overall design: This deep sequence study was designed to determine the gene expression profile in the Tlr2 mutant and heterozygote by M.marinum infection. RNA was isolated at 4 days post infection. Tlr2 mutants and heterozygotes zebrafish embryos were micro-injected into the caudal vein with 150CFU M.marinum, or PBS as a control at 28 hours post fertilization. After injections embryso were transerred into fresh egg water and incubated at 28 degree. At 4 days post infection triplicateds of 10 embryos per condition were snapfrozen in liquid nitogen, and total RNA was isolated using TRIZOL reagent.
Infection and RNA-seq analysis of a zebrafish tlr2 mutant shows a broad function of this toll-like receptor in transcriptional and metabolic control and defense to Mycobacterium marinum infection.
No sample metadata fields
View SamplesThe goal of this project was to assess differential gene expression in the Ventral Nerve Cord (VNC) of adult Drosophila 5 hours after severing of the legs, wings and head. Overall design: Gene expression was assessed in 2 conditions (No Injury and 5-hrs after Injury) in the w1118 strain of Drosophila melanogaster. 5 independent biological replicates were used for each condition. RNA was isolated from the adult Ventral Nerve Cord (VNC) for the gene expression analysis (RNAseq).
A novel <i>Drosophila</i> injury model reveals severed axons are cleared through a Draper/MMP-1 signaling cascade.
Specimen part, Cell line, Subject
View SamplesChromatin in eukaryotic nuclei is organized at multiple scales, from individual nucleosomes to specific loops between regulatory sequences, to the folding of large genomic regions into topological domains and segregation of whole chromosomes into territories. Many of the chromatin proteins that regulate this architecture, including the essential Polycomb Group (PcG) proteins, are themselves organized into subnuclear structures. Deciphering mechanistic links between protein organization and genome architecture requires precise description and mechanistic perturbations of both. Using super-resolution microscopy, we characterized the nanoscale organization of PcG proteins in Drosophila cells and find hundreds of small protein clusters, distinct from the large PcG bodies present in just a few copies per cell that have been the focus of previous investigations. We manipulated PcG clusters either by disrupting the polymerization activity of the conserved Sterile Alpha Motif (SAM) of the PcG protein Polyhomeotic (Ph) or increasing Ph levels in Drosophila S2 cells. Disrupting clustering using Ph SAM mutations disrupts chromatin interactions on scales from 50kb to 13Mb while increasing Ph levels increases both cluster number and long range chromatin interactions. RNA-seq and qPCR indicate that both perturbations also alter expression levels of many genes. Molecular simulations suggest a model in which PcG cluster formation on chromatin is governed by the kinetics of association between Ph SAMs and PcG cluster size is bounded by the affinity and occupancy of chromatin binding sites. Our results suggest that nanoscale organization of PcG proteins into small, abundant clusters on chromatin through the polymerization activity of Ph SAM shapes genome architecture by mediating numerous long-range chromatin interactions. Overall design: Two biological replicates of three RNA-seq samples from S2 cells, cells overexpresing wild-type Ph, and cells overexpressing polymerization defective Ph-ML
Chromatin topology is coupled to Polycomb group protein subnuclear organization.
Cell line, Subject
View SamplesHuman testicular cells were isolated mechanically and enzymatically from testis of braindead donors and from urological samples. The expression of genes was studied at baseline and 1,25(OH)2D treated conditions.
Testicular synthesis and vitamin D action.
Specimen part
View SamplesTo characterize LICs in ALL irrespective of surface markers expression, we investigated leukemia initiating activities of cellular subfractions of patient-derived xenograft BCP-ALL cells sorted according to different cell cycle phases (i.e. G0/G1 and G2/M) followed by transplantation onto NOD/SCID mice. All cell fractions led to leukemia engraftment indicating LIC activity irrespective of cell cycle stage. Most importantly, cells isolated from G0/G1 cell cycle phases led to early leukemia engraftment in contrast to cells from late cell cycle (G2/M). To further characterize cells with different engraftment potential in vivo, we analyzed the gene expression profiles of early (G1b early) and late (G2/M) engrafting cells.
Leukemia reconstitution <i>in vivo</i> is driven by cells in early cell cycle and low metabolic state.
Specimen part
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