Background: Long non-coding RNAs (lncRNAs) are increasingly implicated as gene regulators and may ultimately be more numerous than protein-coding genes in the human genome. Despite large numbers of reported lncRNAs, reference annotations are likely incomplete due to their lower and tighter tissue-specific expression compared to mRNAs. An unexplored factor potentially confounding lncRNA identification is inter-individual expression variability. Here, we characterize lncRNA natural expression variability in human primary granulocytes. Results: We annotate granulocyte lncRNAs and mRNAs in RNA-seq data from ten healthy individuals, identifying multiple lncRNAs absent from reference annotations, and use this to investigate three known features (higher tissue-specificity, lower expression, and reduced splicing efficiency) of lncRNAs relative to mRNAs. Expression variability was examined in seven individuals sampled three times at one or more than one month intervals. We show that lncRNAs display significantly more inter-individual expression variability compared to mRNAs. We confirm this finding in 2 independent human datasets by analyzing multiple tissues from the GTEx project and lymphoblastoid cell lines from the GEUVADIS project. Using the latter dataset we also show that including more human donors into the transcriptome annotation pipeline allows identification of an increasing number of lncRNAs, but minimally affects mRNA gene number. Conclusions: A comprehensive annotation of lncRNAs is known to require an approach that is sensitive to low and tight tissue-specific expression. Here we show that increased inter-individual expression variability is an additional general lncRNA feature to consider when creating a comprehensive annotation of human lncRNAs or proposing their use as prognostic or disease markers. Overall design: We used PolyA+ RNA-seq data from human primary granulocytes of 10 healthy individuals to de novo annotate lncRNAs and mRNAs in this cell type and ribosomal depleted (total) RNA-seq data from seven of these individuals sampled three times to analyze lncRNA amd mRNA expression variability
Long non-coding RNAs display higher natural expression variation than protein-coding genes in healthy humans.
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View SamplesComparison of the meis2b+ and the meis2b- halves of the atrium of the adult zebrafish atrium reveals the existence of two different transcriptional domains. These two domains analogous to that of the two atria in terrestrial vertebrates Overall design: To determine the expression profiles of the Tg(meis2b-reporter)-positive vs -negative atrial compartments, a total of 6 hearts of 3 mpf Tg(meis2b-reporter) zebrafish were micro-dissected. A total of 4 pools were made: the first two pools, each contained 3 Tg(meis2b-reporter)-positive atrial compartments, and the other two contained the Tg(meis2b-reporter)-negative halves.
Distinct myocardial lineages break atrial symmetry during cardiogenesis in zebrafish.
Age, Specimen part, Cell line, Subject
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Chromatin structure and gene expression programs of human embryonic and induced pluripotent stem cells.
Cell line
View SamplesKnowledge of both the global chromatin structure and the gene expression programs of human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells should provide a robust means to assess whether the genomes of these cells have similar pluripotent states. Recent studies have suggested that ES and iPS cells represent different pluripotent states with substantially different gene expression profiles. We describe here a comparison of global chromatin structure and gene expression data for a panel of human ES and iPS cells. Genome-wide maps of nucleosomes with histone H3K4me3 and H3K27me3 modifications indicate that there is little difference between ES and iPS cells with respect to these marks. Gene expression profiles confirm that the transcriptional programs of ES and iPS cells show very few consistent differences. Although some variation in chromatin structure and gene expression was observed in these cell lines, these variations did not serve to distinguish ES from iPS cells.
Chromatin structure and gene expression programs of human embryonic and induced pluripotent stem cells.
Cell line
View SamplesSkeletal muscle stem cells (MuSC), also called satellite cells, are indispensable for maintenance and regeneration of adult skeletal muscles. Yet, a comprehensive picture of the regulatory events controlling the fate of MuSC is missing. Here, we determine the proteome of MuSC to design a loss-of-function screen, and identify 120 genes important for MuSC function including the arginine methyltransferase Prmt5. MuSC-specific inactivation of Prmt5 in adult mice prevents expansion of MuSC, abolishes long-term MuSC maintenance and abrogates skeletal muscle regeneration. Interestingly, Prmt5 is dispensable for proliferation and differentiation of Pax7(+) myogenic progenitor cells during mouse embryonic development, indicating significant differences between embryonic and adult myogenesis. Mechanistic studies reveal that Prmt5 controls proliferation of adult MuSC by direct epigenetic silencing of the cell cycle inhibitor p21. We reason that Prmt5 generates a poised state that keeps MuSC in a standby mode, thus allowing rapid MuSC amplification under disease conditions. Overall design: RNA from cultured satellite cells on Ion torrent sequencer
RNA-Seq analysis of isolated satellite cells in Prmt5 deficient mice.
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View SamplesMLL-fusion proteins are potent inducers of cancer in hematopoietic cells, where they are known to cause changes in global gene expression. How MLL-fusion proteins interact with the genome has not been established, so we have limited understanding of the pathway by which these proteins generate aberrant gene expression programs. Here we describe how the MLL-AF4 protein occupies the genome in human leukemia cells and its striking effects on chromatin states. We find that the MLL-AF4 fusion protein selectively occupies regions of the genome that contain developmental regulatory genes important for hematopoietic stem cell identity and self-renewal. These MLL-AF4 bound regions have grossly altered chromatin structure, with histone modifications catalyzed by Trithorax Group (TrxG) proteins and Dot1 extending across unusually large domains. This indicates that a key feature of MLL-associated leukemogenesis is aberrant targeting of chromatin modifiers to regions of the genome controlling hematopoietic development. Our results define the direct targets of the MLL-fusion protein, reveal the global role of epigenetic misregulation in leukemia, and identify new targets for therapeutic intervention in human cancer.
Aberrant chromatin at genes encoding stem cell regulators in human mixed-lineage leukemia.
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View SamplesIdentifying the interaction partners of non-coding RNAs is essential for elucidating their functions. We have developed an approach, termed microRNA-cross-linking and immunoprecipitation (miR-CLIP), using pre-miRNAs modified with psoralen and biotin to capture their targets in cells. Photo-cross-linking and Argonaute 2-immunopurification followed by streptavidin affinity-purification of probe-linked RNAs provided selectivity in the capture of targets, identified by deep-sequencing. MiR-CLIP with pre-miR-106a, a miR-17-5p family member, identified hundreds of putative targets in HeLa cells, many carrying conserved sequences complementary to the miRNA seed but also many that were not predicted computationally. MiR-106a overexpression experiments confirmed that miR-CLIP captured functional targets, including H19, a long-non-coding RNA that is expressed during skeletal muscle cell differentiation. We showed that miR-17-5p family members bind H19 in HeLa cells and myoblasts. During myoblast differentiation levels of H19, miR-17-5p family members and mRNA targets changed in a manner suggesting that H19 acts as a sponge for these miRNAs. Overall design: Two replicates of three cDNA libraries were submitted to deep sequencing: a sample from RNA-7-transfected cells; a sample from pre-miR-106a transfected cells; and a control sample.
miR-CLIP capture of a miRNA targetome uncovers a lincRNA H19-miR-106a interaction.
No sample metadata fields
View SamplesIdentifying the interaction partners of non-coding RNAs is essential for elucidating their functions. We have developed an approach, termed microRNA-cross-linking and immunoprecipitation (miR-CLIP), using pre-miRNAs modified with psoralen and biotin to capture their targets in cells. Photo-cross-linking and Argonaute 2-immunopurification followed by streptavidin affinity-purification of probe-linked RNAs provided selectivity in the capture of targets, identified by deep-sequencing. MiR-CLIP with pre-miR-106a, a miR-17-5p family member, identified hundreds of putative targets in HeLa cells, many carrying conserved sequences complementary to the miRNA seed but also many that were not predicted computationally. MiR-106a overexpression experiments confirmed that miR-CLIP captured functional targets, including H19, a long-non-coding RNA that is expressed during skeletal muscle cell differentiation. We showed that miR-17-5p family members bind H19 in HeLa cells and myoblasts. During myoblast differentiation levels of H19, miR-17-5p family members and mRNA targets changed in a manner suggesting that H19 acts as a sponge for these miRNAs. Overall design: Two replicates of two cDNA libraries were submitted to deep sequencing: a sample from siH19-transfected cells and a control sample.
miR-CLIP capture of a miRNA targetome uncovers a lincRNA H19-miR-106a interaction.
No sample metadata fields
View SamplesBackground: E-cadherin is an adherens junction protein that forms homophilic intercellular contacts in epithelial cells while also interacting with the intracellular cytoskeletal networks. It has roles including establishment and maintenance of cell polarity, differentiation, migration and signalling in cell proliferation pathways. Its downregulation is commonly observed in epithelial tumours and is a hallmark of the epithelial to mesenchymal transition (EMT). Methods: To improve our understanding of how E-cadherin loss contributes to tumorigenicity, we investigated the impact of its elimination from the non-tumorigenic breast cell line MCF10A. We performed cell-based assays and whole genome RNAseq to characterize an isogenic MCF10A cell line that is devoid of CDH1 expression due to an engineered homozygous 4bp deletion in CDH1 exon 11. Results: The E-cadherin-deficient line, MCF10A CDH1-/- showed subtle morphological changes, weaker cell-substrate adhesion, delayed migration, but retained cell-cell contact, contact growth inhibition and anchorage-dependent growth. Within the cytoskeleton, the apical microtubule network in the CDH1-deficient cells lacked the radial pattern of organization present in the MCF10A cells and F-actin formed thicker, more numerous stress fibres in the basal part of the cell. Whole genome RNAseq identified compensatory changes in the genes involved in cell-cell adhesion while genes involved in cell-substrate adhesion, notably ITGA1, COL8A1, COL4A2 and COL12A1, were significantly downregulated. Key EMT markers including CDH2, FN1, VIM and VTN were not upregulated although increased expression of proteolytic matrix metalloprotease and kallikrein genes was observed. Conclusions: Overall, our results demonstrated that E-cadherin loss alone was insufficient to induce an EMT or enhance transforming potential in the non-tumorigenic MCF10A cells but was associated with broad transcriptional changes associated with tissue remodelling. Overall design: Examination of the impact of E-cadherin (CDH1) loss in an isogenic pair of breast cell lines.
E-cadherin loss alters cytoskeletal organization and adhesion in non-malignant breast cells but is insufficient to induce an epithelial-mesenchymal transition.
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View SamplesWe report molecular characterization of human brown and white adipocytes. We showed that PAZ6 and SW872 cells exhibit classical molecular and phenotypic markers of brown and white adipocytes, respectively. However, SGBS cells presented a versatile phenotype of adipocyte Overall design: Sequencing of three human adipocytes cell lines (SGBS, SW872 and PAZ6) in undifferentiated and differentiated stages.
Comprehensive molecular characterization of human adipocytes reveals a transient brown phenotype.
No sample metadata fields
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