Many genes determining cell identity are regulated by clusters of Mediator-bound enhancer elements collectively referred to as super-enhancers. These super-enhancers have been proposed to manifest higher-order properties important in development and disease. Here we report a comprehensive functional dissection of one of the strongest putative super-enhancers in erythroid cells. By generating a series of mouse models, deleting each of the five regulatory elements of the a-globin super-enhancer individually and in informative combinations, we demonstrate that each constituent enhancer seems to act independently and in an additive fashion with respect to hematological phenotype, gene expression, chromatin structure and chromosome conformation, without clear evidence of synergistic or higher-order effects. Our study highlights the importance of functional genetic analyses for the identification of new concepts in transcriptional regulation. Overall design: Mouse fetal liver erythroid RNA-seq. The RNA of the erythroid cells was metabolically labelled using 4-thiourdine nucleotide analogue supplementation of viable cells in culture. RNA transcripts that incorporated the analogue and hence were synthesised during this period of exposure, were then isolated from the pre-exiting bulk RNA by the addition of a biotin moiety and pull down.
Genetic dissection of the α-globin super-enhancer in vivo.
Specimen part, Subject
View SamplesSaccharomyces cerevisiae IMS0002 which, after metabolic and evolutionary engineering, ferments the pentose sugar arabinose. Glucose and arabinose-limited anaerobic chemostat cultures of IMS0002 and its non-evolved ancestor IMS0001 were subjected to transcriptome analysis to identify key genetic changes contributing to efficient arabinose utilization by strain IMS0002.
Metabolome, transcriptome and metabolic flux analysis of arabinose fermentation by engineered Saccharomyces cerevisiae.
Disease, Treatment
View SamplesBackground: Evolutionary engineering is a powerful approach to isolate suppressor mutants and industrially relevant genotypes. Until recently, DNA microarray analysis was the only affordable genome-wide approach to identify the responsible mutations. This situation has changed due to the rapidly decreasing costs of whole genome (re)sequencing. DNA microarray-based mRNA expression analysis and whole genome resequencing were combined in a study on lactate transport in Saccharomyces cerevisiae. Jen1p is the only S. cerevisiae lactate transporter reported in literature. To identify alternative lactate transporters, a jen1 strain was evolved for growth on lactate. Results: Two independent evolution experiments yielded Jen1p-independent growth on lactate (max 0.14 and 0.18 h-1 for single-cell lines IMW004 and IMW005, respectively). Whereas mRNA expression analysis did not provide leads, whole-genome resequencing showed different single nucleotide changes (C755G/Leu219Val and C655G/Ala252Gly) in the acetate transporter gene ADY2. Analysis of mRNA levels and depth of coverage of DNA sequencing combined with karyotyping, gene deletions and diagnostic PCR showed that in IMW004 an isochromosome III (~475 kb), which contains two additional copies of ADY2C755G, was formed via crossover between YCLW15 and YCRC6. Introduction of the ADY2 alleles in a jen1 ady2 strain resulted in growth on lactate (max 0.14 h-1 for Ady2pLeu219Val and 0.12 h-1 for Ady2pAla252Gly). Conclusions: Whole-genome resequencing of yeast strains obtained from independent evolution experiments enabled rapid identification of a key gene that was not identified by mRNA expression analysis of the same strains. Reverse metabolic engineering showed that mutated alleles of ADY2 (C655G and C755G) encode efficient lactate transporters.
Laboratory evolution of new lactate transporter genes in a jen1Δ mutant of Saccharomyces cerevisiae and their identification as ADY2 alleles by whole-genome resequencing and transcriptome analysis.
No sample metadata fields
View SamplesLuminal, basal, stromal, and endothelial cells were MACS sorted from whole tissue. Targets from five biological replicates of each were generated and the expression profiles were determined using Affymetrix U133 Plus 2.0 arrays. These data represent cell specific transcriptomes.
Transcriptomes of human prostate cells.
No sample metadata fields
View SamplesThe complexity of metazoan organisms requires precise spatiotemporal regulation of gene expression during development. To identify different modes of developmental gene regulation we measured the transcriptome throughout development of the nematode Caenorhabditis elegans by mRNA sequencing with high temporal resolution. We find that approximately 2,000 transcripts undergo expression oscillations synchronized with larval transitions while thousands of genes are expressed in temporal gradients, similar to known timing regulators. By counting transcripts in individual animals, we show that the pulsatile expression of the microRNA (miRNA) lin-4 maintains the temporal gradient of its target lin-14 by dampening its expression oscillations. Our results demonstrate that this insulation is optimal when pulsatile expression of the miRNA and its target is synchronous. We propose that such a miRNA-mediated incoherent feed-forward loop is a potent filter that prevents propagation of potentially deleterious gene expression fluctuations during the development of an organism. Overall design: We analyzed RNA-seq data of wild-type worms at two different temperatures, 20C and 25C, from samples picked every 2hrs and 1.5 hrs, resspectively, spanning all larval stages (L1,L2,L3,L4). At 20C we picked samples for L1-L3 (sample DH2: 0 hrs to 38 hrs) and for L4 (sample DH5: 38 hrs to 48 hrs) from independent populations. At 25C, all samples were picked from the same worm population (sample DH3: 0 hrs to 28.5 hrs). This time course ends at 28.5 hrs since at higher temperature nematode development is accelarated. Finally, we measured mRNA expression at 20C in a lin-4 knockout mutant worm (lin-4(e912)), again spanning all larval stages (sample DH4: 0 hrs to 48 hrs). Each sequencing sample consisted of a mixture of all time points with mRNA from different time points barcoded with Illumina barcodes and was sequenced on one or more lanes (DH2: 3 lanes; DH3: 3 lanes; DH4: 4 lanes; DH5: 1 lane) of an Illumina HiSeq2000.
Dampening of expression oscillations by synchronous regulation of a microRNA and its target.
Cell line, Subject
View SamplesWe present ScarTrace, a single-cell sequencing strategy that allows us to simultaneously quantify information on clonal history and cell type for thousands of single cells obtained from different organs from adult zebrafish. Using this approach we show that all blood cells types in the kidney marrow arise from a small set of multipotent embryonic. In contrast, we find that cells in the eyes, brain, and caudal tail fin arise from many embryonic progenitors, which are more restricted and produce specific cell types in the adult tissue. Next we use ScarTrace to explore when embryonic cells commit to forming either left or right organs using the eyes and brain as a model system. Lastly we monitor regeneration of the caudal tail fin and identify a subpopulation of resident macrophages that have a clonal origin that is distinct from other blood cell types. Overall design: Single cell sequencing data from cells isolated from zebrafish organs (whole kidney marrow, forebrain, hindbrain, left eye, right eye, left midbrain, right midbrain, and regenerated fin). For each cell, we provide libraries with transcritpome and with clonal information, respectively.
Whole-organism clone tracing using single-cell sequencing.
Specimen part, Subject
View SamplesAdult neurogenesis in the murine dentate gyrus occurs in a specialized microenvironment that sustains the generation of neurons during life. To fully understand adult neurogenesis, it is essential to determine the neural stem cell (NSC) and progenitor developmental stages, their molecular determinants, and the niche cellular and molecular composition. We report on a single cell RNA sequencing study of the hippocampal niche, performed by isolating all the non-neuronal cell populations. Our analysis provides a comprehensive description of the dentate gyrus cells and allows the identification of exclusive cell type-specific markers. We define the developmental stages and transcriptional dynamics of NSCs and progenitors, and find that while NSCs represent a heterogeneous cellular continuum, progenitors can be grouped in distinct subtypes. We determine the oligodendrocyte lineage and transcriptional dynamics, and describe microglia transcriptional profile and activation state. The combined data constitutes a valuable resource to understand regulatory mechanisms of adult neurogenesis. Overall design: We generated transciptome data from cells unbiasely sorted from the hippocampal neurogenic niche after depleting the neuronal population
A Single-Cell RNA Sequencing Study Reveals Cellular and Molecular Dynamics of the Hippocampal Neurogenic Niche.
Specimen part, Cell line, Subject
View SamplesLgr5+ adult intestinal stem cells are highly proliferative throughout life. Single Lgr5+ stem cells can be cultured into 3D epithelial organoids containing all cell types at nearnormal ratios. Culture conditions to generate the main cell types have been established previously, but signals inducing the various types of enteroendocrine cells (EECs) have remained elusive. Here we generate quiescent Lgr5+ stem cells in vitro by inhibition of the EGF-receptor (EGFR) and mitogen-associated protein kinase (MAPK) signaling pathways in organoids, a state that can be readily reversed. Quiescent Lgr5+ stem cells gain a distinct molecular signature, biased towards EEC differentiation. Indeed, combined inhibition of Wnt, Notch and MAPK pathways efficiently generates a diversity of EEC subtypes in vitro. Our observations uncouple Wnt-dependent stem cell maintenance from EGF-dependent proliferation and cell fate choice, and provide an in vitro approach for the study of the elusive EECs. Overall design: We established a stable culture of quiescent Lgr5+ intestinal stem cells in culture. These highly resemble quiescent secretory precursors, which has high EEC differentiation potential. Following on this lead, we elucidated what signals are required to generate EEC cells of all varieties, and provide a method to produce these EEC cells in large numbers.
Induced Quiescence of Lgr5+ Stem Cells in Intestinal Organoids Enables Differentiation of Hormone-Producing Enteroendocrine Cells.
Specimen part, Cell line, Subject
View SamplesGene expression heterogeneity in the pluripotent state of mouse embryonic stem cells (mESCs) has been increasingly well-characterized. In contrast, exit from pluripotency and lineage commitment have not been studied systematically at the single-cell level. Here we measured the gene expression dynamics of retinoic acid driven mESC differentiation using an unbiased single-cell transcriptomics approach. We found that the exit from pluripotency marks the start of a lineage bifurcation as well as a transient phase of susceptibility to lineage specifying signals. Our study revealed several transcriptional signatures of this phase, including a sharp increase of gene expression variability and a handover between two classes of transcription factors. In summary, we provide a comprehensive analysis of lineage commitment at the single cell level, a potential stepping stone to improved lineage control through timing of differentiation cues. Overall design: Bulk and single-cell RNA-seq (SCRB-seq and SMART-seq) of mouse embryonic stem cells after different periods of continuous exposure to retinoic acid. Bulk RNA-seq of cell lines derived after retinoic exposure and after differentiation with retinoic acid and MEK inhibitor combined.
Dynamics of lineage commitment revealed by single-cell transcriptomics of differentiating embryonic stem cells.
Cell line, Subject
View SamplesUnderstanding the development and function of an organ requires the characterization of all of its cell types. Traditional methods for visualizing and isolating sub-populations of cells are based on mRNA or protein expression of only few known marker genes. The unequivocal identification of a specific marker gene, however, poses a major challenge, particularly if this cell type is rare. Identifying rare cell types, such as stem cells, short-lived progenitors, cancer stem cells, or circulating tumor cells is crucial to acquire a better understanding of normal or diseased tissue biology. To address this challenge we sequenced the transcriptome of hundreds of randomly selected cells from mouse intestinal organoids, cultured self-organizing epithelial structures that contain all cell lineages of the mammalian intestine. Organoid buds, like intestinal crypts, harbor stem cells that continuously differentiate into a variety of cell types, occurring at widely different abundances. Since available computational methods can only resolve more abundant cell types, we developed RaceID, an algorithm for rare cell type identification in complex populations of single cells. We demonstrate that this algorithm can resolve cell types represented by only a single cell in a population of randomly sampled organoid cells. We use this algorithm to identify Reg4 as a novel marker for enteroendocrine cells, a rare population of hormone producing intestinal cells. Next, we use Reg4 expression to enrich for these rare cells and investigate the heterogeneity within this population. Reassuringly, RaceID confirmed the existence of known enteroendocrine lineages, and moreover, discovered novel subtypes, which we subsequently validated in vivo. Having validated RaceID by this proof-of-principle experiment we then apply the algorithm to ex vivo isolated LGR5 positive cells and their direct progeny and demonstrate homogeneity of the stem cell pool. We envision broad applicability of our method for discovering rare cell types and the corresponding marker genes in healthy and diseased organs. Overall design: Small intestinal crypts were isolated from a single wild-type C57BL/6 mouse, a Reg4-dsRed-knock-in mouse and an Lgr5-GFP-DTR mouse. The crypts were propagated and expanded in culture as organoids. For each experiment, multiple organoids were harvested and dissociated into single cells. Each experiment was done twice, using different passage of the same organoid culture. We also included a pool-and-split control for 96 Reg4-dsRed positive intetsinal cells and a control library with 5 mouse embryonic stem cells (wells 1-5), 5 mouse embryonic fibroblasts (wells 6-10), 75 random organoid cells (wells 11-85), 5 wells without primer and without template (wells 86 and 93-96), and five wells with primer and without template (wells 87-92). We also sequenced two 96 well plates of Lgr5-EGFP positive single cells isolated ex vivo, and Lgr5 progeny collected after five days of lineage tracing. Label induction was performed using an Lgr5-Cre reporter mouse expressing YFP from Rosa26 promoter with a loxP flanked transcriptional road block in between. Five 96 well plates of YFP positive were sequenced. Sample number four also contains also unrelated samples (single cell barcode 49-96), which should be discarded.
Single-cell messenger RNA sequencing reveals rare intestinal cell types.
No sample metadata fields
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