Ectopic expression of the transcription factors Oct4, Sox2, Klf4 and c-Myc (OSKM) can reprogram somatic cells into induced pluripotent stem cells (iPSCs). These iPSCs are highly similar to embryonic stem cells and can be used for regenerative medicine, drug screening and disease modelling. Despite recent advances, reprogramming is a slow and inefficient process. This suggests that there are several safeguarding mechanisms to counteract cell fate conversion. Cellular senescence is one of these barriers, which is mediated through activation of the tumour suppressors p53/p21CIP1, p15INK4b and p16INK4a. In this study, we have screened for shRNAs blunting reprogramming-induced senescence. We integrated single-cell RNA sequencing (scRNA-Seq) with shRNA screening to investigate the mechanism of action of the identified candidates. Overall design: 376 samples: 280 IMR90 cells expressing OSKM and shRNA library derived from the shRNA screen (bypassing senescence), 64 OSKM-expressing IMR90 cells (senescent), 32 IMR90 cells expressing control vector
Coupling shRNA screens with single-cell RNA-seq identifies a dual role for mTOR in reprogramming-induced senescence.
Specimen part, Subject
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Cell-Cycle-Dependent Reconfiguration of the DNA Methylome during Terminal Differentiation of Human B Cells into Plasma Cells.
Specimen part, Subject
View SamplesMolecular mechanisms underlying terminal differentiation of B-cells into plasma cells are major determinants of adaptive immunity but remain only partially understood. Here, we present the transcriptional and epigenomic landscapes of cell subsets arising from activation of human naive B-cells and differentiation into plasmablasts. Cell proliferation of activated B cells was linked to a slight decrease in DNA methylation levels but followed by a committal step in which an S-phase-synchronized differentiation switch was associated with an extensive DNA demethylation and local acquisition of 5-hydroxymethylcytosine at enhancers and genes related to plasma cell identity.
Cell-Cycle-Dependent Reconfiguration of the DNA Methylome during Terminal Differentiation of Human B Cells into Plasma Cells.
No sample metadata fields
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Global transcriptome profiling identifies KLF15 and SLC25A10 as modifiers of adipocytes insulin sensitivity in obese women.
Sex, Specimen part, Disease
View SamplesThe aim of this study was to identify new genes controlling insulin sensitivity in adipocytes from obese women with either insulin-resistant (OIR) or -sensitive (OIS) adipocytes.
Global transcriptome profiling identifies KLF15 and SLC25A10 as modifiers of adipocytes insulin sensitivity in obese women.
Sex, Specimen part, Disease
View SamplesThe aim of this study was to identify new genes controlling insulin sensitivity in adipocytes from obese women with either insulin-resistant (OIR) or -sensitive (OIS) adipocytes.
Global transcriptome profiling identifies KLF15 and SLC25A10 as modifiers of adipocytes insulin sensitivity in obese women.
Specimen part, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Nucleosome positioning changes during human embryonic stem cell differentiation.
Specimen part, Cell line
View SamplesNucleosomes are the basic unit of chromatin. Nucleosome positioning (NP) plays a key role in transcriptional regulation and other biological processes. To better understand NP we used MNase-seq to investigate changes that occur as human embryonic stem cells (hESCs) transition to nascent mesoderm and then to smooth muscle cells (SMCs). Compared to differentiated cell derivatives, nucleosome occupancy at promoters and other notable genic sites, such as exon/intron junctions and adjacent regions, in hESCs shows a stronger correlation with transcript abundance and is less influenced by sequence content. Upon hESC differentiation, genes being silenced, but not genes being activated, display a substantial change in nucleosome occupancy at their promoters. Genome-wide, we detected a shift of NP to regions of higher G+C content as hESCs differentiate to SMCs. Notably, genomic regions with higher nucleosome occupancy harbor twice as many GC changes but fewer than half AT changes, compared to regions with lower nucleosome occupancy. Finally, our analysis indicates that the hESC genome is not rearranged and has a sequence mutation rate resembling normal human genomes. Our study reveals another unique feature of hESC chromatin, and sheds light on the relationship between nucleosome occupancy and sequence G+C content.
Nucleosome positioning changes during human embryonic stem cell differentiation.
Specimen part, Cell line
View SamplesThe exosome-independent exoribonuclease DIS3L2 is mutated in Perlman syndrome. Here we used extensive global transcriptomic and targeted biochemical analyses to identify novel DIS3L2 substrates in human cells. We show that DIS3L2 regulates pol II transcripts, comprising selected canonical and histone-coding mRNAs, and a novel FTL_short RNA from the ferritin mRNA 5'' UTR. Importantly, DIS3L2 contributes to surveillance of pre-snRNAs during their cytoplasmic maturation. Among pol III transcripts, DIS3L2 particularly targets vault and Y RNAs and an Alu-like element BC200 RNA, but not Alu repeats, which are removed by exosome-associated DIS3. Using 3'' RACE-Seq, we demonstrate that all novel DIS3L2 substrates are uridylated in vivo by TUT4/TUT7 poly(U) polymerases. Uridylation-dependent DIS3L2-mediated decay can be recapitulated in vitro, thus reinforcing the tight cooperation between DIS3L2 and TUTases. Together these results indicate that catalytically inactive DIS3L2, characteristic of Perlman syndrome, can lead to deregulation of its target RNAs to disturb transcriptome homeostasis. Overall design: To investigate DIS3L2 functions genome-wide, total RNA samples were collected from model cell lines producing either WT or mut DIS3L2 three days after induction with doxycycline. The RNA samples were rRNA-depleted before preparation of strand-specific total RNA libraries according to the standard TruSeq (Illumina) protocol. TruSeq library preparation favours RNA molecules longer than 200 nt, and shorter transcripts are suboptimal for sequencing via this protocol. Thus, to obtain information about potential DIS3L2 RNA substrates with lengths between 20 and 220 nt, another RNA-Seq was carried out in parallel (with size selection through gel purification). The stable inducible HEK293 cell lines producing DIS3L2 variants were obtained using “pAL_01” and “pAL_02” plasmid constructs and the Flp-In™ T-REx™ system according to the manufacturer’s guidelines. “pAL_01” and “pAL_02” plasmids are vectors for co-expression of recoded C-terminal FLAG-tagged DIS3L2 [wild type (WT) variant or its catalytic mutant counterpart (mut), respectively] and sh-miRNAs directed against endogenous DIS3L2 mRNA.
Perlman syndrome nuclease DIS3L2 controls cytoplasmic non-coding RNAs and provides surveillance pathway for maturing snRNAs.
No sample metadata fields
View SamplesA multi-subunit exosome complex is a major eukaryotic exoribonuclease that in the cytoplasm requires the SKI complex for activity. In yeast, SKI forms a heterotetramer and delivers RNA substrates directly into the exosome channel. Such cooperation requires Ski7 protein, which links the exosome and SKI complexes. However, since the human genome does not encode an orthologue of the yeast Ski7, the factor mediating SKI and exosome linkage in human cells is unknown. Proteomic analysis revealed that the human cytoplasmic exosome interacts with HBS1LV3, a protein encoded by a newly discovered short splicing isoform of HBS1L. HBS1LV3 recruits the SKI complex to the exosome. In contrast, the canonical HBS1L variant, HBS1LV1, acting as a ribosome dissociation factor, does not associate with the exosome and instead interacts with the mRNA surveillance factor PELOTA. HBS1LV3 contains a new domain of unknown structure with the short linear motif RxxxFxxxL, which is responsible for exosome binding, and may interact with the exosome core subunit RRP43 in way that resembles the association between Rrp6 RNase and Rrp43 in yeast. Depletion of HBS1LV3 and the SKI complex helicase SKI2W similarly affected the transcriptome by strongly upregulating a large number of genes. Moreover, following HBS1LV3 or SKI2W depletion the half-lives of representative upregulated mRNAs were increased, thus supporting the involvement of HBS1LV3 and SKI2W in the same mRNA degradation pathway. In contrast, HBS1LV1 depletion had little effect on transcriptome homeostasis. Our data indicate that human HBS1LV3 is the long-sought factor that links the exosome and SKI complexes to regulate cytoplasmic mRNA decay. Overall design: Examination of siRNA-mediated silencing in HEK293 cell lines. To identify transcripts that are degraded by cytoplasmic SKI/HBS1LV3/exosome supercomplexes, we used specific siRNAs to knock down HBS1LV1, HBS1LV3 or SKIV2L gene expression in (i) WT HEK293 cells and (ii) HEK293 cells rescued with siRNA insensitive protein. Analyses were performed in triplicate.
A short splicing isoform of HBS1L links the cytoplasmic exosome and SKI complexes in humans.
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