The purpose of the experiment was to generate a time course of gene expression following irradiation. The goal was then to model this data to extract hidden variables - chiefly, the activity profiles of the p53 transcription factor. Using this information the aim was to predict which transcripts changed by IR were targets of p53. Cells in log phase (1 x 106 ml-1) were ?-irradiated with 5 Gy at room temperature (RT) at a dose rate of 2.45 Gy per minute with a 137Cs ?-irradiator. Cells were harvested at 0, 2, 4, 6, 8, 10 and 12 hours, and RNA and protein were extracted (Trizol, Invitrogen). Affymetrix U133A arrays were hybridized as standard (www.affymetrix.co.uk). Array quality was determined using R and GCOS .rpt file values. The time course was replicated three times from independent cell preparations.
Ranked prediction of p53 targets using hidden variable dynamic modeling.
Specimen part, Disease, Cell line, TimeView Samples
A study of diabetic neuropathy in dorsal root ganglia from streptozotocin-diabetic male wistar rats over the first 8 weeks of diabetes
Identification of changes in gene expression in dorsal root ganglia in diabetic neuropathy: correlation with functional deficits.
Sex, Age, Specimen part, Disease, Disease stage, TimeView Samples
Identification of temporal changes in gene expression in macrophages isolated from the site of nerve injury. Overall design: Macrophages were profiled at 3 timepoints (5, 14, and 28 days) after nerve injury with 2-3 independent biological replicates per timepoint.
Temporal changes in macrophage phenotype after peripheral nerve injury.
Subject, TimeView Samples
Type 1 diabetes (T1D) is caused by autoimmune destruction of pancreatic ß cells. Mounting evidence supports a central role for ß-cell alterations in triggering the activation of self-reactive T-cells in T1D. However, the early deleterious events that occur in ß cells, underpinning islet autoimmunity are not known. We hypothesized that epigenetic modifications induced in ß cells by inflammatory mediators play a key role in initiating the autoimmune response. We analyzed DNA methylation (DNAm) patterns and gene expression in human islets exposed to IFNa, a cytokine associated with T1D development. We found that IFNa triggers DNA demethylation and increases expression of genes controlling inflammatory and immune pathways. We then demonstrated that DNA demethylation was caused by up-regulation of the exoribonuclease, PNPase Old-35 (PNPT1), which caused degradation of miR-26a. This in turn promoted the up-regulation of ten-eleven translocation TET2 enzyme and increased 5-hydoxymethylcytosine levels in human islets and pancreatic ß-cells. Moreover, we showed that specific IFNa expression in the ß cells of IFNa-INS1CreERT2 transgenic mice, led to development of T1D that was preceded by increased islet DNA hydroxymethylation through a PNPT1/TET2-dependent mechanism. Our results suggest a new mechanism through which IFNa regulates DNAm in ß cells, leading to changes in expression of genes in inflammatory and immune pathways that can initiate islet autoimmunity in T1D. Overall design: We exposed human pancreatic islets from three donors to 2000 IU IFNa and assessed gene expression by RNAseq. The cDNA library was prepared using Illumina TruSeq RNA Sample Prep Kits. Next generation sequencing was performed on Illumina HiSeq2000 using the Single-Read Cluster Generation kit v2 and SBS Sequencing kit v3. Image analysis and base calling were conducted using the SDS 2.5/RTA1.5 software.
Epigenetic modulation of β cells by interferon-α via PNPT1/mir-26a/TET2 triggers autoimmune diabetes.
Specimen part, Disease stage, Treatment, SubjectView Samples
Cell-and context-specific activities of nuclear receptors may in part be due to distinct coregulator complexes recruited to distinct subsets of target genes. RIP140 (also called NRIP1) is a ligand-dependent corepressor that is inducible with retinoic acid (RA). We have shown previously that silencing of RIP140 enhances RA-induced differentiation and enhances the induction of model RA target genes in human embryonal carcinoma cells (EC). Through use of microarray technology we sought to elucidate in a de novo fashion the global role of RIP140 in RA-dependent signaling. RIP140-dependent gene expression was largely consistent with RIP140 functioning to limit RAR signaling. Few if any genes were regulated in a manner to support a role for RIP140 in active repression. Interestingly, approximately half of the RA-dependent genes were unaffected by RIP140, suggesting that RIP140 may discriminate between different classes of RA target genes. RIP140 silencing also accelerated RA target gene activation and sensitized EC cells to low doses of RA. Together the data suggests that the RIP140-dependent RA target genes identified here may be particularly important in mediating RA-induced tumor cell differentiation. RIP140 may be an attractive target to sensitize tumor cells to retinoid-based differentiation therapy.
Selective repression of retinoic acid target genes by RIP140 during induced tumor cell differentiation of pluripotent human embryonal carcinoma cells.
No sample metadata fieldsView Samples
Self-renewal of embryonic stem cells (ESCs) cultured in serum-LIF is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here we purify ESCs with distinct TF expression levels from serum-LIF cultures to uncover early events during commitment from nave pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in NANOGlow cells. Independent Esrrb reporter lines demonstrate that ESRRBnegative ESCs cannot effectively self-renew. Upon ESRRB loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in ESRRBhigh cells. Class I elements lose NANOG and OCT4 binding in ESRRBnegative ESCs and associate with genes expressed preferentially in nave ESCs. In contrast, class II elements retain OCT4 but not NANOG binding in ESRRBnegative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from nave pluripotency.
Esrrb extinction triggers dismantling of naïve pluripotency and marks commitment to differentiation.
Specimen partView Samples
The 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 fieldsView Samples
This SuperSeries is composed of the SubSeries listed below.
Acute hypersensitivity of pluripotent testicular cancer-derived embryonal carcinoma to low-dose 5-aza deoxycytidine is associated with global DNA Damage-associated p53 activation, anti-pluripotency and DNA demethylation.
Specimen part, Cell lineView Samples
A 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.
No sample metadata fieldsView Samples