Protein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3'' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks. Overall design: We generated protein occupancy cDNA libraries for two biological replicates. Briefly, we crosslinked 4SU-labeled cells and purified protein-mRNA complexes using oligo(dT)-beads. The precipitate was treated with RNAse I to reduce the protein-crosslinked RNA fragments to a length of about 30-60 nt. To remove non-crosslinked RNA, protein-RNA complexes were precipitated with ammonium sulfate and blotted onto nitrocellulose. The RNA was recovered by Proteinase K treatment, ligated to cloning adapters, and reverse transcribed. The resulting cDNA libraries were PCR-amplified and next-generation sequenced
The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
Treatment, Subject
View SamplesProtein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3'' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks. Overall design: To obtain a more detailed picture of the RNA present in the pooled precipitates of four consecutive oligo(dT)-purifications, we constructed a cDNA library by random priming of 4-thiouridine (4SU)- and 6-thioguanosine (6SG)-labeled RNA derived from UV-irradiated (365 nm)and non-irradiated cells. Digital gene expression analysis of the cDNA library of non-irradiated cells, labeled with 4SU and 6SG, was performed. To monitor the incorporation of photoreactive nucleotides into mRNA, we isolated 4SU- and 6SG-labeled RNA from the oligo(dT) precipitate of non-crosslinked cells by biotinylation and streptavidin purification (Dolken et al., 2008).
The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
Treatment, Subject
View SamplesHere we studied the effects of anticonvulsant drug exposure in a human embryonic stem cell (hESC) based neuro- developmental toxicity test (hESTn). During neural differentiation the cells were exposed, for either 1 or 7 days, to non-cytotoxic concentration ranges of valproic acid (VPA) or carbamazepine (CBZ), anti-epileptic drugs known to cause neurodevelopmental toxicity.
Gene Expression Regulation and Pathway Analysis After Valproic Acid and Carbamazepine Exposure in a Human Embryonic Stem Cell-Based Neurodevelopmental Toxicity Assay.
Time
View SamplesPurpose: To investigate alterations in subcutaneous white adipose gene expression induced by genetic AMPK activation in vivo, in mice fed a chow or a high-fat diet. Methods: Subcutaneous white adipose tissue mRNA profiles of wild-type transgenic (WT-Tg) mice and mice expressing a gain-of-function AMPK mutant gamma1 subunit (D316A-Tg) were generated by deep sequencing. Results: RNA sequencing revealed over 3000 differentially expressed genes between WT-Tg and D316A-Tg subcutaneous white adipose tissue (WATsc) from mice fed a high fat diet (HFD), of which many were classified as 'skeletal muscle-associated'. Interestingly, uncoupling protein 1 (UCP1), associated with 'beige' adipocyte formation in WATsc, was not differentially expressed. On a chow diet, many differentially expressed genes were also identified, with gene ontology analysis identifiying glycolysis, TCA cycle and brown fat differentiation as highly enriched; key features of brown adipocyte identity. HFD-associated skeletal-muscle associated gene expression was either not significantly altered, or significantly down-regulated on a chow diet, indicating a diet-induced gene signature in D316A-Tg WATsc. Conclusions: Our study revealed gene signatures indicative of brown adipocyte development on a chow diet, where no overt metabolic phenotype was observed in gain-of-function animals. When fed a HFD, WATsc from D316A-Tg mice displayed a muscle-like gene signature, expressing key components of creatine and calcium thermogenic cycles including Ckmt2 (creatine kinase, mitochondrial 2) Atp2a1 (SERCA1-sarco/endoplasmic reticulum ATPase 1) and ryr1 (ryanodine receptor 1). UCP1 expression was not altered between WT-Tg and D316A-Tg mice fed a HFD. Our findings suggest a novel role for AMPK in the regulation of white adipocyte identity and a potentially novel cell population that, when metabolically challenged, preferrentially utilise muscle-like thermogenic futile cycles independent of UCP1 to mediate whole organism energy expenditure. Overall design: Whole subcutaneous white adipose tissue mRNA profiles were generated from mice fed either chow or 45% high-fat diet.
AMPK activation protects against diet induced obesity through Ucp1-independent thermogenesis in subcutaneous white adipose tissue.
Age, Specimen part, Cell line, Subject
View SamplesZebrafish embryos have been proposed as an attractive alternative model system for hepatotoxicity testing.
A transcriptomics-based hepatotoxicity comparison between the zebrafish embryo and established human and rodent in vitro and in vivo models using cyclosporine A, amiodarone and acetaminophen.
Compound
View SamplesIn acute promyelocytic leukemia (APL), differentiation therapy with all-trans retinoic acid (ATRA)
Chemokine induction by all-trans retinoic acid and arsenic trioxide in acute promyelocytic leukemia: triggering the differentiation syndrome.
Specimen part
View SamplesWT J1 and 3B3L cells (in which Dnmt3B and Dnm3L are constitutively expressed from an exogenous construct) were cultured under both serum/LIF and 2i/LIF conditions. 3B3L cells do not show ground state-associated hypomethylation phenotype. This experiment sought to analyse the gene expression changes between the two conditions. Overall design: Three biological replicates per condition J1 serum, J1 2i, 3B3-3l serum, 3B3-3l 2i.
DNA Methylation Directs Polycomb-Dependent 3D Genome Re-organization in Naive Pluripotency.
Specimen part, Cell line, Subject
View SamplesThe goal of this study is to measure Arabidopsis mRNA transcription and mRNA decay rates genome wide at two temperatures, and thus to calculate the temperature coefficient of both processes. Sensing and response to ambient temperature is important for controlling growth and development of many organisms, in part by regulating mRNA levels. mRNA abundance can change with temperature, but it is unclear whether this results from changes to transcription or decay rates and whether passive or active temperature regulation is involved. Results Using a base analogue labelling method we directly measured the temperature coefficient (Q10) of mRNA synthesis and degradation rates of the Arabidopsis transcriptome. We show that for most genes transcript levels are buffered against passive increases in transcription rates by balancing passive increases in the rate of decay. Strikingly, for temperature-responsive transcripts, increasing temperature raises transcript abundance primarily by promoting faster transcription relative to decay and not vice versa, suggesting a global transcriptional mechanism process exists for the activethat controls of mRNA abundance by temperature/
Direct measurement of transcription rates reveals multiple mechanisms for configuration of the Arabidopsis ambient temperature response.
Specimen part, Treatment, Time
View SamplesTFIID is a central player in activated transcription initiation. Recent evidence suggests that the role and composition of TFIID is more diverse than previously understood. To investigate the effects of changing the composition of TFIID in a simple system we depleted TAF1 from Drosophila cells and determined the consequences on metal induced transcription at an inducible gene, Metallothionein B (MtnB). We observe a marked increase in the levels of both the mature message and pre-mRNA in TAF1 depleted cells. Under conditions of continued metal exposure, we show that TAF1 depletion increases the magnitude of the initial transcription burst, but has no effect on the timing of that burst. We also show that TAF1 depletion causes delay in the shut-off of transcription upon removal of the stimulus. Thus TAFs are involved in both establishing an upper limit of transcription during induction and efficiently turning the gene off once the inducer is removed. Using genomewide nascent-seq we identify hundreds of genes that are controlled in a similar manner indicating that the findings at this inducible gene are likely generalizable to a large set of promoters. There is a long-standing appreciation for the importance of the spatial and temporal control of transcription. Here we uncover an important third dimension of control, the magnitude of the response. Our results show that the magnitude of the transcriptional response to the same signaling event, even at the same promoter, can vary greatly depending on the composition of the TFIID complex in the cell. Overall design: Nascent RNA was sequenced from replicate samples of Drosophila S2 cells treated with double-stranded RNA directed against E. coli LacI (Control) or against Drosophlia TAF1 (experimental). Reads per kilo-base per million (RPKM) was determined for each gene and the control and experimental samples were compared to determine the genes that were affected by the depletion of TAF1.
Holo-TFIID controls the magnitude of a transcription burst and fine-tuning of transcription.
Specimen part, Subject
View SamplesMaternal environment is an important regultor of seed dormancy, but the mechanisms underlying the process are poorly understood. We have found that genes in the circadian clock control dormancy, in part through their regulation of the canonical photoperiod pathway known from research into flowering time control. In this experiment we compare the affects of altering seed maturation temperature or maternal photoperiod on dry seed transcriptomes, and the photoperiod-insenstive ft-1 mutant to wt type Ler. In this way we are identifying gene expression programmes which result from the seed's response to maternal environmental experience.
Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors.
Specimen part
View Samples