Translation and mRNA degradation are intimately connected, yet the mechanisms that regulate them are not fully understood. Here we examine the regulation of translation and mRNA stability in mouse embryonic stem cells (ESCs) and during differentiation. In contrast to previous reports, we found that transcriptional changes account for most of the molecular changes during ESC differentiation. Within ESCs translation level and mRNA stability are positively correlated. The RNA-binding protein DDX6 has been implicated in processes involving both translational repression and mRNA destabilization; in yeast DDX6 connects codon optimality and mRNA stability and in mammals DDX6 is involved in microRNA-mediated repression. We generated DDX6 KO ESCs and found that while there was minimal connection between codon usage and stability changes, the loss of DDX6 leads to the translational depression of microRNA targets. Surprisingly, the translational derepression of microRNA targets occurs without affecting mRNA stability. Furthermore, DDX6 KO ESCs share overlapping phenotypes and global molecular changes with ESCs that completely lack all microRNAs. Together our results demonstrate that the loss of DDX6 decouples the two forms of microRNA induced repression and emphasize that translational repression by microRNAs is underappreciated. Overall design: 4-thiouridine (4su) metabolic labeling was performed on mouse embryonic stem cells (ESCs) and Epiblast like cells (EpiLCs).
Decoupling the impact of microRNAs on translational repression versus RNA degradation in embryonic stem cells.
Specimen part, Disease, Subject
View SamplesMitochondria are able to modulate cell state and fate during normal and pathophysiologic conditions through a nuclear mediated mechanism collectively termed as a retrograde response. Our previous studies in Drosophila have clearly established that progress through the cell cycle is precisely regulated by the intrinsic activity of the mitochondrion by specific signaling cascades mounted by the cell. As a means to further our understanding of how mitochondrial energy status affects nuclear control of basic cell decisions we have employed Affymetrix microarray-based transcriptional profiling of Drosophila S2 cells knocked down for the gene encoding subunit Va of the complex IV of the mitochondrial electron transport chain. The profiling data identifies up-regulation of glycolytic genes and metabolic studies confirm this increase in glycolysis. The transcriptional portrait which emerges implicates many signaling systems, including a p53 response, an insulin response, and up-regulation of conserved mitochondrial responses. This rich dataset provides many novel targets for further understanding the mechanism whereby the mitochondrion may direct cellular fate decisions. The data also provides a salient model of the shift of metabolism from a predominately oxidative state towards a predominately aerobic glycolytic state, and therefore provides a model of energy substrate management not unlike that found in cancer.
Expression profiling of attenuated mitochondrial function identifies retrograde signals in Drosophila.
Cell line
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Integrated expression profiles of mRNA and miRNA in polarized primary murine microglia.
Specimen part
View SamplesThe aim of this study was to determine the role that miRNAs have on influencing murine microgial phenotypes under M1(LPS) and M2a (IL-4) stimulating conditions.
Integrated expression profiles of mRNA and miRNA in polarized primary murine microglia.
Specimen part
View SamplesMany new alternative splice forms have been detected at the transcript level using next generation sequencing (NGS) methods, especially RNA-Seq, but it is not known how many of these transcripts are being translated. Leveraging the unprecedented capabilities of NGS, we collected RNA-Seq and proteomics data from the same cell population (Jurkat cells) and created a bioinformatics pipeline that builds customized databases for the discovery of novel splice-junction peptides. Results: Eighty million paired-end Illumina reads and ~500,000 tandem mass spectra were used to identify 12,873 transcripts (19,320 including isoforms) and 6,810 proteins. We developed a bioinformatics workflow to retrieve high-confidence, novel splice junction sequences from the RNA data, translate these sequences into the analogous polypeptide sequence, and create a customized splice junction database for MS searching. Overall design: Jurkat T-cell mRNA was analyzed on an Illumina HiSeq2000. ~80 million paired end reads (2x200bp, ~350bp lengths) were collected.
Discovery and mass spectrometric analysis of novel splice-junction peptides using RNA-Seq.
Cell line
View SamplesMouse oocyte maturation, fertilization, and reprogramming occur in the absence of transcription and thus must be regulated post-transcriptionally. Surprisingly, a major form of post-transcriptional regulation, microRNA-based transcript destabilization and translational inhibition, is lost during this developmental window. Here we evaluate the conservation, timing, and mechanism behind the loss of microRNA activity in oocytes. In both mouse and frogs, microRNA function was active in growing oocytes, but then lost during oocyte maturation. RNA-sequencing of the maturing oocytes uncovered expression of an alternative isoform of Ago2 lacking domains critical for its function. Introduction of full-length Ago2 together with an exogenous microRNA destabilized microRNA luciferase reporters. However, endogenous targets were still largely unaffected. These findings suggest that while it is possible to re-activate some aspects of microRNA activity by introducing full length Ago2, there are additional mechanisms to protect endogenous transcripts from microRNA activity in oocytes. Overall design: Total RNA from mouse GV and MII oocytes, embryonic stem cells, epi cells
Expression of Alternative Ago2 Isoform Associated with Loss of microRNA-Driven Translational Repression in Mouse Oocytes.
Specimen part, Subject
View SamplesBACKGROUND: Climate change will lead in the future to an occurrence of heat waves with a higher frequency and duration than observed today, which has the potential to cause severe damage to seedlings of temperate maize genotypes. In this study, we aimed to (I) assess phenotypic variation for heat tolerance of temperate European Flint and Dent maize inbred lines, (II) investigate the transcriptomic response of temperate maize to linearly increasing heat levels and, (III) identify genes associated with heat tolerance in a set of genotypes with contrasting heat tolerance behaviour. RESULTS: Strong phenotypic differences with respect to heat tolerance were observed between the examined maize inbred lines on a multi-trait level. We identified 607 heat responsive genes as well as 39 heat tolerance genes. CONCLUSION: Our findings indicate that individual inbred lines developed different genetic mechanisms in response to heat stress. We applied a novel statistical approach enabling the integration of multiple genotypes and stress levels in the analysis of abiotic stress expression studies. Overall design: Identifcation of differentially expressed genes between 8 genotypes and 3 heat levels
Genome-wide expression profiling and phenotypic evaluation of European maize inbreds at seedling stage in response to heat stress.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNA expression changes during interferon-beta treatment in the peripheral blood of multiple sclerosis patients.
Sex, Disease
View SamplesThe purpose of this study was to investigate the expression dynamics of mRNAs and microRNAs in response to subcutaneous IFN-beta-1b treatment (Betaferon, 250 g every other day) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS) or relapsing-remitting type of the disease (RRMS).
MicroRNA expression changes during interferon-beta treatment in the peripheral blood of multiple sclerosis patients.
Sex, Disease
View SamplesEpithelial-mesenchymal transition (EMT) is a pivotal process in development and disease. In carcinogenesis, various signaling pathways are known to trigger EMT by inducing the expression of EMT transcription factors (EMT-TFs) like SNAIL1, ultimately promoting invasion, metastasis and chemoresistance. However, how EMT is executed downstream of EMT-TFs is incompletely understood. Here, using human colorectal cancer (CRC) and mammary cell line models of EMT, we demonstrate that SNAIL1 critically relies on bone morphogenetic protein (BMP) signaling for EMT execution. This activity requires the transcription factor SMAD4 common to BMP/TGFβ pathways, but is TGFβ signaling-independent. Further, we define a signature of BMP-dependent genes in the EMT-transcriptome which orchestrate EMT-induced invasiveness, and are found to be regulated in human CRC transcriptomes and during EMT in vivo. Collectively, our findings substantially augment the knowledge of mechanistic routes whereby EMT can be effectuated, which is relevant for the conceptual understanding and therapeutic targeting of EMT processes.
Canonical BMP Signaling Executes Epithelial-Mesenchymal Transition Downstream of SNAIL1.
Specimen part
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