N6-methyladenosine (m6A) is a common modification of mRNA, with potential roles in fine-tuning the RNA life cycle, but little is known about the pathways regulating this process and its physiological role. Here, we used mass-spectrometry to identify a dense network of proteins physically interacting with METTL3, a core component of the methyltransferase complex, and show that two of them, WTAP and KIAA1429, are required for methylation. Combining high resolution m6A-Seq with knockdown of WTAP allowed us to define accurate maps, at near single-nucleotide resolution, of sites of mRNA methylation across four dynamic programs in human and mouse, including development, differentiation, reprogramming and immune response. Internal WTAP-dependent methylation sites were largely static across the different surveyed conditions and present in the majority of mRNAs. However, methylations were found at much lower levels within highly expressed mRNAs, and methylation is inversely correlated with mRNA stability, consistent with a role in establishing an overall basal, cell-type invariant, distribution of degradation rates. In addition, we identify thousands of WTAP-independent methylation sites at transcription initiation sites, forming part of the mRNA cap structure. We show that the methylations occur at the first transcribed nucleotide, and find that thousands of transcripts are present in different isoforms differing in the methylation state of the first transcribed nucleotide, a previously unappreciated complexity of the transcriptome. Together, our data sheds new light on the proteomic and transcriptional underpinnings of this epitranscriptomic modification in mammals. Overall design: Examination of m6A methylation in human Hek293 and A549 cell lines, in human embryonic stem cells (ESCs) undergoing differentiation to neural progenitor cells (NPCs), in OKMS inducible fibroblasts reprogrammed into iPSC, and upon knockdown of factors using siRNAs or shRNAs.
Perturbation of m6A writers reveals two distinct classes of mRNA methylation at internal and 5' sites.
No sample metadata fields
View SamplesN6-methyladenosine (m6A) is a common modification of mRNA, with potential roles in fine-tuning the RNA life cycle, but little is known about the pathways regulating this process and its physiological role. Here, we used mass-spectrometry to identify a dense network of proteins physically interacting with METTL3, a core component of the methyltransferase complex, and show that two of them, WTAP and KIAA1429, are required for methylation. Combining high resolution m6A-Seq with knockdown of WTAP allowed us to define accurate maps, at near single-nucleotide resolution, of sites of mRNA methylation across four dynamic programs in human and mouse, including development, differentiation, reprogramming and immune response. Internal WTAP-dependent methylation sites were largely static across the different surveyed conditions and present in the majority of mRNAs. However, methylations were found at much lower levels within highly expressed mRNAs, and methylation is inversely correlated with mRNA stability, consistent with a role in establishing an overall basal, cell-type invariant, distribution of degradation rates. In addition, we identify thousands of WTAP-independent methylation sites at transcription initiation sites, forming part of the mRNA cap structure. We show that the methylations occur at the first transcribed nucleotide, and find that thousands of transcripts are present in different isoforms differing in the methylation state of the first transcribed nucleotide, a previously unappreciated complexity of the transcriptome. Together, our data sheds new light on the proteomic and transcriptional underpinnings of this epitranscriptomic modification in mammals. Overall design: Examination of m6A methylation across different knockdowns using shRNAs in mouse embryonic fibroblasts, in embyronic and adult brains, and in dendritic cell stimulated with LPS.
Perturbation of m6A writers reveals two distinct classes of mRNA methylation at internal and 5' sites.
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View SamplesThe goal of this project is to generate transcriptome profiling of intestinal stem cells for a systemic analysis of cellular pathways involved in responses to fasting. Overall design: Examination of one cell type in two conditions.
Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging.
Age, Specimen part, Cell line, 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 SamplesTranslation 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 SamplesThe role of chronic hepatitis C virus (HCV) in the pathogenesis of HCV-associated hepatocellular carcinoma (HCC) is not completely understood, particularly at the molecular level.
Genes involved in viral carcinogenesis and tumor initiation in hepatitis C virus-induced hepatocellular carcinoma.
Specimen part
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
View SamplesThis SuperSeries is composed of the SubSeries listed below.
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
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