Expression analysis of DamP mRNAs using expressed molecular barcodes
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae S288C Saccharomyces cerevisiae
PROVIDER: GSE53954 | GEO | 2014/01/10
SECONDARY ACCESSION(S): PRJNA234034
REPOSITORIES: GEO
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Project description:We have generated 979 yeast strains in which the natural 3' UTR of essential gene mRNAs has been replaced by the same long 1.4 kb artificial 3' UTR (DAmP modification). Nonsense mediated mRNA decay (NMD) of these mRNA reporters was tested by using Agilent barcode microarrays by taking advantage of molecular barcodes introduced just downstream the stop codon during strain construction. We introduced in each DAmP strain either a neutral mutation (deletion of YEL068C) or the deletion of essential factors for NMD: NAM7 and NMD2. The resulting haploid cells were tested for changes in DAmP mRNA levels by comparing an RNA sample with a DNA genomic sample. Differences between the samples indicate the sensibility of the DAmP mRNAs to degradation through NMD. The large scale results were validated by Q-PCR analysis of individual strains. A strong negative correlation between the level of destabilization elicited by a long 3' UTR and the size of the coding sequence suggests that long ORF mRNAs can escape NMD even in the presence of a long 3' UTR. Three samples were analysed and for each sample a technical replicate was performed, starting from the raw cellular material. YEL068C samples represent the reference population while NMD2 and NAM7 samples are the ones important for the analysis. Only a very limited part of the Agilent barcode microarray signal (barcodes corresponding to the “up” tag in the DamP strain) was used for the interpretation of the data.
2014-01-10 | E-GEOD-53954 | biostudies-arrayexpress
Project description:Nonsense-mediated mRNA decay (NMD) is a eukaryotic, translation-dependent degradation pathway that targets mRNAs with premature termination codons and also regulates the expression of some mRNAs that encode full-length proteins. Although many genes express NMD-sensitive transcripts, identifying them based on short-read sequencing data remains a challenge. To identify and analyze endogenous targets of NMD, we applied cDNA Nanopore sequencing and short-read sequencing to human cells with varying expression levels of NMD factors. Our approach detects full-length NMD substrates that are highly unstable and increase in levels or even only appear when NMD is inhibited. Among the many new NMD-targeted isoforms that our analysis identified, most derive from alternative exon usage. The isoform-aware analysis revealed many genes with significant changes in splicing but no significant changes in overall expression levels upon NMD knockdown. NMD-sensitive mRNAs have more exons in the 3΄UTR and for mRNAs with a termination codon in the last exon. The length of the 3΄UTR per se does not correlate with NMD sensitivity. Analysis of splicing signals reveals isoforms where NMD has been co-opted in the regulation of gene expression, but a main function is most likely to rid the transcriptome of isoforms resulting from spurious splicing events. Long-read sequencing enabled the identification of many novel NMD-sensitive mRNAs and revealed both known and unexpected features concerning their biogenesis and their biological role. Our data provide a highly valuable resource of human NMD transcript targets for future genomic and transcriptomic applications.
2021-07-20 | E-MTAB-10452 | biostudies-arrayexpress
Project description:Analysis of miRNA-targeted cellular NMD substrates in HeLa cell. The hypothesis tested in the present study was that endogenous NMD substrates containing long 3' untranslated region may targeted for miRNA. Results provide important information expanding the roles of miRISC in the posttranscriptional regulation of gene expression: a new cross-talk between miRNA-mediated gene silencing and NMD. ABSTRACT: Imperfect base-pairing between microRNA (miRNA) and the 3’-untranslated region (3’UTR) of target mRNA triggers translational repression of the target mRNA. Here, we provide evidence that human Argonaute 2 (Ago2) targets cap-binding protein (CBP)80/20- and exon junction complex (EJC)-bound mRNAs and inhibits nonsense-mediated mRNA decay (NMD), which is tightly restricted to CBP80/20-bound mRNAs. Furthermore, microarray analyses reveal that a subset of cellular transcripts, which are expected to be targeted for NMD, is stabilized by miRNA-mediated gene silencing. The regulation of NMD by miRNAs will shed light on a new post-transcriptional regulation mechanism of gene expression in mammalian cells
2010-03-08 | GSE16170 | GEO
Project description:Analysis of miRNA-targeted cellular NMD substrates in HeLa cell. The hypothesis tested in the present study was that endogenous NMD substrates containing long 3' untranslated region may targeted for miRNA. Results provide important information expanding the roles of miRISC in the posttranscriptional regulation of gene expression: a new cross-talk between miRNA-mediated gene silencing and NMD. ABSTRACT: Imperfect base-pairing between microRNA (miRNA) and the 3â-untranslated region (3âUTR) of target mRNA triggers translational repression of the target mRNA. Here, we provide evidence that human Argonaute 2 (Ago2) targets cap-binding protein (CBP)80/20- and exon junction complex (EJC)-bound mRNAs and inhibits nonsense-mediated mRNA decay (NMD), which is tightly restricted to CBP80/20-bound mRNAs. Furthermore, microarray analyses reveal that a subset of cellular transcripts, which are expected to be targeted for NMD, is stabilized by miRNA-mediated gene silencing. The regulation of NMD by miRNAs will shed light on a new post-transcriptional regulation mechanism of gene expression in mammalian cells Total RNA obtained from HeLa cells with downregulation of Ago2 or Ago2/UPF1 by siRNA. The up- or down-regulated transcripts were compared to control siRNA treated HeLa cell RNA extract. Significant transcripts were confirmed by replication.
2010-04-09 | E-GEOD-16170 | biostudies-arrayexpress
Project description:Alternative polyadenylation (APA) produces transcript 3’ untranslated regions (3’UTRs) with distinct sequences, lengths, stability, and functions. We show here that APA products include a class of cryptic nonsense-mediated mRNA decay (NMD) substrates with extended 3’UTRs that gene- or transcript-level analyses of NMD often fail to detect. Transcriptome-wide, the core NMD factor UPF1 preferentially recognizes long 3’UTR products of APA, leading to their systematic downregulation. Further, we find that many APA events consistently observed in multiple tumor types are controlled by NMD. Additionally, PTBP1, previously implicated in direct modulation of co-transcriptional polyA site choice, regulates the balance of short and long 3’UTR isoforms by inhibiting NMD. Our data suggest that PTBP1 binding near polyA sites can drive production of long 3’UTR APA products in the nucleus and/or protect them from decay in the cytoplasm. Together, our findings reveal a widespread role for NMD in shaping the outcomes of APA.
2020-05-28 | GSE138736 | GEO
Project description:Nonsense-mediated mRNA decay (NMD) is a eukaryotic RNA degradation pathway that targets for degradation faulty mRNAs with premature termination codons as well as many physiological mRNAs encoding full-length proteins. Consequently, NMD functions in both, quality control and post-transcriptional regulation of gene expression, and it has been implicated in the modulation of cancer progression. To investigate the role of NMD in cancer, we knocked out SMG7 in the HT1080 human fibrosarcoma cell line. SMG7 is involved in deadenylation-coupled exonucleolytic mRNA decay, one of the two main degradation pathways in mammalian NMD. Genome-wide proteomic and transcriptomic analyses confirmed that NMD is severely compromised in these SMG7-knockout HT1080 cells. We compared the oncogenic properties between the parental, the SMG7-knockout, and a rescue cell line in which we re-introduced both isoforms of SMG7. In parallel, we tested the effect of a drug inhibiting the NMD factor SMG1 on the HT1080 cells to distinguish NMD-dependent effects from putative NMD-independent functions of SMG7. Using cell-based assays as well as a mouse xenograft tumor model, we show that the oncogenic properties of the parental HT1080 cells areseverely compromised when NMD is inhibited. Molecular pathway analysis revealed a strong reduction of the matrix metalloprotease 9 (MMP9) gene expression in NMD-suppressed cells. Since MMP9 expression promotes cancer cell migration and invasion, metastasis and angiogenesis, its downregulation in NMD-suppressed cells explains, at least partially, their reduced tumorigenicity. Collectively, our findings emphasize the therapeutic potential of NMD inhibition for the treatment ofcertain types of cancer.
2023-09-19 | PXD041853 | Pride
Project description:Nonsense-mediated mRNA decay (NMD) has been intensively studied as a surveillance pathway that degrades erroneous transcripts arising from mutations or mis-splicing. Additional roles for NMD in determining mRNA stability in regular gene expression have emerged as well, yet it is poorly known which functions the pathway has in regular mammalian physiology in vivo. Here, we report a novel conditional Smg6 mouse allele that allows converting wild-type SMG6 to a nuclease-mutant version of the protein. We analyzed the consequences of an inactive NMD pathway on the function of the circadian clock whose mechanism is known to depend on high turnover rates of their oscillating mRNAs and proteins. Fibroblast and liver clocks show strong lengthening of free-running circadian periods under Smg6 mutant conditions. We identify a specific core clock component, Cry2, as directly NMD-regulated through its long 3' UTR. Our findings indicate that NMD has been co-opted as an mRNA decay pathway to limit the temporal availability of CRY2, one of the key transcriptional repressors in the rhythm-generating feedback loop, expanding the known scope of NMD regulation in vivo.
2022-11-14 | GSE208768 | GEO
Project description:Nonsense-mediated mRNA decay (NMD) has been intensively studied as a surveillance pathway that degrades erroneous transcripts arising from mutations or mis-splicing. Additional roles for NMD in determining mRNA stability in regular gene expression have emerged as well, yet it is poorly known which functions the pathway has in regular mammalian physiology in vivo. Here, we report a novel conditional Smg6 mouse allele that allows converting wild-type SMG6 to a nuclease-mutant version of the protein. We analyzed the consequences of an inactive NMD pathway on the function of the circadian clock whose mechanism is known to depend on high turnover rates of their oscillating mRNAs and proteins. Fibroblast and liver clocks show strong lengthening of free-running circadian periods under Smg6 mutant conditions. We identify a specific core clock component, Cry2, as directly NMD-regulated through its long 3' UTR. Our findings indicate that NMD has been co-opted as an mRNA decay pathway to limit the temporal availability of CRY2, one of the key transcriptional repressors in the rhythm-generating feedback loop, expanding the known scope of NMD regulation in vivo.
2022-11-14 | GSE208764 | GEO
Project description:Nonsense-mediated mRNA decay (NMD) controls the quality of eukaryotic gene expression and also degrades physiologic mRNAs. How NMD targets are identified is incompletely understood. A central NMD factor is the ATP-dependent RNA helicase UPF1. Neither the distance in space between the termination codon and the poly(A) tail nor the binding of steady-state, largely hypophosphorylated UPF1 is a discriminating marker of cellular NMD targets, unlike for PTC-containing reporter mRNAs when compared to their PTC-free counterparts. Here, we map phosphorylated UPF1 (p-UPF1) binding sites using transcriptome-wide footprinting or DNA oligonucleotide-directed mRNA cleavage to report that p-UPF1 provides the first reliable cellular NMD-target marker. p-UPF1 is enriched on NMD target 3'UTRs along with SMG5 and SMG7 but not SMG1 or SMG6. Immunoprecipitations of UPF1 variants deficient in various aspects of the NMD process in parallel with FRET experiments reveal that ATPase/helicase-deficient UPF1 manifests high levels of RNA binding and disregulated hyperphosphorylation, whereas wild-type UPF1 releases from nonspecific RNA interactions in an ATP hydrolysis-dependent mechanism until an NMD target is identified. 3'UTR-associated UPF1 undergoes regulated phosphorylation on NMD targets, providing a binding platform for mRNA degradative activities. p-UPF1 binding to NMD target 3'UTRs is stabilized by SMG5 and SMG7. Our results help to explain why steady-state UPF1 binding is not a marker for cellular NMD substrates and how this binding is transformed to induce mRNA decay.
2014-08-15 | GSE60045 | GEO
Project description:The RNA helicase UPF1 is best known for its key function in mRNA nonsense-mediated mRNA decay (NMD), but has also been implicated in additional mRNA turnover mechanisms, telomere homeostasis, and DNA replication. In NMD, UPF1 recruitment to target mRNAs is thought to occur through interaction with release factors at terminating ribosomes, but evidence for translation-independent interaction of UPF1 with the 3M-bM-^@M-^Y untranslated region (UTR) of mRNAs has also been reported. To map UPF1 binding sites transcriptome-wide, we performed individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP) in human cells, untreated or after inhibiting translation by puromycin. We found a strong association of UPF1 with 3M-bM-^@M-^Y UTRs in undisturbed, translationally active cells and a significant increase in UPF1 binding to coding sequence (CDS) after translation inhibition. These results indicate that UPF1 binds RNA before translation and gets displaced from the CDS by translating ribosomes. This evidence for translation-independent UPF1-RNA interaction, which is corroborated by RNA immunoprecipitations experiments and by our observation that UPF1 also crosslinks to long non-coding RNAs, suggests that the decision to trigger NMD occurs after association of UPF1 with the mRNA, presumably through activation of RNA-bound UPF1 by aberrant translation termination. Examination of Upf1 binding preferences via iCLIP in untreated HeLa cells and HeLa cells, where translation is blocked by puromycin treatment in vivo crosslinking and immunoprecipitation strategy (iCLIP)
2013-06-20 | E-GEOD-47976 | biostudies-arrayexpress