scholarly journals Regulation of Natural mRNAs by the Nonsense-Mediated mRNA Decay Pathway

2014 ◽  
Vol 13 (9) ◽  
pp. 1126-1135 ◽  
Author(s):  
Megan Peccarelli ◽  
Bessie W. Kebaara
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Regulation Of Gene Expression ◽  
Degradation Pathway ◽  
Mrna Degradation ◽  
Content Type ◽  
Mrna Regulation ◽  
Premature Termination Codons ◽  
Nonsense Mediated Mrna Decay ◽  
Eukaryotic Organisms

ABSTRACT The nonsense-mediated mRNA decay (NMD) pathway is a specialized mRNA degradation pathway that degrades select mRNAs. This pathway is conserved in all eukaryotes examined so far, and it triggers the degradation of mRNAs that prematurely terminate translation. Originally identified as a pathway that degrades mRNAs with premature termination codons as a result of errors during transcription, splicing, or damage to the mRNA, NMD is now also recognized as a pathway that degrades some natural mRNAs. The degradation of natural mRNAs by NMD has been identified in multiple eukaryotes, including Saccharomyces cerevisiae , Drosophila melanogaster , Arabidopsis thaliana , and humans. S. cerevisiae is used extensively as a model to study natural mRNA regulation by NMD. Inactivation of the NMD pathway in S. cerevisiae affects approximately 10% of the transcriptome. Similar percentages of natural mRNAs in the D. melanogaster and human transcriptomes are also sensitive to the pathway, indicating that NMD is important for the regulation of gene expression in multiple organisms. NMD can either directly or indirectly regulate the decay rate of natural mRNAs. Direct NMD targets possess NMD-inducing features. This minireview focuses on the regulation of natural mRNAs by the NMD pathway, as well as the features demonstrated to target these mRNAs for decay by the pathway in S. cerevisiae . We also compare NMD-targeting features identified in S. cerevisiae with known NMD-targeting features in other eukaryotic organisms.

scholarly journals Regulation of Multiple Core Spliceosomal Proteins by Alternative Splicing-Coupled Nonsense-Mediated mRNA Decay

2008 ◽  
Vol 28 (13) ◽  
pp. 4320-4330 ◽  
Author(s):  
Arneet L. Saltzman ◽  
Yoon Ki Kim ◽  
Qun Pan ◽  
Matthew M. Fagnani ◽  
Lynne E. Maquat ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Mrna Decay ◽  
Splice Variants ◽  
Cellular Functions ◽  
Regulate Gene Expression ◽  
Premature Termination Codons ◽  
Microarray Profiling ◽  
Nonsense Mediated Mrna Decay ◽  
Regulate Gene

ABSTRACT Alternative splicing (AS) can regulate gene expression by introducing premature termination codons (PTCs) into spliced mRNA that subsequently elicit transcript degradation by the nonsense-mediated mRNA decay (NMD) pathway. However, the range of cellular functions controlled by this process and the factors required are poorly understood. By quantitative AS microarray profiling, we find that there are significant overlaps among the sets of PTC-introducing AS events affected by individual knockdown of the three core human NMD factors, Up-Frameshift 1 (UPF1), UPF2, and UPF3X/B. However, the levels of some PTC-containing splice variants are less or not detectably affected by the knockdown of UPF2 and/or UPF3X, compared with the knockdown of UPF1. The intron sequences flanking the affected alternative exons are often highly conserved, suggesting important regulatory roles for these AS events. The corresponding genes represent diverse cellular functions, and surprisingly, many encode core spliceosomal proteins and assembly factors. We further show that conserved, PTC-introducing AS events are enriched in genes that encode core spliceosomal proteins. Where tested, altering the expression levels of these core spliceosomal components affects the regulation of PTC-containing splice variants from the corresponding genes. Together, our results show that AS-coupled NMD can have different UPF factor requirements and is likely to regulate many general components of the spliceosome. The results further implicate general spliceosomal components in AS regulation.

scholarly journals Interrogating the degradation pathways of unstable mRNAs with XRN1-resistant sequences

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Volker Boehm ◽  
Jennifer V. Gerbracht ◽  
Marie-Charlotte Marx ◽  
Niels H. Gehring
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Mrna Degradation ◽  
Eukaryotic Cells ◽  
Mrna Turnover ◽  
Degradation Pathways ◽  
Messenger Rnas ◽  
Endonucleolytic Cleavage ◽  
Nonsense Mediated Mrna Decay ◽  
Cytokine Mrnas

Abstract The turnover of messenger RNAs (mRNAs) is a key regulatory step of gene expression in eukaryotic cells. Due to the complexity of the mammalian degradation machinery, the contribution of decay factors to the directionality of mRNA decay is poorly understood. Here we characterize a molecular tool to interrogate mRNA turnover via the detection of XRN1-resistant decay fragments (xrFrag). Using nonsense-mediated mRNA decay (NMD) as a model pathway, we establish xrFrag analysis as a robust indicator of accelerated 5′–3′ mRNA decay. In tethering assays, monitoring xrFrag accumulation allows to distinguish decapping and endocleavage activities from deadenylation. Moreover, xrFrag analysis of mRNA degradation induced by miRNAs, AU-rich elements (AREs) as well as the 3′ UTRs of cytokine mRNAs reveals the contribution of 5′–3′ decay and endonucleolytic cleavage. Our work uncovers formerly unrecognized modes of mRNA turnover and establishes xrFrag as a powerful tool for RNA decay analyses.

scholarly journals Nonsense-mediated mRNA decay utilizes complementary mechanisms to suppress mRNA and protein accumulation

2021 ◽  
Author(s):  
Dylan B. Udy ◽  
Robert K Bradley
Keyword(s):  
Mrna Decay ◽  
Mrna Degradation ◽  
Protein Accumulation ◽  
Safe Harbor ◽  
Reporter System ◽  
Truncated Protein ◽  
Protein Levels ◽  
Premature Termination Codons ◽  
Nonsense Mediated Mrna Decay ◽  
Accurate Quantification

Nonsense-mediated mRNA decay (NMD) is an essential, highly conserved quality control pathway that detects and degrades mRNAs containing premature termination codons (PTCs). Although the essentiality of NMD is frequently ascribed to its prevention of truncated protein accumulation, the extent to which NMD actually suppresses proteins encoded by NMD-sensitive transcripts is less well-understood than NMD-mediated suppression of mRNA. Here, we describe a reporter system that permits accurate quantification of both mRNA and protein levels via stable integration of paired reporters encoding NMD-sensitive and -insensitive transcripts into the AAVS1 safe harbor loci in human cells. We use this system to demonstrate that NMD suppresses proteins encoded by NMD-sensitive transcripts by up to ~8-fold more than the mRNA itself. Our data indicate that NMD limits the accumulation of proteins encoded by NMD substrates by mechanisms beyond mRNA degradation, such that even when NMD-sensitive mRNAs escape destruction, their encoded proteins are still effectively suppressed.

scholarly journals Nonsense-mediated mRNA decay relies on “two-factor authentication” by SMG5-SMG7

2020 ◽  
Author(s):  
Volker Boehm ◽  
Sabrina Kueckelmann ◽  
Jennifer V. Gerbracht ◽  
Thiago Britto-Borges ◽  
Janine Altmüller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Translation Termination ◽  
Mrna Degradation ◽  
Eukaryotic Gene Expression ◽  
Eukaryotic Gene ◽  
Nonsense Mediated Mrna Decay ◽  
Functional Hierarchy ◽  
Improved Model ◽  
Dependent Pathway

AbstractEukaryotic gene expression is constantly regulated and controlled by the translation-coupled nonsense-mediated mRNA decay (NMD) pathway. Aberrant translation termination leads to NMD activation and robust clearance of NMD targets via two seemingly independent and redundant mRNA degradation branches. Here, we uncover that the loss of the first SMG5-SMG7-dependent pathway also inactivates the second SMG6-dependent branch, indicating an unexpected functional hierarchy of the final NMD steps. Transcriptome-wide analyses of SMG5-SMG7-depleted cells confirm complete NMD inhibition resulting in massive transcriptomic alterations. The NMD activity conferred by SMG5-SMG7 is determined to varying degrees by their interaction with the central NMD factor UPF1, heterodimer formation and the initiation of deadenylation. Surprisingly, we find that SMG5 functionally substitutes SMG7 and vice versa. Our data support an improved model for NMD execution that requires two-factor authentication involving UPF1 phosphorylation and SMG5-SMG7 recruitment to access SMG6 activity.

scholarly journals Regulation of gene expression by translation factor eIF5A: Hypusine-modified eIF5A enhances nonsense-mediated mRNA decay in human cells

Translation ◽  
2017 ◽  
Vol 5 (2) ◽  
pp. e1366294 ◽  
Author(s):  
Mainul Hoque ◽  
Ji Yeon Park ◽  
Yun-juan Chang ◽  
Augusto D. Luchessi ◽  
Tavane D. Cambiaghi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Regulation Of Gene Expression ◽  
Human Cells ◽  
Translation Factor ◽  
Nonsense Mediated Mrna Decay

scholarly journals Nonsense-mediated mRNA decay uses complementary mechanisms to suppress mRNA and protein accumulation

2021 ◽  
Vol 5 (3) ◽  
pp. e202101217
Author(s):  
Dylan B Udy ◽  
Robert K Bradley
Keyword(s):  
Mrna Decay ◽  
Mrna Degradation ◽  
Protein Accumulation ◽  
Safe Harbor ◽  
Reporter System ◽  
Truncated Protein ◽  
Protein Levels ◽  
Premature Termination Codons ◽  
Nonsense Mediated Mrna Decay ◽  
Accurate Quantification

Nonsense-mediated mRNA decay (NMD) is an essential, highly conserved quality control pathway that detects and degrades mRNAs containing premature termination codons. Although the essentiality of NMD is frequently ascribed to its prevention of truncated protein accumulation, the extent to which NMD actually suppresses proteins encoded by NMD-sensitive transcripts is less well-understood than NMD-mediated suppression of mRNA. Here, we describe a reporter system that permits accurate quantification of both mRNA and protein levels via stable integration of paired reporters encoding NMD-sensitive and NMD-insensitive transcripts into the AAVS1 safe harbor loci in human cells. We use this system to demonstrate that NMD suppresses proteins encoded by NMD-sensitive transcripts by up to eightfold more than the mRNA itself. Our data indicate that NMD limits the accumulation of proteins encoded by NMD substrates by mechanisms beyond mRNA degradation, such that even when NMD-sensitive mRNAs escape destruction, their encoded proteins are still effectively suppressed.

scholarly journals A UPF1 variant drives conditional remodeling of nonsense-mediated mRNA decay

2021 ◽  
Author(s):  
Sarah E. Fritz ◽  
Soumya Ranganathan ◽  
J. Robert Hogg
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Gene Expression Regulation ◽  
Translation Termination ◽  
Translational Repression ◽  
The Core ◽  
Human Genes ◽  
Rna Quality Control ◽  
Nonsense Mediated Mrna Decay

AbstractThe nonsense-mediated mRNA decay (NMD) pathway monitors translation termination to degrade transcripts with premature stop codons and regulate thousands of human genes. Due to the major role of NMD in RNA quality control and gene expression regulation, it is important to understand how the pathway responds to changing cellular conditions. Here we show that an alternative mammalian-specific isoform of the core NMD factor UPF1, termed UPF1LL, enables condition-dependent remodeling of NMD specificity. UPF1LL associates more stably with potential NMD target mRNAs than the major UPF1SL isoform, expanding the scope of NMD to include many transcripts normally immune to the pathway. Unexpectedly, the enhanced persistence of UPF1LL on mRNAs supports induction of NMD in response to rare translation termination events. Thus, while canonical NMD is abolished by translational repression, UPF1LL activity is enhanced, providing a mechanism to rapidly rewire NMD specificity in response to cellular stress.

scholarly journals REDIportal: millions of novel A-to-I RNA editing events from thousands of RNAseq experiments

2020 ◽  
Vol 49 (D1) ◽  
pp. D1012-D1019 ◽  
Author(s):  
Luigi Mansi ◽  
Marco Antonio Tangaro ◽  
Claudio Lo Giudice ◽  
Tiziano Flati ◽  
Eli Kopel ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Comparative Genomics ◽  
Rna Editing ◽  
Innate Immune Response ◽  
Transcriptome Sequencing ◽  
Regulation Of Gene Expression ◽  
Innate Immune ◽  
Neurotransmitter Receptors ◽  
Eukaryotic Organisms

Abstract RNA editing is a relevant epitranscriptome phenomenon able to increase the transcriptome and proteome diversity of eukaryotic organisms. ADAR mediated RNA editing is widespread in humans in which millions of A-to-I changes modify thousands of primary transcripts. RNA editing has pivotal roles in the regulation of gene expression or modulation of the innate immune response or functioning of several neurotransmitter receptors. Massive transcriptome sequencing has fostered the research in this field. Nonetheless, different aspects of the RNA editing biology are still unknown and need to be elucidated. To support the study of A-to-I RNA editing we have updated our REDIportal catalogue raising its content to about 16 millions of events detected in 9642 human RNAseq samples from the GTEx project by using a dedicated pipeline based on the HPC version of the REDItools software. REDIportal now allows searches at sample level, provides overviews of RNA editing profiles per each RNAseq experiment, implements a Gene View module to look at individual events in their genic context and hosts the CLAIRE database. Starting from this novel version, REDIportal will start collecting non-human RNA editing changes for comparative genomics investigations. The database is freely available at http://srv00.recas.ba.infn.it/atlas/index.html.

scholarly journals Nonsense-Mediated mRNA Decay Mutation in Aspergillus nidulans

2006 ◽  
Vol 5 (11) ◽  
pp. 1838-1846 ◽  
Author(s):  
Igor Y. Morozov ◽  
Susana Negrete-Urtasun ◽  
Joan Tilburn ◽  
Christine A. Jansen ◽  
Mark X. Caddick ◽  
...  
Keyword(s):  
Aspergillus Nidulans ◽  
Mrna Decay ◽  
Premature Termination ◽  
Regulation Of Gene Expression ◽  
Premature Termination Codon ◽  
Termination Codon ◽  
Urate Oxidase ◽  
Genes Encoding ◽  
Nonsense Mediated Mrna Decay ◽  
Nonsense Codons

ABSTRACT An Aspergillus nidulans mutation, designated nmdA1, has been selected as a partial suppressor of a frameshift mutation and shown to truncate the homologue of the Saccharomyces cerevisiae nonsense-mediated mRNA decay (NMD) surveillance component Nmd2p/Upf2p. nmdA1 elevates steady-state levels of premature termination codon-containing transcripts, as demonstrated using mutations in genes encoding xanthine dehydrogenase (hxA), urate oxidase (uaZ), the transcription factor mediating regulation of gene expression by ambient pH (pacC), and a protease involved in pH signal transduction (palB). nmdA1 can also stabilize pre-mRNA (unspliced) and wild-type transcripts of certain genes. Certain premature termination codon-containing transcripts which escape NMD are relatively stable, a feature more in common with certain nonsense codon-containing mammalian transcripts than with those in S. cerevisiae. As in S. cerevisiae, 5′ nonsense codons are more effective at triggering NMD than 3′ nonsense codons. Unlike the mammalian situation but in common with S. cerevisiae and other lower eukaryotes, A. nidulans is apparently impervious to the position of premature termination codons with respect to the 3′ exon-exon junction.

Sign in / Sign up

Export Citation Format

Share Document