Presence of NAD+-capped RNA in human cells: function and removal by the DXO deNADing Protein
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE90884 | GEO | 2017/03/09
SECONDARY ACCESSION(S): PRJNA356287
REPOSITORIES: GEO
Similar Datasets
Project description:The 5´-end 7-methylguanosine cap structure has long been known as a signature feature of eukaryotic cellular and viral mRNAs that confers mRNA stability and efficient translation. Recent findings in diverse organisms have demonstrated that RNAs can additionally possess a non-canonical cap structure consisting of a nicotinamide adenosine dinucleotide (NAD+) at their 5´ end in place of m7G. It has been shown that 5´ end-NAD+ cap promotes rapid decay of the RNA at least in part by the DXO family of proteins in mammalian cells. This observation led to the hypothesis that mammalian cells harbor additional deNADding enzymes that may function in distinct pathways. Here we report Nudt12 efficiently removes NAD+ caps and functions as alternate cellular deNADding enzyme that targets NAD+-capped RNAs distinct from DXO. Importantly, with the use of an NAD-Cap Detection (NAD-CapD) approach that utilizes enzymatic properties to release intact NAD+/NADH from the 5´ end of NAD-capped cellular RNAs and a colorimetric NAD Quantitation to detect released NAD+/NADH, we can follow total cellular NAD+ cap levels. Removal of Nudt12 or DXO deNADding enzymes from cells significantly increased levels of NAD+-capped cellular RNAs. Moreover, fungal Rai1 and Dxo1, previously demonstrated to possess deNADding activity in vitro, can also function as deNADding enzymes in yeast cells. Double disruption of Rai1 and Dxo1 in yeast cells lead to accumulation of NAD+-capped RNAs, indicating that both enzymes function to clear NAD+ from the 5´ end of RNAs. Finally, our findings established that alterations in cellular NAD+ levels impact NAD+-capped RNA levels implying NAD+ capping is a modulated process that may be linked to the metabolic state of the cell.
2019-05-20 | GSE110801 | GEO
Project description:NAD besides its key role in cellular metabolism can serve as an alternative 5’ cap at several short non-coding RNAs. However, the function of the NAD cap remains elusive. Here, we investigate NAD capping of RNAs upon HIV-1 infection, which is associated with intracellular pellagra – depletion of NAD/NADH cellular pool. We applied NAD captureSeq on HIV-1 infected/noninfected cells and we revealed that four snRNAs (U1, U4ATAC, U5E and U7) and four snoRNAs (snord3G, snord102, snorA50A and snord3B) lost NAD cap upon HIV-1 infection. Interestingly, U1 snRNA was previously shown to be essential for HIV-1 replication. We provide evidence that the NAD cap reduces the stability of the U1 - HIV-1 pre-mRNA duplex. The importance of NAD RNA cap in HIV-1 infection was further supported by NAD decapping enzyme DXO overexpression, which led to increase in HIV-1 infectivity. This is the first example of NAD cap function in mammalian cells and suggests a general role of non-canonical RNA caps in antiviral innate immunity response.
2024-05-16 | GSE191019 | GEO
Project description:Mammalian mRNAs are generated by complex and coordinated biogenesis pathways and acquire 5'-end m7G caps that play fundamental roles in processing and translation. Here we show that several selenoprotein mRNAs are not recognized efficiently by translation initiation factor eIF4E because they bear a hypermethylated cap. This cap modification is acquired via a 5M-bM-^@M-^Yend maturation pathway similar to that of the small nucle(ol)ar RNAs (sn- and snoRNAs). Our findings also establish that the trimethylguanosine synthase 1 (Tgs1) interacts with selenoprotein mRNAs for cap hypermethylation and that assembly chaperones and core proteins devoted to sn- and snoRNP maturation contribute to recruiting Tgs1 to selenoprotein mRNPs. We further demonstrate that the hypermethylated-capped selenoprotein mRNAs localize to the cytoplasm, are associated with polysomes and thus translated. Moreover, we found that the activity of Tgs1, but not of eIF4E, is required for the synthesis of the GPx1 selenoprotein in vivo. In total 7 samples; 3 control IP (HeLa 1,2 & 9), 2 TGS1-SF IP(C2 & C2b) and 2 TGS1-LF IP(C7 & C7b)
2014-05-14 | E-GEOD-57625 | biostudies-arrayexpress
Project description:Eukaryotic messenger RNAs (mRNAs) possess a 5’-end N7-methyl guanosine (m7G) cap that promotes their translation and stability. However, it was recently demonstrated that eukaryotic mRNAs can also carry a 5' end nicotinamide adenine dinucleotide (NAD+) cap that promotes mRNA decay mediated by the NAD+ decapping enzyme DXO1. However, the dynamic regulation of NAD+ capping in plant remains unknown. Here, we describe the global landscape of NAD+-capped RNAs in Arabidopsis thaliana, and demonstrate that DXO1 is responsible for removal of these 5’-end modifications and facilitates mRNA degradation in plant transcriptomes. We also reveal that in the absence of DXO1 NAD+-capped mRNAs are unstable and processed into smRNAs. Furthermore, we find that Abscisic Acid (ABA) remodel the landscape of RNA cap epitransciptome, and the mRNA lost their NAD+ cap contribute to their stability under ABA. Overall, our results support a link between ABA response and RNA NAD+ capping.
2020-11-23 | GSE142389 | GEO
Project description:Eukaryotic messenger RNAs (mRNAs) possess a 5’-end N7-methyl guanosine (m7G) cap that promotes their translation and stability. However, it was recently demonstrated that eukaryotic mRNAs can also carry a 5' end nicotinamide adenine dinucleotide (NAD+) cap that promotes mRNA decay mediated by the NAD+ decapping enzyme DXO1. However, the dynamic regulation of NAD+ capping in plant remains unknown. Here, we describe the global landscape of NAD+-capped RNAs in Arabidopsis thaliana, and demonstrate that DXO1 is responsible for removal of these 5’-end modifications and facilitates mRNA degradation in plant transcriptomes. We also reveal that in the absence of DXO1 NAD+-capped mRNAs are unstable and processed into smRNAs. Furthermore, we find that Abscisic Acid (ABA) remodel the landscape of RNA cap epitransciptome, and the mRNA lost their NAD+ cap contribute to their stability under ABA. Overall, our results support a link between ABA response and RNA NAD+ capping.
2020-11-23 | GSE142388 | GEO
Project description:Mammalian mRNAs are generated by complex and coordinated biogenesis pathways and acquire 5'-end m7G caps that play fundamental roles in processing and translation. Here we show that several selenoprotein mRNAs are not recognized efficiently by translation initiation factor eIF4E because they bear a hypermethylated cap. This cap modification is acquired via a 5’end maturation pathway similar to that of the small nucle(ol)ar RNAs (sn- and snoRNAs). Our findings also establish that the trimethylguanosine synthase 1 (Tgs1) interacts with selenoprotein mRNAs for cap hypermethylation and that assembly chaperones and core proteins devoted to sn- and snoRNP maturation contribute to recruiting Tgs1 to selenoprotein mRNPs. We further demonstrate that the hypermethylated-capped selenoprotein mRNAs localize to the cytoplasm, are associated with polysomes and thus translated. Moreover, we found that the activity of Tgs1, but not of eIF4E, is required for the synthesis of the GPx1 selenoprotein in vivo.
2014-05-14 | GSE57625 | GEO
Project description:RNA capping and decapping tightly coordinate with transcription, translation, and RNA decay to regulate gene expression. The DXO/Rai1 family of proteins have been implicated in mRNA decapping and decay, and mammalian DXO was recently found to also function as a decapping enzyme for NAD+-capped RNAs (NAD-RNA). The Arabidopsis genome contains a single gene encoding a DXO/Rai1 protein, AtDXO1. Here we show that AtDXO1 possesses both NAD-RNA decapping activity and 5’-3’ exonuclease activity and that the atdxo1 mutation increases the stability of NAD-RNAs. The atdxo1 mutant displays severe growth retardation, pale color, and multiple developmental defects. Transcriptome profiling analysis showed that the atdxo1 mutation leads to elevated expression of defense-related genes and down-regulation of photosynthesis genes. The autoimmunity phenotype of the mutant could be suppressed by either eds1 or npr1 mutation. Surprisingly, the various phenotypes associated with the atdxo1 mutant could be complemented by the enzymatically inactive AtDXO1. We found that AtDXO1 interacts with RNA cap methyltransferase (CMT). The atdxo1 mutation apparently enhances post-transcriptional gene silencing by elevating levels of siRNAs. Our study indicates that AtDXO1 regulates gene expression in various biological and physiological processes through its pleiotropic molecular functions in mediating RNA processing and decay.
2020-06-16 | GSE132553 | GEO
Project description:The 5’ end of a eukaryotic mRNA generally has a methyl guanosine cap (m7G cap) that not only protects the mRNA from degradation but also mediates almost all other aspects of gene expression. Some RNAs in E. coli, yeast, and mammals were recently found to contain an NAD+ cap at their 5’ ends. Here we report development of a new method – NAD tagSeq – for transcriptome-wide identification and quantification of NAD+-capped RNAs (NAD-RNAs). The method uses first an enzymatic reaction and then a click chemistry reaction to label NAD-RNAs with a synthetic RNA tag. The tagged RNA molecules can be enriched and directly sequenced using the Oxford Nanopore sequencing technology. NAD tagSeq not only allows more accurate identification and quantification of NAD-RNAs but can also reveal sequences of whole NAD-RNA transcripts. Using NAD tagSeq, we found that NAD-RNAs in Arabidopsis are mostly produced from a few thousand protein-coding genes, with over 60% of them from fewer than 200 genes. The top 2,000 genes that were found to produce the highest numbers of NAD-RNAs were enriched in the gene ontology terms of responses to oxidative stress and other stresses, photosynthesis, and protein synthesis. For some Arabidopsis genes, over 10% of their transcripts could be NAD-capped. The NAD-RNAs in Arabidopsis have similar overall sequence structures to their canonical m7G-capped mRNAs. The identification and quantification of NAD-RNAs and revealing their sequence features provide essential steps toward understanding functions of NAD-RNAs.
2019-07-01 | GSE127755 | GEO
Project description:RNA polymerase II transcripts receive a protective 5ʹ m7G cap early during transcription. An alternative cap can be acquired when RNA pol II initiation uses the redox cofactor nicotinamide adenine dinucleotide (NAD) to generate NAD-capped RNAs. The biology of mammalian NAD-RNAs, including its turnover and physiological roles are not completely understood. Here we identify NUDT12 as a cytosolic decapping enzyme for NAD-RNAs. Structural, biochemical and functional studies reveal how homodimerization modulates specificity of NUDT12 for NAD-RNAs as substrate. NUDT12 is localized within a few discrete cytoplasmic granules that are distinct from P-bodies. We identity Bleomycin hydrolase (BLMH) as a factor that associates with NUDT12 in a large ~600 kDa dodecamer complex, and we demonstrate that BLMH is required for correct localization of NUDT12 into these granules. This complex is functional in human cell cultures, as artificial tethering of BLMH to a reporter mRNA results in downregulation of reporter expression, similar to that seen with tethering of NUDT12. Analysis of mouse liver transcriptome from the Nudt12 knockout mouse reveals that a select set of RNAs are regulated, including a significant upregulation of circadian clock transcripts. Given that NAD biosynthesis is under circadian control, our study points to a physiological role for the cytosolic surveillance of NAD-RNAs.
2019-12-25 | GSE138019 | GEO
Project description:All eukaryotic mRNAs contain a 7-methylguanosine (m7G) cap which serves as a platform that recruits proteins to support essential biological functions such as mRNA processing, nuclear export and cap-dependent translation. Although the caping is one of the first steps of transcription and uncapped mRNA is not functional, the fate and turnover of uncapped transcripts have not been studied extensively. Here, we employed fast nuclear depletion of the capping enzymes in yeast Saccharomyces cerevisiae to uncover the turnover of transcripts that failed to be capped. We found that the degradation of non-capped mRNA is mainly performed by Xrn1, the exonuclease which is predominantly localized in the cytoplasm, and the fate of such transcripts is determined principally by the abundance of their synthesis. Nuclear depletion of the capping enzymes increased the levels of poorly expressed mRNAs and non-coding RNAs and did not affect the distribution of RNA Polymerase II on chromatin. Overall, our data indicate that mRNAs that failed to be capped are not directed to any specific quality-control pathway and are stochastically degraded.
2022-09-25 | GSE213942 | GEO