The study of modified RNA known as epitranscriptomics has become increasingly relevant in our understanding of disease-modifying mechanisms.Methylation of N6 adenosine(m^(6)A)and C5 cytosine(m^(5)C)bases occur on mRNA...The study of modified RNA known as epitranscriptomics has become increasingly relevant in our understanding of disease-modifying mechanisms.Methylation of N6 adenosine(m^(6)A)and C5 cytosine(m^(5)C)bases occur on mRNAs,tRNA,mt-tRNA,and rRNA species as well as non-coding RNAs.With emerging knowledge of RNA binding proteins that act as writer,reader,and eraser effector proteins,comes a new understanding of physiological processes controlled by these systems.Such processes when spatiotemporally disrupted within cellular nanodomains in highly specialized tissues such as the brain,give rise to different forms of disease.In this review,we discuss accumulating evidence that changes in the m^(6)A and m^(5)C methylation systems contribute to neurocognitive disorders.Early studies first identified mutations within FMR1 to cause intellectual disability Fragile X syndromes several years before FMR1 was identified as an m^(6)A RNA reader protein.Subsequently,familial mutations within the m^(6)A writer gene METTL5,m^(5)C writer genes NSUN2,NSUN3,NSUN5,and NSUN6,as well as THOC2 and THOC6 that form a protein complex with the m^(5)C reader protein ALYREF,were recognized to cause intellectual development disorders.Similarly,differences in expression of the m^(5)C writer and reader effector proteins,NSUN6,NSUN7,and ALYREF in brain tissue are indicated in individuals with Alzheimer's disease,individuals with a high neuropathological load or have suffered traumatic brain injury.Likewise,an abundance of m^(6)A reader and anti-reader proteins are reported to change across brain regions in Lewy bodies diseases,Alzheimer's disease,and individuals with high cognitive reserve.m^(6)A-modified RNAs are also reported significantly more abundant in dementia with Lewy bodies brain tissue but significantly reduced in Parkinson's disease tissue,whilst modified RNAs are misplaced within diseased cells,particularly where synapses are located.In parahippocampal brain tissue,m^(6)A modification is enriched in transcripts associated with psychiatric disorders including conditions with clear cognitive deficits.These findings indicate a diverse set of molecular mechanisms are influenced by RNA methylation systems that can cause neuronal and synaptic dysfunction underlying neurocognitive disorders.Targeting these RNA modification systems brings new prospects for neural regenerative therapies.展开更多
Ever since the first RNA nucleoside modification was charac- terized in 1957 [1], over 100 distinct chemical modifications have been identified in RNA to date [2]. Most of these modi- fications were characterized in n...Ever since the first RNA nucleoside modification was charac- terized in 1957 [1], over 100 distinct chemical modifications have been identified in RNA to date [2]. Most of these modi- fications were characterized in non-coding RNAs （ncRNAs）, including tRNA, rRNA, and small nuclear RNA （snRNA） [3]. Studies in the past few decades have located various mod- ifications in these ncRNAs and revealed their functional roles [3]. For instance, NLmethyladenosine （mlA）, which is typically found at position 58 in the tRNA T-loop of eukaryotes, func- tions to stabilize tRNA tertiary structure [4] and affect transla- tion by regulating the associations between tRNA and polysome [5]. Pseudouridine （tp） in snRNA can fine-tune branch site interactions and affect mRNA splicing [6].展开更多
We are very pleased to announce a special issue,to be published in the Spring of 2022,on"RNA Modifications and Epitranscriptomics"in the journal Genomics,Proteomics&Bioinformatics(GPB).More than 100 dist...We are very pleased to announce a special issue,to be published in the Spring of 2022,on"RNA Modifications and Epitranscriptomics"in the journal Genomics,Proteomics&Bioinformatics(GPB).More than 100 distinct chemical modifications to RNA have been characterized so far.They are prevalent in non-coding RNA,including rRNA,tRNA,and small nuclear RNA(snRNA).展开更多
BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic comp...BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic complication,usually occurs at an earlier age and progresses faster than age-related cataracts.Evidence has linked N6-methyladenosine(m6A)to DC progression.However,there exists a lack of understanding regarding RNA m6A modifications and the role of m6A in DC pathogenesis.AIM To elucidate the role played by altered m6A and differentially expressed mRNAs(DEmRNAs)in DC.METHODS Anterior lens capsules were collected from the control subjects and patients with DC.M6A epitranscriptomic microarray was performed to investigate the altered m6A modifications and determine the DEmRNAs.Through Gene Ontology and pathway enrichment(Kyoto Encyclopedia of Genes and Genomes)analyses,the potential role played by dysregulated m6A modification was predicted.Real-time polymerase chain reaction was further carried out to identify the dysregulated expression of RNA methyltransferases,demethylases,and readers.RESULTS Increased m6A abundance levels were found in the total mRNA of DC samples.Bioinformatics analysis predicted that ferroptosis pathways could be associated with m6A-modified mRNAs.The levels of five methylation-related genes-RBM15,WTAP,ALKBH5,FTO,and YTHDF1-were upregulated in DC samples.Upregulation of RBM15 expression was verified in SRA01/04 cells with high-glucose medium and in samples from DC patients.CONCLUSION M6a mRNA modifications may be involved in DC progression via the ferroptosis pathway,rendering novel insights into therapeutic strategies for DC.展开更多
Inherited retinal dystrophies (IRDs) are major causes of visual impairment and irreversible blindness worldwide, while the precise molecular and genetic mechanisms are still elusive. N6-methyladenosine (m^(6)A) modifi...Inherited retinal dystrophies (IRDs) are major causes of visual impairment and irreversible blindness worldwide, while the precise molecular and genetic mechanisms are still elusive. N6-methyladenosine (m^(6)A) modification is the most prevalent internal modification in eukaryotic mRNA. YTH domain containing 2 (YTHDC2), an m^(6)A reader protein, has recently been identified as a key player in germline development and human cancer. However, its contribution to retinal function remains unknown. Here, we explore the role of YTHDC2 in the visual function of retinal rod photoreceptors by generating rod-specific Ythdc2 knockout mice. Results show that Ythdc2 deficiency in rods causes diminished scotopic ERG responses and progressive retinal degeneration. Multi-omics analysis further identifies Ppef2 and Pde6b as the potential targets of YTHDC2 in the retina. Specifically, via its YTH domain, YTHDC2 recognizes and binds m^(6)A-modified Ppef2 mRNA at the coding sequence and Pde6b mRNA at the 5′-UTR, resulting in enhanced translation efficiency without affecting mRNA levels. Compromised translation efficiency of Ppef2 and Pde6b after YTHDC2 depletion ultimately leads to decreased protein levels in the retina, impaired retinal function, and progressive rod death. Collectively, our finding highlights the importance of YTHDC2 in visual function and photoreceptor survival, which provides an unreported elucidation of IRD pathogenesis via epitranscriptomics.展开更多
2′-O-methylation(Nm)is one of the most abundant RNA epigenetic modifications and plays a vital role in the post-transcriptional regulation of gene expression.Current Nm mapping approaches are normally limited to high...2′-O-methylation(Nm)is one of the most abundant RNA epigenetic modifications and plays a vital role in the post-transcriptional regulation of gene expression.Current Nm mapping approaches are normally limited to highly abundant RNAs and have significant technical hurdles in m RNAs or relatively rare non-coding RNAs(nc RNAs).Here,we developed a new method for enriching Nm sites by using RNA exoribonuclease and periodate oxidation reactivity to eliminate 2′-hydroxylated(2′-OH)nucleosides,coupled with sequencing(Nm-REP-seq).We revealed several novel classes of Nm-containing nc RNAs as well as m RNAs in humans,mice,and drosophila.We found that some novel Nm sites are present at fixed positions in different t RNAs and are potential substrates of fibrillarin(FBL)methyltransferase mediated by sno RNAs.Importantly,we discovered,for the first time,that Nm located at the 3′-end of various types of nc RNAs and fragments derived from them.Our approach precisely redefines the genome-wide distribution of Nm and provides new technologies for functional studies of Nm-mediated gene regulation.展开更多
N6-Methyladenosine(m^(6)A)is the most abundant internal chemical modification in eukaryotic mRNA and plays important roles in gene expression regulation,including transcriptional and post-transcriptional regulation.m^...N6-Methyladenosine(m^(6)A)is the most abundant internal chemical modification in eukaryotic mRNA and plays important roles in gene expression regulation,including transcriptional and post-transcriptional regulation.m^(6)A is a reversible modification that is installed,removed,and recognized by methyltransferases(writers),demethylases(erasers),and m^(6)A-binding proteins(readers),respectively.Recently,the breadth of research on m^(6)A in plants has expanded,and the vital roles of m^(6)A in plant development,biotic and abiotic stress responses,and crop trait improvement have been investigated.In this review,we discuss recent developments in research on m^(6)A and highlight the detection methods,distribution,regulatory proteins,and molecular and biological functions of m^(6)A in plants.We also offer some perspectives on future investigations,providing direction for subsequent research on m^(6)A in plants.展开更多
The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-wither...The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor.However,the effects of the m^(6)A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized.We performed an integrated RNA methylome and transcriptome analysis to explore the m^(6)Amediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea(Camellia sinensis)leaves under solar-withering conditions.Dynamic changes in global m^(6)A level in tea leaves were mainly controlled by two m^(6)A erasers(CsALKBH4A and CsALKBH4B)during solar-withering treatments.Differentially methylated peak-associated genes following solarwithering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways.Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid,catechin,and theaflavin contents by triggering alternative splicing-mediated regulation.Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m^(6)A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.展开更多
Acetylation of N^(4)-cytidine(ac^(4)C)has recently been discovered as a novel modification of mRNA.RNA ac^(4)C modification has been shown to be a key regulator of RNA stability,RNA translation,and the thermal stress ...Acetylation of N^(4)-cytidine(ac^(4)C)has recently been discovered as a novel modification of mRNA.RNA ac^(4)C modification has been shown to be a key regulator of RNA stability,RNA translation,and the thermal stress response.However,its existence in eukaryotic mRNAs is still controversial.In plants,the existence,distribution pattern,and potential function of RNA ac^(4)C modification are largely unknown.Here we report the presence of ac^(4)C in the mRNAs of both Arabidopsis thaliana and rice(Oryza sativa).By comparing two ac^(4)C sequencing methods,we found that RNA immunoprecipitation and sequencing(acRIP-seq),but not ac^(4)C sequencing,was suitable for plant RNA ac^(4)C sequencing.We present transcriptome-wide atlases of RNA ac^(4)C modification in A.thaliana and rice mRNAs obtained by acRIP-seq.Analysis of the distribution of RNA ac^(4)C modifications showed that ac^(4)C is enriched near translation start sites in rice mRNAs and near translation start sites and translation end sites in Arabidopsis mRNAs.The RNA ac^(4)C modification level is positively correlated with RNA half-life and the number of splicing variants.Similar to that in mammals,the translation efficiency of ac^(4)C target genes is significantly higher than that of other genes.Our in vitro translation results confirmed that RNA ac^(4)C modification enhances translation efficiency.We also found that RNA ac^(4)C modification is negatively correlated with RNA structure.These results suggest that ac^(4)C is a conserved mRNA modification in plants that contributes to RNA stability,splicing,translation,and secondary structure formation.展开更多
Cancer metastasis is the major cause of cancer-related deaths and accounts for poor therapeutic outcomes.A metastatic cas-cade is a series of complicated biological processes.N6-methyladenosine(m^(6)A)is the most abun...Cancer metastasis is the major cause of cancer-related deaths and accounts for poor therapeutic outcomes.A metastatic cas-cade is a series of complicated biological processes.N6-methyladenosine(m^(6)A)is the most abundant and conserved epi-transcriptomic modification in eukaryotic cells,which has great impacts on RNA production and metabolism,including RNA splicing,processing,degradation and translation.Accumulating evidence demonstrates that m^(6)A plays a critical role in regulating cancer metastasis.However,there is a lack of studies that review the recent advances of m^(6)A in cancer metastasis.Here,we systematically retrieved the functions and mechanisms of how the m^(6)A axis regulates metastasis,and especially summarized the organ-specific liver,lung and brain metastasis mediated by m^(6)A in various cancers.Moreover,we discussed the potential application of m^(6)A modification in cancer diagnosis and therapy,as well as the present limitations and future perspectives of m^(6)A in cancer metastasis.This review provides a comprehensive knowledge on the m^(6)A-mediated regulation of gene expression,which is helpful to extensively understand the complexity of cancer metastasis from a new epitranscriptomic point of view and shed light on the developing novel strategies to anti-metastasis based on m^(6)A alteration.展开更多
Over 17 and 160 types of chemical modifications have been identified in DNA and RNA,respectively.The interest in understanding the various biological functions of DNA and RNA modifications has lead to the cutting-edge...Over 17 and 160 types of chemical modifications have been identified in DNA and RNA,respectively.The interest in understanding the various biological functions of DNA and RNA modifications has lead to the cutting-edged fields of epigenomics and epitranscriptomics.Developing chemical and biological tools to detect specific modifications in the genome or transcriptome has greatly facilitated their study.Here,we review the recent technological advances in this rapidly evolving field.We focus on high-throughput detection methods and biological findings for these modifications,and discuss questions to be addressed as well.We also summarize third-generation sequencing methods,which enable long-read and single-molecule sequencing of DNA and RNA modification.展开更多
Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, s...Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, such as viruses. Gene expression is controlled through multiple mechanisms that are coordinated to ensure the proper and timely expression of each gene. Many of these mechanisms target the life cycle of the RNA molecule, from transcription to translation. Recently, another layer of regulation at the RNA level involving RNA modifications has gained renewed interest of the scientific community. The discovery that N6-methyladenosine （m6A）, a mod- ification present in mRNAs and long noncoding RNAs, can be removed by the activity of RNA demethylases, launched the field of epitranscriptomics; the study of how RNA function is regulated through the addition or removal of post-transcriptional modifications, similar to strategies used to regulate gene expression at the DNA and protein level. The abundance of RNA post-transcriptional modifications is determined by the activity of writer complexes （methylase） and eraser （RNA demethylase） proteins. Subsequently, the effects of RNA modifications materialize as changes in RNA structure and/or modulation of interactions between the modified RNA and RNA binding proteins or regulatory RNAs. Disruption of these pathways impairs gene expression and cellular function. This review focuses on the links between the RNA modification m6A and its implications in human diseases.展开更多
The biological functions of the epitranscriptomic modification N^(6)-methyladenosine(m^(6)A)in plants are not fully understood.CPSF30-L is a predominant isoform of the polyadenylation factor CPSF30 and consists of CPS...The biological functions of the epitranscriptomic modification N^(6)-methyladenosine(m^(6)A)in plants are not fully understood.CPSF30-L is a predominant isoform of the polyadenylation factor CPSF30 and consists of CPSF30-S and an m^(6)A-binding YTH domain.Little is known about the biological roles of CPSF30-L and the molecular mechanism underlying its m^(6)A-binding function in alternative polyadenylation.Here,we charac-terized CPSF30-L as an Arabidopsis m^(6)A reader whose m^(6)A-binding function is required for the floral tran-sition and abscisic acid(ABA)response.We found that the m^(6)A-binding activity of CPSF30-L enhances the formation of liquid-like nuclear bodies,where CPSF30-L mainly recognizes m*A-modified far-upstream elements to control polyadenylation site choice.Deficiency of CPSF30-L lengthens the 3'untranslated region of three phenotypes-related transcripts,thereby accelerating their mRNA degradation and leading to late flowering and ABA hypersensitivity.Collectively,this study uncovers a new molecular mechanism for m^(6)A-driven phase separation and polyadenylation in plants.展开更多
More than 100 types of chemical modifications in RNA have been well documented. Recently, several modifications, such as N6-methyladenosine （m^6A）, have been detected in mRNA, opening the window into the realm of ep...More than 100 types of chemical modifications in RNA have been well documented. Recently, several modifications, such as N6-methyladenosine （m^6A）, have been detected in mRNA, opening the window into the realm of epitranscriptomies. The m^6A modification is the most abundant modification in mRNA and non-coding RNA （ncRNA）. At the molecular level, m^6A affects almost all aspects of mRNA metabolism, including splicing, translation, and stability, as well as microRNA （miRNA） maturation, playing essential roles in a range of cellular processes. The m^6A modification is regulated by three classes of proteins generally referred to as the ＂writer＂ （adenosine methyltransferase）, ＂eraser＂ （m^6A demethylating enzyme）, and ＂reader＂ （m^6A-binding protein）. The m^6A modification is reversibly installed and removed by writers and erasers, respectively. Readers, which are members of the YT521-B homology （YTH） family proteins, selectively bind to RNA and affect its fate in an m^6A-dependent manner. In this review, we summarize the structures of the functional proteins that modulate the m^6A modification, and provide our insights into the m^6A-mediated gene regulation.展开更多
Like protein and DNA, different types of RNA molecules undergo various modifications. Accumulating evidence suggests that these RNA modifications serve as sophisticated codes to mediate RNA behaviors and many importan...Like protein and DNA, different types of RNA molecules undergo various modifications. Accumulating evidence suggests that these RNA modifications serve as sophisticated codes to mediate RNA behaviors and many important biological functions. N^6-methyladenosine （m^6A） is the most abundant internal RNA modification found in a variety of eukaryotic RNAs, including but not limited to mRNAs, tRNAs, rRNAs, and long non-coding RNAs （lncRNAs）. In mammalian cells, m^6A can be incorporated by a methyltransferase complex and removed by demethy- lases, which ensures that the m^6A modification is reversible and dynamic. Moreover, m^6A is recognized by the YT521-B homology （YTH） domain-containing proteins, which subsequently direct different complexes to regulate RNA signaling pathways, such as RNA metabolism, RNA splicing, RNA folding, and protein translation. Herein, we summarize the recent progresses made in understanding the molecular mechanisms underlying the m^6A recognition by YTH domaincontaining proteins, which would shed new light on m^6A-specific recognition and provide clues to the future identification of reader proteins of many other RNA modifications.展开更多
More than 100 modifications have been found in RNA. Analogous to epigenetic DNA methylation, epitranscriptomic modifications can be written, read, and erased by a complex network of proteins. Apart from Na-methyladeno...More than 100 modifications have been found in RNA. Analogous to epigenetic DNA methylation, epitranscriptomic modifications can be written, read, and erased by a complex network of proteins. Apart from Na-methyladenosine （m6A）, N1-methyladenosine （mXA） has been found as a reversible modification in tRNA and mRNA. mlA occurs at positions 9, 14, and 58 of tRNA, with m1A58 being critical for tRNA stability. Other than the hundreds of m1A sites in mRNA and long non-coding RNA transcripts, transcriptome-wide mapping of m1A also identifies 〉 20 m1A sites in mitochondrial genes, m1A in the coding region of mitochondrial transcripts can inhibit the translation of the corresponding proteins. In this review, we summarize the current understanding of mlA in mRNA and tRNA, covering high-throughput sequencing methods developed for m1A methylome, m1A-related enzymes （writers and erasers）, as well as its functions in mRNA and tRNA.展开更多
The advent of high-throughput sequencing technol- ogies coupled with new detection methods of RNA modifica- tions has enabled investigation of a new layer of gene regulation - the epitranscriptome. With over loo known...The advent of high-throughput sequencing technol- ogies coupled with new detection methods of RNA modifica- tions has enabled investigation of a new layer of gene regulation - the epitranscriptome. With over loo known RNA modifications, understanding the repertoire of RNA modifications is a huge undertaking. This review summarizes what is known about RNA modifications with an emphasis on discoveries in plants. RNA ribose modifications, base methyl- ations and pseudouridylation are required for normal develop- ment in Arabidopsis, as mutations in the enzymes modifying them have diverse effects on plant development and stress responses. These modifications can regulate RNA structure, turnover and translation. Transfer RNA and ribosomal RNA modifications have been mapped extensively and their functions investigated in many organisms, including plants. Recent work exploring the locations, functions and targeting of N6-methyladenosine （m^6A）, 5-methylcytosine （m^5C）, pseudour- idine （up）, and additional modifications in mRNAs and ncRNAs are highlighted, as well as those previously known on tRNAs and rRNAs. Many questions remain as to the exact mechanisms of targeting and functions of specific modified sites and whether these modifications have distinct functions in the different classes of RNAs.展开更多
The m^6A modification has been implicated as an important epitranscriptomic marker, which plays extensive roles in the regulation of transcript stability, splicing, translation, and localization. Nevertheless, only so...The m^6A modification has been implicated as an important epitranscriptomic marker, which plays extensive roles in the regulation of transcript stability, splicing, translation, and localization. Nevertheless, only some genes are repeatedly modified across various conditions and the principle of m^6A regulation remains elusive. In this study, we performed a systems-level analysis of human genes frequently regulated by m^6A modification （m^6Afreq genes） and those occasionally regulated by m^6A modification （m^6Aocca genes）. Compared to the m^6Aocca genes, the m^6Afreq genes exhibit gene importance-related features, such as lower dN/dS ratio, higher protein-protein interaction network degree, and reduced tissue expression specificity. Signaling network analysis indicates that the m^6Afreq genes are associated with downstream components of signaling cascades, high-linked signaling adaptors, and specific network motifs like incoherent feed forward loops. Moreover, functional enrichment analysis indicates significant overlaps between the m^6Afreq genes and genes involved in various layers of gene expression, such as being the microRNA targets and the regulators of RNA processing. Therefore, our findings suggest the potential interplay between m^6A epitranscriptomic regulation and other gene expression regulatory machineries.展开更多
基金funded by Notingham University and the Neuroscience Support Group Charity,UK(to HMK)supported by a CONACYT PhD scholarshipMD?was supported by the Postdoctoral Research Fellowship Program of TUBITAK。
文摘The study of modified RNA known as epitranscriptomics has become increasingly relevant in our understanding of disease-modifying mechanisms.Methylation of N6 adenosine(m^(6)A)and C5 cytosine(m^(5)C)bases occur on mRNAs,tRNA,mt-tRNA,and rRNA species as well as non-coding RNAs.With emerging knowledge of RNA binding proteins that act as writer,reader,and eraser effector proteins,comes a new understanding of physiological processes controlled by these systems.Such processes when spatiotemporally disrupted within cellular nanodomains in highly specialized tissues such as the brain,give rise to different forms of disease.In this review,we discuss accumulating evidence that changes in the m^(6)A and m^(5)C methylation systems contribute to neurocognitive disorders.Early studies first identified mutations within FMR1 to cause intellectual disability Fragile X syndromes several years before FMR1 was identified as an m^(6)A RNA reader protein.Subsequently,familial mutations within the m^(6)A writer gene METTL5,m^(5)C writer genes NSUN2,NSUN3,NSUN5,and NSUN6,as well as THOC2 and THOC6 that form a protein complex with the m^(5)C reader protein ALYREF,were recognized to cause intellectual development disorders.Similarly,differences in expression of the m^(5)C writer and reader effector proteins,NSUN6,NSUN7,and ALYREF in brain tissue are indicated in individuals with Alzheimer's disease,individuals with a high neuropathological load or have suffered traumatic brain injury.Likewise,an abundance of m^(6)A reader and anti-reader proteins are reported to change across brain regions in Lewy bodies diseases,Alzheimer's disease,and individuals with high cognitive reserve.m^(6)A-modified RNAs are also reported significantly more abundant in dementia with Lewy bodies brain tissue but significantly reduced in Parkinson's disease tissue,whilst modified RNAs are misplaced within diseased cells,particularly where synapses are located.In parahippocampal brain tissue,m^(6)A modification is enriched in transcripts associated with psychiatric disorders including conditions with clear cognitive deficits.These findings indicate a diverse set of molecular mechanisms are influenced by RNA methylation systems that can cause neuronal and synaptic dysfunction underlying neurocognitive disorders.Targeting these RNA modification systems brings new prospects for neural regenerative therapies.
基金supported by the National Key Research and Development Program from the Ministry of Science and Technology of China(Grant No.2016YFC0900300)the Beijing Natural Science Foundation(Grant No.5162012)of China awarded to CY
文摘Ever since the first RNA nucleoside modification was charac- terized in 1957 [1], over 100 distinct chemical modifications have been identified in RNA to date [2]. Most of these modi- fications were characterized in non-coding RNAs （ncRNAs）, including tRNA, rRNA, and small nuclear RNA （snRNA） [3]. Studies in the past few decades have located various mod- ifications in these ncRNAs and revealed their functional roles [3]. For instance, NLmethyladenosine （mlA）, which is typically found at position 58 in the tRNA T-loop of eukaryotes, func- tions to stabilize tRNA tertiary structure [4] and affect transla- tion by regulating the associations between tRNA and polysome [5]. Pseudouridine （tp） in snRNA can fine-tune branch site interactions and affect mRNA splicing [6].
文摘We are very pleased to announce a special issue,to be published in the Spring of 2022,on"RNA Modifications and Epitranscriptomics"in the journal Genomics,Proteomics&Bioinformatics(GPB).More than 100 distinct chemical modifications to RNA have been characterized so far.They are prevalent in non-coding RNA,including rRNA,tRNA,and small nuclear RNA(snRNA).
基金Supported by the National Natural Science Foundation of China,No.82171039.
文摘BACKGROUND Cataracts remain a prime reason for visual disturbance and blindness all over the world,despite the capacity for successful surgical replacement with artificial lenses.Diabetic cataract(DC),a metabolic complication,usually occurs at an earlier age and progresses faster than age-related cataracts.Evidence has linked N6-methyladenosine(m6A)to DC progression.However,there exists a lack of understanding regarding RNA m6A modifications and the role of m6A in DC pathogenesis.AIM To elucidate the role played by altered m6A and differentially expressed mRNAs(DEmRNAs)in DC.METHODS Anterior lens capsules were collected from the control subjects and patients with DC.M6A epitranscriptomic microarray was performed to investigate the altered m6A modifications and determine the DEmRNAs.Through Gene Ontology and pathway enrichment(Kyoto Encyclopedia of Genes and Genomes)analyses,the potential role played by dysregulated m6A modification was predicted.Real-time polymerase chain reaction was further carried out to identify the dysregulated expression of RNA methyltransferases,demethylases,and readers.RESULTS Increased m6A abundance levels were found in the total mRNA of DC samples.Bioinformatics analysis predicted that ferroptosis pathways could be associated with m6A-modified mRNAs.The levels of five methylation-related genes-RBM15,WTAP,ALKBH5,FTO,and YTHDF1-were upregulated in DC samples.Upregulation of RBM15 expression was verified in SRA01/04 cells with high-glucose medium and in samples from DC patients.CONCLUSION M6a mRNA modifications may be involved in DC progression via the ferroptosis pathway,rendering novel insights into therapeutic strategies for DC.
基金supported by the National Natural Science Foundation of China(81970841,82101160,82121003)the Department of Science and Technology of Sichuan Province(2023ZYD0172,2023YFS0161)+3 种基金the program of Science and Technology International Cooperation Project of Qinghai province(China)(No.2022-HZ-814)Sichuan Intellectual Property Office(China)(No.2022-ZS-0070)the CAMS Innovation Fund for Medical Sciences(2019-12M-5-032)Open Project of Henan Provincial Key Laboratory of Ophthalmology and Visual Science(20KFKT02).
文摘Inherited retinal dystrophies (IRDs) are major causes of visual impairment and irreversible blindness worldwide, while the precise molecular and genetic mechanisms are still elusive. N6-methyladenosine (m^(6)A) modification is the most prevalent internal modification in eukaryotic mRNA. YTH domain containing 2 (YTHDC2), an m^(6)A reader protein, has recently been identified as a key player in germline development and human cancer. However, its contribution to retinal function remains unknown. Here, we explore the role of YTHDC2 in the visual function of retinal rod photoreceptors by generating rod-specific Ythdc2 knockout mice. Results show that Ythdc2 deficiency in rods causes diminished scotopic ERG responses and progressive retinal degeneration. Multi-omics analysis further identifies Ppef2 and Pde6b as the potential targets of YTHDC2 in the retina. Specifically, via its YTH domain, YTHDC2 recognizes and binds m^(6)A-modified Ppef2 mRNA at the coding sequence and Pde6b mRNA at the 5′-UTR, resulting in enhanced translation efficiency without affecting mRNA levels. Compromised translation efficiency of Ppef2 and Pde6b after YTHDC2 depletion ultimately leads to decreased protein levels in the retina, impaired retinal function, and progressive rod death. Collectively, our finding highlights the importance of YTHDC2 in visual function and photoreceptor survival, which provides an unreported elucidation of IRD pathogenesis via epitranscriptomics.
基金supported by the National Key R&D Program of China(2019YFA0802202)the National Natural Science Foundation of China(91940304,31971228,31900903,31970604,32100467,32225011)the Youth Science and Technology Innovation Talent of Guangdong Te Zhi Plan(2019TQ05Y181)。
文摘2′-O-methylation(Nm)is one of the most abundant RNA epigenetic modifications and plays a vital role in the post-transcriptional regulation of gene expression.Current Nm mapping approaches are normally limited to highly abundant RNAs and have significant technical hurdles in m RNAs or relatively rare non-coding RNAs(nc RNAs).Here,we developed a new method for enriching Nm sites by using RNA exoribonuclease and periodate oxidation reactivity to eliminate 2′-hydroxylated(2′-OH)nucleosides,coupled with sequencing(Nm-REP-seq).We revealed several novel classes of Nm-containing nc RNAs as well as m RNAs in humans,mice,and drosophila.We found that some novel Nm sites are present at fixed positions in different t RNAs and are potential substrates of fibrillarin(FBL)methyltransferase mediated by sno RNAs.Importantly,we discovered,for the first time,that Nm located at the 3′-end of various types of nc RNAs and fragments derived from them.Our approach precisely redefines the genome-wide distribution of Nm and provides new technologies for functional studies of Nm-mediated gene regulation.
基金supported by the National Natural Science Foundation of China(22225704,21820102008,92053109)the National Basic Research Program of China(2019YFA0802201)the Beijing Natural Science Foundation(Z200010).
文摘N6-Methyladenosine(m^(6)A)is the most abundant internal chemical modification in eukaryotic mRNA and plays important roles in gene expression regulation,including transcriptional and post-transcriptional regulation.m^(6)A is a reversible modification that is installed,removed,and recognized by methyltransferases(writers),demethylases(erasers),and m^(6)A-binding proteins(readers),respectively.Recently,the breadth of research on m^(6)A in plants has expanded,and the vital roles of m^(6)A in plant development,biotic and abiotic stress responses,and crop trait improvement have been investigated.In this review,we discuss recent developments in research on m^(6)A and highlight the detection methods,distribution,regulatory proteins,and molecular and biological functions of m^(6)A in plants.We also offer some perspectives on future investigations,providing direction for subsequent research on m^(6)A in plants.
基金supported by the Earmarked Fund for China Agriculture Research System of Ministry of Finance and Ministry of Agriculture and Rural Affairs(Grant No.CARS-19)the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University(Grant No.324-1122yb070)+7 种基金the Scientific Research Foundation of Horticulture College of Fujian Agriculture and Forestry University(Grant No.2019B01)the Rural Revitalization Tea Industry Technical Service Project of Fujian Agriculture and Forestry University(Grant No.11899170145)the“Double first-class”scientific and technological innovation capacity and enhancement cultivation plan of Fujian Agriculture and Forestry University(Grant No.KSYLP004)the 6.18 Tea Industry Technology Branch of Collaborative Innovation Institute(Grant No.K1520001A)the Fujian Agriculture and Forestry University Construction Project for Technological Innovation and Service System of Tea Industry Chain(Grant No.K1520005A01)the Construction of Plateau Discipline of Fujian Province(Grant No.102/71201801101)the Tea Industry Branch of Collaborative Innovation Institute of Fujian Agriculture and Forestry University(Grant No.K1521015A)the Special Fund for Science and Technology Innovation of Fujian Zhang Tianfu Tea Development Foundation(Grant No.FJZTF01),China.
文摘The epitranscriptomic mark N6-methyladenosine(m^(6)A),which is the predominant internal modification in RNA,is important for plant responses to diverse stresses.Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor.However,the effects of the m^(6)A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized.We performed an integrated RNA methylome and transcriptome analysis to explore the m^(6)Amediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea(Camellia sinensis)leaves under solar-withering conditions.Dynamic changes in global m^(6)A level in tea leaves were mainly controlled by two m^(6)A erasers(CsALKBH4A and CsALKBH4B)during solar-withering treatments.Differentially methylated peak-associated genes following solarwithering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways.Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid,catechin,and theaflavin contents by triggering alternative splicing-mediated regulation.Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m^(6)A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.
基金support from the National Natural Science Foundation of China(32070613,32270623)the Science and Technology Innovation Program of Hunan Province(2021RC3045)+1 种基金support from the National Natural Science Foundation of China(U20A2029)support from the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20200468).
文摘Acetylation of N^(4)-cytidine(ac^(4)C)has recently been discovered as a novel modification of mRNA.RNA ac^(4)C modification has been shown to be a key regulator of RNA stability,RNA translation,and the thermal stress response.However,its existence in eukaryotic mRNAs is still controversial.In plants,the existence,distribution pattern,and potential function of RNA ac^(4)C modification are largely unknown.Here we report the presence of ac^(4)C in the mRNAs of both Arabidopsis thaliana and rice(Oryza sativa).By comparing two ac^(4)C sequencing methods,we found that RNA immunoprecipitation and sequencing(acRIP-seq),but not ac^(4)C sequencing,was suitable for plant RNA ac^(4)C sequencing.We present transcriptome-wide atlases of RNA ac^(4)C modification in A.thaliana and rice mRNAs obtained by acRIP-seq.Analysis of the distribution of RNA ac^(4)C modifications showed that ac^(4)C is enriched near translation start sites in rice mRNAs and near translation start sites and translation end sites in Arabidopsis mRNAs.The RNA ac^(4)C modification level is positively correlated with RNA half-life and the number of splicing variants.Similar to that in mammals,the translation efficiency of ac^(4)C target genes is significantly higher than that of other genes.Our in vitro translation results confirmed that RNA ac^(4)C modification enhances translation efficiency.We also found that RNA ac^(4)C modification is negatively correlated with RNA structure.These results suggest that ac^(4)C is a conserved mRNA modification in plants that contributes to RNA stability,splicing,translation,and secondary structure formation.
基金supported by the Key Program of the National Natural Science Foundation of China(81930074,2020-2024)the Major Program of National Natural Science Foundation of China(91959203,2020-2023)the Natural Science Foundation of China(81672820,2017-2020,81672378,2017-2020,82173093)。
文摘Cancer metastasis is the major cause of cancer-related deaths and accounts for poor therapeutic outcomes.A metastatic cas-cade is a series of complicated biological processes.N6-methyladenosine(m^(6)A)is the most abundant and conserved epi-transcriptomic modification in eukaryotic cells,which has great impacts on RNA production and metabolism,including RNA splicing,processing,degradation and translation.Accumulating evidence demonstrates that m^(6)A plays a critical role in regulating cancer metastasis.However,there is a lack of studies that review the recent advances of m^(6)A in cancer metastasis.Here,we systematically retrieved the functions and mechanisms of how the m^(6)A axis regulates metastasis,and especially summarized the organ-specific liver,lung and brain metastasis mediated by m^(6)A in various cancers.Moreover,we discussed the potential application of m^(6)A modification in cancer diagnosis and therapy,as well as the present limitations and future perspectives of m^(6)A in cancer metastasis.This review provides a comprehensive knowledge on the m^(6)A-mediated regulation of gene expression,which is helpful to extensively understand the complexity of cancer metastasis from a new epitranscriptomic point of view and shed light on the developing novel strategies to anti-metastasis based on m^(6)A alteration.
基金This work was supported by the National Natural Science Foundation of China(Grant No.31861143026 to C.Y.)the Ministry of Science and Technology of China(Grant Nos.2019YFA0110902 and 2019YFA08002501 to C.Y.)the Ludwig Institute for Cancer Research(C-X.S.),Cancer Research UK(C63763/A26394 and C63763/A27122 to C-X.S.)NIHR Oxford Biomedical Research Centre(to C-X.S.)and Emerson Collective(to C-X.S.).L-Y.Z.is supported by China Scholarship Council.The views expressed are those of the authors and not necessarily those of the NHS,the NIHR or the Department of Health.We apologize for not being able to cite all the publications related to this topic due to space constraints of the journal.
文摘Over 17 and 160 types of chemical modifications have been identified in DNA and RNA,respectively.The interest in understanding the various biological functions of DNA and RNA modifications has lead to the cutting-edged fields of epigenomics and epitranscriptomics.Developing chemical and biological tools to detect specific modifications in the genome or transcriptome has greatly facilitated their study.Here,we review the recent technological advances in this rapidly evolving field.We focus on high-throughput detection methods and biological findings for these modifications,and discuss questions to be addressed as well.We also summarize third-generation sequencing methods,which enable long-read and single-molecule sequencing of DNA and RNA modification.
基金supported by the Intramural Research Program of the NIH,National Cancer Institute,Center for Cancer Research,United States of America
文摘Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, such as viruses. Gene expression is controlled through multiple mechanisms that are coordinated to ensure the proper and timely expression of each gene. Many of these mechanisms target the life cycle of the RNA molecule, from transcription to translation. Recently, another layer of regulation at the RNA level involving RNA modifications has gained renewed interest of the scientific community. The discovery that N6-methyladenosine （m6A）, a mod- ification present in mRNAs and long noncoding RNAs, can be removed by the activity of RNA demethylases, launched the field of epitranscriptomics; the study of how RNA function is regulated through the addition or removal of post-transcriptional modifications, similar to strategies used to regulate gene expression at the DNA and protein level. The abundance of RNA post-transcriptional modifications is determined by the activity of writer complexes （methylase） and eraser （RNA demethylase） proteins. Subsequently, the effects of RNA modifications materialize as changes in RNA structure and/or modulation of interactions between the modified RNA and RNA binding proteins or regulatory RNAs. Disruption of these pathways impairs gene expression and cellular function. This review focuses on the links between the RNA modification m6A and its implications in human diseases.
基金This work was supported by the National Natural Science Foundation of China(nos.21822702,21820102008,92053109,and 21432002)the National Basic Research Program of China(2017YFA0505201 and 2019YFA0802201).
文摘The biological functions of the epitranscriptomic modification N^(6)-methyladenosine(m^(6)A)in plants are not fully understood.CPSF30-L is a predominant isoform of the polyadenylation factor CPSF30 and consists of CPSF30-S and an m^(6)A-binding YTH domain.Little is known about the biological roles of CPSF30-L and the molecular mechanism underlying its m^(6)A-binding function in alternative polyadenylation.Here,we charac-terized CPSF30-L as an Arabidopsis m^(6)A reader whose m^(6)A-binding function is required for the floral tran-sition and abscisic acid(ABA)response.We found that the m^(6)A-binding activity of CPSF30-L enhances the formation of liquid-like nuclear bodies,where CPSF30-L mainly recognizes m*A-modified far-upstream elements to control polyadenylation site choice.Deficiency of CPSF30-L lengthens the 3'untranslated region of three phenotypes-related transcripts,thereby accelerating their mRNA degradation and leading to late flowering and ABA hypersensitivity.Collectively,this study uncovers a new molecular mechanism for m^(6)A-driven phase separation and polyadenylation in plants.
基金supported by the National Natural Science Foundation of China(Grant No.31722017)
文摘More than 100 types of chemical modifications in RNA have been well documented. Recently, several modifications, such as N6-methyladenosine （m^6A）, have been detected in mRNA, opening the window into the realm of epitranscriptomies. The m^6A modification is the most abundant modification in mRNA and non-coding RNA （ncRNA）. At the molecular level, m^6A affects almost all aspects of mRNA metabolism, including splicing, translation, and stability, as well as microRNA （miRNA） maturation, playing essential roles in a range of cellular processes. The m^6A modification is regulated by three classes of proteins generally referred to as the ＂writer＂ （adenosine methyltransferase）, ＂eraser＂ （m^6A demethylating enzyme）, and ＂reader＂ （m^6A-binding protein）. The m^6A modification is reversibly installed and removed by writers and erasers, respectively. Readers, which are members of the YT521-B homology （YTH） family proteins, selectively bind to RNA and affect its fate in an m^6A-dependent manner. In this review, we summarize the structures of the functional proteins that modulate the m^6A modification, and provide our insights into the m^6A-mediated gene regulation.
基金supported by the National Natural Science Foundation of China awarded to SL(Grant No.31500601)and CX(Grants Nos.31570737 and 31770806)supported by the“1000 Young Talents Program”of China
文摘Like protein and DNA, different types of RNA molecules undergo various modifications. Accumulating evidence suggests that these RNA modifications serve as sophisticated codes to mediate RNA behaviors and many important biological functions. N^6-methyladenosine （m^6A） is the most abundant internal RNA modification found in a variety of eukaryotic RNAs, including but not limited to mRNAs, tRNAs, rRNAs, and long non-coding RNAs （lncRNAs）. In mammalian cells, m^6A can be incorporated by a methyltransferase complex and removed by demethy- lases, which ensures that the m^6A modification is reversible and dynamic. Moreover, m^6A is recognized by the YT521-B homology （YTH） domain-containing proteins, which subsequently direct different complexes to regulate RNA signaling pathways, such as RNA metabolism, RNA splicing, RNA folding, and protein translation. Herein, we summarize the recent progresses made in understanding the molecular mechanisms underlying the m^6A recognition by YTH domaincontaining proteins, which would shed new light on m^6A-specific recognition and provide clues to the future identification of reader proteins of many other RNA modifications.
基金supported by the National Basic Research Program of China (Grant Nos. 2016YFC0900302 and 2017YFA0505201)the National Natural Science Foundation of China (Grant No. 21432002)
文摘More than 100 modifications have been found in RNA. Analogous to epigenetic DNA methylation, epitranscriptomic modifications can be written, read, and erased by a complex network of proteins. Apart from Na-methyladenosine （m6A）, N1-methyladenosine （mXA） has been found as a reversible modification in tRNA and mRNA. mlA occurs at positions 9, 14, and 58 of tRNA, with m1A58 being critical for tRNA stability. Other than the hundreds of m1A sites in mRNA and long non-coding RNA transcripts, transcriptome-wide mapping of m1A also identifies 〉 20 m1A sites in mitochondrial genes, m1A in the coding region of mitochondrial transcripts can inhibit the translation of the corresponding proteins. In this review, we summarize the current understanding of mlA in mRNA and tRNA, covering high-throughput sequencing methods developed for m1A methylome, m1A-related enzymes （writers and erasers）, as well as its functions in mRNA and tRNA.
基金supported by ARC grants DP110103805 and FT13100525 awarded to I.S.and an APA and a GRDC PhD topup scholarship awarded to A.B.
文摘The advent of high-throughput sequencing technol- ogies coupled with new detection methods of RNA modifica- tions has enabled investigation of a new layer of gene regulation - the epitranscriptome. With over loo known RNA modifications, understanding the repertoire of RNA modifications is a huge undertaking. This review summarizes what is known about RNA modifications with an emphasis on discoveries in plants. RNA ribose modifications, base methyl- ations and pseudouridylation are required for normal develop- ment in Arabidopsis, as mutations in the enzymes modifying them have diverse effects on plant development and stress responses. These modifications can regulate RNA structure, turnover and translation. Transfer RNA and ribosomal RNA modifications have been mapped extensively and their functions investigated in many organisms, including plants. Recent work exploring the locations, functions and targeting of N6-methyladenosine （m^6A）, 5-methylcytosine （m^5C）, pseudour- idine （up）, and additional modifications in mRNAs and ncRNAs are highlighted, as well as those previously known on tRNAs and rRNAs. Many questions remain as to the exact mechanisms of targeting and functions of specific modified sites and whether these modifications have distinct functions in the different classes of RNAs.
基金supported by the National Natural Science Foundation of China (Grant Nos. 81670462 and 81422006 to QC)China Postdoctoral Science Foundation (Grant No. 2016M591024 to YZ)
文摘The m^6A modification has been implicated as an important epitranscriptomic marker, which plays extensive roles in the regulation of transcript stability, splicing, translation, and localization. Nevertheless, only some genes are repeatedly modified across various conditions and the principle of m^6A regulation remains elusive. In this study, we performed a systems-level analysis of human genes frequently regulated by m^6A modification （m^6Afreq genes） and those occasionally regulated by m^6A modification （m^6Aocca genes）. Compared to the m^6Aocca genes, the m^6Afreq genes exhibit gene importance-related features, such as lower dN/dS ratio, higher protein-protein interaction network degree, and reduced tissue expression specificity. Signaling network analysis indicates that the m^6Afreq genes are associated with downstream components of signaling cascades, high-linked signaling adaptors, and specific network motifs like incoherent feed forward loops. Moreover, functional enrichment analysis indicates significant overlaps between the m^6Afreq genes and genes involved in various layers of gene expression, such as being the microRNA targets and the regulators of RNA processing. Therefore, our findings suggest the potential interplay between m^6A epitranscriptomic regulation and other gene expression regulatory machineries.
