Enhancing m^(6)A modification in the motor cortex facilitates corticospinal tract remodeling after spinal cord injury

Spinal cord injury typically causes corticospinal tract disruption. Although the disrupted corticospinal tract can self-regenerate to a certain degree, the underlying mechanism of this process is still unclear. N6-methyladenosine(m^(6)A) modifications are the most common form of epigenetic regulation at the RNA level and play an essential role in biological processes. However, whether m^(6)A modifications participate in corticospinal tract regeneration after spinal cord injury remains unknown. We found that expression of methyltransferase 14 protein(METTL14) in the locomotor cortex was high after spinal cord injury and accompanied by elevated m^(6)A levels. Knockdown of Mettl14 in the locomotor cortex was not favorable for corticospinal tract regeneration and neurological recovery after spinal cord injury. Through bioinformatics analysis and methylated RNA immunoprecipitation-quantitative polymerase chain reaction, we found that METTL14 regulated Trib2 expression in an m^(6)A-regulated manner, thereby activating the mitogen-activated protein kinase pathway and promoting corticospinal tract regeneration. Finally, we administered syringin, a stabilizer of METTL14, using molecular docking. Results confirmed that syringin can promote corticospinal tract regeneration and facilitate neurological recovery by stabilizing METTL14. Findings from this study reveal that m^(6)A modification is involved in the regulation of corticospinal tract regeneration after spinal cord injury.

Decoding m^(6)A mRNA methylation by reader proteins in liver diseases

N6-methyladenosine(m^(6)A)is a dynamic and reversible epigenetic regulation.As the most prevalent internal post-transcriptional modification in eukaryotic RNA,it participates in the regulation of gene expression through various mechanisms,such as mRNA splicing,nuclear export,localization,translation efficiency,mRNA stability,and structural transformation.The involvement of m^(6)A in the regulation of gene expression depends on the specific recognition of m^(6)A-modified RNA by reader proteins.In the pathogenesis and treatment of liver disease,studies have found that the expression levels of key genes that promote or inhibit the development of liver disease are regulated by m^(6)A modification,in which abnormal expression of reader proteins determines the fate of these gene transcripts.In this review,we introduce m^(6)A readers,summarize the recognition and regulatory mechanisms of m^(6)A readers on mRNA,and focus on the biological functions and mechanisms of m^(6)A readers in liver cancer,viral hepatitis,non-alcoholic fatty liver disease(NAFLD),hepatic fibrosis(HF),acute liver injury(ALI),and other liver diseases.This information is expected to be of high value to researchers deciphering the links between m^(6)A readers and human liver diseases.

m^(6)A甲基化修饰在肿瘤中作用的研究进展

RNA的表观遗传修饰在恶性肿瘤中发挥着重要的调控作用,因此受到人们的广泛关注。N6-甲基腺嘌呤是发生于腺苷N6位上的甲基化修饰,是真核细胞信使RNA上主要的表观遗传修饰。m^(6)A甲基化修饰由m^(6)A甲基转移酶催化,其核心组分包括METTL3、METTL14;由m^(6)A去甲基化酶去除,包括FTO、ALKBH5;并被m^(6)A甲基识别蛋白识别,包括YTHDF1-3、IGF2BP1-3等。m^(6)A甲基化修饰参与RNA代谢的各个阶段,包括:稳定、剪接、出核、翻译和降解等。m^(6)A相关调节蛋白能够通过多种机制调控肿瘤的发生发展:影响m^(6)A甲基化修饰水平,进而在肿瘤细胞增殖、侵袭转移及耐药等过程中发挥重要作用。目前为止,m^(6)A甲基化修饰在人类肿瘤中的作用机制尚未完全阐明。本文概述了m^(6)A修饰的基本功能,并重点介绍其在肿瘤中的作用机制,最后讨论针对肿瘤中m^(6)A修饰的治疗策略。

The RNA binding protein EHD6 recruits the m^(6)A reader YTH07 and sequesters OsCOL4 mRNA into phase-separated ribonucleoprotein condensates to promote rice flowering

N6-Methyladenosine(m^(6)A)is one of the most abundant modifications of eukaryotic mRNA,but its comprehensive biological functionality remains further exploration.In this study,we identified and characterized a new flowering-promoting gene,EARLY HEADING DATE6(EHD6),in rice.EHD6 encodes an RNA recognition motif(RRM)-containing RNA binding protein that is localized in the non-membranous cytoplasm ribonucleoprotein(RNP)granules and can bind both m^(6)A-modified RNA and unmodified RNA indiscriminately.We found that EHD6 can physically interact with YTH07,a YTH(YT521-B homology)domain-containing m^(6)A reader.We showed that their interaction enhances the binding of an m^(6)A-modified RNA and triggers relocation of a portion of YTH07 from the cytoplasm into RNP granules through phase-separated condensation.Within these condensates,the mRNA of a rice flowering repressor,CONSTANS-like 4(OsCOL4),becomes sequestered,leading to a reduction in its protein abundance and thus accelerated flowering through the Early heading date 1 pathway.Taken together,these results not only shed new light on the molecular mechanism of efficient m^(6)A recognition by the collaboration between an RNA binding protein and YTH family m^(6)A reader,but also uncover the potential for m^(6)A-mediated translation regulation through phaseseparated ribonucleoprotein condensation in rice.

RNA m^6A甲基化修饰的研究进展

RNA m^6A甲基化修饰是发生在RNA腺嘌呤(A)第6位N原子上的一种转录后修饰方式。它是由甲基转移酶和去甲基酶以及识别蛋白所催化的一种动态可逆的修饰方式,具有重要的调控功能。本文综述了m^6A甲基化的发现、相关酶的作用以及在生命过程中的重要功能,以期对未来研究m^6A在牛的遗传育种方面的调控作用提供重要的理论支持。

m^(6)A modification of plant virus enables host recognition by NMD factors in plants

N^(6)-methyladenosine(m^(6)A)is the most abundant eukaryotic mRNA modification and is involved in various biological processes.Increasing evidence has implicated that m^(6)Amodification is an important anti-viral defense mechanism in mammals and plants,but it is largely unknown how m^(6)Aregulates viral infection in plants.Here we report the dynamic changes and functional anatomy of m^(6)Ain Nicotiana benthamiana and Solanum lycopersicum during Pepino mosaic virus(PepMV)infection.m^(6)Amodification in the PepMV RNA genome is conserved in these two species.Overexpression of the m^(6)Awriters,mRNA adenosine methylase A(MTA),and HAKAI inhibit the PepMV RNA accumulation accompanied by increased viral m^(6)Amodifications,whereas deficiency of these writers decreases the viral RNA m^(6)Alevels but enhances virus infection.Further study reveals that the cytoplasmic YTH-domain family protein NbECT2A/2B/2C as m^(6)Areaders are involved in anti-viral immunity.Protein-protein interactions indicate that NbECT2A/2B/2C interact with nonsense-mediated mRNA decay(NMD)-related proteins,including NbUPF3 and NbSMG7,but not with NbUPF1.m^(6)Amodification-mediated restriction to PepMV infection is dependent on NMD-related factors.These findings provide new insights into the functionality of m^(6)Aanti-viral activity and reveal a distinct immune response that NMD factors recognize the m^(6)Areaders-viral m^(6)ARNA complex for viral RNA degradation to limit virus infection in plants.

The m^(6)A reader SiYTH1 enhances drought tolerance by affecting the messenger RNA stability of genes related to stomatal closure and reactive oxygen species scavenging in Setaria italica

Foxtail millet(Setaria italica),a vital drought-resistant crop,plays a significant role in ensuring food and nutritional security.However,its drought resistance mechanism is not fully understood.N6-methyladenosine(m^(6)A)modification of RNA,a prevalent epi-transcriptomic modification in eukaryotes,provides a binding site for m^(6)A readers and affects plant growth and stress responses by regulating RNA metabolism.In this study,we unveiled that the YT521-B homology(YTH)family gene SiYTH1 positively regulated the drought tolerance of foxtail millet.Notably,the siyth1 mutant exhibited reduced stomatal closure and augmented accumulation of excessive H_(2)O_(2)under drought stress.Further investigations demonstrated that SiYTH1 positively regulated the transcripts harboring m^(6)A modification related to stomatal closure and reactive oxygen species(ROS)scavenging under drought stress.SiYTH1 was uniformly distributed in the cytoplasm of SiYTH1-GFP transgenic foxtail millet.It formed dynamic liquid-like SiYTH1 cytosol condensates in response to drought stress.Moreover,the cytoplasmic protein SiYTH1 was identified as a distinct m^(6)A reader,facilitating the stabilization of its directly bound SiARDP and ROS scavenging-related transcripts under drought stress.Furthermore,natural variation analysis revealed SiYTH1AGTG as the dominant allele responsible for drought tolerance in foxtail millet.Collectively,this study provides novel insights into the intricate mechanism of m^(6)A reader-mediated drought tolerance and presents a valuable genetic resource for improving drought tolerance in foxtail millet breeding.

核内m^(6)A阅读蛋白与选择性剪接在疾病中的研究进展

N6-甲基腺苷(m^(6)A)是一种动态可逆的表观调控,是最常见的内部转录后修饰。甲基化酶发生m^(6)A修饰,去甲基化酶擦除修饰,并依赖阅读蛋白对m^(6)A修饰后的RNA的特异性识别。m^(6)A修饰通过招募调节选择性剪接的特定RNA结合蛋白或直接影响RNA结合蛋白与其靶RNA之间的相互作用来调节选择性剪接的模式。m^(6)A修饰扩大了疾病治疗策略的范围,而选择性剪接为m^(6)A阅读蛋白在疾病发生和进展中的机制提供了新见解。该文介绍了m^(6)A阅读蛋白与选择性剪接,全面总结了细胞核内所有的m^(6)A阅读蛋白对信使RNA(messenger RNA,mRNA)的识别和选择性剪接的调控机制,重点阐述了m^(6)A阅读蛋白在多种癌症、流感病毒、白血病等疾病中的生物学功能和作用机制,并探讨m^(6)A依赖性选择性剪接在治疗中的潜在策略。

m^(6)A调控相分离的研究进展

液-液相分离(Liquid-liquid phase separation,LLPS)是胞内分子因理化性质聚集或分离而形成的无膜细胞器,在细胞中发挥十分重要的功能。m^(6)A作为RNA上最丰富的修饰也与LLPS密切相关,然而m^(6)A对相分离的调控机制还并不清楚,该文总结m^(6)A RNA通过与蛋白相互作用,改变RNA定位,改变RNA结构,与其他RNA修饰协同作用等方式调控相分离,同时阐述通过相分离调控的相关生物学功能,提供m^(6)A调控相分离介导的生物过程的新视角,为后续的研究提供参考。

FLK is an mRNA m^(6)A reader that regulates floral transition by modulating the stability and splicing of FLC in Arabidopsis

N^(6)-methyladenosine(m^(6)A),which is added,removed,and interpreted by m^(6)A writers,erasers,and readers,respectively,is the most abundant modification in eukaryotic mRNAs.The m^(6)A marks play a pivotal role in the regulation of floral transition in plants.FLOWERING LOCUS K(FLK),an RNA-binding protein harboring K-homology(KH)motifs,is known to regulate floral transition by repressing the levels of a key floral repressor FLOWERING LOCUS C(FLC)in Arabidopsis.However,the molecular mechanism underlying FLK-mediated FLC regulation remains unclear.In this study,we identified FLK as a novel mRNA m^(6)A reader protein that directly binds the m^(6)A site in the 3ʹ-untranslated region of FLC transcripts to repressing FLC levels by reducing its stability and splicing.Importantly,FLK binding of FLC transcripts was abolished in vir-1,an m^(6)A writer mutant,and the late-flowering phenotype of the flk mutant could not be rescued by genetic complementation using the mutant FLKm gene,in which the m^(6)A reader encoding function was eliminated,indicating that FLK binds and regulates FLC expression in an m^(6)A-dependent manner.Collectively,our study has addressed a long-standing question of how FLK regulates FLC transcript levels and established a molecular link between the FLK-mediated recognition of m^(6)A modifications on FLC transcripts and floral transition in Arabidopsis.

m^(6)A RNA甲基化修饰在植物中的研究进展

N6-甲基腺苷(N6-methyladenosine,m^(6)A)修饰是发生在RNA分子上最广泛的化学修饰之一,在转录后调控中发挥着重要作用。m^(6)A甲基转移酶和去甲基化酶协同调控m^(6)A修饰的动态变化,而识别酶特异性地结合m^(6)A修饰位点,影响RNA的代谢和加工,从而产生不同的生物学功能。本文对植物中m^(6)A甲基化元件、m^(6)A修饰对mRNA的影响,以及检测技术进行了综述,并着重总结了m^(6)A修饰在调控植物生长发育和逆境应答等方面的研究进展,以期为深入开展植物m^(6)A相关研究提供理论参考。

Marking RNA:m^6A writers,readers,and functions in Arabidopsis

N^6-methyladenosine(m^6A)emerges as an important modification in eukaryotic mRNAs.m^6A has first been reported in 1974,and its functional significance in mammalian gene regulation and importance for proper development have been well established.An arsenal of writer,eraser,and reader proteins accomplish deposition,removal,and interpretation of the m^6A mark,resulting in dynamic function.This led to the concept of an epitranscriptome,the compendium of RNA species with chemical modification ofthe nucleobases in the cell,in analogy to the epigenome.While m^6A has long been known to also exist in plant mRNAs,proteins involved in m^6A metabolism have only recently been detected by mutant analysis,homology search,and mRNA interactome capture in the reference plant Arabidopsis thaliana.Dysregulation ofthe m^6A modification causes severe developmental abnormalities of leaves and roots and altered timing of reproductive development.Furthermore,m^6A modification affects viral infection.Here,we discuss recent progress in identifying m^6A sites transcriptome-wide,in identifying the molecular players involved in writing,removing,and reading the mark,and in assigning functions to this RNA modification in 4.thaliana.We highlight similarities and differences to m^6A modification in mammals and provide an outlook on important questions that remain to be addressed.

m^(6)A reader Igf2bp3 enables germ plasm assembly by mA-dependent regulation of gene expression in zebrafish

Bucky ball(Buc)is involved in germ plasm(GP)assembly during early zebrafish development by regulating GP mRNA expression via an unknown mechanism.The present study demonstrates that an m^(6)A reader Igf2bp3 interacts and colocalizes with Buc in the GP.Similar to the loss of Buc,the genetic deletion of maternal igf2bp3 in zebrafish leads to abnormal GP assembly and insufficient germ cell specification,which can be partially restored by the injection of igf2 bp3 mRNA.Igf2bp3 binds to m^(6)A-modified GPorganizer and GP mRNAs in an m^(6)A-dependent manner and prevents their degradation.These findings indicate that the functions of Igf2bp3,a direct effector protein of Buc,in GP mRNA expression and GP assembly involve m^(6)A-dependent regulation;these results emphasize a critical role of m^(6)A modification in the process of GP assembly.

Arab/c/opste N^(6)-methyladenosine reader CPSF30-L recognizes FUE signals to control polyadenylation site choice in liquid-like nuclear bodies

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.

Structural Insights into N^6-methyladenosine (m^6A) Modification in the Transcriptome

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.

N^(6)-methyladenosine and Its Implications in Viruses

N6-methyladenine(m^(6)A)is the most abundant RNA modification in mammalian messenger RNAs(mRNAs),which participates in and regulates many important biological activities,such as tissue development and stem cell differentiation.Due to an improved understanding of m^(6)A,researchers have discovered that the biological function of m^(6)A can be linked to many stages of mRNA metabolism and that m^(6)A can regulate a variety of complex biological processes.In addition to its location on mammalian mRNAs,m^(6)A has been identified on viral transcripts.m^(6)A also plays important roles in the life cycle of many viruses and in viral replication in host cells.In this review,we briefly introduce the detection methods of m^(6)A,the m^(6)A-related proteins,and the functions of m^(6)A.We also summarize the effects of m^(6)A-related proteins on viral replication and infection.We hope that this review provides researchers with some insights for elucidating the complex mechanisms of the epitranscriptome related to viruses,and provides information for further study of the mechanisms of other modified nucleobases acting on processes such as viral replication.We also anticipate that this review can stimulate collaborative research from different fields,such as chemistry,biology,and medicine,and promote the development of antiviral drugs and vaccines.