New insights into developmental biology of Eimeria tenella revealed by comparative analysis of mRNA N6-methyladenosine modification between unsporulated oocysts and sporulated oocysts

Evidence showed that N6-methyladenosine(m^(6)A)modification plays a pivotal role in influencing RNA fate and is strongly associated with cell growth and developmental processes in many species.However,no information regarding m^(6)A modification in Eimeria tenella is currently available.In the present study,we surveyed the transcriptome-wide prevalence of m^(6)A in sporulated oocysts and unsporulated oocysts of E.tenella.Methylated RNA immunoprecipitation sequencing(MeRIP-seq)analysis showed that m^(6)A modification was most abundant in the coding sequences,followed by stop codon.There were 3,903 hypermethylated and 3,178 hypomethylated mRNAs in sporulated oocysts compared with unsporulated oocysts.Further joint analysis suggested that m^(6)A modification of the majority of genes was positively correlated with mRNA expression.The mRNA relative expression and m^(6)A level of the selected genes were confirmed by quantitative reverse transcription PCR(RT-qPCR)and MeRIP-qPCR.GO and KEGG analysis indicated that differentially m^(6)A methylated genes(DMMGs)with significant differences in mRNA expression were closely related to processes such as regulation of gene expression,epigenetic,microtubule,autophagy-other and TOR signaling.Moreover,a total of 96 DMMGs without significant differences in mRNA expression showed significant differences at protein level.GO and pathway enrichment analysis of the 96 genes showed that RNA methylation may be involved in cell biosynthesis and metabolism of E.tenella.We firstly present a map of RNA m^(6)A modification in E.tenella,which provides significant insights into developmental biology of E.tenella.

N6-methyladenosine methylation regulates the tumor microenvironment of Epstein-Barr virus-associated gastric cancer

BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric cancer(EBVaGC)is a distinctive molecular subtype of GC.We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.AIM To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.METHODS First,The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC(EBVnGC).Second,we identified Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional enrichment of m6A-related differentially expressed genes.We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment(TME).Finally,cell counting kit-8 cell proliferation test,transwell test,and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1(IGFBP1)in EBVaGC cell lines.RESULTS m6A methylation regulators were involved in the occurrence and development of EBVaGC.Compared with EBVnGC,the expression levels of m6A methylation regulators Wilms tumor 1-associated protein,RNA binding motif protein 15B,CBL proto-oncogene like 1,leucine rich pentatricopeptide repeat containing,heterogeneous nuclear ribonucleoprotein A2B1,IGFBP1,and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC(P<0.05).The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher(P=0.046).GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC.Compared with EBVnGC,the infiltration of activated CD4+T cells,activated CD8+T cells,monocytes,activated dendritic cells,and plasmacytoid dendritic cells were significantly upregulated in EBVaGC(P<0.001).In EBVaGC,the expression level of proinflammatory factors interleukin(IL)-17,IL-21,and interferon-γ and immunosuppressive factor IL-10 were significantly increased(P<0.05).In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line(SNU719)than in an EBVnGC cell line(AGS)(P<0.05).IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719.Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.CONCLUSION m6A regulators could remodel the TME of EBVaGC,which is classified as an immune-inflamed phenotype and referred to as a“hot”tumor.Among these regulators,we demonstrated that IGFBP1 affected proliferation,migration,and apoptosis.

Advances of N6-methyladenosine modification on circular RNA in hepatocellular carcinoma

N6-methyladenosine(m6A)is a reversible epigenetic modification, which is one of the most abundant modifiers in eukaryotic cells and has been commonly reported in messenger RNAs and non-coding RNAs. The processing modification of m6A regulates RNA transcription, processing, splicing, degradation, and translation, and plays an important role in the biological process of tumors. Circular RNA, which lacks the 5' cap structure, has been mistakenly regarded as a "junk sequence" generated by accidental shearing during the transcription process. However, it has been found that circRNAs can be involved in tumor invasion and metastasis through microRNAs, binding proteins, translated peptides, and m6A modifications. In this paper, we reviewed the role of m6A modifications in circRNA regulation and their functions in hepatocellular carcinoma and discussed their potential clinical applications and future development in this field.

Lipid metabolism and m^(6)A RNA methylation are altered in lambs supplemented rumen-protected methionine and lysine in a low-protein diet

Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rumen-protected methionine and lysine(RML)in a low-protein(LP)diet on lipid metabolism,m^(6)A RNA methylation,and fatty acid(FA)profiles in the liver and muscle of lambs were investigated.Sixty-three male lambs were divided into three treatment groups,three pens per group and seven lambs per pen.The lambs were fed a 14.5%crude protein(CP)diet(adequate protein[NP]),12.5%CP diet(LP),and a LP diet plus RML(LP+RML)for 60 d.Results:The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin(P=0.07),triglyceride(P=0.05),and non-esterified FA(P=0.08).Feeding a LP diet increased the enzyme activity or m RNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet.This effect was reversed by supplementation of RML with a LP diet.The inclusion of RML in a LP diet affected the polyunsaturated fatty acids(PUFA),n-3 PUFA,and n-6 PUFA in the liver but not in the muscle,which might be linked with altered expression of FA desaturase-1(FADS1)and acetyl-Co A carboxylase(ACC).A LP diet supplemented with RML increased(P<0.05)total m^(6)A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein(FTO)and alk B homologue 5(ALKBH5).The m RNA expressions of methyltransferase-like 3(METTL3)and methyltransferase-like 14(METTL14)in the LP+RML diet group were lower than those in the other two groups.Supplementation of RML with a LP diet affected only liver YTH domain family(YTHDF2)proteins(P<0.05)and muscle YTHDF3(P=0.09),which can be explained by limited m^(6)Abinding proteins that were mediated in m RNA fate.Conclusions:Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle.These changes in fat metabolism may be associated with the modification of m^(6)A RNA methylation.

Analysis of N6-methyladenosine-modified mRNAs in diabetic cataract

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.

Aberrant expression of enzymes regulating m^6A mRNA methylation: implication in cancer

N^6-methyladenosine(m^6 A) is an essential RNA modification that regulates key cellular processes, including stem cell renewal,cellular differentiation, and response to DNA damage. Unsurprisingly, aberrant m^6 A methylation has been implicated in the development and maintenance of diverse human cancers. Altered m^6 A levels affect RNA processing, mRNA degradation, and translation of mRNAs into proteins, thereby disrupting gene expression regulation and promoting tumorigenesis. Recent studies have reported that the abnormal expression of m^6 A regulatory enzymes affects m^6 A abundance and consequently dysregulates the expression of tumor suppressor genes and oncogenes, including MYC, SOCS2, ADAM19, and PTEN. In this review, we discuss the specific roles of m^6 A missing space "writers", "erasers", and "readers" in normal physiology and how their altered expression promotes tumorigenesis. We also describe the potential of exploiting the aberrant expression of these enzymes for cancer diagnosis, prognosis, and the development of novel therapies.

Epigenetic N6-methyladenosine modification of RNA and DNA regulates cancer

The biological roles of N6 methylation of nucleic acids have been extensively studied.Adenine methylation of RNA is the most prevalent RNA modification and has widespread effects on RNA splicing,translation,localization,and stability.Aberrant dynamic regulation of RNA N6-methyladenosine(m6 A)has been reported in numerous human diseases,including several cancers.In recent years,eukaryotic DNA N6-methyladenosine(6 mA)has also been reported and implicated in cancer progression and tumorigenesis.In this review,we summarize the contributions of N6-methyladenosine modification to cancer biology and pathogenesis in the context of both RNA and DNA.We also highlight the clinical relevance of targeting these modifications as a therapeutic strategy for cancer.

Genome-wide map of N6-methyladenosine circular RNAs identified in mice model of severe acute pancreatitis

BACKGROUND Severe acute pancreatitis(SAP)is a deadly inflammatory disease with complex pathogenesis and lack of effective therapeutic options.N6-methyladenosine(m6A)modification of circRNAs plays important roles in physiological and pathological processes.However,the roles of m6A circRNA in the pathological process of SAP remains unknown.AIM To identify transcriptome-wide map of m6A circRNAs and to determine their biological significance and potential mechanisms in SAP.METHODS The SAP in C57BL/6 mice was induced using 4%sodium taurocholate salt.The transcriptome-wide map of m6A circRNAs was identified by m6A-modified RNA immunoprecipitation sequencing.The biological significance of circRNAs with differentially expressed m6A peaks was evaluated through gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis.The underlying mechanism of m6A circRNAs in SAP was analyzed by constructing of m6A circRNAmicroRNA networks.The expression of demethylases was determined by quantitative polymerase chain reaction and western blot to deduce the possible mechanism of reversible m6A process in SAP.RESULTS Fifty-seven circRNAs with differentially expressed m6A peaks were identified by m6A-modified RNA immunoprecipitation sequencing,of which 32 were upregulated and 25 downregulated.Functional analysis of these m6A circRNAs in SAP found some important pathways involved in the pathogenesis of SAP,such as regulation of autophagy and protein digestion.In m6A circRNA–miRNA networks,several important miRNAs participated in the occurrence and progression of SAP were found to bind to these m6A circRNAs,such as miR-24-3p,miR-26a,miR-92b,miR-216b,miR-324-5p and miR-762.Notably,the total m6A level of circRNAs was reduced,while the demethylase alkylation repair homolog 5 was upregulated in SAP.CONCLUSION m6A modification of circRNAs may be involved in the pathogenesis of SAP.Our findings may provide novel insights to explore the possible pathogenetic mechanism of SAP and seek new potential therapeutic targets for SAP.

METTL3-mediated m^(6)A RNA methylation regulates dorsal lingual epithelium homeostasis

The dorsal lingual epithelium,which is composed of taste buds and keratinocytes differentiated from K14^(+)basal cells,discriminates taste compounds and maintains the epithelial barrier.N6-methyladenosine(m^(6)A)is the most abundant mRNA modification in eukaryotic cells.How METTL3-mediated m^(6)A modification regulates K14^(+)basal cell fate during dorsal lingual epithelium formation and regeneration remains unclear.Here we show knockout of Mettl3 in K14^(+)cells reduced the taste buds and enhanced keratinocytes.Deletion of Mettl3 led to increased basal cell proliferation and decreased cell division in taste buds.Conditional Mettl3 knock-in mice showed little impact on taste buds or keratinization,but displayed increased proliferation of cells around taste buds in a protective manner during post-irradiation recovery.Mechanically,we revealed that the most frequent m^(6)A modifications were enriched in Hippo and Wnt signaling,and specific peaks were observed near the stop codons of Lats1 and FZD7.Our study elucidates that METTL3 is essential for taste bud formation and could promote the quantity recovery of taste bud after radiation.

m^(6)A甲基化修饰在眼科疾病中的研究进展

N6-甲基腺苷(m^(6)A)是真核细胞中最普遍、最丰富和最保守的RNA内部修饰方式。m^(6)A修饰主要通过m^(6)A甲基转移酶、m^(6)A去甲基化酶和m^(6)A甲基化识别蛋白调节RNA的剪接、稳定性、输出、降解和翻译等。近年来的研究发现,m^(6)A甲基化异常可能介导眼部的多种病理过程,参与代谢性、炎症性、退行性眼病和眼部肿瘤的发生发展,如糖尿病视网膜病变、白内障、年龄相关性黄斑变性、葡萄膜黑色素瘤等。本文就m^(6)A甲基化修饰在眼部组织细胞和眼科疾病中的作用进行综述,阐明m^(6)A甲基化在眼病中的潜在分子机制,可能为某些眼科疾病的患者提供新的治疗思路。

Regulations of m^(6)A methylation on tomato fruit chilling injury

Tomato fruit are sensitive to chilling injury(CI)during cold storage.Several factors have been discovered to be involved in chilling injury of tomato fruit.Plant hormones play an important regulatory role,however,the relationship between chilling injury and N6-methyladenosine(m^(6)A)methylation of transcripts in plant hormone pathways has not been reported yet.In order to clarify the complex regulatory mechanism of m^(6)A methylation on chilling injury in tomato fruit,Nanopore direct RNA sequencing was employed.A large number of enzymes and transcription factors were found to be involved in the regulation process of fruit chilling injury,which were associated with plant hormone,such as 1-aminocyclopropane 1-carboxylate synthase(ACS),aspartate aminotransferase(AST),auxin response factor(ARF2),ethylene response factor 2(ERF2),gibberellin 20-oxidase-3(GA20ox)and jasmonic acid(JA).By conjoint analysis of the differential expression transcripts related to chilling injury andm^(6)Amethylation differential expression transcripts 41 differential expression transcripts were identified involved in chilling injury including 1-aminocyclopropane-1-carboxylate oxidase(ACO)and pectinesterase(PE)were down-regulated and heat shock cognate 70 kD protein 2(cpHSC70),HSP70-binding protein(HspBP)and salicylic acid-binding protein 2(SABP2)were up-regulated.Our results will provide a deeper understanding for chilling injury regulatory mechanism and post-harvest cold storage of tomato fruit.

m^6A RNA甲基化在非小细胞肺癌中的研究进展

m^6A修饰是真核生物mRNA中最丰富的修饰之一,该过程受m^6A甲基转移酶和去甲基化酶的共同调控。m^6A修饰后的RNA能够被m^6A识别蛋白特异性识别并结合,进而介导RNA的剪接、成熟、出核、降解和翻译等。目前国内外对于m^6A修饰及其相关蛋白如何参与非小细胞肺癌发生发展的研究,主要集中于细胞恶性增殖、迁移、侵袭、转移和耐药等方面。m^6A修饰相关蛋白在肺癌组织标本和血液循环肿瘤细胞(circulating tumor cell, CTC)中表达异常,有望成为肺癌诊断和预后判断的潜在分子标志物。本文围绕m^6A修饰相关蛋白的组成、作用方式、在非小细胞肺癌恶性进展中的生物学功能,以及针对m^6A修饰的靶向治疗等方面的研究进展进行综述,旨在为非小细胞肺癌的早期临床诊断和靶向药物的开发提供新思路。

The role of m^(6)A RNA methylation in autoimmune diseases: Novel therapeutic opportunities

N6-methyladenosine m^(6)A modifications,as one of the most common forms of in-ternal RNA chemical modifications in eukaryotic cells,have gained increasing attention in recent years.The m^(6)A RNA modifications exert various crucial roles in various biological pro-cesses,such as embryonic development,neurogenesis,circadian rhythms,and tumorigenesis.Recent advances have highlighted that m^(6)A RNA modification plays an important role in im-mune response,especially in the initiation and progression of autoimmune diseases.In this re-view,we summarized the regulatory mechanisms of m^(6)A methylation and its biological functions in the immune system and mainly focused on recent progress in research on the po-tential role of m^(6)A RNA methylation in the pathogenesis of autoimmune diseases,thus providing possible biomarkers and potential targets for the prevention and treatment of auto-immunediseases.

m^(6)A RNA甲基化对神经系统发育及其相关疾病的调控作用

N^(6)-甲基腺苷(m^(6)A)甲基化是RNA水平转录后的表观遗传学修饰,由RNA甲基转移酶催化腺嘌呤在N^(6)位置发生甲基化的过程,调控RNA稳定性、定位、运输、剪切和翻译,将影响mRNA的命运与转归,进而影响机体结构和功能的改变.新近研究表明m^(6)A甲基化修饰在神经发育、传导、再生及学习记忆功能等方面发挥重要的作用,并与神经退行性疾病密切相关.环境中的外源因素引起m^(6)A甲基化改变,可引起神经损伤,并影响其修复过程,进而调控神经系统发育及其相关疾病的发生发展.外源因素与RNA甲基化的关联,将有助于探索神经系统疾病的病因和机制,为其精准预防和干预治疗提供新的参考靶点。

m^(6)A-RNA甲基化在NSCLC中的生物学功能研究进展

基因调节受损是许多疾病的核心,包括发育系统疾病和癌症。N6甲基腺苷的可调节的甲基化是哺乳动物RNA修饰的重要组成部分,已被越来越多的研究证明其在各种生物学过程及癌症发病机制中发挥重要作用。这种RNA化学标记可由“writers”蛋白(甲基转移酶)产生,并可由“ereasers”蛋白(去甲基酶)逆转,这些化学修饰可以由“readers”蛋白(甲基化阅读蛋白)识别,并依此来调节下游分子机制。RNA m^(6)A修饰在重要的生物学过程中起着重要作用,有研究表明,m^(6)A在NSCLC的发生、转移及侵袭方面至关重要,m^(6)A的研究也为NSCLC治疗提供了新的思路,本文就m^(6)A在NSCLC中的病因、发展、耐药等方面进行一一论述,目的是从表观遗传学方面进一步挖掘肺癌发生发展的生物学机制,为NSCLC的靶向治疗提供研究思路。

RNA m^(6)A修饰在肺部疾病中的研究进展

N^(6)-甲基腺苷(N^(6)-methyladenosine,m^(6)A)修饰是指RNA中腺苷的第6位氮原子处发生的甲基化修饰。在已发现的RNA修饰中,m^(6)A修饰被认为是真核生物mRNA中最常见的修饰类型。此外,这种甲基化修饰也可发生在rRNA、tRNA、miRNA、circRNA和lncRNA[1]。

The m6A methylation landscape stratifies hepatocellular carcinoma into 3 subtypes with distinct metabolic characteristics

Objective:Epigenetic aberration plays an important role in the development and progression of hepatocellular carcinoma(HCC).However,the alteration of RNA N6-methyladenosine(m6A)modifications and its role in HCC progression remain unclear.We therefore aimed to provide evidence using bioinformatics analysis.Methods:We comprehensively analyzed the m6A regulator modification patterns of 605 HCC samples and correlated them with metabolic alteration characteristics.We elucidated 390 gene-based m6A-related signatures and defined an m6Ascore to quantify m6A modifications.We then assessed their values for predicting prognoses and therapeutic responses in HCC patients.Results:We identified 3 distinct m6A modification patterns in HCC,and each pattern had distinct metabolic characteristics.The evaluation of m6A modification patterns using m6Ascores could predict the prognoses,tumor stages,and responses to sorafenib treatments of HCC patients.A nomogram based on m6Ascores showed high accuracy in predicting the overall survival of patients.The area under the receiver operating characteristic curve of predictions of 1,3,and 5-year overall survivals were 0.71,0.69,and 0.70 in the training cohort,and in the test cohort it was 0.74,0.75,and 0.71,respectively.M6Acluster C1,which corresponded to hypoactive mRNA methylation,lower expression of m6A regulators,and a lower m6Ascore,was characterized by metabolic hyperactivity,lower tumor stage,better prognosis,and lower response to sorafenib treatment.In contrast,m6Acluster C3 was distinct in its hyperactive mRNA methylations,higher expression of m6A regulators,and higher m6Ascores,and was characterized by hypoactive metabolism,advanced tumor stage,poorer prognosis,and a better response to sorafenib.The m6Acluster,C2,was intermediate between C1 and C3.Conclusions:HCCs harbored distinct m6A regulator modification patterns that contributed to the metabolic heterogeneity and diversity of HCC.Development of m6A gene signatures and the m6Ascore provides a more comprehensive understanding of m6A modifications in HCC,and helps predict the prognosis and treatment response.

m^(6)A RNA甲基化调节因子与肝细胞癌预后的关系

目的探讨N^(6)-甲基腺嘌呤(m^(6)A)RNA甲基化调节因子与肝细胞癌(HCC)预后的关系。方法从美国国家癌症研究所基因组数据共享中心下载HCC样本和正常对照样本的RNA-seq转录组数据,并收集HCC样本临床病理资料。从RNA-seq转录组数据中获取FTO、YTHDC2、YTHDC1、ALKBH5、KIAA1429、METTL3、HNRNPC、YTHDF2、RBM15、YTHDF1、WTAP、METTL14、ZC3H13等十三种m^(6)A RNA甲基化调节因子的表达数据,比较HCC样本和正常对照样本m^(6)A RNA甲基化调节因子表达。采用单因素Cox回归分析和Lasso Cox回归分析筛选与HCC预后相关的m^(6)A RNA甲基化调节因子,并构建风险模型,分析风险模型与HCC预后的关系。结果 HCC样本FTO、YTHDC2、YTHDC1、ALKBH5、KIAA1429、METTL3、HNRNPC、YTHDF2、RBM15、YTHDF1、WTAP表达均高于正常对照样本(P均<0.01),而两样本METTL14、ZC3H13表达比较差异均无统计学意义(P均>0.05)。YTHDF1、ZC3H13、YTHDF2、METTL3和KIAA1429等五种m^(6)A RNA甲基化调节因子是影响HCC预后的危险因素(P均<0.05)。其中,ZC3H13高表达者预后良好,而YTHDF1、YTHDF2、METTL3、KIAA1429高表达者预后较差。根据YTHDF1、ZC3H13、YTHDF2、METTL3、KIAA1429等五种m^(6)A RNA甲基化调节因子构建HCC预后风险模型,然后将HCC患者分为高风险者与低风险者,高风险者5年生存率明显低于低风险者(P<0.05);ROC曲线分析显示,该风险模型的曲线下面积为0.619。单因素和多因素Cox回归分析显示,风险模型评分是影响HCC预后的独立危险因素(P<0.01)。结论 m^(6)A RNA甲基化调节因子表达与HCC预后密切相关,有可能作为肿瘤诊断的分子标志物和潜在的治疗靶点。

Learning Sequential and Structural Dependencies Between Nucleotides for RNA N6-Methyladenosine Site Identification

N6-methyladenosine(m6A)is an important RNA methylation modification involved in regulating diverse biological processes across multiple species.Hence,the identification of m6A modification sites provides valuable insight into the biological mechanisms of complex diseases at the post-transcriptional level.Although a variety of identification algorithms have been proposed recently,most of them capture the features of m6A modification sites by focusing on the sequential dependencies of nucleotides at different positions in RNA sequences,while ignoring the structural dependencies of nucleotides in their threedimensional structures.To overcome this issue,we propose a cross-species end-to-end deep learning model,namely CR-NSSD,which conduct a cross-domain representation learning process integrating nucleotide structural and sequential dependencies for RNA m6A site identification.Specifically,CR-NSSD first obtains the pre-coded representations of RNA sequences by incorporating the position information into single-nucleotide states with chaos game representation theory.It then constructs a crossdomain reconstruction encoder to learn the sequential and structural dependencies between nucleotides.By minimizing the reconstruction and binary cross-entropy losses,CR-NSSD is trained to complete the task of m6A site identification.Extensive experiments have demonstrated the promising performance of CR-NSSD by comparing it with several state-of-the-art m6A identification algorithms.Moreover,the results of cross-species prediction indicate that the integration of sequential and structural dependencies allows CR-NSSD to capture general features of m6A modification sites among different species,thus improving the accuracy of cross-species identification.

Ferroptosis:a critical mechanism of N^(6)-methyladenosine modification involved in carcinogenesis and tumor progression

Ferroptosis is an iron-dependent regulatory cell necrosis induced by iron overload and lipid peroxidation.It occurs when multiple redoxactive enzymes are ectopically expressed or show abnormal function.Hence,the precise regulation of ferroptosis-related molecules is mediated across multiple levels,including transcriptional,posttranscriptional,translational,and epigenetic levels.N^(6)-methyladenosine(m^(6)A)is a highly evolutionarily conserved epigenetic modification in mammals.The m^(6)A modification is commonly linked to tumor proliferation,progression,and therapy resistance because it is involved in RNA metabolic processes.Intriguingly,accumulating evidence suggests that dysregulated ferroptosis caused by the m^(6)A modification drives tumor development.In this review,we summarized the roles of m^(6)A regulators in ferroptosis-mediated malignant tumor progression and outlined the m^(6)A regulatory mechanism involved in ferroptosis pathways.We also analyzed the potential value and application strategies of targeting m^(6)A/ferroptosis pathway in the clinical diagnosis and therapy of tumors.