Post-transcriptional RNA Modification Research Articles

YTHDF1 and YTHDC1 m6A reader proteins regulate HTLV-1 tax and hbz activity.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus responsible for adult T-cell leukemia/lymphoma (ATLL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a progressive neurodegenerative disease. Regulation of viral gene expression plays a key role in viral persistence and pathogenesis. However, the molecular mechanisms underlying this fine-tuned regulation remain poorly understood. Little is known regarding RNA chemical modifications of HTLV-1 RNA and how these affect viral biology and disease development. Post-transcriptional chemical modification of RNA is common in eukaryotes, with N6-methyladenosine (m6A) being the most prevalent. In this study, we investigated the role of m6A RNA modifications on HTLV-1 gene expression. Using MeRIP-Seq, we mapped the sites of m6A modification to the 3' end of the viral genome. We found HTLV-1 RNA, as well as viral oncogene transcripts tax and hbz, contained m6A modifications. m6A-depletion in HTLV-1-transformed cells decreased sense-derived viral genes (Tax, Gag, and Env) and increased antisense-derived Hbz expression. Tax and hbz transcripts were bound by reader proteins YTHDF1 and YTHDC1 in a panel of HTLV-1 T-cell lines. Using expression vectors and shRNA-mediated knockdown, we found that YTHDF1 had opposing effects on viral gene expression, decreasing sense-derived viral genes and increasing antisense-derived Hbz. Upon further study, the YTHDF1 effects on tax abundance were dependent on tax m6A deposition. The nuclear m6A reader protein YTHDC1 affected the abundance of both sense- and antisense-derived viral transcripts and specifically enhanced the nuclear export of tax transcript. Collectively, our results demonstrate global m6A levels and m6A reader proteins YTHDF1 and YTHDC1 regulate HTLV-1 gene expression.IMPORTANCEHuman T-cell leukemia virus type 1 (HTLV-1) persistence and pathogenesis are controlled through tight regulation of viral gene expression. The fate of RNA can be controlled by epigenetic modifications that impact gene expression without altering the DNA sequence. Our study details the impact of N6-methyladenosine (m6A) RNA chemical modifications on HTLV-1 gene expression. We found that reductions in global m6A levels affected viral gene expression, decreasing Tax and other sense-derived viral genes, whereas increasing the antisense-derived Hbz. Our results suggest the oncogenic viral transcripts, tax and hbz, are m6A-modified in cells. We found that these viral RNA modifications are interpreted by reader proteins YTHDF1 and YTHDC1, which dictate the fate of the viral RNA. Understanding HTLV-1 RNA chemical modifications offers potential insights into novel therapeutic strategies for HTLV-1-associated diseases.

Deployment and transcriptional evaluation of nitisinone, an FDA-approved drug, to control bed bugs.

Bed bugs are blood-feeders that rapidly proliferate into large indoor infestations. Their bites can cause allergies, secondary infections and psychological stress, among other problems. Although several tactics for their management have been used, bed bugs continue to spread worldwide wherever humans reside. This is mainly due to human-mediated transport and their high resistance to several classes of insecticides. New treatment options with novel modes of action are required for their control. In this study, we evaluated the use of nitisinone (NTBC), an FDA-approved drug, for bed bug control in an insecticide-susceptible (HH) and an insecticide-resistant (CIN) population. Although NTBC was lethal to both populations when administered orally or applied topically in very low doses, we observed a slight but significant resistance in the CIN population. Transcriptomic analysis in both populations indicated that NTBC treatment elicited a broad suppression of genes associated with RNA post-transcriptional modifications, translation, endomembrane system, protein post-translational modifications and protein folding. The CIN population exhibited higher adenosine triphosphate (ATP) production and xenobiotic detoxification. Feeding studies on a mouse model suggest that NTBC could be used as a control method of bed bugs by host treatment. The results indicate that NTBC can be used as a new active ingredient for bed bug control by topical or oral treatment and shed light on the molecular mechanisms of suppressed tyrosine metabolism following NTBC treatment. © 2025 Society of Chemical Industry.

Dynamic Roles of RNA and RNA Epigenetics in HTLV-1 Biology.

Since the discovery of RNA in the early 1900s, scientific understanding of RNA form and function has evolved beyond protein coding. Viruses, particularly retroviruses like human T-cell leukemia virus type 1 (HTLV-1), rely heavily on RNA and RNA post-transcriptional modifications to regulate the viral lifecycle, pathogenesis, and evasion of host immune responses. With the emergence of new sequencing technologies in the last decade, our ability to dissect the intricacies of RNA has flourished. The ability to study RNA epigenetic modifications and splice variants has become more feasible with the recent development of third-generation sequencing technologies, such as Oxford nanopore sequencing. This review will highlight the dynamic roles of known RNA and post-transcriptional RNA epigenetic modifications within HTLV-1 biology, including viral hbz, long noncoding RNAs, microRNAs (miRNAs), transfer RNAs (tRNAs), R-loops, N6-methyladenosine (m6A) modifications, and RNA-based therapeutics and vaccines.

5-Methylcytosine-modified circRNA-CCNL2 regulates vascular remdeling in hypoxic pulmonary hypertension through binding to FXR2.

Pulmonary hypertension (PH) is a malignant cardiovascular disease with a complex etiology. 5-Methylcytosine (m5C) is a post-transcriptional RNA modification identified in both stable and highly abundant RNAs, with a lower frequency of occurrence in circular RNAs (circRNAs). Nevertheless, the function of m5C-modified circRNAs in the pathogenesis of PH remains uncertain. The objective of this study was to investigate the biological role and molecular mechanisms of m5C-modified circRNA-CCNL2 in hypoxic PH pulmonary vascular remodeling. Our findings revealed that hypoxia downregulates circCCNL2 expression, and overexpression of circCCNL2 attenuates PH progression and inhibits the proliferation of pulmonary artery smooth muscle cell (PASMCs). Bioinformatics predictions indicated the presence of m5C modification sites in circCCNL2, which NSUN2 mediated. The downregulation of NSUN2 resulted in a reduction in m5C modification of circCCNL2. It was also observed that the stability of circRNAs was associated with the proliferation of PASMCs. From a mechanistic standpoint, low expression of circCCNL2 resulted in reduced binding of FXR2, while increased association of free FXR2 with CDKL3 led to enhanced proliferation of PASMCs. Notably, circCCNL2 expression was found to be regulated by alternative splicing involving SRSF2, with reduced pre-CCNL2 splicing resulting from low SRSF2 expression, ultimately leading to decreased circCCNL2 expression. This is the first demonstration that m5C-modified circCCNL2 can slow the development of PH and inhibit the proliferation of PASMCs by binding to FXR2. These findings offer new insights into the regulation of circRNAs through m5C modifications and the role of epigenetic reprogramming in PH.

Using Zebrafish Models to Study Epitranscriptomic Regulation of CNS Functions.

Epitranscriptomic regulation of cell functionsinvolves multiple post-transcriptional chemical modifications of coding and non-coding RNA that are increasingly recognized in studying human brain disorders. Although rodent models are presently widely used in neuroepitranscriptomic research, the zebrafish (Danio rerio) has emerged as a useful and promising alternative model species. Mounting evidence supports the importance of RNA modifications in zebrafish CNS function, providing additional insights into epitranscriptomic mechanisms underlying a wide range of brain disorders. Here, we discuss recent data on the role of RNA modifications in CNS regulation, with a particular focus on zebrafish models, as well as evaluate current problems, challenges, and future directions of research in this field of molecular neurochemistry.

RNA methylation modifications in neurodegenerative diseases: Focus on their enzyme system.

Neurodegenerative diseases (NDs) constitute a significant public health challenge, as they are increasingly contributing to global mortality and morbidity, particularly among the elderly population. Pathogenesis of NDs is intricate and multifactorial. Recently, post-transcriptional modifications (PTMs) of RNA, with a particular focus on mRNA methylation, have been gaining increasing attention. At present, several regulatory genes associated with mRNA methylation have been identified and closely associated with neurodegenerative disorders. This review aimed to summarize the RNA methylation enzymes system, including the writer, reader, and eraser proteins and delve into their functions in the central nervous system (CNS), hoping to open new avenues for exploring the mechanisms and therapeutic strategies for NDs. Recently, studies have highlighted the critical role of RNA methylation in the development and function of the CNS, and abnormalities in this process may contribute to brain damage and NDs, aberrant expression of enzymes involved in RNA methylation has been implicated in the onset and development of NDs.

Mouse models for understanding physiological functions of ADARs.

Adenosine-to-inosine (A-to-I) editing, is a highly prevalent posttranscriptional modification of RNA, mediated by the adenosine deaminases acting on RNA (ADAR) proteins. Mammalian transcriptomes contain tens of thousands to millions of A-to-I editing events. Mutations in ADAR can result in rare autoinflammatory disorders such as Aicardi-Goutières syndrome (AGS) through to irreversible conditions such as motor neuron disease, amyotrophic lateral sclerosis (ALS). Mouse models have played an important role in our current understanding of the physiology of ADAR proteins. With the advancement of genetic engineering technologies, a number of new mouse models have been recently generated, each providing additional insight into ADAR function. This review highlights both past and current mouse models, exploring the methodologies used in their generation, their respective discoveries, and the significance of these findings in relation to human ADAR physiology.

Genome-Wide Identification and Expression Analysis of Members in the YT521-B Homology Domain-Containing RNA Binding Protein Family in Ginkgo biloba.

N6-methyladenosine (m6A) is a widespread post-transcriptional modification of RNA in eukaryotes. The conserved YTH-domain-containing RNA binding protein has been widely reported to serve as a typical m6A reader in various species. However, no studies have reported the m6A readers in Ginkgo biloba (G. biloba). In this study, a systematic analysis of the m6A reader (YTH) gene family was performed on G. biloba, identifying 10 YTH genes in its genome. Phylogenetic analysis of protein-coding sequences revealed that YTH genes from G. biloba could be classified into two subgroups: GbDC1 and GbDC2 in GbDC and GbDF1-8 in GbDF, each with similar motifs and gene structures. In G. biloba, the predicated aromatic cage pocket of the YTH domains in the YTH gene family is uniformly composed of tryptophan residues (WWW). Subcellular localization experiments verified that GbDC1 is indeed localized in the nucleus, while GbDF1 is localized in both the nucleus and the cytoplasm. The expression patterns of the identified m6A reader genes showed a wide distribution but were tissue-specific. Most genes were highly expressed in leaves, followed by the stem, while the lowest expression tendency was found in the roots. Cis-regulatory element analysis predicted the possible functions of YTH genes in G. biloba, which were mainly responsive to plant hormones such as ABA and MeJA, as well as stress responses. Furthermore, the expression levels of YTH genes indeed changed significantly after ABA, MeJA, and NaCl treatments, suggesting that they can be affected by these abiotic factors. In addition, the PLAAC prediction results indicate that prion domains exist in GbDF1, GbDF2, GbDF3, GbDF4, GbDF6, GbDF7, GbDF8, and GbDC1, and phase separation is possible. This study provides a foundation for further investigation of the effects of m6A methylation on gene expression regulation in G. biloba and other forest trees.

Cannabinoids shift the basal ganglia microRNA m 6 A methylation profile towards an anti-inflammatory phenotype in SIV-infected rhesus macaques.

Epitranscriptomic modifications modulate diverse biological processes like regulation of gene expression, abundance, location and function. N6-methyladenosine (m 6 A) methylation has been shown to regulate various diseases, including cancer and inflammation. While there is evidence that m 6 A modification is functionally relevant in neural development and differentiation, the role of m 6 A modification in HIV neuropathogenesis is unknown. Here, we used anti-N6-methyladenosine (m 6 A) antibody immunoprecipitation and microarray profiling to identify m 6 A modifications in miRNAs in basal ganglia (BG) of Rhesus macaques (RMs) that were uninfected (VEH) and SIV-infected on combination anti-retroviral therapy (cART) and either VEH-treated (VEH/SIV/cART), or THC:CBD-treated (THC:CBD/SIV/cART). Ingenuity pathway analysis was conducted to understand the biological implications of miRNA m 6 A methylation in HIV neuropathogenesis. Finally, to understand the functional significance of m 6 A modifications in miRNAs, we overexpressed FAM-labeled wild-type or m 6 A-modified miR-194-5p in SCC-25 cells and determined its impact on the expression of its target, STAT1, an interferon-stimulated transcription factor known to drive persistent neuroinflammation in several neurodegenerative diseases. HIV/SIV infection promoted an overall hypomethylated miRNA m 6 A profile. While the overall hypomethylated m 6 A profile was not significantly impacted by THC:CBD, specific miRNAs predicted to target proinflammatory genes showed markedly reduced m 6 A methylation levels compared to the VEH-treated RMs. Additionally, specific BG tissue miRNAs bearing m 6 A epi-transcriptomic marks were transferred and detected in BG-derived extracellular vesicles. Mechanistically, the DRACH motif in the seed region of miR-194-5p was significantly m 6 A hypomethylated in THC:CBD/SIV/cART RMs. In SCC-25 cells, unlike wild-type miR-194-5p, transfected m 6 A-modified miR-194-5p mimics failed to downregulate STAT1 protein expression. Further, compared to VEH/SIV/cART RMs, THC:CBD administration significantly reduced m 6 A methylation of 44 miRNAs directly involved in regulating CNS network genes. These results underscore the need for investigating the qualitative, and posttranscriptional modifications in RNA along with the more traditional, quantitative alterations in pathological conditions or in response to disease modifying treatments. Our findings indicate that m 6 A epitranscriptomic marks in the seed nucleotide region can impair miRNA function and that cannabinoids may preserve it by reducing m 6 A methylation levels. Finally, these findings provide a novel mechanistic (miRNA m 6 A hypomethylation) explanation underlying the anti-neuroinflammatory effects of phytocannabinoids in HIV/SIV infection.

Emerging influence of RNA post-transcriptional modifications in the synovial homeostasis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is an important autoimmune disease that affects synovial tissues, accompanied by redness, pain, and swelling as main symptoms, which will limit the quality of daily life and even cause disability. Multiple coupling effects among the various cells in the synovial micro-environment modulate the poor progression and development of diseases. Respectively, synovium is the primary target tissue of inflammatory articular pathologies; synovial hyperplasia, and excessive accumulation of immune cells lead to joint remodelling and destroyed function. In general, epigenetic modification is an effective strategy to regulate dynamic balance of synovial homeostasis. Several typical post-transcriptional changes in cellular RNA can control the post-transcriptional modification of RNA structure. It can inhibit important processes, including degradation of RNA and nuclear translocation. Recent studies have found that RNA modification regulates the homeostasis of the synovial micro-environment and forms an intricate network in the "bone-cartilage-synovium" feedback loop. Aberrant regulation of RNA methylation triggers the pathological development of RA. Collectively, this review summarises recent advanced research about RNA modification in modulating synovial homeostasis by making close interaction among resident synovial macrophages, fibroblasts, T cells, and B cells, which could display the dramatic role of RNA modifications in RA pathophysiological process and perform the promising therapeutic target for treating RA.

The transcription factor FgSfp1 orchestrates mycotoxin deoxynivalenol biosynthesis in Fusarium graminearum

Fusarium graminearum (F. graminearum) and its derivative mycotoxin deoxynivalenol (DON) are highly concerned with food safety and sustainability worldwide. Although several transcription factors (TFs) had been elucidated, molecular mechanism participates in DON biosynthesis regulation remains largely unrevealed. Here, we first characterized a zinc finger-contained TF in F. graminearum, FgSfp1, which is indispensable for DON production since its depletion resulting in a 95.4% DON yielding reduction. Interestingly, contrast to previous knowledge, all TRI-cluster genes were abnormally upregulated in ΔFgSfp1 while Tri proteins abundance rationally decreased simultaneously. Further evidence show FgSfp1 could coordinate genetic translation pace by manipulating ribosomal biogenesis process. Specifically, FgSfp1-depletion leads to ribosome biogenesis assembly factor (RiBi) expression attenuation along with DON precursor acetyl-CoA synthase reduction since FgSfp1 actively interacts with RNA 2’-O-methylation enzyme FgNop1 revealed by Bi-FC. It subsequently influences mRNA translation pace. In conclusion, we elucidated that the FgSfp1 orchestrates DON biosynthesis via participating RNA posttranscriptional modification for ribosomal RNA maturation, offering insights into the DON biosynthesis regulation. Ultimately, this TF might be a key regulator for DON contamination control in the whole food chain.

Transcriptome-wide identification and analysis reveals m6A regulation of metabolic reprogramming in shrimp (Marsupenaeus japonicus) under virus infection.

It has been reported that the most common post-transcriptional modification of eukaryotic RNA is N6-methyladenosine (m6A). Previous studies show m6A is a key regulator for viral infection and immune response. However, whether there is a pathogen stimulus-dependent m6A regulation in invertebrate shrimp has not been studied. In this study, we performed a transcriptome-wide profiling of mRNA m6A methylation in shrimp (Marsupenaeus japonicus) after white spot syndrome virus (WSSV) infection by methylated RNA immunoprecipitation sequencing (MeRIP-seq). A total of 15,436 m6A peaks were identified in the shrimp, distributed in 8,108 genes, mainly enriched in the CDS, 3' UTR region and near the stop codon. After WSSV infection, we identified 2,260 m6A peaks with significantly changes, of which 1,973 peaks were significantly up-regulated and 287 peaks were significantly down-regulated. 1,795 genes were identified as differentially methylated genes. GO and KEGG analysis showed that hyper-methylated genes or hypo-methylated genes were highly associated with innate immune process and related to metabolic pathways including HIF-1 signaling pathway, lysine degradation and Wnt signaling pathway. Combined analysis showed a positive correlation between m6A methylation levels and mRNA expression levels. In addition, computational predictions of protein-protein interaction indicated that genes with altered levels of m6A methylation and mRNA expression clustered in metabolism, DNA replication, and protein ubiquitination. ZC3H12A and HIF-1 were two hub genes in protein-protein interaction (PPI) network that involved in immune and metabolism processes, respectively. Our study explored the m6A methylation pattern of mRNA in shrimp after WSSV infection, exhibited the first m6A map of shrimp at the stage of WSSV induced metabolic reprogramming. These findings may reveal the possible mechanisms of m6A-mediated innate immune response in invertebrates.

Abstract 4137846: Smooth muscle expression of RNA editing enzyme ADAR1 controls vascular integrity and progression of atherosclerosis

Mapping the genomic architecture of complex disease has been predicated on the understanding that genetic variants influence disease risk through modifying gene expression. However, recent discoveries have revealed that a significant burden of disease heritability in common autoinflammatory disorders and coronary artery disease is mediated through genetic variation modifying post-transcriptional modification of RNA through adenosine-to-inosine (A-to-I) RNA editing. This common RNA modification is catalyzed by ADAR enzymes, where ADAR1 edits specific immunogenic double stranded RNA (dsRNA) to prevent activation of the double strand RNA (dsRNA) sensor MDA5 ( IFIH1 ) and stimulation of an interferon stimulated gene (ISG) response. Multiple lines of human genetic data indicate impaired RNA editing and increased dsRNA sensing to be an important mechanism of coronary artery disease (CAD) risk. Here, we provide a crucial link between observations in human genetics and mechanistic cell biology leading to progression of CAD. Through analysis of human atherosclerotic plaque, we implicate the vascular smooth muscle cell (SMC) to have a unique requirement for RNA editing, and that ISG induction occurs in SMC phenotypic modulation, implicating MDA5 activation. Through culture of human coronary artery SMCs, generation of a conditional SMC specific Adar1 deletion mouse model on a pro-atherosclerosis background, and with incorporation of single cell RNA sequencing cellular profiling, we further show that Adar1 controls SMC phenotypic state, is required to maintain vascular integrity, and controls progression of atherosclerosis and vascular calcification. Our data implicates MDA5 activation to occur in SMC phenotypic modulation and accelerates formation of chondromyocytes in a distinct cellular lineage trajectory — indicating a cell type and context specific requirement of RNA editing. Through this work, we describe a fundamental new mechanism of CAD, where RNA editing and sensing of dsRNA in a cell type and context specific mechanism mediates disease progression, bridging our understanding of human genetics and disease causality.

RNA editing-induced structural and functional adaptations of NAD9 in Triticum aestivum under drought stress.

Mitochondria are essential organelles in eukaryotic cells, producing ATP through the electron transport chain to supply energy for cellular activities. Beyond energy production, mitochondria play crucial roles in cellular signaling, stress responses, and the regulation of reactive oxygen species. In plants, mitochondria are one of the keys to responding to environmental stresses which can significantly affect crop productivity, particularly in crops like wheat. RNA editing, a post-transcriptional RNA modification process in mitochondria, is linked to regulating these stress responses. This study explores RNA editing patterns in the nad9 gene of wheat drought-tolerant (Giza168) and drought-sensitive (Gemmiza10) wheat cultivars under drought stress to understand plant adaptation mechanisms. RNA-seq data for these cultivars were analyzed using CLC Genomic Workbench to identify RNA editing sites in the nad9 gene, examining subsequent amino acid changes and predicting secondary structure modifications. These RNA editing sites were validated using qRT-PCR on drought-treated seedlings at 0, 2, and 12 hours post-treatment. Protein models were generated using AlphaFold, with functional predictions and structure verification conducted using various bioinformatics tools to investigate the effect of RNA editing on protein level. The results showed significant RNA editing events, especially C-to-T conversions, in the nad9 gene across different drought exposure times. Giza168 had 22 editing sites, while Gemmiza10 had 19, with several showing significant differences between control and stress conditions. RNA editing influenced the NAD9 protein's secondary structure, particularly beta sheets, and 3D modeling highlighted the structural impacts of these edits. The N-terminal region of NAD9 contained important regulatory motifs, suggesting a complex regulatory environment. This study reveals key editing sites that differ between drought-tolerant and sensitive wheat cultivars, impacting NAD9 protein structures and highlighting the role of RNA editing in enhancing drought resilience. Additionally, the study suggests potential regulatory mechanisms, including phosphorylation and ubiquitination that influence mitochondrial stability and function.

Stress-induced modification of Escherichia coli tRNA generates 5-methylcytidine in the variable loop

There has been recent interest in trying to understand the connection between transfer RNA (tRNA) posttranscriptional modifications and changes in-cellular environmental conditions. Here, we report on the identification of the modified nucleoside 5-methylcytidine (m5C) in Escherichia coli tRNAs. This modification was determined to be present at position 49 of tRNA Tyr-QUA-II. Moreover, m5C levels in this tRNA are significantly elevated under high reactive oxygen specieis (ROS) conditions in E. coli cells. We identified the known ribosomal RNA methyltransferase rsmF as the enzyme responsible for m5C synthesis in tRNA and enzyme transcript levels are responsive to elevated levels of ROS in the cell. We further find that changes in m5C levels in this tRNA are not specific to Fenton-like reaction conditions elevating ROS, but heat shock can also induce increased modification of tRNA Tyr-QUA-II. Altogether, this work illustrates how cells adapt to changing environmental conditions through variations in tRNA modification profiles.

TRNA modification enzyme-dependent redox homeostasis regulates synapse formation and memory

Post-transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA-modifying enzyme that methylates wobble uridines in a subset of tRNAs to modulate translation. Through methylation of tRNA-selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit reduced protein synthesis in the nervous system, including a specific decrease in selenoprotein levels. Either loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 null animals also exhibit associative memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA wobble uridine modification in redox homeostasis in the developing nervous system and reveal antioxidants as a potential therapy for ALKBH8-associated intellectual disability.

Progressive polyadenylation and m6A modification of Ighg1 mRNA maintain IgG1 antibody homeostasis in antibody-secreting cells

Antigen-specific antibodies are generated by antibody-secreting cells (ASCs). How RNA post-transcriptional modification affects antibody homeostasis remains unclear. Here, we found that mRNA polyadenylations and N6-methyladenosine (m6A) modifications maintain IgG1 antibody production in ASCs. IgG heavy-chain transcripts (Ighg) possessed a long 3' UTR with m6A sites, targeted by the m6A reader YTHDF1. B cell-specific deficiency of YTHDF1 impaired IgG production upon antigen immunization through reducing Ighg1 mRNA abundance in IgG1+ ASCs. Disrupting either the m6A modification of a nuclear-localized splicing intermediate Ighg1 or the nuclear localization of YTHDF1 reduced Ighg1 transcript stability. Single-cell RNA sequencing identified an ASC subset with excessive YTHDF1 expression in systemic lupus erythematosus patients, which was decreased upon therapy with immunosuppressive drugs. In a lupus mouse model, inhibiting YTHDF1-m6A interactions alleviated symptoms. Thus, we highlight a mechanism in ASCs to sustain the homeostasis of IgG antibody transcripts by integrating Ighg1 mRNA polyadenylation and m6A modification.

The RNA m5C methyltransferase NSUN1 modulates human malaria gene expression during intraerythrocytic development.

Plasmodium falciparum is the most damaging malaria pathogen and brings a heavy burden to global health. Host switching and morphological changes in P. falciparum are dependent on an effective gene expression regulatory system. C5 methylation of cytosines is a common RNA modification in eukaryotes, and the NSUN family are essential m5C modification executors. Currently, little is known about this family in Plasmodium spp. In this study, we focus on exploring the function of PfNSUN1 protein. An efficient CRISPR/Cas9 gene editing technique was applied to construct the PfNSUN1 knockdown strain. The knockdown efficiency was confirmed by growth curves and western blot experiments. The knockdown transcriptome data was acquired to find differentially expressed genes, and target genes of PfNSUN1 protein were identified by RNA immunoprecipitation and high-throughput sequencing experiments. The efficiency of PfNSUN1 protein down-regulated was about 34%. RNA-seq data revealed that differentially expressed genes were mainly down-regulated. And there were 224, 278, 556 genes that were down-regulated with more than 2-fold changes and p-adj<0.05 at ring, trophozoite and schizont stages, respectively. PfNSUN1 protein was significantly enriched on 154 target genes, including 28S ribosomal RNA and pfap2-g5 transcription factor. PfNSUN1 is a crucial RNA post-transcriptional modification protein in P. falciparum. It plays a pivotal role in regulating gene expression and parasite growth by targeting 28S ribosomal RNA and pfap2-g5 transcription factor.

Sex-specific Concordance of Striatal Transcriptional Signatures of Opioid Addiction in Human and Rodent Brains.

Opioid use disorder (OUD) has emerged as a severe, ongoing public health emergency. Current, frontline addiction treatment strategies fail to produce lasting abstinence in most users. This underscores the lasting effects of chronic opioid exposure and emphasizes the need to understand the molecular mechanisms of drug seeking and taking, but also how those alterations persist through acute and protracted withdrawal. Here, we used RNA sequencing in post-mortem human tissue from males (n=10) and females (n=10) with OUD and age and sex-matched comparison subjects. We compared molecular alterations in the nucleus accumbens (NAc) and dorsolateral prefrontal cortex (DLPFC) between humans with OUD and rodent models across distinct stages of opioid use and withdrawal (acute and prolonged) using differential gene expression and network-based approaches. We found that the molecular signature in the NAc of females with OUD mirrored effects seen in the NAc of female mice at all stages of exposure. Conversely, males with OUD showed strong overlap in expression profile with rats in acute withdrawal. Co-expression networks involved in post-transcriptional modification of RNA and epigenetic modification of chromatin state. This study provides fundamental insight into the converging molecular pathways altered by opioids across species. Further, this work helps to disentangle which alterations observed in humans with OUD are driven by acute drug exposure and which alterations are consequences of chronic exposure.

N6-Methyladenosine Modification-Related Genes Express Differentially in Sterile Male Cattle-Yaks.

N6-methyladenosine (m6A), an RNA post-transcriptional modification, plays a crucial role in spermatogenesis. Cattle-yaks are interspecific hybrid offsprings of yak and cattle, and male cattle-yaks are sterile. This study aims to investigate the role of m6A modification in male cattle-yak infertility. Herein, testicular tissues were analyzed via histological observations, immunohistochemical assays, reverse-transcription quantitative polymerase chain reaction, Western blotting, and immunofluorescence assays. The results revealed that male cattle-yaks presented smaller testes (5.933 ± 0.4885 cm vs. 7.150 ± 0.3937 cm), with only single cell layers in seminiferous tubules, and weakened signals of m6A regulators such as METTL14 (methyltransferase-like 14), ALKBH5 (alpha-ketoglutarate-dependent hydroxylase homolog 5), FTO (fat mass and obesity-associated protein), and YTHDF2 (YTH N6-methyladenosine RNA binding protein F2), both at the RNA and protein levels, compared with those of yaks. Altogether, these findings suggest that m6A modification may play a crucial role in male cattle-yak sterility, providing a basis for future studies.