Project description:The aging brain is highly vulnerable to cellular stress, and neurons often employ numerous mechanisms to combat neurotoxic proteins and promote healthy brain aging. The RNA modification m6A has been shown to be a critical regulator of RNA stability and translation in cells during stress. m6A is highly enriched in the Drosophila brain and is critical for the acute heat stress response. Here we examine m6A response to chronic stresses of aging and degenerative disease. In the brain, m6A levels dynamically increased with age and disease, marking critical signaling pathway transcripts that become downregulated in age and disease. Unexpectedly, there is opposing regulation of m6A transcript translation in neural vs glial cells, which conferred different outcomes on animal healthspan with Mettl3 knockdown to reduce m6A. Moreover, these data reveal that knockdown of Mettl3 in glial tauopathy is beneficial, leading to increased animal survival. These findings provide mechanistic insight into regulation of m6A modified transcripts with age and disease that varies based on cell type.
Project description:We developed a novel approach, m6A-seq, for high-resolution mapping of the transcriptome-wide m6A landscape, based on antibody-mediated capture followed by massively parallel sequencing Identification of m6A modified sequences in mouse liver and human brain
Project description:Both N6-methyladenosine (m6A) mediates RNA fates and ubiquitin mediates protein fates play an important role in either physiology or pathology including cancer, yet how long noncoding RNAs (lncRNAs) are involved in a link of molecular fate between m6A and ubiquitin remains unknown. Here, we reveal a role for a lncRNA Downregulated RNA in Cancer (DRAIC) to suppress tumor growth and metastasis in clear cell Renal Carcinoma (ccRCC). Mechanistically, DRAIC physically interacts with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and enhances its protein stability by blocking E3 ligase F-box protein 11 (FBXO11)-mediated ubiquitin and proteasome-dependent degradation. Subsequently, hnRNPA2B1 destabilizes m6A modified-type 1 insulin-like growth factor receptor (IGF1R) to lead to inhibition of ccRCC progression. Moreover, four m6A modification sites of IGF1R are identified and results in its mRNA degradation. Collectively, our findings reveal that DRAIC/hnRNPA2B1 axis regulates IGF1R mRNA expression in an m6A-dependent manner and highlights an important mechanism of IGF1R fate. These findings shed light on DRAIC/hnRNPA2B1/FBXO11/IGF1R axis as potential therapeutic targets in ccRCC and build a link of molecular fate between m6A-modified RNA and ubiquitin-modified protein.
Project description:N6-methyladenosine (m6A) is a widespread reversible chemical modification of RNAs, implicated in many aspects of RNA metabolism. Little quantitative information exists as to either how many transcript copies of particular genes are m6A modified (âm6A levelsâ), or the relationship of m6A modification(s) to alternative RNA isoforms. To deconvolute the m6A epitranscriptome, we developed m6A level and isoform-characterization sequencing (m6A-LAIC-seq). We found that cells exhibit a broad range of non-stoichiometric m6A levels with cell type specificity. At the level of isoform characterization, we discovered widespread differences in use of tandem alternative polyadenylation (APA) sites by methylated and nonmethylated transcript isoforms of individual genes. Strikingly, there is a strong bias for methylated transcripts to be coupled with proximal APA sites, resulting in shortened 3â untranslated regions (3â-UTRs), while nonmethylated transcript isoforms tend to use distal APA sites. m6A-LAIC-seq yields a new perspective on transcriptome complexity and links APA usage to m6A modifications. m6A-LAIC-seq of H1-ESC and GM12878 cell lines, each cell line has two replicates
Project description:N6-methyladenosine (m6A) is the most abundant mRNA nucleotide modification and regulates critical aspects of cellular physiology and differentiation. m6A is thought to mediate its effects through a complex network of interactions between different m6A sites and three functionally distinct cytoplasmic YTHDF m6A-binding proteins (DF1, DF2, and DF3). In contrast to the prevailing model, we show that DF proteins bind the same m6A-modified mRNAs, rather than different mRNAs. Furthermore, we find that DF proteins do not induce translation in HeLa cells. Instead, the DF paralogs act redundantly to mediate mRNA degradation and cellular differentiation. The ability of DF proteins to regulate stability and differentiation becomes evident only when all three DF paralogs are simultaneously depleted. Our studies reveal a unified model of m6A function in which all m6A-modified mRNAs are subjected to the combined action of the YTHDF proteins in proportion to the number of m6A sites.
Project description:Both N6-methyladenosine (m6A) mediates RNA fates and ubiquitin mediates protein fates play an important role in either physiology or pathology including cancer, yet how long noncoding RNAs (lncRNAs) are involved in a link of molecular fate between m6A and ubiquitin remains unknown. Here, we reveal a role for a lncRNA Downregulated RNA in Cancer (DRAIC) to suppress tumor growth and metastasis in clear cell Renal Carcinoma (ccRCC). Mechanistically, DRAIC physically interacts with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and enhances its protein stability by blocking E3 ligase F-box protein 11 (FBXO11)-mediated ubiquitin and proteasome-dependent degradation. Subsequently, hnRNPA2B1 destabilizes m6A modified-type 1 insulin-like growth factor receptor (IGF1R) to lead to inhibition of ccRCC progression. Moreover, four m6A modification sites of IGF1R are identified and results in its mRNA degradation. Collectively, our findings reveal that DRAIC/hnRNPA2B1 axis regulates IGF1R mRNA expression in an m6A-dependent manner and highlights an important mechanism of IGF1R fate. These findings shed light on DRAIC/hnRNPA2B1/FBXO11/IGF1R axis as potential therapeutic targets in ccRCC and build a link of molecular fate between m6A-modified RNA and ubiquitin-modified protein.
Project description:Both N6-methyladenosine (m6A) mediates RNA fates and ubiquitin mediates protein fates play an important role in either physiology or pathology including cancer, yet how long noncoding RNAs (lncRNAs) are involved in a link of molecular fate between m6A and ubiquitin remains unknown. Here, we reveal a role for a lncRNA Downregulated RNA in Cancer (DRAIC) to suppress tumor growth and metastasis in clear cell Renal Carcinoma (ccRCC). Mechanistically, DRAIC physically interacts with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and enhances its protein stability by blocking E3 ligase F-box protein 11 (FBXO11)-mediated ubiquitin and proteasome-dependent degradation. Subsequently, hnRNPA2B1 destabilizes m6A modified-type 1 insulin-like growth factor receptor (IGF1R) to lead to inhibition of ccRCC progression. Moreover, four m6A modification sites of IGF1R are identified and results in its mRNA degradation. Collectively, our findings reveal that DRAIC/hnRNPA2B1 axis regulates IGF1R mRNA expression in an m6A-dependent manner and highlights an important mechanism of IGF1R fate. These findings shed light on DRAIC/hnRNPA2B1/FBXO11/IGF1R axis as potential therapeutic targets in ccRCC and build a link of molecular fate between m6A-modified RNA and ubiquitin-modified protein.
Project description:N6-methyladenosine (m6A) is one of the most abundant modifications in eukaryotic RNA. Recent mapping of m6A methylomes in mammals, yeast, and plants as well as characterization of m6A methyltransferases, demethylases, and binding proteins have revealed regulatory functions of this dynamic RNA modification. In bacteria, although m6A is present in ribosomal RNA (rRNA), its occurrence in messenger RNA (mRNA) still remains elusive. Here, we used liquid chromatography-mass spectrometry (LC-MS) to calculate the m6A/A ratio in mRNA from a wide range of bacterial species, which demonstrates that m6A is an abundant mRNA modification in tested bacteria. Subsequent transcriptome-wide m6A profiling in Escherichia coli and Pseudomonas aeruginosa revealed a conserved distinct m6A pattern that is significantly different from that in eukaryotes. Most m6A peaks are located inside open reading frames (ORF), and carry a unique consensus motif (GCCAU). Functional enrichment analysis of bacterial m6A peaks indicates that the majority of m6A-modified transcripts are associated with respiration, amino acids metabolism, stress response, and small RNAs genes, suggesting potential regulatory roles of m6A in these pathways. m6A profiling in E.coli and P.aeruginosa mRNA
Project description:Roles of m6A-modified mRNA transcripts in the context of MI were preliminarily verified. In the context of m6A methylation, three hub mRNAs were validated to impact the process of apoptosis/angiogenesis. Our study provided theoretical basis and innovative targets for treatment of MI and paved the way for future investigations aiming at exploring upstream epigenetic mechanisms of pathogenesis after MI.