Project description:We present an improved version of DART-seq which utilizes a variant of the YTH domain engineered to achieve enhanced m6A recognition in APO1-YTH (D422N). In addition, we develop in vitro DART-seq and show that it performs similarly to cellular DART-seq and can map m6A in any sample of interest using nanogram amounts of total RNA.
Project description:We report evolved TadA-assisted N6-methyladenosine sequencing (eTAM-seq), an enzyme-assisted sequencing technology for quantitative, base-resolution profiling of m6A. eTAM-seq functions by global adenosine deamination, enabling detection of m6A as persistent A. We demonstrate adenosine-to-inosine (I) conversion rates up to 99% using a hyperactive TadA variant. With eTAM-seq, we profile and quantify m6A in the whole transcriptomes of HeLa cells and mouse embryonic stem cells (mESCs), with simultaneous deconvolution of the transcriptome and epitranscriptome. Further, we showcase deep sequencing-free, site-specific m6A quantification with as few as 10 cells, an input demand that is at least 4 orders of magnitude lower than existing methods. Collectively, eTAM-seq enables sensitive detection and faithful quantification of m6A with limited RNA input, representing a novel solution to deciphering the epitranscriptome.
Project description:We report evolved TadA-assisted N6-methyladenosine sequencing (eTAM-seq), an enzyme-assisted sequencing technology for quantitative, base-resolution profiling of m6A. eTAM-seq functions by global adenosine deamination, enabling detection of m6A as persistent A. We demonstrate adenosine-to-inosine (I) conversion rates up to 99% using a hyperactive TadA variant. With eTAM-seq, we profile and quantify m6A in the whole transcriptomes of HeLa cells and mouse embryonic stem cells (mESCs), with simultaneous deconvolution of the transcriptome and epitranscriptome. Further, we showcase deep sequencing-free, site-specific m6A quantification with as few as 10 cells, an input demand that is at least 4 orders of magnitude lower than existing methods. Collectively, eTAM-seq enables sensitive detection and faithful quantification of m6A with limited RNA input, representing a novel solution to deciphering the epitranscriptome.
Project description:We report evolved TadA-assisted N6-methyladenosine sequencing (eTAM-seq), an enzyme-assisted sequencing technology for quantitative, base-resolution profiling of m6A. eTAM-seq functions by global adenosine deamination, enabling detection of m6A as persistent A. We demonstrate adenosine-to-inosine (I) conversion rates up to 99% using a hyperactive TadA variant. With eTAM-seq, we profile and quantify m6A in the whole transcriptomes of HeLa cells and mouse embryonic stem cells (mESCs), with simultaneous deconvolution of the transcriptome and epitranscriptome. Further, we showcase deep sequencing-free, site-specific m6A quantification with as few as 10 cells, an input demand that is at least 4 orders of magnitude lower than existing methods. Collectively, eTAM-seq enables sensitive detection and faithful quantification of m6A with limited RNA input, representing a novel solution to deciphering the epitranscriptome.
Project description:m6A is a widespread RNA modification which plays important roles in the regulation of gene expression. Methods for the global detection of m6A rely on immunoprecipitation of methylated transcripts using m6A antibodies. However, these methods are costly and require large amounts of input RNA, making them prohibitive for many experiments. Here, we describe DART-seq, an antibody-free method for m6A detection which enables transcriptome-wide mapping of m6A residues using low amounts of input material. DART-seq can be used to obtain global m6A maps using as little as 10 nanograms of total RNA and at single-molecule resolution. This method offers several improvements over current techniques and will facilitate detection of m6A in limiting cell and tissue types.
Project description:N6-methyladenosine (m6A) is the most abundant modified base in eukaryotic mRNA and has been linked to diverse effects on mRNA fate and function. Current m6A mapping approaches rely on immunoprecipitation of m6A-containing RNA fragments to identify regions of transcripts that contain m6A. This approach localizes m6A residues to 100-200 nt-long regions of transcripts. The precise position of m6A in mRNAs cannot be identified on a transcriptome-wide level because there are no chemical methods to distinguish between m6A and adenosine. Here we show that anti-m6A antibodies can induce specific mutational signatures at m6A residues after ultraviolet light-induced antibody-RNA crosslinking and reverse transcription. Similarly, we find these antibodies induce mutational signatures at N6, 2’-O-dimethyladenosine (m6Am), a nucleotide found at the first encoded position of certain mRNAs. Using these mutational signatures, we map m6A and m6Am at single-nucleotide resolution in human and mouse mRNA and identify snoRNAs as a novel class of m6A-containing ncRNAs. UV-crosslinking and immunoprecipitation with m6A-specific antibodies was used to map m6A and m6Am in cellular RNA with single nucleotide resolution.
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 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:m6A is a ubiquitous RNA modification in eukaryotes. Transcriptome-wide m6A patterns in Arabidopsis have been assayed recently. However, m6A differential patterns among organs have not been well characterized. The goal of the study is to comprehensively analyze m6A patterns of numerous types of RNAs, the relationship between transcript level and m6A methylation extent, and m6A differential patterns among organs in Arabidopsis. In total, 18 libraries were sequneced. For the 3 organs: leaf, flower and root, each organ has mRNA-Seq, m6A-Seq and Input sequenced. And each sequence has 2 replicats.
Project description:This SuperSeries is composed of the following subset Series: GSE36958: Gene expression profiles of WT and ime4-/- mutant yeast cells, under vegetative and meiosis-inducing conditions GSE37001: METTL3 KD in HepG2 cells GSE37002: m6A mapping in human RNA (with treatments) GSE37003: m6A mapping in human RNA (untreated) GSE37004: m6A mapping in mouse RNA (mouse liver and human brain) Refer to individual Series